Kenwood 823

[mike49504]

I repaired the power supply in this amp and outputs.

I have rail voltage on outputs and + - on the opamps on the main board i checked the switches and pots But still have no output on left channel.

Wondering where i start checking Left channel is dead

 

[mike49504]

Ok heres what i found on this amp.

If the low pass filter is on both channels produce output. If i turn the low pass filter off left channel is dead.

Bad switch??

 

[Perry Babin]

Check for signal on the switch. Drive signal into the good channel and see which pins have audio. Drive signal into the other channel. Do you have audio on the other row of pins?

This is probably best done with audio or a test signal that has more than one frequency.

 

[mike49504]

I cant find a signal on the switch for either channel.
Unless my scope is set wrong. I have it set on 2us 5v/div

 

[Perry Babin]

2mS, not uS. Try lowering the voltage to 1v. Disconnect the speakers and drive a strong signal into the amp. It will make it easier to see.

 

[mike49504]

Ok i did what u said and The pins on the switch are showing audio on 3 of the pins.(right channel)

Left channel no audio on any of the pins

If i switch it to lowpass filter i have audio on both left and right channel pins of the switch

 

[Perry Babin]

You need to confirm that the left channel signal is reaching the board. Check for signal on the biard just inside the RCA jacks.

Can you email me a photo at the best resolution possible?

babin_perry@yahoo.com

 

[mike49504]

Where do i test for audio?

 

[Perry Babin]

The first place would be on the back of the RCA jacks. Feed signal only into the dead channel input. Place the switch in stereo mode.

 

[mike49504]

Ok i have audio on the back of the rca jacks

 

[Perry Babin]

Check for audio on pins 1 and 7 of all of the op-amps. Drive the signal into the good channel first and make a hote of which pins/op-amps have signal. Then do the same for the other channel Only drive signal into one channel at a time.

 

[mike49504]

Perry,

I traced the audio signal all the way up to the small board . The board with the gain pot power light crossover switch so i have clean audio up to that point but nothing comming back out of the board in full range mode For the left (dead) channel

 

[Perry Babin]

Photos of that board?

 

[mike49504]

Heres the small board i have audio up to for the left channel

 

[Perry Babin]

Do you have both positive and negative regulated voltage on the power supply pins of the op-amps?

Audio on the output pins of any of the op-amps?

 

[mike49504]

Found the problem theese black plugs something wasent making full contact.

I took them out and solderd the leads right to the main board amp powers up and plays fine

 

[mike49504]

Now off to fix my fav amp of all the rockford 1500bd for the 4th time