Amiga 600 Power Issue - Help required.

[slimf]

Hi Everyone..

Just hoping for a little help..

I have been  recapping some Amiga's and one of my Amiga's has a power issue. The  miggy wasn't working when I got it so Ive done a bit of digging.

The Amiga 600 is a REV 1.5 - and the circuit diagram attached with voltages is taken from the 1.5 circuit diagram.

This is with a KNOWN good Power supply.

The voltages are all over the place.

Ive checked the inductors - they are all 1.2ohms which seems about right.

Any clues? This board has been recapped - However it made no difference to this power problem.

I  have removed a few of the caps on the under side of the board (C800)  and it tested fine. The others would appear to be OK, but if I had more  of a clue as to the problem I could remove the others and test out of  circuit.

Any help appreciated.

[slimf]

Thanks for the tip Robert.. Your clue about floating ground helped a lot.

I did a check over the board - Its solid as. So I got stuck in with the multimeter.. Seems there was a break somwhere between the ground pin on the power socket and the inductor. Causing the floating ground.

I was able to rectify by putting a temporary jumper (see pic)

The trace that connects these two points is short, and on the top side of the board and is almost 100% covered by the inductor and the power socket.

After putting the temporary wire in place, the miggy fired up - probably for the first time in 18 years.

:-)

Now I just need to decide how to fix permanently - Either find some fine wire and replace the temporary wire or to desolder both the power socket and inductor in an attempt to find the break.

Advice?

[slimf]

I had already resoldered all the joints on the power socket and inductor - So must be broken track under the power socket on top side of board.

Ive replaced the wire jumper with a much smaller guage wire and neatened it all up.. Just put back into the case and booted workbench 3.1.  :-)

Now onto recapping my next Amiga.. At least the rest work.