On Sat, 23 Jan 2016, Jules Richardson wrote:
On 01/22/2016 06:26 PM, Tothwolf wrote:
The translucent yellow Rifa (now owned by Kemet) class X/Y safety
capacitors in particular have a 100% failure rate and are on my
replace-on-sight list. They usually begin to show visible signs of
cracking in
On Sat, 23 Jan 2016, tony duell wrote:
Incidentally, some machines have those sealed metal cans containing
filter capacitors, inductors and sometimes discharge resistors [2]. Has
anyone ever had the capacitors in one of those fail?
Actually, yes. I had one fail in one of my scopes. I don't re
On Sat, 23 Jan 2016, Mattis Lind wrote:
I don't have a ESR meter or similar. It is not shorted at least and
the resistance is in the several mega ohm range when measuring in
circuit. Are they likely to go bad in a non catastrophic way?
They can. The translucent yellow Rifa (now owned by Kemet
On Sat, 23 Jan 2016, Chuck Guzis wrote:
On 01/23/2016 02:40 PM, Pontus wrote:
All I could find were new similar Kemet capacitors. Do you know if
newer Kemet suffer from the same problem and I will regret buying them?
I usually replace the Rifa capacitors with equivalent polyester safety
caps
On 01/23/2016 02:40 PM, Pontus wrote:
All I could find were new similar Kemet capacitors. Do you know if newer
Kemet suffer from the same problem and I will regret buying them?
I usually replace the Rifa capacitors with equivalent polyester safety
caps (X or Y rated). Kemets are most common
On 01/23/2016 01:26 AM, Tothwolf wrote:
They can. The translucent yellow Rifa (now owned by Kemet) class X/Y
safety capacitors in particular have a 100% failure rate and are on my
replace-on-sight list. They usually begin to show visible signs of
cracking in their outer casing before they fin
>
> It's a well-known fault, but has anyone ever known one fail and actually
> cause any damage (other than to itself)? AIUI, they're there to reduce
Not really. Maybe a blown fuse. I have had the live-earth capacitor in a filter
fail and trip the RCD in my consumer unit (meaning I was in the da
On 1/23/2016 5:40 AM, Mattis Lind wrote:
This is a 0.0033 uF 1600VDC SPARAGUE capacitor. It looks nice and orange
and there are no signs of cracks whatsoever.
What is the likelihood of this being bad?
Not highly likely, but possible. Just
put another one in temporarily and see
if it solv
On 01/22/2016 06:26 PM, Tothwolf wrote:
The translucent yellow Rifa (now owned by Kemet) class X/Y safety
capacitors in particular have a 100% failure rate and are on my
replace-on-sight list. They usually begin to show visible signs of cracking
in their outer casing before they finally go out wi
>
> Well. It depends if you read the schematics before you do so. In this case
> I powered the startup voltage from a 12 V bench supply. Normally the
> startup voltage comes from a small mains transformer and a 7812. Then I
> supplied the primary side voltage for the main switch transistor using a
> From: Mattis Lind
> I don't have an capacitance / ESR meter so I cannot check it.
If you do a lot of work with analog components (and it sounds like you do),
it's probably worth getting capacitance and ESR meters, they can be obtained
(new) on eBay for not that much. I have one of each
>>>
>> I don't have a ESR meter or similar. It is not shorted at least and the
>> resistance is in the several mega ohm range when measuring in circuit. Are
>> they likely to go bad in a non catastrophic way?
>>
>
> They can. The translucent yellow Rifa (now owned by Kemet) class X/Y
> safety capac
>
>
>> Well. It depends if you read the schematics before you do so.
>>
>
> Assuming they're available for the particular PSU one is attempting to
> test.
>
>
Yes of course. If I have a PSU where I have doubts about the function and
there is no schematic I spend a few hours trace out the relevant p
>
> Speaking generally, I don't know that that will necessarily save one (in
> using a variac on a SMPS).
>
I for one think it is a good practice to start carefully. I like the idea
of bringing up the voltage over capacitors and other electronics in a
controlled manner. Electronics that had been s
On 2016-Jan-22, at 3:56 PM, Mattis Lind wrote:
> 2016-01-22 21:48 GMT+01:00 j...@cimmeri.com :
>> On 1/22/2016 2:54 PM, Mattis Lind wrote:
>>
>>> Short: R27 in my VT100 PSU is hot and smelling. Why?
>>>
>>> Long: I think it has been 20 years since I powered up this VT100 so I did
>>> it carefully
On Sat, 23 Jan 2016, Mattis Lind wrote:
2016-01-23 0:32 GMT+01:00 Peter Coghlan :
R27 is part of the snubber network on the primary side of this
forward-type SMPS PSU. But why it it getting so hot. Is it normal? I
have completely forgotten how a VT100 smell when running...
Snubber as in a re
On 1/22/2016 6:56 PM, Mattis Lind wrote:
2016-01-22 21:48 GMT+01:00 j...@cimmeri.com:
On 1/22/2016 2:54 PM, Mattis Lind wrote:
Short: R27 in my VT100 PSU is hot and smelling. Why?
Long: I think it has been 20 years since I powered up this VT100 so I did
it carefully. Used a Variac and a benc
2016-01-23 0:32 GMT+01:00 Peter Coghlan :
> >
> > R27 is part of the snubber network on the primary side of this
> forward-type
> > SMPS PSU. But why it it getting so hot. Is it normal? I have completely
> > forgotten how a VT100 smell when running...
> >
>
> Snubber as in a resistor in series wit
2016-01-22 21:48 GMT+01:00 j...@cimmeri.com :
> On 1/22/2016 2:54 PM, Mattis Lind wrote:
>
>> Short: R27 in my VT100 PSU is hot and smelling. Why?
>>
>> Long: I think it has been 20 years since I powered up this VT100 so I did
>> it carefully. Used a Variac and a bench supply. It switched just fin
>
> R27 is part of the snubber network on the primary side of this forward-type
> SMPS PSU. But why it it getting so hot. Is it normal? I have completely
> forgotten how a VT100 smell when running...
>
Snubber as in a resistor in series with a capacitor across the primary?
If so check the capacit
On 1/22/2016 2:54 PM, Mattis Lind wrote:
Short: R27 in my VT100 PSU is hot and smelling. Why?
Long: I think it has been 20 years since I powered up this VT100 so I did
it carefully. Used a Variac and a bench supply. It switched just fine and
delivered the steady 5V out when the input was at appr
Short: R27 in my VT100 PSU is hot and smelling. Why?
Long: I think it has been 20 years since I powered up this VT100 so I did
it carefully. Used a Variac and a bench supply. It switched just fine and
delivered the steady 5V out when the input was at approx 50V (115V input).
All the other voltages
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