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4032 cbm pet no video

Desperado

Desperado

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Joined
Nov 25, 2017
Messages
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Hi my friends, how are you?
I'm in Covid red zone now in Milan...
I bought 4032 CBM PET but i can't see nothing on screen...i can see only random characters and Symbols if i try tun turn of and on faster....
I downloaded Daver2 Pettester v.4 and i inserted it on ud8 socket...
How can i do to know if roms test it's good?
Ram chips are all "G".
Thanks so much!
 
Stay safe and well then...

If the RAM tests return all G then the test should move on to display the ROM checksums. If the ROM checksum screen does not appear, something is wrong with the previous (RAM) tests.

Can you post a video of the power-up display with my PETTESTER EPROM installed?

Dave
 
No problem.

It looks like you have BASIC 4 installed.

If you read my documentation (!) you will see that ROMS B, C and F match the checksums for BASIC 4 whereas ROM D doesn't.

Furthermore, the checksum for ROM D is changing - indicating that the contents read slightly differently each time the checksum routine runs.

Therefore, ROM D is most likely the culprit.

The keyboard values should also all be '00' not 'fd'. There may (therefore) also be something wrong with the keyboard PIA. Try operating some keys and see what happens on the keyboard display...

Also, let the countdown count down to 0 and let it run the full memory test...

Dave
 
daver2 said:
No problem.

It looks like you have BASIC 4 installed.

If you read my documentation (!) you will see that ROMS B, C and F match the checksums for BASIC 4 whereas ROM D doesn't.

Furthermore, the checksum for ROM D is changing - indicating that the contents read slightly differently each time the checksum routine runs.

Therefore, ROM D is most likely the culprit.

The keyboard values should also all be '00' not 'fd'. There may (therefore) also be something wrong with the keyboard PIA. Try operating some keys and see what happens on the keyboard display...

Also, let the countdown count down to 0 and let it run the full memory test...

Dave
Click to expand...

Thanks Daver2!
When i run pettester, keyboard connector wasn't connected on board....
Rom "D" is Ud8 or other??
 
It looks like the Zimmer’s website is down at the moment, so I can’t confirm UD8 for the Dxxx ROM.

But if there is a ROM at that location, it is a pretty good bet!

Dave
 
Swap the ROM to another socket. I'd have to look at the decoding as to which socket it best. Some of the decoding may be done inside the ROM while most is on the board. The fact that it is changing may be a socket contact issue. If it checks good in another location, I'd replace the socket. It is possible that there is addressing conflict. Us a scope and look at the data lines and trigger on that ROM's enable.
Dwight
 
Dwight Elvey said:
Swap the ROM to another socket. I'd have to look at the decoding as to which socket it best. Some of the decoding may be done inside the ROM while most is on the board. The fact that it is changing may be a socket contact issue. If it checks good in another location, I'd replace the socket. It is possible that there is addressing conflict. Us a scope and look at the data lines and trigger on that ROM's enable.
Dwight
Click to expand...

Hi Dwight, ok i try!Thanks!
 
daver2 said:
It looks like the Zimmer’s website is down at the moment, so I can’t confirm UD8 for the Dxxx ROM.

But if there is a ROM at that location, it is a pretty good bet!

Dave
Click to expand...

Sorry Daver but in UD8 socket there is PETTESTER now!! ;)
 
Welcome back; long time no see ;-)

Is UD7 in a socket? If it is, you could try putting it into UD3 and running a jumper to the UD7 chip enable to bypass the UD7 socket.

If it's soldered then you'll probably have to replace it.

Good luck!
 
Update:

I changed eprom in "D" socket but i have same black screen....If now i run PETTESTER i can see this screen on picture, now value in "D" are stable!
I connected keyboard connector but nothing changes...if i try to press any key nothing happens :(
Schermata 2021-03-15 alle 20.14.47.jpg
 
A bit of “self help” training required...

1. Read my user manual for the PETTESTER ROM and see if the checksums correctly correspond from the display to the manual contents for BASIC 4.

If they do, the possible culprit could be the EDIT ROM itself (remember, we swapped this for my PETTESTER ROM).

I still don’t like the keyboard display bytes. There is something wrong with the keyboard PIA.

I would also check the IRQ and NMI signals on the CPU. If either of these are permanently LOW this could also be why BASIC won’t start.

Dave
 
dave_m said:
No, the EDIT ROM should be for a PET with a CRT Controller (assuming you have a 4032).

If you have a 50 Hz system, use a 901498-01 2K binary file.
If you have a 60 Hz system, use a 901499-01 2K binary file.

The sum check for your D ROM is correct.
Click to expand...



I have 4032 pet 50hz with no crtc controller...
 
OK then your file should be OK. Did you make sure to burn it into a 2716 or 2516 (2K). A 4K eprom will not do unless you used a 2732 with data in upper 2K address range.
-dave_m
 
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