Repairing a Kenwood C1

[jaybirdss396]

The value isn't real critical, that cap is just there to bleed noise off the power line. But you need a cap rated for "across the line" use.

Something like this is what you want. https://www.mouser.com/ProductDetai...GAEpiMZZMu3dWSqd4Tl0B9%2BtugryrL8fY1J9rQ3QuU=

 

[simpsonsons]

OK awesome, thank you! Would this be appropriate for C2 as well since it is the same value as C1?

I will order tonight. If there are any other parts might be smart to include in order I would appreciate the advice.

Will change C1 and report back asap

 

[jaybirdss396]

Yes that cap would be fine for C2.

 

[jaybirdss396]

It's doubtful C1 is your problem. If it was shorted the breaker supplying the wall outlet would have tripped. If C1 failed open it would still work fine as that is just a noise filter. It's really looking like a fried transformer. If your getting power into the transformer but nothing out that's pretty much all it could be. If you do replace the transformer you need to try and find the root cause of why it failed first. Something after the transformer drew excess current, possibly a bad power supply cap, shorted transistor, etc...

 

[simpsonsons]

ah gotcha. Would it be wise to pull the board then and test all components in the power supply section?

Could have plugging in the power amp to the kenwood caused the excess current draw?

Also... where would I look to get a replacement transformer?

And lastly... if I got a replacement transformer would it be possible to install a fuse to protect it while I test out the main issue?

EDIT* As for the cause... hmm it was stored in a rather humid basement so I suppose also the transformer could have simply rusted out? Sounds like maybe I should pull the transformer and test for continuity and maybe also look for a thermal fuse.

 

[jaybirdss396]

Plugging that amp in shouldn't have effected the transformer, it's probably just coincidence. Yes I would pull the transformer and ohm it out. Probably be easiest to find a used transformer, maybe put a WTB ad in Barter Town. You could easily put a fuse in line with the primary of the power transformer, 1.5amp should be fine.

Yes it would be a good idea to check components in the power supply section.

I have one of these preamps that I bought used after it had been sitting a long time. When I first plugged it in one of the ICs in the phono stage shorted out and took out some neighboring transistors and resistors. I think I remember seeing a few other people with that same problem too, so that's something else to check.

 

[simpsonsons]

got it. Yeahh thinking coincidence too.

thanks for the barter town tip!


thanks will check phono stage too. I *think* it has its own power section so could easily be that



Will report back when I have been able to test everything. Thank you for the help from this community! Really appreciate it.

 

[simpsonsons]

Well. I removed the transformer and it did indeed test as OL. I dug around in it to look for a thermal fuse but could not find one. I may have located the short... but unfortunately cut the secondary winding with my screwdriver so its trash now anyway...

So do indeed need to find a new transformer. Is my only hope to source one from a broken c1? Im trying to nail down the stats for this step down transformer but am having trouble reading the schematic, not sure if anyone has some advice.