Help with dead Commodore 1802

[roadrash]

Re: Help with dead Commodore 1802

just a thought, check the mains smoothing cap - the big electrolytic.

I temoved it and my component tester says consistanty its around 54nf when it should be 150uf 400wv. I still have this resistor showing a dead short that isba red,purple,silver,silver

[stj]

Re: Help with dead Commodore 1802

red purple silver silver is 2.7ohms 10% i think - that's probably less than your test-leads, so it's fine

[roadrash]

Re: Help with dead Commodore 1802

So if that filter cap is 54nf is it ok? Its marked as 150uf and 400wv. Isn't 54nf nano farad?

[stj]

Re: Help with dead Commodore 1802

yes, it's fuckered as AVE would say!
that could have been the fault.

[R_J]

Re: Help with dead Commodore 1802

That main cap. being open would cause the problem. I had a power smps recently that had a near open main filter and it would blow the main fuse even though everything else (fet etc.) checked ok. All I needed to replace was the main filter and the power supply worked.

[roadrash]

Re: Help with dead Commodore 1802

Right so I just use a 150uf 400v one then?
What is 400wv or is that just volts?

[R_J]

Re: Help with dead Commodore 1802

WV= Working Voltage. Thats how they some were marked in the past. it just means Voltage rating of the cap.

[stj]

Re: Help with dead Commodore 1802

you can use 450v if it helps it fit the board better

a rubicon BXW series is probably a good choice if the size matches.

[Agent24]

Re: Help with dead Commodore 1802

WV= Working Voltage. Thats how they some were marked in the past. it just means Voltage rating of the cap.

Some older capacitors may also have two voltage markings; WV for Working Voltage, and SV for Surge Voltage.

[stj]

Re: Help with dead Commodore 1802

try tweeking the focus control - if you know your cables are well shielded

[stj]

Re: Help with dead Commodore 1802

focus can drift as components age - try ajusting it.

[roadrash]

Re: Help with dead Commodore 1802

At last the replacement capacitor arrived.
Ive soldered it in a plugged it in and nothong happened and neither of the light bulbs we soldered in lit up. Should they have? Should i remove that bulb bridging where the resistor was and solder back in the resistor now.

[stj]

Re: Help with dead Commodore 1802

check your fuses - the lamps should do something even if the cap was not fitted

[roadrash]

Re: Help with dead Commodore 1802

check your fuses - the lamps should do something even if the cap was not fitted

There is 250v ac entering the psu and the fuse is ok.

[stj]

Re: Help with dead Commodore 1802

refit / connect everything other than the big resistor and try.

[roadrash]

Re: Help with dead Commodore 1802

refit / connect everything other than the big resistor and try.

Ok done that and it powered up without blowing anything but can see anything like the power light iluminate but at least i dont think anything blew.

[roadrash]

Re: Help with dead Commodore 1802

Ok done that and it powered up without blowing anything but can see anything like the power light iluminate but at least i dont think anything blew.

That was a bit unclear. Ive plugged it in and its taken power without blowing anything so thats got to be good. I still have the light bulb in place instead of the big resistor but I removed the light bulb and soldered back in the coil. I can sometimes faintly hear something when i turn it on but otherwise it doesnt do anything.

[stj]

Re: Help with dead Commodore 1802

so the only lamp is inplace of the inrush resistor?
then it should be glowing.

[roadrash]

Re: Help with dead Commodore 1802

so the only lamp is inplace of the inrush resistor?
then it should be glowing.

No the lamp thats in place of the resistor doesnt glow and the heater on the tube isnt glowing either.

[stj]

Re: Help with dead Commodore 1802

i'll go over the schematic again on saturday