H/K Citation Twenty Two Problems

[scootchu]

I picked up a Harman Kardon Citation 22 Amp for pretty much a song because it has issues.

Problems: No sound, No level meter activity, blown left channel fuse.

I have 14.9 mv coming out of the right channel with no input to the amp. I also have no sound whatsoever out of the right channel when feeding it a signal.

What I have done so far:
Disconnected the left channel transformer from the board and fired the amp up. No blown fuse, so I am assuming the left transformer is okay and not shorted.

Checked the main driver board for cracks, scorched parts, lifted traces, bad solder and it pretty much looked to be okay.

Desoldered the pre-driver board which connected to the main board in a perpendicular manner. Checked if for the same and it too looked okay. Re-soldered it.

Checked the rectifiers against each other and they both check out the same, which leads me to believe that they are okay.


Now I am not that adept at systematic troubleshooting when it comes to amps, so please humor me.

Questions:
Do I now start checking the output drivers?
I am asumming the amp has two discreet paths, so why no sound out of the right channel if I show 14.9mv? I was guessing that one of the transformers powered the predriver circuit, but I am probably wrong.

I have the service manual and would appreciate any help I can get to get this amp up and sounding sweet. I want the power it has to run my Polk SDA-SRS II's
Thanks
Scott

[scootchu]

Anyone?

[PhantomBox]

Hi.
I have the same amplifier (H/K Citation 22). A reasent power spike (115VAC) blew one fuse, and something else. I just don't know what exactly this "else" is.
With the blown fuse, the power indicator (HIGH VOLTAGE led) is on, and that's about it: no sound at all.
Maybe you fixed your amp in the meatime? Could you give me a hint on what you finally did, I mean after all these tests?
I'm not so great at fixing these kind of amps, either.

Any comment appreciated, and thanks.

[scootchu]

I wound up pulling the output drivers and testing them. Turns out the left side had a shorted pair.
One way from what I can rememeber is accessing from the bottom check the mainboard with a voltmeter set to continiuity and check for shorts between board traces. You will know what I mean when you see where the output transistors are soldered.

If you find one side seems to have shorts everywhere chances are that there is a bad set of transistors on that side. If that is the case you can desolder the legs of the drivers and test each one. Google how to check them.

One good thing is that the replacements are really inexpensive and you can install them yourself, if you can solder.

I would recommend a desoldering iron, the kind with a squeeze bulb to pull the old solder away from the board.

[PhantomBox]

OK. In the end I desoldered all transistors fixed to the same heatsink at one chanel and removed the complete heatsink.
one pair of output transistors and the audio drivers (transistors as well) had to be replaced.
The toughest things were A: locating the transistors and B: puting the heatsink (with 10 transistors attached) back into place.
Then I soldered it to the board, said a little prayer and turned it on and "voala": it worked.

Thanks for your hint, scootchu

[pmanaudio]

Hi there,
I'm not sure if you managed to fix this amp or not and since this an old posting. I thought I'd help out. Let me know. I just fixed mine with the same problem and found a real interesting issue with the left channel. Hope to hear from you.
Regards
Paresh