New Project on the bench Kenwood KA-5700 Amp

[Mike Sweeney]

I normally work on Marantz gear but I got a good deal on this Kenwood amp and decided to have some fun. Overall, it was clean but dusty with the normal gunk on the controls.

No burned parts and it did work but weakly when I gave it a trial run. When I pulled the filter caps out 6800uf at 42 volts, I tested them. They passed ESR but failed on leak testing.. couldn't get above 20 volts without significant leakage. Like the Marantz units, this is pretty normal from what I've seen. I replaced those with 6800 uf at 80 volts. I might replace them later with a bit more capacitance but this is what I had in the parts bin. All the caps so far have been leaky and now I'm waiting for some non-polarized caps and a new protection relay. I just finished a KD 2070 turntable which will be matched up to this amp when it's done

 

[kaplang]

I went to high school with someone named Kenny Wood. Everyone called him Ken for short.

 

[Mike Sweeney]

Whoot!! Got 95% done enough to bring it up with new caps and relay. Still a few minor caps to swap out but damn it sounds good now. Replaced the lamp witj an LED lamp, deoxit the controls, new relay, diodes, caps. Still need some safety caps to replace thr old ones. She draws .25 amps at 117 volts and 17.5 watts

Just in time for th playoffs

 

[Diathesis]

Nice! I do enjoy listening to mine! Where did you get your LED meter light?

 

[Mike Sweeney]

Bobs Vintage Electronics off Amazon .. I've bought a few things from him before and I've always been happy with it. I could have worked out something from Pepboys etc but this was far easier
https://www.amazon.com/gp/product/B01FO5PEDI

 

[Mike Sweeney]

Done!! Both the KA5500 and KT5500 tuner. Kicks butt and sounds really well.

I replaced the two zeners with new zeners 4005s that i bought years ago from radio. Shack for a past project

I had to replace one of my new led lamps. It was erratic and would flicker. It started after i adjustef vr2 for the stereo led. Mine was at 16 khz instead of the 19 called for. I ened up deoxit the pot then flush it with cleaner then using deoxit shield for the final fix. Now it's 19 khz rock steady. I wasted some time trying to work out why this would mess with the led. It didn't and can't

 

[llwhtt]

I don't think you can replace Zener diodes with 1N4005 rectifier diodes.

Craig

 

[Mike Sweeney]

I probably mis-spoke here with the 1S2076 by calling it a zener.. that was the next line down. This diode is replaced by 1N4005