Hi The ‘bodge’ is a 30 year old ‘oops’ and should be present, if I remember they are both ground wires :) They have been on every T102 I have looked at but perhaps they fixed the board layout in the newer runs so I would not like to claim it was standard.
You may have already tried these options but…. Have you tried the RAMTST.BA or RAMCHK.BA utilities to check the SRAM is OK? They are available at http://www.club100.org/library/libutl.html The T102 PCB is not very good quality and traces tend to develop micro-cracks after a while, it could be that one of the lines to an SRAM is cracked? I had that issue with a T102 where a trace to the reset capacitor was cracked, only discovered after some continuity testing. The bad trace meant the T102 only started after power on with a push of the reset button. I assume you have checked the +5V is good as are –5V and VB? None of the Electrolytic caps have leaked? If voltage levels are not quite right some of the chips will not operate correctly and may exhibit weird behaviors. One tedious option is to use a magnifying glass to inspect all the through hole part solder joints. Again I have found areas of a board that had not been reflowed properly causing dry joints on a board that had been working. In this case it was the Clock IC which had the bad joints causing the clock to produce odd results and a few other things to fail. From: M100 <[email protected]<mailto:[email protected]>> on behalf of Josh Malone <[email protected]<mailto:[email protected]>> Reply-To: <[email protected]<mailto:[email protected]>> Date: Monday, September 25, 2017 at 7:32 AM To: Model 100 Discussion <[email protected]<mailto:[email protected]>> Subject: [M100] M102 weird behavior and bodge wires All, I'm trying to track down the source of odd behavior in my 102. It's had a long history of memory problems that I thought I had resolved by replacing the decoder IC. Some time after that, it developed an issue where trying to load CO exes via basic loaders would cold-start the system and it would boot reporting only 8k installed. Greg suggested a bad solder joint, so I reflowed all the RAM and decoder joints on the board. THis has changed the behavior a bit. This time I was able to load TSD.DO via telcom, but "load"ing it into BASIC cold-started the machine to reporting ~11k free. Also, while soldering the RAMs I noticed what looks to be a very bad bodge on the printer port. These 2 are clearly making contact (verified w/ meter). The top wire goes to a cap to ground, the bottom one runs to a pin on an IC that I didn't bother checking. Are these normal on a 102? https://drive.google.com/file/d/0BwcKlz5N5PLcYnR6XzZPYlpyRDNXNWo2THhPYURpMlQzZWc4/view?usp=sharing Thanks, -Josh
