Hi banman, these docs are really helpful. I'll review these signals and compare with my working machine.
Repair and soldering video also is awesome! Great explanation, thank you so much.
Search found 31 matches
- Wed Aug 10, 2022 9:47 am
- Forum: Help!
- Topic: c64 - ASSY 250425 Black Screen
- Replies: 86
- Views: 12491
- Wed Jul 27, 2022 3:42 pm
- Forum: Help!
- Topic: c64 - ASSY 250425 Black Screen
- Replies: 86
- Views: 12491
Re: c64 - ASSY 250425 Black Screen
Hi, it was the MPU pin 16
- Mon Jul 25, 2022 8:14 pm
- Forum: Help!
- Topic: c64 - ASSY 250425 Black Screen
- Replies: 86
- Views: 12491
Re: c64 - ASSY 250425 Black Screen
Hello, Here some facts so far: 1) I've tested the voltages in the board and they are OK. 2) During the ICs pull of process always the pin 15 (S/LUM) of VIC II chip remains LOW (no signal) 3) MPU, SID, CIA1, CIA2, PLA, VIC II, RAM Memories (x8), 74LS257 (U13 and U25), 3 ROMS (Kernal, Basic, Chars), U...
- Tue Jul 19, 2022 7:18 pm
- Forum: Help!
- Topic: c64 - ASSY 250425 Black Screen
- Replies: 86
- Views: 12491
Re: c64 - ASSY 250425 Black Screen
I forgot to mention that the Dead Test don't flashes as usual, in all the process of removing or putting chips
- Tue Jul 19, 2022 6:45 pm
- Forum: Help!
- Topic: c64 - ASSY 250425 Black Screen
- Replies: 86
- Views: 12491
Re: c64 - ASSY 250425 Black Screen
Hi, Just to tell you that if I remove all chips as you mentioned only with MPU/VIC/PLA + clock 8701 + 556 (for ready signal) and with the Dead Test Cartridge, a periodically signal appears on pin 38. Even putting all chips this signal remains while Dead Test Cart. is connected. MPU pin 15 in YELLOW ...
- Tue Jul 19, 2022 11:20 am
- Forum: Help!
- Topic: c64 - ASSY 250425 Black Screen
- Replies: 86
- Views: 12491
Re: c64 - ASSY 250425 Black Screen
Ok, I will try this approach this afternoon. The good thing is that I have all IC socketed at this point. I really need to fix it, I'm learning and trying it for more than 1 year so far :S , and I'm getting almost crazy! - "Have you been testing the pins on the VIC II chip as you run your obser...
- Mon Jul 18, 2022 8:57 pm
- Forum: Help!
- Topic: c64 - ASSY 250425 Black Screen
- Replies: 86
- Views: 12491
Re: c64 - ASSY 250425 Black Screen
Hello, many thank you for your effort and help, I really appreciate it. Well, I spent time trying to identify if something change checking MPU pins removing one by one the chips as you suggested, but nothing has changed, so I decided to continue removing more and more, and at the end with only MPU, ...
- Sun Jul 17, 2022 11:12 am
- Forum: Help!
- Topic: c64 - ASSY 250425 Black Screen
- Replies: 86
- Views: 12491
Re: c64 - ASSY 250425 Black Screen
Pin 29 nothing special pin29.png Pin 38 , interesting thing: 1) A similar pulse of yours appears on startup, but after a second no more pulses comes: pin38.png In 2us here is the pic on start up also... pin38 2us.png 2) Finally, if I put my Dead Test cartridge, then pin 38 have this pulse periodica...
- Sun Jul 17, 2022 11:04 am
- Forum: Help!
- Topic: c64 - ASSY 250425 Black Screen
- Replies: 86
- Views: 12491
Re: c64 - ASSY 250425 Black Screen
Hello! I removed the SID and take some measures as you suggested. Here are the results: Pin 15 It seems to have some quick activity on start up, and after a second go high as usual. Here is the pic during this period, some time is a almost 4v square signal, sometimes it looks like different. pin15.p...
- Tue Jul 12, 2022 4:58 pm
- Forum: Help!
- Topic: c64 - ASSY 250425 Black Screen
- Replies: 86
- Views: 12491
Re: c64 - ASSY 250425 Black Screen
Hi, I share here two more videos: 1) Test MPU pins using the 6510 chip from the good board (c64-2) in my bad board c64-1 https://www.youtube.com/watch?v=DVDgqSwKKwc I think I got similar results... 2) Second video just pins 9,10,11 and 12, removing the logic chips. https://www.youtube.com/watch?v=aj...