left channel issues Parasound HCA-1200A

[Big Jim 007]

I have a Parasound HCA-1200II amplifer that has been in storage for over a year. It sounded wonderful and worked properly when I put it in storage. I was cobbling together a secondary system and to my dismay, the left channel was very distorted and was kicking in the internal circuit breaker on the Parasound.

I checked all the connections and reversed the interconnects to see if it was a bad cable....I checked the speaker cables and they were fine...bottom line is that something is amiss with the left channel. I even hooked it up with another preamp and it still did the same thing...went through 3 sets of speakers and still had a highly distorted left channel.

Is this something that can be fixed by opening her up and cleaning all contact points with contact cleaner?

Could it have gone bad due not using it?

Thanks,
Jim

 

[ryuuoh]

Have you measured the outputs for dc voltage?

 

[Big Jim 007]

Have you measured the outputs for dc voltage?

No, what am I looking for when and if I do?

Jim

 

[ryuuoh]

Assuming the amp is not in protection, remove speakers, turn off or disconnect the pre amp, and measure for DC voltage at the speaker terminals. I don't know about your particular amp, but DC offset should typically be in the low millivolts.
It sounds like your problem is deeper than simple offset, but checking it will tell us if that's a symptom of deeper problems.

 

[Big Jim 007]

Assuming the amp is not in protection, remove speakers, turn off or disconnect the pre amp, and measure for DC voltage at the speaker terminals. I don't know about your particular amp, but DC offset should typically be in the low millivolts.
It sounds like your problem is deeper than simple offset, but checking it will tell us if that's a symptom of deeper problems.

What I will try when I get the time is to open it up and see if it is dirty inside and clean it out. I cannot see what would happen from just sitting unplugged other than is has become a dust/bug/dirt magnet from being in storage.

If that doesn't fix the issue, I will most likely sell it as is on eBay with full disclosure.

Jim

 

[jdcglasnost]

Have a HCA-800II, was taking too long to come out of protection, so I replaced some bad caps in the protection circuit and amp board and it is now 100%. Just going from the hip, and something that happened while it sat around, I'm going to guess the caps on this unit as well, but check that DC offset, you don't want to damage your speakers.

 

[Big Jim 007]

I believe it will be in the DC Offset as it was moving the cones on the left channel big time. I will try and make time check the DC Offset. I already have everything unplugged coming into it and know to plug it in and then set my multimeter at 200mV setting on the DC range. I will be taking the readings directly from the speaker connectors.

I will report back with the readings. However, I might just go for a Adcom or even a Dynaco to replace it.

Jim

 

[Big Jim 007]

DC-Offset Tested well within proper limits!

The DC-Offset measured 1.6mv Right Channel and 1.8mv Left Channel. It took almost a minute for it to go from protection mode to ready to go. I gave it one last chance and it again kicked immediately into protection mode.

It will be listed and hopefully someone with the knowledge to fix it will get it and enjoy as I had.

Jim