I1 repeating error with Diag Cart

Problems with your machine in general.
Post Reply
PhilC
Trusted Guru
Trusted Guru
Posts: 1435
Joined: Fri Mar 23, 2018 8:22 pm

I1 repeating error with Diag Cart

Post by PhilC » Fri May 03, 2019 8:06 pm

Hi All,

Two of the boards that I got the other day have the same error when booting, white border with black screen which is usually memory as you know.

Putting the diag cart into the board gives me the following error codes repeatedly
Capture.PNG
Capture.PNG (11.05 KiB) Viewed 213 times
The vague description in the service manual says a data line is stuck. Do you guys have any idea whether this means its stuck in 1 or 0 state, as in faulty ram or maybe corroded contacts etc. In fairness, these two boards look pretty good, so I suspect I just have a dodgy ram chip.

User avatar
exxos
Site Admin
Site Admin
Posts: 6857
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: I1 repeating error with Diag Cart

Post by exxos » Fri May 03, 2019 8:28 pm

Id assume the 1 is the error, but never seen that screen before.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

PhilC
Trusted Guru
Trusted Guru
Posts: 1435
Joined: Fri Mar 23, 2018 8:22 pm

Re: I1 repeating error with Diag Cart

Post by PhilC » Fri May 03, 2019 9:47 pm

It looks like its something to do with CAS not pulsing on the higher bank? CAS stays high all the time.

User avatar
exxos
Site Admin
Site Admin
Posts: 6857
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: I1 repeating error with Diag Cart

Post by exxos » Fri May 03, 2019 10:00 pm

If its a 16 chip RAM bank, then likely you have bad ram chip, whichever is going to bit 14 by the looks of it.
4MB STFM 1.44 FD- VELOCE+ 020 STE - 4MB STE 32MHz - STFM 16MHz - STM - MEGA ST - Falcon 030 CT60 - Atari 2600 - Atari 7800 - Gigafile - SD Floppy Emulator - PeST - HxC - CosmosEx - Ultrasatan - various clutter

https://www.exxoshost.co.uk/atari/ All my hardware guides - mods - games - STOS
https://www.exxoshost.co.uk/atari/last/storenew/ - All my hardware mods for sale - Please help support by making a purchase.

PhilC
Trusted Guru
Trusted Guru
Posts: 1435
Joined: Fri Mar 23, 2018 8:22 pm

Re: I1 repeating error with Diag Cart

Post by PhilC » Fri May 03, 2019 10:05 pm

Ok, that explains the error message, cool, thanks for that exxos.

Now to track it down (well, maybe tomorrow anyway)

czietz
Posts: 90
Joined: Sun Jan 14, 2018 1:02 pm

Re: I1 repeating error with Diag Cart

Post by czietz » Sat May 04, 2019 1:35 pm

Like exxos said: Probably the RAM chip for bit 14 is faulty. Other possible causes are the buffer (74xx244) or latch (74xx373) responsible for that bit. Due to the multitude of Atari board layouts it's not possible to give you the component designators, though. If in doubt, look into the schematic and trace it on the board.

PhilC
Trusted Guru
Trusted Guru
Posts: 1435
Joined: Fri Mar 23, 2018 8:22 pm

Re: I1 repeating error with Diag Cart

Post by PhilC » Sat May 04, 2019 2:07 pm

Thank you, yes I've looked and just need time with the scope to verify which chips against the schematic.

All part of the learning process.

Post Reply