Dead TT030 Repair

[grunwald]

I have used Idolon Tech Keypad-Fix before and it worked fairly well. Do not however accidently spill it over a video card. It doesn't end well.. :D

keyboard repair.jpg

[grunwald]

No new updates on the ST ram board issue. I did find that although the system will boot up with the 2mb plugged in (but not recognized), it will not boot with a 8mb card. I get the vertical bars and a "I2" Ram Disturbance error through the RS232. I have toned every data, address, and control line from the ram card sockets back through the motherboard. One thing occured to me this weekend was that this unit and another, came to me with CaTTamaran accelerators attached about six years ago. I removed the CaTT units and reattached the cut leads when I first began to troubleshoot the boards. I am wondering if I missed something on this motherboard that might be related.....

20240612_204334.jpg

[pakman]

Been out of town for a bit and just getting back on this project. I verified that the BNK5 and SEL lines on both of the MMUs (Mother board and Ram board), were properly pulled up or down accordingly. Jumping 1/2 on the RAM board's W1 Jumper connects BKN5 to SEL and pulls it high. This is what triggers the I5 error when booting into the Diagnostic cartridge. Without the cartridge, the system will boot normally, but will not recognize the extra 2Mb of Ram. Does anyone know how Configuration Register at FF8000 interacts with the BNK5/SEL lines to shift memory banks? Also, does anyone know what the Diag. Cart is checking for immediately after it displays "Hello World"? That may provide a clue what is stopping the system from recognizing the 2Mb board. The one other issue I found was when booted to the desktop, hitting Ctrl/Alt/Del does nothing. Not sure if this is connected. Other than these issues, everything else on the system seems to be working properly. This fault seems to be somewhat unique given that I have not found a single reference to the "I5 Error" on any of the Atari boards.

How about progress on this issue?

[grunwald]

I have been traveling for work over the last few weeks and have not had time to continue the quest. I am still poring over the schematics in search of a specific control line that could cause the symptoms noted. I suspect it has something to do with the bank select lines, but have not found the root cause. I am open to any and all suggestions! :)

[Steve]

@grunwald In the last few years the Thunder/Storm team re-created their own TT booster called the SpeedyTT. I think that the kind of knowledge and insight they posses might be very helpful to you. Have you tried asking Matthias for his advice? His email is Thunderstorm@tuxie.de

[pakman]

I am open to any and all suggestions! :)

Let's do following test:
- Install a known good 2MB STRAM card and switch on your TT.
- According to earlier tests you did I expect the additional STRAM won't be detected by TOS. So far so good..
- Please run YARTTT.TOS (https://www.chzsoft.de/site/site/assets ... rt0231.zip) in manual mode and check some address range which relates to the STRAM extension board (let's say from 0x00300000 to 0x00301000). What is the result?

[grunwald]

I am out of town until Friday, but will try it this weekend. Thanks!

[grunwald]

I ran the test from 300000 - 3010000. The error was consistant until I reached 300ea6 where it began to go erratic. See attached:

[pakman]

I ran the test from 300000 - 3010000. The error was consistant until I reached 300ea6 where it began to go erratic. See attached:

Ok, I will have a look at it later, may take some time..

Meanwhile let's make sure that the STRAM on the mainboard works properly.
Please run YARTTT again, this time in "S" mode, thus testing the whole STRAM which has been identified by TOS.

[grunwald]

I actually did that prior to running manual mode. It ran for over 100 passes with no errors. All of the onboard ram has been replaced with new drams.