A500 stuck on grey/white screen

[dougal]

This is one of my spare A500 boards. Its a Rev6A.

When switched on it gets stuck on a grey/white screen.

I used a good power supply and connected just a floppy drive to it. I have tried with and without the floppy drive. Also tried it with and without the 512K Ram expansion.

I've also done the 1MB Chipram fix. Same with & without the fix and with & without expansion board.

Tried re-seating the socketed chips and switching the CIA's. Also tried replacing PAULA, DENISE, CPU, KICKSTART & GARRY. The only chip I have NOT tried replacing is the AGNUS because from the spares I have one of them is most likely dead and the other is an 8375 from an A500 plus which is not compatible. But i did remove it properly and re-seat it again.

What I can say is that i plugged in an Action Reply MKIII and when i press the FREEZE button most times it takes me to the Action Replay screen though i did not type anything as i did not have a keyboard plugged in.

The motherboard looks good and there is no visable damage anywhere. It worked fine for years until recently.

 

[Chinners]

If it's of any help to you, I have a complete set of socketed chips from a R6 motherboard I could send to you for postage... although it appears you have tried swapping all the chips out.

The board was working when I extracted them, but it took up too much space

 

[dougal]

If it's of any help to you, I have a complete set of socketed chips from a R6 motherboard I could send to you for postage... although it appears you have tried swapping all the chips out.

The board was working when I extracted them, but it took up too much space

It's possible that my spare PAULA is faulty. But i could be sure by swapping from a known good A500 board before asking you for yours.

Will give it a go and let you know.. Cheers

 

[rkauer]

Normally a grey/white screen is caused by a faulty Agnus.

 

[woodycool]

This happened to my A500+ when the battery leaked

 

[dougal]

Fixed!!

Was a faulty CIA

 

[Chinners]

Well, I suppose I'll offer the chips I salvaged here for someone else if they are not needed

 

[dougal]

Well, I suppose I'll offer the chips I salvaged here for someone else if they are not needed

Yes thanks for the offer .. Its still temperamental and won't always work but i doubt its a chip.

Could it be faulty caps? When i switch it off it makes a squeaking sound from the speakers. Sounds like a capacitor/s problem no ?

Update: I cleaned around one of the CAPS (C816) and it is working much better now. So far it booted every time

Also note: I accidentally broke of one of the pins from the 8372A Agnus. But the Amiga is working perfectly. This should not be a problem no ?

 

[rkauer]

Agnus have a few unused pins. If it's working, don't worry. Also some pins are redundant earth.