https://www.perplexity.ai/search/perplexity-i-was-flashing-a-la-gK_JkBHdRtaYTTybWGrbiw?login-new=false&login-source=requestAccessLoginGate#6
# Perplexity. I was flashing a laptop motherboard working in the bios,
but I’m just a disabled hobbyist. I moved to a new location and
plugged it in and heard a “pop!” and now it doesn’t do anything, no
power light when plugged in. It was hard for me to get this specific
motherboard. I’d like to build skills to recover from this situation,
but it’s still new to me. Can you introduce a concept that would be
good to learn, for me to know that some day I could diagnose and
repair a laptop motherboard when i have this “pop!” experience?
## Understanding Power Sequencing: Your Path to Laptop Motherboard
Repair Mastery
I'm sorry about your laptop motherboard—that "pop" followed by no
power is a challenging situation, but it's entirely reasonable that
you could develop the skills to diagnose and eventually repair boards
like this. The concept I'd recommend focusing on is **power sequencing
and voltage rail tracing**.
### What is Power Sequencing?
Power sequencing is the step-by-step process by which a laptop
motherboard brings itself to life when you plug in power or press the
power button. Think of it as a choreographed dance where different
voltage levels must appear in a specific order, with each stage
enabling the next. When you heard that "pop," something in this
sequence likely failed—possibly a capacitor, MOSFET, or voltage
regulator—and now the chain is
broken.[^1_1][^1_2][^1_3][^1_4][^1_5][^1_6][^1_7]
Understanding power sequencing means recognizing that your motherboard
doesn't just "turn on" all at once. Instead, it follows this general
progression:[^1_6][^1_8][^1_9]
**Stage 1: Always-On Power (VALW/B+)**
When you plug in the adapter, the first thing that happens is the
creation of "always-on" voltages—typically 3.3V and 5V that exist even
when the laptop appears off. These power critical management chips
like the charging IC and the Embedded Controller
(EC).[^1_4][^1_10][^1_8]
**Stage 2: Embedded Controller Wake-Up**
The EC is a small microcontroller that acts as the motherboard's
"brain" before the main CPU takes over. It manages power button
detection, battery charging, thermal monitoring, and critically, it
controls which voltage regulators turn on and when. The EC receives
signals from the charging circuit that power is available and begins
orchestrating the next stages.[^1_10][^1_11][^1_12][^1_9]
**Stage 3: Secondary Voltages**
The EC sends enable signals to various voltage regulator modules
(VRMs), which are circuits built around MOSFETs, inductors (coils),
and capacitors. These convert the incoming voltage (often 19V from
your adapter) down to the specific voltages needed by different
components—1.8V for memory, 1.05V for CPU core, 3.3V for peripherals,
etc..[^1_13][^1_14][^1_15][^1_16][^1_17][^1_18]
**Stage 4: Main Power Rails**
Once all the preliminary voltages are stable, the EC allows the main
CPU power to come up, and only then will the system attempt to
boot.[^1_9][^1_6]
### Why This Matters for Your "Pop" Problem
When something in this sequence fails, everything downstream stops.
That "pop" you heard was likely a component in the early power stages
failing—commonly a MOSFET in a voltage regulator circuit, a capacitor,
or even a fuse. Since you're getting absolutely no power light, the
failure is probably in the very first stage—the always-on power
section.[^1_19][^1_20][^1_21][^1_22][^1_1][^1_4][^1_9]
### The Practical Skill: Voltage Rail Tracing with a Multimeter
The diagnostic technique that makes power sequencing knowledge
actionable is **voltage rail tracing**. Here's how it
works:[^1_23][^1_24][^1_25]
**Equipment You'll Need:**
- A digital multimeter with DC voltage and diode modes[^1_26][^1_27][^1_23]
- Ideally, the schematic or boardview for your specific
motherboard[^1_28][^1_29][^1_30]
**The Process:**[^1_25][^1_15][^1_31]
1. **Set your multimeter to DC voltage mode (20V range)**[^1_15][^1_25]
2. **Connect the adapter (but don't press power yet)**
3. **Place the black probe on any ground point** (usually the metal
shielding or screw holes)
4. **Systematically check voltage test points** following the power sequence:
- First, verify 19V (or your adapter voltage) at the power
jack[^1_25][^1_15]
- Check for 3.3V and 5V "always" voltages at ceramic capacitors
near power management ICs[^1_8][^1_15]
- Look for 3.3V at pin 8 of the BIOS chip[^1_32][^1_15]
- Check inductor/coil outputs for their respective voltages[^1_31][^1_15]
**What You're Looking For:**[^1_22][^1_31][^1_25]
Each voltage should be present at specific locations. If you find 19V
at the input but no 3.3V and 5V always voltages, you've isolated the
problem to that first conversion stage. If those voltages exist but
nothing happens when you press power, the issue is likely further
along in the sequence or with the EC itself.[^1_15][^1_9]
### Using Diode Mode for Short Circuit Detection
The other critical multimeter technique is using **diode mode** to
detect short circuits before even applying power. In diode mode, your
multimeter sends a small constant current and measures voltage drop.
On a healthy board, you'll see specific readings at different points.
A short circuit will show as a very low reading (often under 0.100V)
where it shouldn't.[^1_33][^1_34][^1_35][^1_36]
The technique is especially powerful when you:
- Check inductors/coils (they should never read as shorted to ground
since they're on power lines)[^1_37]
- Compare readings between a known-good board and your failed board[^1_35]
- Systematically test voltage rails before powering up to avoid
further damage[^1_36][^1_37]
### Components You'll Learn to Identify
As you study power sequencing, you'll become familiar with these key
components:[^1_38][^1_16][^1_39][^1_13]
**MOSFETs**: Act as electronic switches controlled by the EC or power
management ICs to gate voltage flow. They're often the components that
fail with that characteristic "pop".[^1_16][^1_17][^1_40][^1_41][^1_1]
**Inductors/Coils**: Store energy magnetically and smooth out
voltage—you'll find them in every voltage regulator circuit. On a
motherboard, they're easy to spot as small cubic or cylindrical
components, often near the CPU.[^1_17][^1_18][^1_16]
**Capacitors**: Filter and stabilize voltages; can fail
catastrophically with physical swelling or
popping.[^1_42][^1_43][^1_1]
**Voltage Regulator ICs**: The "brains" of each power conversion
circuit, controlling the MOSFETs.[^1_44][^1_16][^1_17]
### Why This Concept Opens Doors
Power sequencing knowledge is foundational because it:
1. **Gives you a systematic troubleshooting methodology** rather than
random component swapping[^1_22][^1_9]
2. **Applies to virtually all laptop motherboards** since they all
follow similar power-up logic[^1_7][^1_4][^1_6]
3. **Allows you to isolate failures to specific stages** without
needing expensive equipment initially[^1_25][^1_15]
4. **Builds naturally into more advanced skills** like schematic
reading and component-level repair[^1_29][^1_28]
### Your Learning Path Forward
Start by watching repair videos that specifically cover power
sequencing and voltage rail testing. Practice on your dead board by
measuring voltages (even though it's failed, you can still learn to
identify components and test points). When you eventually get
schematics or a donor board, you can compare your readings to
understand what *should* be
happening.[^1_45][^1_32][^1_6][^1_35][^1_15][^1_25]
The beauty of this approach is that it doesn't require you to fix your
board immediately—it builds a mental model of how motherboards work
that will serve you for years. Each board you examine will teach you
more about the patterns, and eventually, tracking down that "pop" will
become second nature.
Remember: electronics repair at this level is entirely reasonable to
learn, especially for someone with your technical background and
problem-solving mindset. The journey from "pop and dead" to "diagnosed
and repaired" is absolutely achievable with systematic study and
practice.
<span
style="display:none">[^1_46][^1_47][^1_48][^1_49][^1_50][^1_51][^1_52][^1_53][^1_54][^1_55][^1_56][^1_57][^1_58][^1_59][^1_60][^1_61][^1_62][^1_63][^1_64][^1_65][^1_66][^1_67][^1_68][^1_69][^1_70][^1_71][^1_72][^1_73][^1_74][^1_75][^1_76][^1_77]</span>
<div align="center">⁂</div>
[^1_1]:
https://www.reddit.com/r/pchelp/comments/1eumeuc/my_pc_made_a_pop_noise_now_it_doesnt_turn_on/
[^1_2]:
https://www.reddit.com/r/PcBuild/comments/17hapt0/i_heard_a_pop_and_now_my_pc_wont_turn_on/
[^1_3]:
https://www.reddit.com/r/buildapc/comments/suw4uw/my_pc_made_a_massive_pop_sound_while_i_was_gaming/
[^1_4]: http://adiedkhazbook.blogspot.com/p/httpwww.html
[^1_5]: https://www.youtube.com/watch?v=IFoSk_70Cqw
[^1_6]: https://www.youtube.com/watch?v=-K1LoLjIlxA
[^1_7]: https://www.youtube.com/watch?v=2g4B4CgXwf0
[^1_8]: https://www.youtube.com/watch?v=ZSqfHDJ16vU
[^1_9]: https://www.youtube.com/watch?v=RB_e8yulh2w
[^1_10]: https://en.wikipedia.org/wiki/Embedded_controller
[^1_11]: https://community.frame.work/t/exploring-the-embedded-controller/12846
[^1_12]:
https://www.reddit.com/r/coreboot/comments/1jnrga6/the_ec_chips_and_very_early_boot_control/
[^1_13]: https://www.youtube.com/watch?v=_pBIUbRdqR8
[^1_14]:
https://www.scribd.com/document/267919901/Power-Delivery-System-in-Motherboards
[^1_15]: https://www.youtube.com/watch?v=cEWoE8GJOXc
[^1_16]: https://www.velocitymicro.com/blog/what-are-motherboard-vrms/
[^1_17]: https://cultists.network/831/motherboard-101-part-1/
[^1_18]:
https://hardwaresecrets.com/everything-you-need-to-know-about-the-motherboard-voltage-regulator-circuit/
[^1_19]:
https://www.laptopsservice.center/blog/laptop-motherboard-damage-symptoms/
[^1_20]:
https://www.dell.com/community/en/conversations/desktops-general-locked-topics/motherboard-or-psu-fried-vostro-400-mt-loud-pop/647e8f1ff4ccf8a8de3c490e?commentId=647e8f4af4ccf8a8de3fdc54\&page=2
[^1_21]:
https://learn.microsoft.com/en-us/answers/questions/3878603/the-pc-i-am-using-made-a-popping-sound-that-was-qu
[^1_22]: https://www.youtube.com/watch?v=4oAAdoCfeBU
[^1_23]:
https://tesmen.com/blogs/tesmen-blogs/how-to-test-a-motherboard-with-a-multimeter
[^1_24]:
https://www.pcbasic.com/blog/how-to-test-a-circuit-board-with-a-multimeter.html
[^1_25]: https://www.youtube.com/watch?v=VWDAzb_XAFs
[^1_26]:
https://hi-spec.com/blogs/news/the-role-of-digital-multimeters-in-computer-repair-a-beginner-s-guide
[^1_27]:
https://kaiweets.com/blogs/news/how-to-test-a-motherboard-with-a-multimeter
[^1_28]: https://www.diy-laptoprepair.com
[^1_29]: https://www.diy-laptoprepair.com/
[^1_30]:
https://www.reddit.com/r/AskElectronics/comments/odudxi/i_want_to_repair_a_broken_laptop_motherboard/
[^1_31]: https://www.youtube.com/watch?v=E80bZ0YT7TY
[^1_32]: https://www.youtube.com/watch?v=sYNTo_4J2AE
[^1_33]:
https://www.eevblog.com/forum/beginners/diode-mode-testing-how-does-it-work/
[^1_34]: https://www.youtube.com/watch?v=6Y2HF12R7lA
[^1_35]: https://www.youtube.com/watch?v=pRpyHF2dfq0
[^1_36]: https://www.youtube.com/watch?v=cmJZjca9Mis
[^1_37]: https://www.youtube.com/watch?v=pZ2ADJGvVYo
[^1_38]: https://www.youtube.com/watch?v=NUEG1_tJIRg
[^1_39]: https://www.youtube.com/watch?v=ex988Ss5yxo
[^1_40]: https://oscarliang.com/how-to-use-mosfet-beginner-tutorial/
[^1_41]:
https://www.reddit.com/r/AskElectronics/comments/1jua1s8/blown_mosfet_on_motherboard_repair/
[^1_42]:
https://forum.vcfed.org/index.php?threads%2Fmotherboard-capacitor-failure.56294%2F
[^1_43]: https://www.youtube.com/watch?v=dbhAmSe9O0Y
[^1_44]: https://en.wikipedia.org/wiki/Voltage_regulator_module
[^1_45]: https://www.youtube.com/watch?v=i293n9VVpHg
[^1_46]: https://www.youtube.com/watch?v=e-tOu5PgM2E
[^1_47]: https://www.scribd.com/doc/145294899/Laptop-Motherboard-Repair
[^1_48]:
https://www.reddit.com/r/buildapc/comments/2acjzd/troubleshooting_pc_will_not_boot_after_power/
[^1_49]: https://www.youtube.com/watch?v=vE5Vm2l9hNQ
[^1_50]: https://www.youtube.com/watch?v=y3JvhGeK6I0
[^1_51]: https://www.youtube.com/watch?v=5hT_rpXWYxo
[^1_52]: https://www.youtube.com/watch?v=qv8qcpRyYQU
[^1_53]:
https://www.reddit.com/r/PcBuildHelp/comments/18gib19/motherboard_has_power_but_wont_turn_on/
[^1_54]:
https://www.reddit.com/r/mobilerepair/comments/1o9oye2/how_to_start_learning_mobile_laptop_repair_as_a/
[^1_55]:
https://forums.tomshardware.com/threads/help-loud-pop-sound-possible-mobo-failure.597325/
[^1_56]: https://www.youtube.com/watch?v=-u8Ioz1EaMc
[^1_57]: https://www.youtube.com/watch?v=pj9EJCKqiT4
[^1_58]:
https://www.reddit.com/r/AskElectronics/comments/kwfbxy/voltage_regulator_schemes_for_multiplerail/
[^1_59]: https://www.youtube.com/watch?v=fY2B7atnSUU
[^1_60]: https://www.youtube.com/watch?v=vnSX34YLjCo
[^1_61]: https://global.aorus.com/blog-detail.php?i=925
[^1_62]:
https://www.reddit.com/r/AskElectronics/comments/izpy7k/what_parts_of_a_typical_pc_motherboard_are/
[^1_63]:
https://www.reddit.com/r/buildapc/comments/dn077p/i_made_a_diagram_for_a_friend_explaining_what/
[^1_64]:
https://community.frame.work/t/changing-the-way-embedded-controller-limits-cpu-power/49858
[^1_65]:
https://www.scribd.com/document/862074440/Power-Sequence-of-Laptop-Motherboard
[^1_66]: https://www.asus.com/support/faq/1050239/
[^1_67]:
https://forums.lenovo.com/t5/Lenovo-Yoga-Series-Laptops/How-to-Reset-the-Embedded-Controller/m-p/5286519
[^1_68]:
https://www.facebook.com/groups/3217527045241387/posts/3234602506867174/
[^1_69]: https://www.youtube.com/watch?v=ElTTOsj3y-Q
[^1_70]:
https://forum.allaboutcircuits.com/threads/computer-motherboard-blown-component.166700/
[^1_71]: https://www.youtube.com/watch?v=Xx_tzwjjIY8
[^1_72]: https://www.youtube.com/watch?v=7QYBrUs6V-c
[^1_73]: https://www.youtube.com/watch?v=M7tmFbIoVLM
[^1_74]:
https://www.reddit.com/r/techsupport/comments/1aikga1/motherboard_repair_component_level/
[^1_75]:
https://www.reddit.com/r/AskElectronics/comments/ivd7dh/shorted_a_couple_of_capacitors_on_a_motherboard/
[^1_76]: https://www.youtube.com/watch?v=qhPZD9avoac
[^1_77]: https://www.youtube.com/watch?v=kr-KXx25ri8
---
# I don’t really watch videos, and I kinda get cross-eyed when
browsing the web. What’s a good resource to maybe print out or buy and
study, to get started with this? These are schematics for a different
motherboard in the same family, I’m not certain why to find the exact
ones but the power is probably the same.
A great print resource for building skills in laptop motherboard
diagnosis—especially with a focus on power sequencing and tracing
voltage rails—is a beginner-friendly electronics textbook or repair
guide that emphasizes schematic reading and practical, step-by-step
troubleshooting. Even if schematics aren't always available for your
exact model, understanding these foundational skills will make nearly
any similar board "readable" to you. Your attached Thinkpad T60
schematic is extremely relevant, especially if it's in the same
family—IBM/Lenovo boards tend to share power architectures and
conventions.[^2_1][^2_2][^2_3]
### Recommended Resources to Buy or Print
- **Practical Electronics for Inventors by Paul Scherz \& Simon Monk**
This book covers basic electronics components, circuit behavior, and
how to use tools (like a multimeter for voltage and diode tests). It's
written for self-learners and hobbyists, and includes many diagrams
and explanations that apply directly to PC motherboards.[^2_4]
- **The Art of Electronics by Horowitz \& Hill**
A classic, thorough reference and "textbook," with explanatory
sections on power supply design, MOSFETs, voltage regulators,
short-circuit analysis, and board-level troubleshooting. This is a
staple for anyone who wishes to deeply understand and study
electronics, not just laptops.[^2_4]
- **Laptop/PC Motherboard Repair Guides**
Books such as "Laptop Motherboard Repair" (PDFs are available on
various sites like Scribd) and guides by Kent Liew or Lee M. Hunsaker
are aimed at technicians and hobbyists, and provide step-by-step
voltage tracing, case studies, and example fault-finding
exercises.[^2_2][^2_3][^2_5]
### How to Use Schematics for Skill Building
Printed schematics (like your Thinkpad T60 PDF) make a practical study
tool for learning real-world diagnosis. Start by locating the
summary/block diagram and the sections titled "Power Sequence".
Practice tracing the flow from DC-IN to battery charger, through each
voltage regulator (MAX8765, MAX1901, etc.), and note the outputs such
as VCC3M, VCC5M, VCCCPUCORE, etc.. You’ll see how different rails
power up, and this tracing exercise aligns perfectly with the
step-by-step techniques outlined in books above.[^2_1]
### Schematic-Led Exercises
- Identify the "always-on" rails—follow from power jack in the
schematic to the first voltage regulators, write out the sequence you
see.[^2_1]
- Locate each voltage rail label (VCC3M, VCC5M, VCC1R8A, etc.) and
note which chips or coils generate those. Mark where to probe them
with a multimeter for expected voltage.[^2_1]
- Find example fuses, MOSFETs, and capacitors in the schematic—try to
locate similar parts on your physical board for hands-on study.[^2_1]
### Building a Print-Based Learning Library
- Print key schematic pages/block diagrams, voltage regulator
sections, and summary tables.
- Print or buy condensed guides on motherboard repair basics (such as
"Motherboard Repair for Beginners").
- Annotate your pages as you learn (mark multimeter probe points,
typical test voltages, and common failure modes).
### Why This Works
Textbooks, technician handbooks, and physical schematics give you
structured, tactile study materials—essential for progressing at your
own pace and returning frequently to reference concepts. Building this
print library makes your troubleshooting systematic and bridges the
gap between theory and hands-on repair.[^2_5][^2_2][^2_4][^2_1]
This combination of practical electronics reading, repair books, and
hands-on schematic work will enable you to hone your skills reliably,
even without relying on videos or web surfing. The skills transfer
strongly to boards in the same family, as manufacturers maintain
similar power sequencing architectures over generations.[^2_1]
<div align="center">⁂</div>
[^2_1]: IBM-Thinkpad-T60-schematic.pdf
[^2_2]: https://www.diy-laptoprepair.com
[^2_3]: https://www.diy-laptoprepair.com/
[^2_4]:
https://hi-spec.com/blogs/news/the-role-of-digital-multimeters-in-computer-repair-a-beginner-s-guide
[^2_5]: https://www.scribd.com/doc/145294899/Laptop-Motherboard-Repair
---
# What you say seems helpful. I’m still having trouble finding a good
resource (or course I suppose) to learn this on my own. I’m also a
little worried about my skills using a multimeter on such fine traces.
I can have trouble with my eyes, my fingers, as well as my attention
span. Let’s move to helping me get set up with good clear next steps.
Not too many. Just one or two.
## Your Two Clear Next Steps
Based on your situation—difficulty with fine traces, vision, and
dexterity challenges—here's what to focus on:
### Step 1: Get the Right Book Resource
**Order the Louis Rossmann "Rossmann Repair Training
Guide"**[^3_1][^3_2][^3_3][^3_4]
This is a freely available PDF that you can download and print, or
read on your device. It's specifically designed for beginners who want
to learn board-level repair without an engineering background. The
guide covers:[^3_2][^3_1]
- Basic electrical concepts (voltage, current, resistance, Ohm's law)
explained through simple analogies[^3_1][^3_2]
- Component identification (resistors, capacitors, MOSFETs)[^3_1]
- How to use a multimeter for troubleshooting[^3_2]
- Logic board repair fundamentals[^3_2]
**Where to get it:** Search "Rossmann Repair Training Guide PDF" or
find it on his forum at boards.rossmanngroup.com. You can download it
as a PDF to print specific sections.[^3_3][^3_5][^3_1]
**Why this one:** It's written specifically for people learning board
repair on their own, it's free, and it's structured for self-paced
study without needing videos. Many technicians recommend this as their
starting point.[^3_4][^3_3][^3_1][^3_2]
### Step 2: Get Physical Tools to Make Probing Easier
**Invest in probe helpers that address your dexterity and vision concerns:**
**A. Multimeter Hook Clips/Extension Probes**[^3_6][^3_7][^3_8]
These attach to your multimeter leads and have spring-loaded hooks
that clip onto test points, so you don't need to hold steady probes
with your fingers. They let you set up the connection and then step
back. Look for "multimeter test lead hook clips" or "extender
probes"—they cost around \$5-15 for a set.[^3_7][^3_8][^3_6]
**B. Helping Hands with Magnifier**[^3_9][^3_10][^3_11][^3_12]
A "third hand" tool holds your board steady while built-in magnifying
glass (typically 2.5-4x magnification) lets you see small components
and traces clearly. The weighted base keeps everything stable, and
adjustable alligator clips secure the board at any angle. Cost:
\$7-20.[^3_10][^3_11][^3_12][^3_9]
These two tools work together: the helping hands hold your board and
magnify it, while the hook clips attach to test points so you don't
need rock-steady hands.[^3_11][^3_12][^3_6]
### Why These Two Steps Work Together
The Rossmann guide will teach you **what to look for and where to
probe**, while the physical tools will make it **physically possible
for you to do the work** despite vision and dexterity challenges. You
can study the guide at your own pace, print the sections you need to
reference, and practice on your motherboard with the proper
setup.[^3_12][^3_3][^3_6][^3_10][^3_11][^3_1][^3_2]
Start with these two things. Don't worry about microscopes,
oscilloscopes, or advanced tools yet. These basics will get you
diagnosing power issues and understanding your board's behavior, which
is exactly what you need right now.[^3_13][^3_14][^3_3][^3_1][^3_2]
<span
style="display:none">[^3_15][^3_16][^3_17][^3_18][^3_19][^3_20][^3_21][^3_22][^3_23][^3_24][^3_25][^3_26][^3_27][^3_28][^3_29][^3_30][^3_31][^3_32][^3_33][^3_34][^3_35][^3_36][^3_37][^3_38][^3_39][^3_40]</span>
<div align="center">⁂</div>
[^3_1]: https://www.scribd.com/document/368611484/Rossmann-Repair-Training-Guide
[^3_2]:
https://www.scribd.com/document/496168011/Rossmann-Repair-Training-Guide-Google-Slides
[^3_3]:
https://boards.rossmanngroup.com/threads/macbook-logic-board-troubleshooting-guide-for-beginners.27082/
[^3_4]:
https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-laptops-tablets-and-mobile-devices/63105-books-on-laptop-motherboard-repair
[^3_5]:
https://docs.google.com/presentation/d/1PkeO_lC5WTPScSV3ZzEEjVuDWeQtL2eHK6jEcf7axA0/edit
[^3_6]:
https://store.roboticsbd.com/electronics-robotics-kit/2180-testing-hook-clip-multimeters-test-lead-extension-probe-aperture-4mm-plug-in-pair-robotics-bangladesh.html
[^3_7]: https://www.fluke.com/en-us/products/accessories/test-leads
[^3_8]:
https://probemaster.com/dmm-multimeter-test-leads/safety-extender-probes-kits/
[^3_9]:
https://www.instructables.com/Helping-Hand-Magnifying-Glass-With-Soldering-Stand/
[^3_10]:
https://glasssupplies41.com/products/third-hand-magnifier-helping-hands-magnifying-glass
[^3_11]: https://www.circuitspecialists.com/helping-hands-third-hand-tools
[^3_12]: https://www.adafruit.com/product/291
[^3_13]: https://tronicsfix.com/blogs/news/microscopes-for-electronic-repair
[^3_14]:
https://www.eevblog.com/forum/beginners/magnifying-glass-or-usb-digital-microscope-for-soldering/
[^3_15]: https://shriraminfotech.net/online-training-course.php
[^3_16]:
https://www.barnesandnoble.com/w/mastering-electronics-repair-v-t-sreekumar/1144912582
[^3_17]: https://www.youtube.com/watch?v=nawKVhKU_do
[^3_18]:
https://books.google.com/books/about/Mastering_Electronics_Repair.html?id=zMdDEQAAQBAJ
[^3_19]: https://www.laptoprepairsecrets.com
[^3_20]:
https://moj-network.ir/files/books_articles/A-Guide-to-Electronic-Maintenance-and-Repairs.pdf
[^3_21]:
https://www.reddit.com/r/IAmA/comments/yytfe2/louis_rossman_and_ifixit_here_making_it_legal_for/
[^3_22]: https://www.mrmtti.in/laptop-desktop-repairing-course-card-level/
[^3_23]: https://www.futurlec.com/BooksService.shtml
[^3_24]: https://archive.org/details/Louis-Rossmann-2015
[^3_25]: https://www.multitechinstitute.com/laptop-repairing-course.php
[^3_26]: http://repo.darmajaya.ac.id/3930/1/Electronic
Troubleshooting, Fourth Edition ( PDFDrive ).pdf
[^3_27]: https://www.laptoprepairworld.com/laptop-repair-training/
[^3_28]: https://www.youtube.com/watch?v=e96C9Xy9Ggc
[^3_29]: https://academy.rewa.tech
[^3_30]: https://www.youtube.com/watch?v=duwr-cNU4xM
[^3_31]:
https://www.circuitspecialists.com/helping-hands-third-hand-tools?srsltid=AfmBOopEXWviKxH3o8irekF1l8xmR1-5dCe1uNPe3kq8QYjeIXv1iPKs
[^3_32]: https://www.triplett.com/collections/test-leads
[^3_33]: https://www.youtube.com/watch?v=C3SbVFFBrhk
[^3_34]:
https://www.reddit.com/r/electricians/comments/ngok5c/help_finding_extended_multimeter_leads/
[^3_35]:
https://www.reddit.com/r/embedded/comments/161clqg/best_digital_microscope_for_soldering/
[^3_36]:
https://www.reddit.com/r/soldering/comments/hvk3r7/which_helping_hands_base_do_you_userecommend/
[^3_37]:
https://www.reddit.com/r/Tools/comments/uh3goy/diy_automotive_electrical_test_leads/
[^3_38]:
https://amscope.com/collections/applications-electronics-circuit-boards-general-electronics-html
[^3_39]: https://www.youtube.com/watch?v=DuXoJUH4mb4
[^3_40]: https://www.youtube.com/watch?v=8aqOVxq__EM
---
# I started viewing the rossman guide but it mostly seemed material
that’s not very new so far. I’m familiar with the basics of voltage
and current, I’ve used breadboards. Where do I find the information on
board repair? One multimeter I have is an innova 3320 I think, how do
I find connectors compatible? But I also might use tools that have
normal headers or solder pads, cheap logic analyzer boards for example
— what would I use there?
## Getting to Board Repair Specifics
Since you're already comfortable with basic electronics, you'll want
to jump to the **practical board repair sections**—schematic reading
and power sequencing—rather than spending time on voltage/current
theory. Here's where to find that:
### Board Repair Material in Text Format
**Power Sequencing Documentation:**
The key resource for learning power sequencing from schematics is
actually in **PDF training materials** rather than the Rossmann guide.
Look for:
- "Laptop Power Sequence Training" PDFs - These detail the S5→S0 power
states and show how voltage regulators sequence from adapter input
through to CPU power[^4_1][^4_2]
- Your **T60 schematic PDF** - Page 1 typically has a power sequence
diagram showing which ICs generate which voltages and in what
order[^4_3][^4_4][^4_5]
The power sequence section of schematics shows the flow: Adapter →
Battery charger → Always-on rails (3.3V, 5V) → EC wake-up → Secondary
rails → CPU/GPU power. This is the practical diagnostic
roadmap.[^4_4][^4_2][^4_3][^4_1]
**Schematic Reading Tutorials (Text-Based):**
- SparkFun's "How to Read a Schematic" guide - Comprehensive written
tutorial on schematic symbols and tracing circuits[^4_6]
- Look for "laptop motherboard schematics analysis" PDFs on repair
forum sites like badcaps.net, dr-bios.com[^4_7][^4_8][^4_9]
### Using BoardView Files
Since you have the T60 schematic, you should also look for **BoardView
files** (.brd, .bvr, .bdv formats). BoardView files are even more
practical than schematics for your situation—they show a **visual map
of the physical board** with every component
labeled.[^4_10][^4_11][^4_12][^4_7]
**Software:** OpenBoardView (free, open-source) or FlexBV[^4_12][^4_8]
**Where to find files:** Search "Thinkpad T60 boardview file" on sites
like badcaps.net forums or vinafix.com[^4_13]
BoardView lets you:
- Click on a component in the visual layout and see its schematic net
name[^4_11][^4_7]
- Find test points for voltage rails by searching for rail names (like
"VCC3M")[^4_10][^4_7]
- Trace connections without following complex schematic
lines[^4_11][^4_7][^4_10]
### Probing Solutions for Your Multimeter \& Logic Analyzers
**For the Innova 3320:**
Your Innova 3320 uses **standard 4mm banana jacks**. The plugs are
"nearly standard probe size" and "interchangeable with standard
probes". This means you can use:[^4_14][^4_15][^4_16]
1. **Standard 4mm banana plug hook clips** - Spring-loaded hooks that
clip to test points[^4_17]
2. **4mm banana to IC clip adapters** - Convert your meter leads to
SMD grabber clips[^4_18][^4_19]
3. **Spring-loaded micro-tip probes** with 4mm banana plugs - These
have fine, spring-loaded needle tips for SMD work[^4_20]
**For Logic Analyzers \& Dev Boards:**
Since your logic analyzer likely has pin headers or flying leads, you
need different probing solutions:
1. **Pogo pins** (spring-loaded test pins) - These can
be:[^4_21][^4_22][^4_23][^4_24][^4_25]
- Soldered directly to a PCB you make as a test jig[^4_22]
- Held in "helping hands" and pressed onto test points[^4_22]
- Used in receptacles for repeated testing[^4_26]
Common types: Mill-Max spring probes, P75-LM style, or cheap Chinese
pogo pins from AliExpress/eBay[^4_27][^4_25][^4_28][^4_22]
2. **SMD Grabber Clips** with 0.64mm or dupont pins that you
can:[^4_19][^4_29][^4_18]
- Crimp or solder to your logic analyzer's flying leads[^4_30]
- Attach to 2.54mm (0.1") header pins via jumper wires
Look for: Pomona 72902, E-Z Hook XKM, or cheap IC test
hooks[^4_31][^4_18][^4_19]
3. **DIY approach:** Buy SMD grabber clips with bare wire ends, then
solder female dupont connectors or pin headers to them so they plug
into your logic analyzer's male headers[^4_30]
### Your Specific Next Steps
**Step 1:** Open your T60 schematic PDF and find:[^4_5]
- The title page/table of contents - locate the "Power Sequence" page number
- The power sequence diagram - this shows the flow from DC input
through all voltage rails
- Print or annotate the power sequence page and the first few pages
showing power input circuitry
**Step 2:** Get probing tools that work with your limitations:
- Order **spring-loaded micro-tip probes** with 4mm banana plugs for
your Innova 3320 (these press and hold themselves on test
points)[^4_20]
- Order **SMD IC grabber clips** with flying leads that you can attach
to your logic analyzer or solder dupont connectors
to[^4_18][^4_19][^4_30]
These spring-loaded tools solve your dexterity challenges—they grip
and hold rather than requiring steady hands.[^4_17][^4_20]
<span
style="display:none">[^4_32][^4_33][^4_34][^4_35][^4_36][^4_37][^4_38][^4_39][^4_40][^4_41][^4_42][^4_43]</span>
<div align="center">⁂</div>
[^4_1]: https://www.youtube.com/watch?v=t4LKvaRrDdI
[^4_2]:
https://www.scribd.com/document/367816445/LAPTOP-POWER-Sequence-training-1-0-0-pdf
[^4_3]: https://www.youtube.com/watch?v=-yMz0kPKhig
[^4_4]: https://www.youtube.com/watch?v=goZR7gvMZec
[^4_5]: IBM-Thinkpad-T60-schematic.pdf
[^4_6]: https://learn.sparkfun.com/tutorials/how-to-read-a-schematic/all
[^4_7]:
https://dr-bios.com/threads/how-to-use-boardview-in-repairing-asus-laptops.24614/
[^4_8]: https://thetechstall.com/category/repair-tools/boardview-software/
[^4_9]:
https://www.badcaps.net/forum/troubleshooting-hardware-devices-and-electronics-theory/troubleshooting-laptops-tablets-and-mobile-devices/63105-books-on-laptop-motherboard-repair
[^4_10]: https://thetechstall.com/dell-13-3380-16824-1-boardview-file/
[^4_11]: https://www.youtube.com/watch?v=YiJFIA-oU40
[^4_12]:
https://bioslaptop.com/en/openboardview-9-0-3-boardview-file-viewer-software/
[^4_13]:
https://www.reddit.com/r/AskElectronics/comments/kj5o82/how_can_i_get_board_view_files_for_free/
[^4_14]: https://lygte-info.dk/review/DMMInnova3320 UK.html
[^4_15]: https://www.summitracing.com/parts/ino-3320
[^4_16]:
https://csr.innova.com/Content/Manual/Innova/100912_3320_93-0041_RevB_Manual_E_Version_Final_downloadable.pdf?r=0.08253397705659157
[^4_17]:
https://store.roboticsbd.com/electronics-robotics-kit/2180-testing-hook-clip-multimeters-test-lead-extension-probe-aperture-4mm-plug-in-pair-robotics-bangladesh.html
[^4_18]: https://www.testandmeasurement.com/doc/test-clips-0002
[^4_19]:
https://www.eevblog.com/forum/testgear/test-clipsgrabbers-for-fine-pitch-ics/
[^4_20]: https://probemaster.com/spring-loaded-micro-tip-test-leads-only/
[^4_21]: https://www.linkedin.com/pulse/how-solder-pogo-pins-pcb-amy-li-t65hc
[^4_22]:
https://learn.adafruit.com/how-to-build-a-testing-fixture/solder-pogo-pins
[^4_23]:
https://www.peaktest.co.uk/resources/technical-how-guides/what-spring-contact-test-probe
[^4_24]: https://www.harwin.com/ezi-range/pogo-pins
[^4_25]: https://www.mouser.com/new/mill-max/mill-max-contactsandprobes/
[^4_26]: https://www.kita-mfg.com/english/use/
[^4_27]: https://www.reddit.com/r/AskElectronics/comments/1am4486/smd_pogo_pins/
[^4_28]: https://www.chinapogopinsupplier.com/products/PCB-Test-Probe.htm
[^4_29]:
https://www.pomonaelectronics.com/products/test-clips/grabber-test-clips
[^4_30]: https://www.youtube.com/watch?v=nV0Isjf5Y_4
[^4_31]: https://www.ebay.com/b/ic-test-clip/bn_7024878769
[^4_32]: https://www.youtube.com/watch?v=jYvVE-4-zmA
[^4_33]:
https://www.autozone.com/test-scan-and-specialty-tools/multimeter/p/innova-auto-ranging-multimeter/64472_0_0
[^4_34]: https://www.innova.com/blogs/fix-advices/how-to-measure-ac-dc-voltage
[^4_35]: https://www.youtube.com/watch?v=3mnsjJClpxw
[^4_36]: https://www.innova.com/products/auto-ranging-dmm-3320
[^4_37]: https://www.mindluster.com/lesson/292920-video
[^4_38]: https://ingun.com/en-US/GKS-354-102-580-U-4000/GKS-354-0001
[^4_39]: https://www.youtube.com/watch?v=blCa8sbWAlY
[^4_40]: https://pmkamerica.com/collections/clamps-hooks-test-probes
[^4_41]:
https://www.reddit.com/r/ElectricalEngineering/comments/1nm5t12/tips_for_logic_analyzer_probes_on_smd_boards/
[^4_42]:
https://www.reddit.com/r/AskEngineers/comments/11tt0sp/are_there_any_soft_probe_options_for_multimeter/
[^4_43]: https://www.pogopin-probe.com
---
# I’m looking into probes. It’s kinda challenging. Let’s start with
something that could add ease, and not cost too much. There are so
many probes! Sometimes I’ve used the kind with the spring-loaded hook,
but the ones I’ve used are far far too big for anything on a laptop
motherboard. I searched ebay for “spring-loaded micro-tip probes 4mm
banana” but got not results! Can you make it seem simpler and clearer?
## Let Me Simplify This for You
You're right—the probe world is overwhelming. Let me give you **one
clear, simple solution** that will work with your Innova 3320 and
won't break the bank.
### What You Actually Need
**"SMD IC Test Hook Clips" or "Mini Grabber Clips"**
These are the small spring-loaded hooks that work on laptop
motherboards. They're called by many names (which makes searching
confusing), but they're all basically the same
thing.[^5_1][^5_2][^5_3][^5_4]
### The Exact Search Terms That Work
Try these on eBay or Amazon:
- **"SMD IC test hook clip"**[^5_3][^5_5][^5_1]
- **"mini grabber test clip"**[^5_2][^5_4][^5_6]
- **"IC hook multimeter probe"**[^5_5][^5_3]
### What to Look For
You want clips that have:
- **A wire/lead attached** (called "pigtail")[^5_7][^5_2]
- **2mm banana plug on the end** (this plugs into your Innova 3320's
jacks)[^5_6]
- **Spring-loaded pincers** that grab components when you release the
button[^5_1][^5_2]
### Specific Product Examples
**Budget Option (\$5-10 for a set):**
- Search "10pcs SMD IC test hook clip" on eBay[^5_3][^5_1]
- These come as bare clips with wires—you can find versions with 2mm
banana plugs already attached[^5_5][^5_3]
**Pre-Made Sets (\$10-15):**
- "Mini grabber test clip with 2mm plug" on eBay or Amazon[^5_6][^5_5]
- These come ready to use—just plug into your multimeter[^5_6]
### Why These Work For You
1. **They're small enough**—the hook is about 4.5mm x 2mm, which can
grab IC legs and small test points[^5_1]
2. **They hold themselves**—spring-loaded so you don't need steady
hands[^5_2][^5_1]
3. **They fit your multimeter**—2mm banana plugs work with standard
4mm banana jacks (they're compatible)[^5_6]
4. **They're cheap**—\$1-2 per clip, or \$5-15 for a full set[^5_8][^5_3][^5_1]
### Alternative: Direct Clip-On Adapters
If you want something even simpler that doesn't replace your probes, look for:
**"Mini grabber clips" with bare wire ends**[^5_4][^5_9][^5_2]
These have:
- A female socket on the wire end that slides onto your existing
multimeter probe tips[^5_10][^5_2]
- The grabber clip on the other end[^5_2]
- Cost: \$5-8 for a set of 5-10[^5_9]
Search: **"mini grabber IC hook female socket"** or **"grabber test
clips with leads"**[^5_9][^5_2]
### My Recommendation
Start with **one cheap set of "SMD IC test hook clips with leads"**
from eBay (\$5-10). Get ones that have the 2mm plug already attached.
This way you can try them without spending much, and they'll plug
right into your Innova 3320.[^5_3][^5_5][^5_6]
The key thing: Don't worry about "spring-loaded micro-tip
probes"—that's not what these are commonly called. The right term is
"SMD IC hook clips" or "mini grabbers".[^5_4][^5_1][^5_2][^5_3]
<span
style="display:none">[^5_11][^5_12][^5_13][^5_14][^5_15][^5_16][^5_17][^5_18][^5_19][^5_20]</span>
<div align="center">⁂</div>
[^5_1]: https://www.newegg.com/p/0AF-001M-00189
[^5_2]: https://digilent.com/shop/mini-grabber-test-clips-with-leads/
[^5_3]: https://www.ebay.com/itm/325171239548
[^5_4]:
https://www.reddit.com/r/AskElectronics/comments/mmksyo/what_are_these_handy_clips_called_and_what_is/
[^5_5]: https://www.ebay.com/itm/125883875733
[^5_6]: https://www.ebay.com/itm/204975522741
[^5_7]: https://www.youtube.com/watch?v=_yH9ytNSG4U
[^5_8]: https://www.aliexpress.com/item/1005005943651049.html
[^5_9]:
https://www.reddit.com/r/AskElectronics/comments/5flyfh/recommendations_for_test_hooks/
[^5_10]:
https://www.eevblog.com/forum/beginners/mini-test-clips-that-fit-directly-on-dmm-probe/
[^5_11]: https://zeph.com/probes_tweezers.htm
[^5_12]:
https://hackaday.com/2018/07/16/review-smd-tweezer-meter-or-tweezer-probes-for-your-multimeter/
[^5_13]: https://www.youtube.com/watch?v=5WxEgrN5K-4
[^5_14]:
https://www.reddit.com/r/AskElectronics/comments/18zghnf/can_i_test_this_ic_with_a_multimeter_if_so_how/
[^5_15]: https://www.fluke.com/en-us/products/accessories/test-leads
[^5_16]: https://www.eevblog.com/forum/testgear/test-leads-for-smd/
[^5_17]:
https://blog.oshpark.com/2018/07/16/review-smd-tweezer-meter-or-tweezer-probes-for-your-multimeter/
[^5_18]: https://www.youtube.com/watch?v=N0_NcjZBuyw
[^5_19]: https://www.ebay.com/itm/365013497888
[^5_20]: https://www.elexp.com/collections/ic-hook-grabbers-test-probes
---
# I feel scared and anxious. Can you give a short reply that makes it
simple? The hooks look really big, and I’m not sure how I’ll connect
the probes to the multimeter. (I also have other multimeters if this
one is weird.) If I were trying the solder points of an IC I don’t
think those hooks would fit. Wouldn’t I need something else?
## You're Right - Let Me Simplify
Take a breath. You need **needle-tip probes**, not hooks. Here's the
simple answer:
### What You Actually Need
**Fine needle probes with sharp tips** - these look like thin metal
needles (about 1mm diameter) that you touch to tiny solder
points.[^6_1][^6_2][^6_3][^6_4]
### The Simple Search Term
On eBay or Amazon, search:
**"needle tip multimeter probe"**[^6_5][^6_4]
### What You'll See
- Two thin probe handles (red and black)
- Sharp metal needle tips at the end[^6_2][^6_3]
- Standard plugs that fit any multimeter[^6_1][^6_2]
- Cost: \$8-20 for a set[^6_6][^6_2][^6_5]
### Specific Recommendations
**Budget (\$8-10):** Generic "needle tip test probe" on eBay[^6_4][^6_5][^6_6]
**Quality (\$100):** Fluke TL910 - these have 1mm tips perfect for IC
pins[^6_3][^6_5]
**Middle (\$40):** Probe Master 9110 kit[^6_2]
### They Connect Easy
The plugs are standard 4mm banana plugs - they push straight into your
Innova 3320's holes. That's it. No adapters needed.[^6_3][^6_1][^6_2]
### For IC Pins Specifically
Yes, needle probes work for IC solder points. The 1mm tip touches
individual IC legs without shorting to neighbors.[^6_4][^6_3]
**One thing to buy: "needle tip multimeter probe" on eBay - around
\$10**[^6_5][^6_6][^6_4]
That's all you need to start.
<span
style="display:none">[^6_10][^6_11][^6_12][^6_13][^6_14][^6_15][^6_16][^6_17][^6_18][^6_19][^6_20][^6_7][^6_8][^6_9]</span>
<div align="center">⁂</div>
[^6_1]:
https://www.reddit.com/r/AskElectronics/comments/nt5vjn/good_probe_kit_for_smd_parts_for_multimeter/
[^6_2]: https://probemaster.com/9110-smd-spring-tip-micro-probe-deluxe-kit/
[^6_3]: https://www.fluke.com/en-us/product/accessories/test-leads/tl910
[^6_4]: https://www.ebay.com/itm/306427444456
[^6_5]: https://www.eevblog.com/forum/testgear/test-leads-for-smd/
[^6_6]:
https://www.reddit.com/r/electronics/comments/50pv99/i_reviewed_a_good_and_cheap_set_of_multimeter/
[^6_7]:
https://organ-needles-probe.com/en/assistance/tip-shape-selection-for-fine-pitch-inspection/
[^6_8]: https://www.fixturfab.com/articles/test-fixture-signal-interfaces
[^6_9]:
https://www.reddit.com/r/AskEngineers/comments/11tt0sp/are_there_any_soft_probe_options_for_multimeter/
[^6_10]:
https://opulent.com.sg/enhancing-test-efficiency-with-pogo-pins-tips-and-tricks/
[^6_11]:
https://www.parts-express.com/21-Piece-Multimeter-Professional-Test-Lead-Kit-with-Case-390-321
[^6_12]: https://promaxpogopin.com/professional/what-is-a-pogo-test-pin/
[^6_13]: https://www.instructables.com/SMD-Test-Probe/
[^6_14]:
https://www.eevblog.com/forum/reviews/good-sharp-fine-tip-multimeter-probes-with-very-flexible-leads/
[^6_15]:
https://www.reddit.com/r/AskElectronics/comments/138o3kw/what_are_the_best_designs_of_pogo_pin_head_shape/
[^6_16]:
https://www.reddit.com/r/AskElectronics/comments/1i6260t/tips_on_probing_fine_pitch_surface_mount_devices/
[^6_17]: https://www.fluke.com/en-us/products/accessories/test-leads
[^6_18]: https://www.youtube.com/watch?v=IqTJ7VX_eSY
[^6_19]:
https://www.reddit.com/r/ElectricalEngineering/comments/1nm5t12/tips_for_logic_analyzer_probes_on_smd_boards/
[^6_20]:
https://www.mouser.com/c/test-measurement/test-equipment-accessories/test-probes/?tip+style=Sharp+Point
---
# I found one that just looks like female plastic, not visible what
the connector is, and it doesn’t have a cable, and it says compatible
with 4mm. I found another that has a cable and says “cross plug with
shield sleeve”. Will either of these work?
## Quick Answer
**First one (female plastic, no cable, "4mm compatible"):** This
sounds like a **replacement tip** that slides onto your existing
multimeter probes. It should work if you already have probe cables. It
just replaces the normal probe tip with a needle tip.[^7_1][^7_2]
**Second one (cable, "cross plug with shield sleeve"):** Yes, this
should work. "Cross plug" typically means a standard 4mm banana plug.
The "shield sleeve" is just safety insulation. If it has the cable
attached, it's complete and ready to use.[^7_3]
### Which to Buy?
If you're unsure, **buy the one with the cable attached** (the "cross
plug" one). It's complete and will definitely work with your
multimeter.[^7_4][^7_3]
The one without a cable only works if you have existing test leads to
attach it to.[^7_2]
### How to Tell if It Will Work
It will work if:
- It says "4mm banana plug" OR "standard multimeter plug"[^7_5][^7_4]
- You see a red and black probe with cables
- The price is around \$8-20 for a pair[^7_6][^7_4]
Can you send me the listing link or a screenshot? I can tell you for
certain if it will work.
<div align="center">⁂</div>
[^7_1]: https://www.eevblog.com/forum/testgear/test-leads-for-smd/
[^7_2]:
https://www.eevblog.com/forum/beginners/mini-test-clips-that-fit-directly-on-dmm-probe/
[^7_3]: https://www.fluke.com/en-us/products/accessories/test-leads
[^7_4]: https://probemaster.com/9110-smd-spring-tip-micro-probe-deluxe-kit/
[^7_5]: https://www.fluke.com/en-us/product/accessories/test-leads/tl910
[^7_6]:
https://www.reddit.com/r/electronics/comments/50pv99/i_reviewed_a_good_and_cheap_set_of_multimeter/
---
#
[https://www.ebay.com/itm/324316135725?_skw=needle-tip+probes&epid=877406725&itmmeta=01K9J7129VFC3PZTHQW2QP6HJ8&hash=item4b82bf812d:g:pmIAAOSwKqpcPfOJ&itmprp=enc%3AAQAKAAAA0FkggFvd1GGDu0w3yXCmi1eQow03aLRLVo16XQa%2FJaBUNvGv0N%2F99siwo8r42kUax5MZAtwsLRq59JV%2B%2FYxrFkQBXk8DoeBHxRv03Mr%2Fh08nQrBYivnlxJgCq4bmcz6xxp%2Bknd%2B8aMYmGo%2FwMFuylLneKADQhKT6z43a98butZO2sYoPAiXJhLBFTqF7Ws7sbmbNGHAiqPb8fMPfDKtrt%2FPQzfLaFzJBTbnO3HBrTzw7eVpajgItn6rEBzMc7HKHuD8nmv2fHSZz1%2B96ekgL8UY%3D%7Ctkp%3ABk9SR46lhMfMZg](https://www.ebay.com/itm/324316135725?_skw=needle-tip+probes&epid=877406725&itmmeta=01K9J7129VFC3PZTHQW2QP6HJ8&hash=item4b82bf812d:g:pmIAAOSwKqpcPfOJ&itmprp=enc%3AAQAKAAAA0FkggFvd1GGDu0w3yXCmi1eQow03aLRLVo16XQa%2FJaBUNvGv0N%2F99siwo8r42kUax5MZAtwsLRq59JV%2B%2FYxrFkQBXk8DoeBHxRv03Mr%2Fh08nQrBYivnlxJgCq4bmcz6xxp%2Bknd%2B8aMYmGo%2FwMFuylLneKADQhKT6z43a98butZO2sYoPAiXJhLBFTqF7Ws7sbmbNGHAiqPb8fMPfDKtrt%2FPQzfLaFzJBTbnO3HBrTzw7eVpajgItn6rEBzMc7HKHuD8nmv2fHSZz1%2B96ekgL8UY%3D%7Ctkp%3ABk9SR46lhMfMZg)
It asks me to select whether I want UT-L20 or UT-L21
## Perfect! Here's Your Answer
**Yes, this listing will work perfectly for you.**
### The Difference Between UT-L20 and UT-L21
**UT-L20:**[^8_1][^8_2][^8_3]
- **Current rating: 10A**
- Safety level: CAT II 600V
- Rod length: 101mm
- Tip length: 16.5mm
**UT-L21:**[^8_2][^8_3][^8_1]
- **Current rating: 20A** (higher current capability)
- Safety level: CAT III 1000V (higher safety rating)
- Rod length: 133mm (slightly longer body)
- Tip length: 15.8mm
### Which Should You Choose?
**Get the UT-L21**[^8_4][^8_3][^8_1]
It's the better version:
- Higher current rating (20A vs 10A)[^8_3][^8_1]
- Better safety rating (CAT III 1000V)[^8_1][^8_3]
- Only slightly longer[^8_1]
For laptop motherboard work, either would work fine, but the UT-L21
gives you more capability for the same price.[^8_3][^8_1]
### Will It Connect to Your Innova 3320?
**Yes, absolutely.** Both models have "cross plug with shield sleeve"
which is a standard 4mm banana plug. This will plug directly into your
Innova 3320's input jacks.[^8_5][^8_6][^8_2][^8_1]
### What You're Getting
- Needle tips that are fine enough for IC pins[^8_3][^8_1]
- 900mm (3 feet) cable length[^8_2][^8_1]
- Standard banana plugs that fit any multimeter[^8_6][^8_5]
- \$6.17 - excellent price[^8_6]
**Go ahead and order the UT-L21.** It will work perfectly for your
motherboard diagnosis work.
<span
style="display:none">[^8_10][^8_11][^8_12][^8_13][^8_14][^8_15][^8_16][^8_17][^8_18][^8_19][^8_20][^8_21][^8_7][^8_8][^8_9]</span>
<div align="center">⁂</div>
[^8_1]: https://cdn.promelec.ru/upload/items/2023/08/01/UT-L Series
Test Leads.pdf
[^8_2]: https://hvactools.com.au/product/uni-t-ut-l-series-test-leads/
[^8_3]: https://matrixonline.pk/index.php?route=product%2Fcategory\&path=255
[^8_4]: https://terminator.ae/product/multi-meter-test-leads-ut-l21/
[^8_5]: https://meters.uni-trend.com/product/ut-l-series/
[^8_6]: https://www.ebay.com/itm/324316135725
[^8_7]:
https://www.ebay.com/itm/324316135725?_skw=needle-tip+probes\&epid=877406725\&itmmeta=01K9J7129VFC3PZTHQW2QP6HJ8\&hash=item4b82bf812d%3Ag%3ApmIAAOSwKqpcPfOJ\&itmprp=enc%3AAQAKAAAA0FkggFvd1GGDu0w3yXCmi1eQow03aLRLVo16XQa%2FJaBUNvGv0N%2F99siwo8r42kUax5MZAtwsLRq59JV%25
[^8_8]:
https://www.alibaba.com/product-detail/UNI-T-Copper-Needle-Test-Pen_1601548271018.html
[^8_9]: https://www.youtube.com/watch?v=_dogqVegV5k
[^8_10]: https://www.youtube.com/watch?v=1NuNPR8Sedg
[^8_11]: https://www.scribd.com/document/668890610/UT-L-Series-Test-Leads
[^8_12]: https://rcl.lt/en/products/?g=a7c94e5ed41ff621b8d1\&seek=fw\&k=1
uni-t-ut201-meters-and-ac-clamp-probes
[^8_13]:
https://www.uni-trend.co.za/itemdetails/accessories/probes-and-test-leads/probes?code=ut---l20\&type=2\&access=2\&id=2f05ea76-e2b4-45c4-b34a-be2128f19f53
[^8_14]: https://www.tme.eu/en/details/utl20/test-leads-sets/uni-t/
[^8_15]: https://www.aliexpress.com/item/32821721616.html
[^8_16]: https://meters.uni-trend.com/products/accessories/
[^8_17]:
https://www.temu.com/at-en/1-set-universal-uni-t-ut-l20-ut-l21-ut-l90-digital-multimeter-test-leads-1000v-20a-fine-needle-probe-wire-pen-cable-accurate-reading-easy-to-test-g-601099523040335.html
[^8_18]: https://www.aliexpress.com/item/1005005682184630.html
[^8_19]: https://www.aliexpress.com/i/1005005682184630.html
[^8_20]: https://vera-electronic.com/product-category/uni-t/uni-t-2/
[^8_21]: https://metastech.com/products/ut-l20
