Hi forum,
I've got this amp, a HK 620. I've had it for ages for my stereo, probably 15 years or more. It's always had a problem where it cuts out, I used to think it was due to leaving stuff on top of it, but lately it's gotten worse. It hardly works at all now.
I used to think blowing into it helped, but I'm not so sure now.
I'm using it with some speakers my uncle made, way back in the day. I think they're pretty good ones. In case it's relevant these switches are on the back. I'm not really sure what they do, and maybe somebody's going to tell me that's the problem.
Can anyone suggest might be up with this amp? Can I rescue it? I'm kind of attached to it since it goes back to me teens
I've got this amp, a HK 620. I've had it for ages for my stereo, probably 15 years or more. It's always had a problem where it cuts out, I used to think it was due to leaving stuff on top of it, but lately it's gotten worse. It hardly works at all now.
I used to think blowing into it helped, but I'm not so sure now.
I'm using it with some speakers my uncle made, way back in the day. I think they're pretty good ones. In case it's relevant these switches are on the back. I'm not really sure what they do, and maybe somebody's going to tell me that's the problem.
Can anyone suggest might be up with this amp? Can I rescue it? I'm kind of attached to it since it goes back to me teens
Unusual to have the difference but not too low.
That's fine, the circuit protection is going to be the standby light.
OK, now we have to wait for the smart guys to step up to the plate as amps aren't my forte and it may be something straightforward they can walk you through.
When's the last time you vacuumed out the dust?
Turn it upside down and have the vacuum ready. If your place is smoke free and isn't near the kitchen, you can get some out by just gently tapping it while upside down with the vacuum ready to catch the crud. After that's done, put the vacuum hose on the blow section and hit it through the vents. You might want to do that outside.
Not saying this is anything close to the problem but you might as well show the HK the love it has shown you over the years.
Not saying this is anything close to the problem but you might as well show the HK the love it has shown you over the years.
I have an HK 230 amp that had this problem, it seems some of the HK amps are notorious for poor quality control.
In my amp the cause was faulty connectors that intermittently went open circuit and shut the amp down.
Hard to track down, A/V amps are more complicated with dozens of connectors and hundreds of pins and the connection was usually OK once you pulled the cover off to check.
Neither the JBL importer service department or the local authorised service reps were able to fix it.
So it may be uneconomic to have your amp professionally repaired but only consider to do it yourself IF YOU CAN DO SO SAFELY
I eventually traced the fault from the circuit schematic but this took months because it was intermittent, only justified by a stubborn commitment to understand amplifiers.
A better tactic, especially if you have less electronics expertise, may be to carefully shake or wiggle each individual connector and board and see if you can find one that causes the problem or fixes it temporarily.
Obviously DON"T ELECTROCUTE YOURSELF OR ANYONE ELSE
Work on the amp while it is disconnected from the mains and powered down.
It is slow to disconnect the amp, check the power supply is down, wiggle a connector, power up, test, repeat - but it won't kill you.
Best wishes
David
Just checked, there's a "Instructable" about an intermittent HK 620 like yours.
Owner pulled it apart and the vibration and disturbance of the vacuum fixes the problem for a while. Almost certainly bad connections.
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