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CWJ_Wilko
December 23rd, 2016, 01:38 AM
Hi all, first post here. Hoping someone can help.

I've just picked up a Toshiba T3200, and while it's in great cosmetic condition, I'm getting this error message and total system halt on power on with BIOS tones:

xxx ERROR DETECTED, ERROR CODE=C3: Mem (base 64KB) fixed data error
xxxx ERROR ADDRESS = 000000
xxxx ERROR PATTERN = 0000

I repair old Apple ][s as a past-time so this isn't totally unfamiliar, but hoping someone could at least narrow this down to whether its the RAM or ROM? As I understand it, The T3200 has 64kb of ROM, which lines up with the 'base 64kb' in this message. I would have assumed that the RAM would be more likely a culprit though?

Anyway will open it up after Xmas and take a look, hoping the problem is obvious...

modem7
December 23rd, 2016, 12:35 PM
Hi all, first post here. Hoping someone can help.
Welcome to these forums.


... but hoping someone could at least narrow this down to whether its the RAM or ROM? As I understand it, The T3200 has 64kb of ROM, which lines up with the 'base 64kb' in this message. I would have assumed that the RAM would be more likely a culprit though?
The maintenance manual for the T3200 is at [here (http://minuszerodegrees.net/manuals/Toshiba/Toshiba.htm#3200)].
In that manual, the error that you are seeing is shown on page 2-15, and relates to RAM (RAM and associated circuitry).
A (crude) check of the ROM is done earlier at check 94.

CWJ_Wilko
December 23rd, 2016, 08:38 PM
Thanks for the reply modem7. Great to see another Aussie here as well.

That's the answer I was hoping for. I did find that page in the maintenance manual but didn't understand the error message, specifically regarding "base 64K" which I thought might refer to the top of memory, which I assumed would be the 64k of ROM.

I'll obviously know more once I start pulling it apart, hoping it's an easy fix. If I need replacement RAM for the 3200, where would I start looking? As I understand it, the first 1mb of RAM in the 3200 is non-removable.

Cheers

modem7
December 25th, 2016, 03:24 PM
That's the answer I was hoping for. I did find that page in the maintenance manual but didn't understand the error message, specifically regarding "base 64K" which I thought might refer to the top of memory, which I assumed would be the 64k of ROM.
In PC's and clones, interrupt vectors and the BIOS data area (BDA) are stored at the start of RAM. And so what one typically sees in the Power-On Self Test (POST) of PC's and clones, is an early check of the start of RAM (the 'base' of RAM) before the POST starts using that RAM. Later, the POST will check the remainder of RAM.


I'll obviously know more once I start pulling it apart, hoping it's an easy fix.
You may have seen that the T3200 maintenance manual is of no help in regard to the particular error message that you are seeing - Toshiba indicate that the rectification action is to, "Replace the system PCB."

So, hopefully a reseat of any chips that can be reseated is the fix.


If I need replacement RAM for the 3200, where would I start looking? As I understand it, the first 1mb of RAM in the 3200 is non-removable.
Of the error message, the "ERROR PATTERN = 0000" bit indicates that none of the 16 data bits are in error. Sometimes, that is an indicator that a parity bit has failed. But a cause could also be the RAM support circuitry.

So replacing the system board hosted RAM (minus video related RAM) is a gamble.

As for identifying which system board chips are RAM, I see that the maintenance manual has a chip identification diagram on pages 5-3 and 5-5.
The diagram on 5-3 shows the video RAM ("V-RAM") and "Advanced Graphics Subsystem" RAM ("AGS RAM"),
The diagram on 5-5 shows the RAM that you are seeking ("System RAM").

As for the system RAM shown on the 5-5 diagram, I see no bit breakdown (parity, data0, data1, data2, ...). That is expected, because Toshiba are not expecting field technicians to do board level repair.