Re: PDP-12 Restoration at the RICM

On 06/05/2016 09:54 AM, Michael Thompson wrote: We fixed the RK05 disk this week. We replaced E3 (LM301A) and E1 (SN7404) on the G938 Servo Preamp module. The COUNT PULSE FWD H and the COUNT PULSE REV H signals from the G938 module are both working now. The drive will now seek correctly using the

Re: PDP-12 Restoration at the RICM

On Tue, Dec 22, 2015 at 08:31:46PM -0500, Michael Thompson wrote: > the [paper tape] reader does not always step correctly and does not > read the tape correctly. Ah, then you have restored it to as-shipped condition :-) mcl

Re: PDP-12 Restoration at the RICM

On Thu, Dec 24, 2015 at 9:59 AM, Michael Thompson < michael.99.thomp...@gmail.com> wrote: > > Kyle's SerialDisk is here: https://github.com/drovak/os8diskserver I just pushed some changes earlier. Hopefully I didn't break too many things! :) The system handler now has support for FRTS. Still nee

Re: PDP-12 Restoration at the RICM

On 2015-Dec-24, at 1:58 PM, Jon Elson wrote: > On 12/24/2015 01:22 PM, Jay Jaeger wrote: >> On 12/24/2015 9:59 AM, Michael Thompson wrote: >> >>> We have been able to fix all types of broken flip-chips. Sourcing the >>> components is sometimes a challenge. The Germanium transistors for the TU20 >>

Re: PDP-12 Restoration at the RICM

On 12/24/2015 01:22 PM, Jay Jaeger wrote: On 12/24/2015 9:59 AM, Michael Thompson wrote: We have been able to fix all types of broken flip-chips. Sourcing the components is sometimes a challenge. The Germanium transistors for the TU20 on the PDP-9 were hard to find. I remember replacing a ger

Re: PDP-12 Restoration at the RICM

On 12/24/2015 9:59 AM, Michael Thompson wrote: > > We have been able to fix all types of broken flip-chips. Sourcing the > components is sometimes a challenge. The Germanium transistors for the TU20 > on the PDP-9 were hard to find. > I remember replacing a germanium (at least I think it was) t

Re: PDP-12 Restoration at the RICM

> > Date: Tue, 22 Dec 2015 20:56:51 -0600 > From: Jay Jaeger > Subject: Re: PDP-12 Restoration at the RICM > Message-ID: <567a0d73.2010...@charter.net> > Content-Type: text/plain; charset=utf-8 > > I have an image of MAINDEC-12-D8CD-PB, and a listing as well >

Re: PDP-12 Restoration at the RICM

On 12/22/2015 7:31 PM, Michael Thompson wrote: > Lots more work on the PDP-12 at the RICM. We got an RS-232 console board > and baud rate generator from Vincent and now have both serial ports > working. Warren modified Kyle's SerialDisk and we booted OS/8 from an > emulated RK05 on the second seri

Re: PDP-12 Restoration at the RICM

I used my PDP-8/e at home to test the RX8E controller and the RX01 floppies that came with the PDP-12. Both worked OK. We found a bad SP380 on a M7102 board in the DW8E the Omnibus expansion chassis. This would not let the SKIP instructions work with the RX8E, RK05, or PC8E. Once we replaced the S

Re: PDP-12 Restoration at the RICM (tony duell)

On Tue, Oct 13, 2015 at 08:32:49PM -0400, Michael Thompson wrote: > > What exactly do you mean by 'glitches'? Are these on a TTL level signal, > > an analogue > > output of the read amplifer, or what? > > > > You can see the logic analyzer trace of many of the TC12 signals here. >

Re: PDP-12 Restoration at the RICM (tony duell)

On 10/13/2015 07:32 PM, Michael Thompson wrote: Tracks 1 & 2 look fine. We swapped the probes for track 2 & 3 just to make sure that it wasn't a logic analyzer problem. A 'scope connected to the differential signals shows the same track 3 glitches. The glitches were present with the TU55 and th

RE: PDP-12 Restoration at the RICM (tony duell)

> > Date: Mon, 12 Oct 2015 18:29:11 + > From: tony duell > Subject: RE: PDP-12 Restoration at the RICM > > > We swapped the TU56 and TU55 drives between the PDP-12 and the PDP-8/I. > We > > Does the TU55 work correctly on the 8/I ? > Yes, it works perfectly.

RE: PDP-12 Restoration at the RICM

From: Paul Koning Sent: Tuesday, October 13, 2015 7:55 AM >> On Oct 12, 2015, at 9:16 PM, Rich Alderson > >> wrote: >> ... >> The M tracks are longitudinally encoded (6-bit values chosen such that >> they read the same as NRZ backwards and forwards for DECtape, 4-bit >> values for LINCtape) to pr

Re: PDP-12 Restoration at the RICM

On 2015-10-13 16:54, Paul Koning wrote: On Oct 12, 2015, at 9:16 PM, Rich Alderson wrote: ... The M tracks are longitudinally encoded (6-bit values chosen such that they read the same as NRZ backwards and forwards for DECtape, 4-bit values for LINCtape) to predefine blocks (cf. disk sectors)

Re: PDP-12 Restoration at the RICM

On Tue, Oct 13, 2015 at 11:16:54AM -0400, william degnan wrote: > Did you ever speak with anyone at System Source (Bob) about their PDP 12? > Maybe they'd be interested in collaborating. http://museum.syssrc.com/ I highly recommend everyone pull up the Univac 490 (1963) page and look in the "gall

Re: PDP-12 Restoration at the RICM

Did you ever speak with anyone at System Source (Bob) about their PDP 12? Maybe they'd be interested in collaborating. http://museum.syssrc.com/ On Tue, Oct 13, 2015 at 10:54 AM, Paul Koning wrote: > > > On Oct 12, 2015, at 9:16 PM, Rich Alderson > wrote: > > > > ... > > The M tracks are longi

Re: PDP-12 Restoration at the RICM

> On Oct 12, 2015, at 9:16 PM, Rich Alderson > wrote: > > ... > The M tracks are longitudinally encoded (6-bit values chosen such that they > read the same as NRZ backwards and forwards for DECtape, 4-bit values for > LINCtape) to predefine blocks (cf. disk sectors) for data. More precisely: i

RE: PDP-12 Restoration at the RICM

From: tony duell Sent: Monday, October 12, 2015 11:29 AM >> We swapped the TU56 and TU55 drives between the PDP-12 and the PDP-8/I. We > Does the TU55 work correctly on the 8/I ? >> The TU55 behaved a little better than the TU56, and sometimes would actually >> boot OS/8. We continued chasing t

Re: PDP-12 Restoration at the RICM

On 10/12/2015 12:40 PM, Michael Thompson wrote: >> >> Date: Sun, 11 Oct 2015 18:44:54 -0500 >> From: Jay Jaeger >> Subject: Re: PDP-12 Restoration at the RICM >> >> Don't forget about the other more remote possibilities: cables, >> backplane, bad

RE: PDP-12 Restoration at the RICM

> We swapped the TU56 and TU55 drives between the PDP-12 and the PDP-8/I. We Does the TU55 work correctly on the 8/I ? > The TU55 behaved a little better than the TU56, and sometimes would > actually boot OS/8. We continued chasing the issue and found glitches on > data channel 3. We have swappe

Re: PDP-12 Restoration at the RICM

> > Date: Sun, 11 Oct 2015 18:44:54 -0500 > From: Jay Jaeger > Subject: Re: PDP-12 Restoration at the RICM > > Don't forget about the other more remote possibilities: cables, > backplane, bad wrap, supply voltages at the actual card(s) for the > mis-behaving cha

Re: PDP-12 Restoration at the RICM

I have no constructive input to share - except the strong memory of the bloke who maintained my pdp-12s for 25 years before I collected them saying that the TC12 was an "absolute bugger" and the hardest part of the machine to troubleshoot! Good luck and don't feel bad about having a hard time with

Re: PDP-12 Restoration at the RICM

On 10/11/2015 9:42 AM, Michael Thompson wrote: > > We are running out of things to try for debugging the TC12 controller in > the PDP-12. At this point we are really stumped as to why the TC12 doesn't > work correctly. We are going to try a few remaining ideas like running the > TC12 from a labora

Re: PDP-12 Restoration at the RICM

On 11 October 2015 at 10:42, Michael Thompson wrote: > We are running out of things to try for debugging the TC12 controller in > the PDP-12. At this point we are really stumped as to why the TC12 doesn't > work correctly. We are going to try a few remaining ideas like running the > TC12 from a la

Re: PDP-12 Restoration at the RICM

We swapped the TU56 and TU55 drives between the PDP-12 and the PDP-8/I. We found that the TU56 uses a double-sided paddle card for the control signals and the TU55 uses a single-sided paddle-card. The TC12 tape controller in the PDP-12 will work with either tape drive if you have the right cable. W

Re: PDP-12 Restoration at the RICM

On 8/17/2015 1:51 PM, Rich Alderson wrote: > From: Jay Jaeger > Sent: Sunday, August 16, 2015 3:18 PM > > On 8/16/2015 9:00 AM, Michael Thompson wrote: > >>> We did a lot more debugging on the TC12 LINCtape controller. > >> Second gut hunch is that it would be hard to see how the drive could >>

RE: PDP-12 Restoration at the RICM

From: Jay Jaeger Sent: Sunday, August 16, 2015 3:18 PM On 8/16/2015 9:00 AM, Michael Thompson wrote: >> We did a lot more debugging on the TC12 LINCtape controller. > Second gut hunch is that it would be hard to see how the drive could > cause this UNLESS the TC12 uses one side of the redundant

Re: PDP-12 Restoration at the RICM

On 8/16/2015 9:00 AM, Michael Thompson wrote: > We did a lot more debugging on the TC12 LINCtape controller. > > We saw a 500ns glitch in the LMU MOTION signal that corresponded to a short > slowdown in tape speed. We will investigate this next week. > > We entered the LINC instruction to check a

Re: PDP-12 Restoration at the RICM

We did a lot more debugging on the TC12 LINCtape controller. We saw a 500ns glitch in the LMU MOTION signal that corresponded to a short slowdown in tape speed. We will investigate this next week. We entered the LINC instruction to check a single block (0707) in the left switches and a block numb

Re: PDP-12 Restoration at the RICM

We found a shorted diode in one of the rectifiers in the +/-42VDC supply in the VR14 that was causing the main fuse to blow. The donor of the PDP-12 gave us a spare so that was an easy fix. We reinstalled the VR14 in the PDP-12 and ran the display diags. The VR14 display actually works! We found

Re: PDP-12 Restoration at the RICM

When we first powered up the PDP-12 the main fuse for the VR12 display blew. A replacement fuse did the same. We thought that the brown goo in the bottom of the chassis had leaked from the high-voltage power supply, and the high-voltage power supply is directly connected to the input, so that was t

RE: PDP-12 Restoration at the RICM

> > We reconnected the Variac to the input and with 10VAC the high-voltage > power supply had a 1000VDC output. We put 10x 500kOhm resistors in series > across the output and increased the Variac voltage. By measuring the > voltage across one resistor we could see that the output was more than > 1

Re: PDP-12 Restoration at the RICM

We spent a few more hours on the PDP-12 today... With the machine just powered on the stack 0/1 regulator output was 20.04V. With tune3 running in field 1 and testing field 0 the stack 0/1 regulator output was 19.93. No memory errors were reported. When the voltage was adjust up to 22.5 and down

Re: PDP-12 Restoration at the RICM

The LINK indicator light on the front panel of the PDP-12 failed two weeks ago. The indicator light bulb failed, briefly shorted, and destroyed the transistor that turns the indicator on. An new transistor and bulb, and all is well. We have been chasing a transient problem in the PDP-12 core memor

RE: PDP-12 Restoration at the RICM

> > Date: Mon, 15 Jun 2015 19:42:42 -0400 > From: Michael Thompson > To: cctech > > The M452 creates a 220 Hz clock for the TTY transmitter and a 880 Hz clock > for the TTY receiver. > The M405 for the DP12-B serial port generated a clock that is 16x the baud > rate which is then divided by an M2

RE: PDP-12 Restoration at the RICM

> > The PDP-12 came to us with an M452 for the 110 baud TTY console and a > home-made adjustable baud rate module for the second serial port. The > adjustable baud rate generator was made by the original user of the system > in the early 80s, and is just a crystal, rotary switch and a Fairchild >

RE: PDP-12 Restoration at the RICM

> > Date: Mon, 15 Jun 2015 05:01:36 + > From: tony duell > Subject: RE: PDP-12 Restoration at the RICM (tony duell) > > > > Tony, thank you for your offer to supply replacement M452 Variable Clock > > modules for the console. We already have one jumpered for 1

RE: PDP-12 Restoration at the RICM

> > The M452 creates a 110 Hz clock for the TTY transmitter and a 880 Hz clock > for the TTY receiver. Does it? The prints I have show the 2 outputs with a factor of 4 (not 8) in frequency. > The M405 for the DP12-B serial port generated a clock that is 16x the baud > rate which is then divided

RE: PDP-12 Restoration at the RICM (tony duell)

> Tony, thank you for your offer to supply replacement M452 Variable Clock > modules for the console. We already have one jumpered for 110 baud for the > Teletype. The other two M452 modules should be jumpered for 9600 baud and > 38400 baud. The second serial port uses a M405 Crystal Clock module

RE: PDP-12 Restoration at the RICM (tony duell)

> > Date: Sun, 14 Jun 2015 15:25:08 + > From: tony duell > To: "General Discussion: On-Topic Posts" > Subject: RE: PDP-12 Restoration at the RICM > > > Warren made an Arduino based programmable baud rate generator that works > > for both serial port

Re: PDP-12 Restoration at the RICM

Dave Tumey sent us a new rubber hammer for the Teletype. This is the part that pushes the print drum against the ribbon and paper to print. These are newly molded parts that have not been available for decades. Works very nicely. The ripple on the power supplies is still going lower as we put more

Re: PDP-12 Restoration at the RICM

> On Jun 14, 2015, at 06:53, Michael Thompson > wrote: > > Dave Tumey sent us a new rubber hammer for the Teletype. This is the part > that pushes the print drum against the ribbon and paper to print. These are > newly molded parts that have not been available for decades. Works very > nicely.

RE: PDP-12 Restoration at the RICM (tony duell)

> > Tony, thank you for your offer to supply replacement M452 Variable Clock > modules for the console. We already have one jumpered for 110 baud for the > Teletype. The other two M452 modules should be jumpered for 9600 baud and > 38400 baud. The second serial port uses a M405 Crystal Clock module

RE: PDP-12 Restoration at the RICM

> The ripple on the power supplies is still going lower as we put more run > time on the system. The power supplies are now within spec. Capacitors reforming naturally? > Warren made an Arduino based programmable baud rate generator that works > for both serial ports. After some debugging, it wo

Re: PDP-12 Restoration at the RICM

Michael, David's product is outstanding! He also makes new foams for the inside alsofor the model 33 and 32 - Ed# _www.smecc.org_ (http://www.smecc.org) In a message dated 6/7/2015 6:58:55 A.M. US Mountain Standard Time, michael.99.thomp...@gmail.com writes: W contacted

Re: PDP-12 Restoration at the RICM

W contacted David Tumey about Teletype hammers. He will send us some as a donation. We put some heat-shrink tubing on to stop further damage. Warren repaired and tested the M706 Teletype receiver. We put it back in the PDP-12 and put the borrowed M706 back in the PDP-8/I. The donor brought another

Re: PDP-12 Restoration at the RICM

I'll add that I've had several platens and power rolls rebuilt by JJ Short and the service was top notch. -C On Jun 4, 2015, at 5:07 PM, Chuck Guzis wrote: > I'll add that if the Rubber Renue treatment is ineffective, you can have your > platen rebuilt by JJ Short: > > http://www.jjshort.com/t

Re: PDP-12 Restoration at the RICM

On 06/02/2015 05:09 AM, Michael Thompson wrote: I sent him an email and asked about the hammer, and a source for paper and ribbons. The platen is hard as a rock, so we will need to do something about that too. There's some stuff called "Rubber Renue" sold for just that purpose. Basically, it

Re: PDP-12 Restoration at the RICM

I'll add that if the Rubber Renue treatment is ineffective, you can have your platen rebuilt by JJ Short: http://www.jjshort.com/typewriter-platen-repair.php --Chuck

Re: PDP-12 Restoration at the RICM

m: "Robert Jarratt" > > Subject: RE: PDP-12 Restoration at the RICM > > > > Yes, the new rubber hammers are available from David Tumey. I think he > > wants > > about $7 for 10 of them. I have a supply of them here in the UK for > anyone > > that needs any

RE: PDP-12 Restoration at the RICM

> > Date: Mon, 1 Jun 2015 09:33:26 +0100 > From: "Robert Jarratt" > Subject: RE: PDP-12 Restoration at the RICM > > Yes, the new rubber hammers are available from David Tumey. I think he > wants > about $7 for 10 of them. I have a supply of them here in

RE: PDP-12 Restoration at the RICM

isterkamp > Sent: 31 May 2015 15:48 > To: General Discussion: On-Topic Posts > Subject: Re: PDP-12 Restoration at the RICM > > Michael, > > Sounds like you're making some real progress. Next time you're near the > ASR33, check the rubber hammer for the prin

Re: PDP-12 Restoration at the RICM

We spent some time on the console Teletype that came with the PDP-12. The platen was nearly impossible to move, so the Line Feed did not work. We removed the platen, and found that the plastic in the bearing area had swollen and was binding. We sanded, cleaned, and lubricate the bearing surface and

Re: PDP-12 Restoration at the RICM

Michael, Sounds like you're making some real progress. Next time you're near the ASR33, check the rubber hammer for the print cylinder. These have a tendency to self destruct and in doing so, destroy the cylinder itself...and they can go at anytime. There's a fellow on the Greenkeys that has to

Re: PDP-12 Restoration at the RICM

If you haven't yet found one, I have spares for the switch cover - I have an entire console and the backplanes (with the cards) whose machine was disassembled out from underneath them. JRJ On 5/10/2015 9:45 AM, Michael Thompson wrote: > Sorry, I sent the message before I was finished. > > The CR

Re: PDP-12 Restoration at the RICM

From: Mike Ross: Tuesday, May 26, 2015 5:48 AM Do tell more about this mythical and very useful sounding board tester? Warren's tester is similar in basic capability to the one that Henk and I did some time ago, with some additional circuitry that's useful for "load testing" -- telling the di

Re: PDP-12 Restoration at the RICM

I think many people would be interested. With an appropriate adapter, his device could test modules from other manufacturers as well. -- Will On Tue, May 26, 2015 at 10:15 AM, Pete Turnbull wrote: > On 26/05/2015 03:02, Ethan Dicks wrote: >> >> On Mon, May 25, 2015 at 8:07 PM, Michael Thompson >

Re: PDP-12 Restoration at the RICM

On 26/05/2015 03:02, Ethan Dicks wrote: On Mon, May 25, 2015 at 8:07 PM, Michael Thompson wrote: Today we pulled all of the M113 flip-chips and tested them Do you have any writeups on Warren's FLIP-CHIP tester? I'd be very interested too, especially since I'm about to try to resurrect a P

Re: PDP-12 Restoration at the RICM

On Mon, May 25, 2015 at 08:07:04PM -0400, Michael Thompson wrote: > so the processor is substantially functional. This is substantially cool. > We tried the ASR33 Teletype that came with the system. The mechanics were > sticky from not being used for 30 years This is substantially crazy :-) IIR

Re: PDP-12 Restoration at the RICM

"The M706 receiver failed in the board tester" Do tell more about this mythical and very useful sounding board tester? I'm looking at my racks and racks of logic, mostly M-series - 12, 16, 18, & 36 bit - and contemplating the debuggering with some dread... Mike On Tue, May 26, 2015 at 12:07 PM,

Re: PDP-12 Restoration at the RICM

On Mon, May 25, 2015 at 8:07 PM, Michael Thompson wrote: > Today we pulled all of the M113 flip-chips and tested them because SN7474 > and SN7400 ICs seem to be a problem in these early DEC systems. I have found from debugging a PDP-8/i and multiple PDP-8/L systems that 80% of my failed ICs are S

Re: PDP-12 Restoration at the RICM

Today we pulled all of the M113 flip-chips and tested them because SN7474 and SN7400 ICs seem to be a problem in these early DEC systems. The ones in slots J33 and K30 were bad. Replacing them fixed the problem with the JMP instruction. We did some more testing with the toggle-in programs and found

Re: PDP-12 Restoration at the RICM

We spent Friday and Saturday debugging the PDP-12. We replaced a bad SN7400 driver chip and three bad bulbs in the front panel. We can now trust what we see on the front panel for debugging information. We tried some of the PDP-8 and LINC instructions and noticed that some of the bits in the Instr