I think it
I think it may be that.
Harman Kardon Twin Power 730, low right channel output
- Thread starter redstarjedi
- Start date
The rear back plane, where all the inputs are connected, is connected to the rest of the unit via a goofy set of long, stiff leads plugging into long connectors on the selector board.
Yes, reflowing all those solder joints is a good first start. A second step should be repeated deoxit'ing of those long, stiff pins and their corresponding connector.
Yes, reflowing all those solder joints is a good first start. A second step should be repeated deoxit'ing of those long, stiff pins and their corresponding connector.
will do when finish the rest of the re-cap. I've done the driver board and the main filter caps.
Oh wow, I never knew that! I've had issues with the right channel intermittently dropping out on my phono input (and only coming back if I pull the plug and reinsert it *with the volume on*), so I will definitely give this a shot later.
So months later. I finally got around to taking the daughter board out re-flowing all solder joints, cleaning the pins and putting it in.
Didn't fix it. But I don't regret it.
Problem was still there. Infact I've the past few months problem became worse. With a channel dropping.
No, it wasn't the switches, and de-oxit didn't help.
My father and I re-flowed the pins on the underside of the preamp board that come from the main amp.
Problem fixed!
Again, I don't regret reflowing and cleaning the daughter board.
Didn't fix it. But I don't regret it.
Problem was still there. Infact I've the past few months problem became worse. With a channel dropping.
No, it wasn't the switches, and de-oxit didn't help.
My father and I re-flowed the pins on the underside of the preamp board that come from the main amp.
Problem fixed!
Again, I don't regret reflowing and cleaning the daughter board.
Attachments
well problem is back. Seems to be in the volume pot this time. No channel drops, but instead one channel is fuzzy sometimes with a tab bit lower volume. If i turn the volume knob back and forth a lot the problem temporarily goes away. Yes, i've used dexoit, and i'll try that one last time. I did notice for the first time that the shaft is slightly bent.
But failing that, are there replacement volume pots available? I saw one on ebay for $90 here : but that is crazy!
Or i can try to take apart the pot and clean it?
I'm wondering what others have done.
after a re-cap i'm soooooo close to having a perfect HK 730
But failing that, are there replacement volume pots available? I saw one on ebay for $90 here : but that is crazy!
Or i can try to take apart the pot and clean it?
I'm wondering what others have done.
after a re-cap i'm soooooo close to having a perfect HK 730
nicholas2381
Super Member
I would think you could get a 100k ohm pot from digikey, mouser, etc. Just make sure it's a match in form factor to the original.
This will get you started: https://www.digikey.com/en/products...jUN0jnNka06bAAi+ACuAEZoWKkAtJmSUNzzuQpq9MJHQA
This will get you started: https://www.digikey.com/en/products...jUN0jnNka06bAAi+ACuAEZoWKkAtJmSUNzzuQpq9MJHQA
nicholas2381
Super Member
Actually, it's probably a 2 gang pot. If so, select that option instead of the single.
I can't seem to find any with two taps on the top. Which I assume are for loudness.
I see plenty dual gang with 6 taps on the bottom. Still could work ?
nicholas2381
Super Member
My fault. Once again, I was doing too many things at once and didn't realize the unique setup. And now I understand the difficulty in finding a replacement. Still, $90 seems pricey to me for a pot. Others may beat me to it, but once I'm done with some other things, I'll see if I can locate a better substitute.
So I just cleaned the HELL out of it again, turned it left and right for a few mins, sprayed it with de-oxit and turned it about 300 times or more and spayed and turned again!
Seems stable now. Let's hope it stays that way.