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Ok, swapped the ROM and it's the same. So the Mega II is the problem. Time to find another board. Thanks everyone for your help! Pitou!

on a socket

CTRL-RESET doesn't drop me into BASIC. It just restart over again (like a power on) Thanks very much for the explanation Gorgonops. I found a ROM replacement on ebay. I'm gonna try that and if it doesn't work, then the Mega II is the culprit. I'm gonna swap the main board. Thanks very much for...

@Elfen, oh I'm very sorry, I was talking about pins on the ROM, not the Mega II. Sorry again for the confusion.

I already checked all pins with an oscilloscope. Continuity is good. Signals seem to be on all pins except for 1,2,4 and 6 if I remember correctly. Again, I'm not sure what to expect on these lines. As for schematics, yes I have them, I even did post them on post #12 of this thread if you want...

I'm not able to get into Applesoft BASIC using ctrl-reset. I also tried running BASIC from a system disk. See this video. test.zip Any idea? Pitou!

@Gorgonops, ok thanks, will try that. I have another question about the ROM chip. it's a 128kx8, so it needs 17 lines of addresses in order to access the entire memory of the rom. The 65SC816 processor seems to be a 24-bit address bus. So not a problem. However, by looking at schematic, only...

@Elfen, very good suggestion, I would try that for sure. However, with no drive connected , it stays on "Check status device" and a kind of bar run from left to right and right to left, like in the 3rd picture on 1st post. Actually I don't know how to drop into AppleSoft BASIC. Any clue...

Well it's hard to tell if it's the ROM chip or the Mega II. I also played around with the scope and followed the schematics, but I'm not able to pinpoint the root cause. Here they are if you are curious :) Schematic Diagram of the Apple IIgs.pdf I can desolder the Mega II if I find another...

I tried reseating the chips and no luck. I'm not sure how to clean the sockets honestly. The problem is also present on the composite output. The monitor is an Apple RGB monitor model A2M6014 I tried the Self test and it seems to stop on that screen. Please note that all characters text in...

I thought about this. Can you tell me which one is it? Just so you know, I also replaced the VGC chip and it made no difference. Thanks!! Pitou

Hello, I have an issue with an Apple IIgs. The text is kind of doubled in Text mode. When I boot a system disk, in graphic mode, everything is fine. I have some experience in electronics and can also solder. I would like to repair it actually. Just to make sure, I tried the monitor on another...