Seduction build issues - please help!

[tristan]

Hi all,

I finished my build of the Seduction with CS4 upgrade last night. Resistance checks were all ok, everything looked to be in the right place. I failed to notice that I had oriented the 220uf 200V capacitor for terminals 11 and 12 around the wrong way (don't ask me how, it's probably the most obviously marked polarised component I've ever had to put into anything) and so I switched it on (with this cap in the wrong way) to do my voltage checks. So, small glow on the tubes, a bit of smoke and I had the Seduction switched off pretty quickly. This morning I replaced the two very obviously burnt out 1K 1/2W resistors (I replaced them with 1/2W Metal Film types, I don't know if this is an issue or not? It was all that I could get my hands on) and I also replaced the 270K 1W, though this one seemed unaffected.

I reoriented the 220uf cap on terminals 11 and 12 (correctly this time), and, after replacing the affected resistors, did my resistance checks again. Again, everything ok, so I proceeded to the voltage checks. The tubes glow very dimly and the LEDs seem to glow fine, however the voltages are far lower than what they are meant to be for example:

Terminal 12 reads 75VDC instead of 135VDC
T 15 reads 100VDC instead of 148VDC
T 25 reads 140VDC instead of 160VDC
T 27, 37 read 12 (!)
T 29, 39 read 3
T 30, 40 read 2.6
T 33, 44 read 75
A1, B1 read 12

Terminals 6 - 11 read fine and I haven't checked the rest yet.

Is there something else I may have burnt out by having that cap in the wrong way the first time? Would the UF4007 diodes be ok or would they likely need replacing? Or is it more likely that I just have a bad solder joint somewhere?

Any help would be appreciated!

thanks,
Tristan.

[Paul Birkeland]

E-mail Eileen at queen(at)bottlehead(dot)com and let her know that you need replacement power supply caps for a Seduction, she will send a few out for you free of charge.

The low voltage could be an iffy cap, or it could be that the 270k resistor you inserted into the circuit might be some lower value that is drawing too much current.  I'd put the original resistor in, it should be just fine.

The 1k 1/2 watt metal film resistors are acceptable substitutes. 

By any chance, was the reversed capacitor the one closest to the two UF-4007 diodes?

[tristan]

Hi there, thanks for your quick reply!

The cap I put in backwards was actually the furthest from the diodes, where the shielded wire connects from the cap to the other parts of the circuit. Do you think that the diodes would be affected?

Tristan.

[Paul Birkeland]

Nope, the diodes will be fine. The cap you flipped around needs to go in the trash though.

[Grainger49]

Just a little information, the cap that was backward was the last of the chain.  The diodes saw some high current but not enough to harm them.  The same thing goes for the first two caps, they are probably just fine but that last cap, it is toast.  Even if it measures well now it has been seriously molested and now is the time to get it replaced.  Otherwise it is going to bite you in the butt in a week or so.

[tristan]

Thanks so much for your help. I just wanted to check that it wasn't likely I damaged the diodes. You both confirmed what I thought I understood about what was likely affected. I've emailed Eileen about obtaining some replacement capacitors and I'll see how I go.

thanks again,
Tristan.