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Tektronix 4052/54 diagnostic ROM pack remade.

I have used one of Jos' Diagnostic ROM Packs to repair one 4052 and three 4054 computers including two 4054 Option 30 boards with memory errors. These early 4116 DRAMs are still available for sale (I've bought dozens on EBAY) - and are the only ICs that I have needed to replace on the computers I repaired.

The Diagnostic ROM Pack can not only pinpoint which DRAM IC has an error, it can also pinpoint bad ROMs by comparing the ROM Checksums against the Tektronix document with 4052/4054 ROM Checksums for different firmware versions. It can also test the CRCs of the ROMs or EPROMs in option ROM Packs - with my BASIC program which uses the Diagnostic ROM Pack CALL"CRC" and lists the CRC for every 4KB ROM or EPROM.

It can also test the 4052/4054 bit-slice CPU microcode!

This Diagnostic ROM Pack is a must have for repairing a Tektronix 4052 or 4054 computer that does not finish power on self-test (BUSY light does not turn off).
 
Exact same experience for me.

Unfortunately in a few months' time I'll have the ROM Pack but not the 4052/4054 to plug it into!
 
Hi Jos,

I received the DRP, and it looks great, thanks!

So I am off to a slow start - I installed it in the ROM slot, and I power up. I have the left most SW ON, and all others OFF, which I believe should set me to sequence through all tests. I tried it in all 4 ROM slots with the same results. See attached pics. Here is what happens:

  • All 8 LEDs on the DRP come on and stay on.
  • None of the 4 lights on the front right of my 4054 ever come on. It seems particularly strange to me that even the POWER light doesn't come on, as I have good 5 Volts. Maybe that lamp is not hard tied to the 5V line, I can check that on the schematic.
  • The 4 LEDs on the top PCB come on and stay on. If I press the RESET on the DRP, upon release the center 2 of those LEDs flash off then back on for a few milliseconds.

I am very new to trouble shooting the Tek displays, so any comments from anyone is welcome.

Thanks!!

Bob
 

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On the 4054A in my care at the moment, the power lamp seems to have a poor connection somewhere. I poked it a few times and this seemed to restore contact. I haven't investigated further, but I thought I'd report since it seems related.
 
The DRP you received has been tested in my 4052 machine with that exact option, i.e. cycle through the tests as you correctly assumed.

- Make sure that the DRP is well seated, it needs a firm push.
- Try some of the other tests (ROM CRC) Just set the switches and press reset.
- As always, test your system with minimal configuration first.

Good luck...
 
stepleton said:
On the 4054A in my care at the moment, the power lamp seems to have a poor connection somewhere. I poked it a few times and this seemed to restore contact. I haven't investigated further, but I thought I'd report since it seems related.
Click to expand...
OK, thanks, that is some good info. One thing I have learned over the years is that most issues are caused by poor mechanical connections. Bob
 
jdreesen said:
The DRP you received has been tested in my 4052 machine with that exact option, i.e. cycle through the tests as you correctly assumed.

- Make sure that the DRP is well seated, it needs a firm push.
- Try some of the other tests (ROM CRC) Just set the switches and press reset.
- As always, test your system with minimal configuration first.

Good luck...
Click to expand...
Hi Jos,

OK, that is a good point. I will try that. I am also going to check the schematic to see where that POWER bulb is connected. I didn't test for 5 volts on all the PCBs, just one. Maybe a bad 5V connection to one of the boards, or maybe just a bad connection to the bulb, or even butned out bulb.

I like your approach is starting simple.

Thanks again.

Bob
 
BJeffway said:
OK, thanks, that is some good info. One thing I have learned over the years is that most issues are caused by poor mechanical connections. Bob
Click to expand...
Based on your comment I located the schematic for the power lamp - I had assumed it was powered by 5V - well you know what they say about assumptions! It is powered by 12V, I didn't know there was a 12V power supply, I had checked all the voltages on the LV PS and 12 wasn't there, so I never checked 12V. The 12V at the lamp is measuring 6V, so there is a problem. I am tracking it down now, as it's possible some of the ICs use 12v.
 
Last edited:
Good progress. I found a bad transistor on the 12V regulator. Q5001 Tek part # is 151-0366-00, MFG Code 03508 MFG Part# X45C277
It is a PNP power transistor TO-220 case. Any ideas where I could find one, or how to find a cross reference to something more available?

I hope it's OK to post this often, and I really appreciate the help.

Bob
 
151-0366-00 translates to a D45C PNP transistor : indeed PNP in a TO220.

Google for tektronix_xref_sm.pdf to get a 400+ page crossreference...
 
jdreesen said:
151-0366-00 translates to a D45C PNP transistor : indeed PNP in a TO220.

Google for tektronix_xref_sm.pdf to get a 400+ page crossreference...
Click to expand...
Thanks much for the part number and the excellent reference. Wow that is an amazing cross reference resource.
 
OK, made good progress over the weekend. Got the +12V supply fixed, it is right on voltage now. Now, on powerup, all the front lamps come on and stay on. Same with all 8 LEDs on DRP. Interestingly now LEDs DS1,2,3 and 4 on the Memory Command Processor Board all come on at Reset, but now DS4 goes off immediately, which indicates MB15 drops low after reset. I put my scope on MB4 (just picked that one randomly, but most look the same) see attached images. So at Reset, MB4 has some activity for about 40ms, then goes into what looks like Hi-Z, as it sits at 1.8V. During that 40ms we get what looks like some fairly decent periodic high pulses, with some not so nice spikes in between. I am a bit stuck as to where to go from her, so any ideas at all would be greatly appreciated. Thanks gentlemen. Bob
 

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Once again pulling up in the "poor mechanical connections" clown car to report that most of the problems I've had with this 4054A here have had to do with mechanical issues:

1. The 8X300 chip on the Option 30 board working its way out of its socket: multiple times
2. Various ROMs: probably at least once, back when we were getting the thing going
3. Cracked solder joints on the "low voltage power supply board"

For problems 1 and 2, the observed behaviour is that the machine just... doesn't. Refuses to start, hangs if it did start, just basically quits doing anything. So, if you're in the mood for trying something really simple, try squishing some socketed chips down into their sockets. (If you haven't already.)
 
stepleton said:
Once again pulling up in the "poor mechanical connections" clown car to report that most of the problems I've had with this 4054A here have had to do with mechanical issues:

1. The 8X300 chip on the Option 30 board working its way out of its socket: multiple times
2. Various ROMs: probably at least once, back when we were getting the thing going
3. Cracked solder joints on the "low voltage power supply board"

For problems 1 and 2, the observed behaviour is that the machine just... doesn't. Refuses to start, hangs if it did start, just basically quits doing anything. So, if you're in the mood for trying something really simple, try squishing some socketed chips down into their sockets. (If you haven't already.)
Click to expand...
I have not tried that, but I think that is an excellent idea, and always good to start with the simple stuff. I think I will leverage each chip out a bit, then press it back in to get even more chance of improving a poor contact. Thanks for the idea!
 
I reseated every socketed chip amd connetor that I could find, no dice. Same result with and without DRP. I have a lot of experience troubleshooting 8 and 16 bit mico's, but I need to study the schematic to understand this system more. Then I will try to put my logic analyzer on the ROM it starts with and see if I can find what's up. Still open to suggestions if anyone has one. Bob
 
Bob,

Check out this 4052/4054 System Test Fixture manual pdf pages 10 and 11:
github.com

Tektronix-4051-4052-4054-Program-Files/4052-4054_SystemTest/Tek_067-0942-99_System_Test_Fixture_instructions.pdf at master · mmcgraw74/Tektronix-4051-4052-4054-Program-Files

Archive of Tektronix 4051 4052 4054 and A series computer programs - mmcgraw74/Tektronix-4051-4052-4054-Program-Files
github.com github.com

All lights on indicates ALU, MCP Handshake, or I/O issue with your 4054A.

ALU issues could be due to bad microcode - here is a link to Jos' ALU ROMs:

My ALU ROMs are also in the same folder with my doc on how to read those ROMs with a DATA I/O programmer.

Monty
 
nikola-wan said:
Bob,

Check out this 4052/4054 System Test Fixture manual pdf pages 10 and 11:
github.com

Tektronix-4051-4052-4054-Program-Files/4052-4054_SystemTest/Tek_067-0942-99_System_Test_Fixture_instructions.pdf at master · mmcgraw74/Tektronix-4051-4052-4054-Program-Files

Archive of Tektronix 4051 4052 4054 and A series computer programs - mmcgraw74/Tektronix-4051-4052-4054-Program-Files
github.com github.com

All lights on indicates ALU, MCP Handshake, or I/O issue with your 4054A.

ALU issues could be due to bad microcode - here is a link to Jos' ALU ROMs:

My ALU ROMs are also in the same folder with my doc on how to read those ROMs with a DATA I/O programmer.

Monty
Click to expand...
Hi Monty,

Thanks very much for the very helpful reply. That page 10 and 11 anr great! I will check the status of those lights tomorrow, and that will really help. I think you could be right about a microcode problem. I scoped the CE pins on all the ROMs and I don't ever see at CE on any of the 8 ROMs, so looks like it never gets to read the ROMs. The first link works great, and I reviewed pages 10 and 11. The second link gives me a ZIP with 9 files: 74S288.label, ALU74288.tst and 160-1688 thru 1695.V10. I don't see both your and Jos's ALU ROMs and I don't see your read instructions for the Data I/O. That System Test Fixture looks great, are there any out there? Man, there is an incredible amount of info on the 4054 out there, and I am slowly collecting it all thanks to the help of the members of the forum. As I continue to learn, I hope to be able to help people in the future, as well. Best, Bob
 
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