Dead 1200 Motherboard

chiark

AmiNerd
Joined
Jan 22, 2008
Posts
2,685
Country
United Kingdom
Region
Yorkshire
Evenin' all :)

My 1200 has been a little intermittent recently, and has now finally refused to turn on. Damn :D

It's a 1D4 revision board with rev 0 budgie and 3.1 ROMS, and I was using it with a blizzard 1230 IV with 32MB ram, and a CF card on an adapter.

I've stripped it and found something foul smelling and sticky on the motherboard board, though it's not from a capacitor: I'd guess it was years old coffee :D.

There's also corrosion in the upper kickstart socket, though from what I cannot tell. It might have been towered in its life I guess, and had a battery leak onto it? Who knows.

There's also a resistor from 1 pad of XC3 to XU3 but this appears to be common to all 1d4 boards. Truly a butcher job though.
Caps all appear fine with no leaks, no explosions, no bulges. Sound was working fine when it worked :D

Anyhow, it's now refusing to power up completely. I've cleaned thoroughly with isopropyl alcohol, and it's still dead.

My suspicions are something in the video circuitry, as sometimes when it did work it would flash blue bars on the initial boot...

Any clues before I put it in the dishwasher? :D
 

chiark

AmiNerd
Joined
Jan 22, 2008
Posts
2,685
Country
United Kingdom
Region
Yorkshire
Damn it, I wish I knew that before ! :D

I am strongly suspecting either a short on the board or a dry joint. The dry joint on SMT is going to be a complete swine to find.

It's just worked. Five times in a row.
 

chiark

AmiNerd
Joined
Jan 22, 2008
Posts
2,685
Country
United Kingdom
Region
Yorkshire
And now the display has collapsed itself down to about 1 inch in the middle of the screen.

(the screen is fine with other amigas - it's on a switchbox and the 1000 output works perfectly)

This could get annoying.

---------- Post added at 18:20 ---------- Previous post was at 16:46 ----------

Perhaps, just perhaps, it's started working again? Perhaps something wasn't quite dry from the isopropyl?

It's working now. Almost reliably. Thing is, I know if I build it back into the case it'll bloody stop working again...
 

chiark

AmiNerd
Joined
Jan 22, 2008
Posts
2,685
Country
United Kingdom
Region
Yorkshire
The patient is back together completely, and fully working :D

Only slight fly in the ointment is that my elbox eide'99 is being "strange" - it's holding the IDE activity light high (but working perfectly apart from that!). The cd adaptor is one of these ones that reports no activity on the IDE chain... And when plugged directly into the mobo doesn't illuminate the light.

I shall put it down to "one of those things".
 
Top Bottom