C128 PSU - Help identifying a component pls as trying to repair supply.

[TonyGoose]

Hello.

Just registered here in hopes someone can help me with a PSU repair I lumbered myself with.
It's an external supply part number 310416-02 for a flat type C128. 240V AC in, 9V AC and 5V DC out.
I don't have the machine here just the supply and only info I was given is it keeps blowing fuses.

Initial findings as follows :-
Both internal fuses blown T1.4A and T315mA
2 fusible links (I assume that's what they were) missing / blown apart or similar.
Dry solder joint on the board for a transformer primary coil connection.
13 Amp fuse in plug    surprisingly not blown 

Guess a picture of what I'm on about might help here so have attached one here somewhere :-



So far done as follows :-

Put fusible links back in using some 5A fuse wire.
Re-soldered the dried out transformer joint.
Removed the output cable for now and checked for short circuits.
Replaced both the blown internal fuses and swapped 13A fuse in plug for a 2A one.

Plugged in to test and as soon as mains switched on just the T315mA fuse blew straight away.

Have removed the transformer and checked for short circuits but seems ok.

In my limited experience with power supplies it's generally duff capacitors causing problems.
So figured cheap enough so may as well just replace the lot.
Searching around here got to a circuit diagram for the supply but sadly no component values.

As a result left wondering what the silvery colour thing is next to the 2200uF 35V electrolytic capacitor.
Looks like a capacitor and similar size and shape to its neighbour but no markings on it anywhere.
There's a + sign under it next to one of its mounting holes and quick test shows continuity in one direction only.

So, can anybody tell me for sure what it is ?  Also any tips on best way to progress next ?

Apologies if I'm being stupidly dense.

Cheers
TG

[hoss48458]

Here`s a link to a external power supply for the 128,  this will help a little.


http://www.zimmers.net/anonftp/pub/cbm/schematics/computers/c128/power/ps-128.gif

[TonyGoose]

Thanks for replying to my post.

That's the diagram I mentioned I found but unfortunately no component values.

Cheers
TG

[hoss48458]

sorry about that,  heres a link to a complete 128 diagram,  info for the power supply within includeing part numers and layout and values,  hope this helps.

you should check the main tranisistor on the heatsink,  its probalble shorted,  start there.

http://www.bombjack.org/commodore/books/pdf/SAMS_Computerfacts_(CC18)_C128.zip