PET 4032 stopped working.

[daver2]

Yes, a NOP generator, a PETTESTER EPROM and a decent oscilloscope should be able to diagnose most PET faults.

I keep meaning to write up a PET repair guide.

Dave

 

[pdblues2231]

Yes, a NOP generator, a PETTESTER EPROM and a decent oscilloscope should be able to diagnose most PET faults.

I keep meaning to write up a PET repair guide.

Dave

Let me ask you are any 4116 compatible? or does it need a certain speed?

 

[daver2]

I think any DRAM with a <= 250 ns access time and a <= 410 ns read/write cycle time should be OK.

If I remember correctly, these are the slowest 4116 DRAM devices I have ever seen.

Of course, 4116 devices are obsolete. As a result, what you are buying is old stock. I have never known any semiconductor get faster with age, only slower!

The 6502 CPU runs at 1 MHz. Memory is only accessed on half of the clock cycle, so the absolute limit is 500 ns.

Dave

 

[daver2]

If you want to populate your second bank of 4116 DRAMs, do it now with PETTESTER...

Dave

 

[pdblues2231]

If you want to populate your second bank of 4116 DRAMs, do it now with PETTESTER...

Dave

It was populated. I had 32k but I took one to install on UA19 so now I am missing one. I want to get to same ram.. I want it to look uniformed and consistent. I was reading your pettester manual and also the IEEE book you mentioned.

 

[dave_m]

Good work, PD. You never quit.
Please report which parts were bad including ROMs and RAM and if you needed to replace any IC sockets.
It looks like you saw the value of using the PETTest4 code and the NOP Generator. The bad address buffer part was quickly found when you used the NOP Generator.

It was great that bit-fixer built it into his latest ROMulator gadget.

 

[dave_m]

I keep meaning to write up a PET repair guide.

That would be a great help to PET users on this Forum along with Hugo’s well done PET technical reports.

 

[pdblues2231]

Good work, PD. You never quit.
Please report which parts were bad including ROMs and RAM and if you needed to replace any IC sockets.
It looks like you saw the value of using the PETTest4 code and the NOP Generator. The bad address buffer part was quickly found when you used the NOP Generator.

It was great that bit-fixer built it into his latest ROMulator gadget.

Slow and steady just like navigating in rough seas. Never Ever Quit!

Total of 4 chips were replaced.
Total of 6 Sockets were replaced.

Symptoms -------------------------------------------------------------------------------------------------------------IC

Reset line would appear ok at start-up but upon warm-up it would bring Reset Line to LO ------------------UB16 (6520)
Reset line would not stay HI ------------------UD15 (7417)
AB5 was stuck on IC side on UD13 pin 14 ------------------UD13 (LS244)
Main RAM chip UA19 faulty at D0 socketed and replaced ------------------UA19(4116)
Kernal ROM was socketed for testing purposes ----------------- UD6
CPU socket was replaced, old white socket unreliable ------------------UB14(6502)

Romulator, NOP generator was used and pettest4 rom in the troubleshooting routines.

In an effort to preserve authenticity and keep it as much OEM as possible all TTL components were acquired at Digi-Key or Mouser and replaced with genuine Texas Instruments.

CHEERS to all....