Penta Mk1 Interference & Bugged Display

4 replies

Hello everyone,

I am a long time forum lurker but have only just signed up today. I have a pair of Mk1 Pentas that my dad gave to me about 5 or 6 years ago (love them). One of the pair has always had some kind of intermittent interference problem where the sound will distort for periods of time (random lengths of time), it has gotten progressively worse and recently i finally decided to pull my finger out and take a look. At first glance i noticed the Mid Range foams were shot so i have replaced these. 

Now this was the first time this speaker has been fully disconnected from the mains for about 2 years, now when i have turned it back on, the interference problem is the same - if not worse, and the display now appears to be bugged out. The speakers are driven from a Harmon Kardon AVR, so the displays do not usually ever output anything. Now there are a couple of items permanently displayed at varying brightness's. My next troubleshooting step was to remove the Amp and see if there are any components that need to be replaced. Has anyone seen something like this before ? Any advice would be greatly appreciated.

 

link

 

Thanks 

I was listening to the Pentas Last night - fairly low volume for about an hour or two. When done i noticed the Amp was warm, going to take it apart this evening and see whats going on.

Bad idle current trimmers.
Replace and readjust.

Martin

Hi Martin,

Thanks for the taking the time to reply, its appreciated. Could this also be the cause of my interference? Or would this likely be a problem elsewhere in the circuit? I have ordered a better Meter to let me test the components in the Amp more accurately.

Now i need to find someone or somewhere i can buy these parts from.

Thanks

Alex

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