My Kenwood KA-801 stopped working. Need Help.

[dvd_mi]

I have a Kenwood KA-801 integrated amplifier. Recently I decided to clean up volume potentiometer (with deoxit), because it was producing static noise while turning. Accidentally i broke one of the wires that was connected (with screw) to the chassis, but soldered it back. Now when I try to power it on it doesn't work. There is no light in VU meters and relay (in the middle of the main board) clicks once, but all fuses are OK. I also noticed that when input is connected and volume is all the way up there is some distorted music coming out from the speakers. Please help!!!

 

[diepbtt]

It seems you still lost GND to volume pot so check it with DMM

 

[dvd_mi]

How to check that (sorry for dumb question)? I checked voltage between 25 and 4 and it's 32V AC. I thought it should be DC.

 

[diepbtt]

Sorry i mistake with points 25 of headphone and power supply section. this Kenwood schematics is a messy thing with point indications.

It seems your figure are fine with 32VAC. Check if any lamp gets loose by cleaning or broken wire from power supply to the VU meter board.

Even if one lamp is burnt both lamps will not light since they are in series

 

[dvd_mi]

I checked lamps and they are crimped to the wires, nothing is loose. I also powered them separately with external 8VDC and they both light up, so why there is 32VAC going to them from the board? Also shouldn't amp work even if lamps would be out? Is that relay click a safety thing?

 

[diepbtt]

Hmm something is wrong here.
First check AC voltage between point 5 and 25, how much you get
Further check 3 resistors whether they are Ok (39 Ohm) or burnt/shorted. if they are OK you have AC voltage drop at each resisitor 39 Ohm x 0.15A = 5.85VAC or 17.55 VAC from 3 these resistors
Then check the ac voltage between points 4 and 25 (it should be 14-15VAC) as well as 26 and 25 (it should be 6-8VAC)

 

[diepbtt]

The amp should work normally if the lamps do not light.
Relay click means the power amp section is Ok but it can not use if you still have problem with the pre amp

 

[dvd_mi]

Got it, click is good. Lamps are fixed, one of the wires at bulb itself was shorted. But amp is still not working. You stated that preamp is causing problems how to test that? There is a quiet very distorted music coming out when any input is connected/selected and volume is at 100%?

 

[diepbtt]

How is your amp before your cleaning?

 

[dvd_mi]

It was working fine. Only static noise while turning volume knob.

 

[diepbtt]

It seems you still lost GND at volume pot. re-check the wirings here t Volume pot.

 

[dvd_mi]

I don't know how, but it started working. I left it alone for couple of days and it works now. I also need help with one capacitor. There are two of them. Both are connecting control board to chassis. One is good and one just broke. I know it is 10000pf, but what voltage??? Picture of it is below.