My new "broken" Parasound HCA-1200

[Snerp]

Well, I opened it up. I'm sure you can imagine my internal dialog when i saw that corrosion. Insert your own favorite four letter word. Good times...

And the big caps feel a bit like the tops are bulging.

 

[whoaru99]

It's not unusual for the plastic cover over the top of the caps to dome up without the caps actually being bulged up. Usually you can tell if you push on them. Bulged caps will feel pretty solid. The plastic merely domed up will yield fairly easily.

But, uhhhh, yeah; looks yucky in there.

 

[Snerp]

It's not unusual for the plastic cover over the top of the caps to dome up without the caps actually being bulged up. Usually you can tell if you push on them. Bulged caps will feel pretty solid. The plastic merely domed up will yield fairly easily.

But, uhhhh, yeah; looks yucky in there.

It felt pretty solid. I don't know though. I really can't imagine that relay clicking If they are bad.

I'll clean it up and get nutty with the deoxit.

 

[cademan]

Can we see the rear connections?

 

[Snerp]

Can we see the rear connections?

My flash is dead. Sorry.

 

[cheap sk8]

I have the same amplifier and two HCA 800 models, very strong amplifiers, love the sound..

The 1200, when I first got it, had been sitting for many years. When I plugged it in, it only had left channel.. I assumed it was going to need a complete overhaul so it sat for several more months..

I decided to clean it up and give it a round of deoxit and to my surprise the right channel came back.. The gain pots can actually get so corroded, there is zero sound..

It's worth a try, you will love that amplifier when you get it going, to me it's a true classic..

BTW, what color is the power light after the relays click?

 

[Snerp]

I have the same amplifier and two HCA 800 models, very strong amplifiers, love the sound..

The 1200, when I first got it, had been sitting for many years. When I plugged it in, it only had left channel.. I assumed it was going to need a complete overhaul so it sat for several more months..

I decided to clean it up and give it a round of deoxit and to my surprise the right channel came back.. The gain pots can actually get so corroded, there is zero sound..

It's worth a try, you will love that amplifier when you get it going, to me it's a true classic..

BTW, what color is the power light after the relays click?

The light is green. I figured for $100 it couldn't be passed up. How funny would it be if a little deoxit is the fix? I'll give it a go tomorrow when I get off work.

 

[Mrv8q]

Interesting rear pix, most audio gear runs left channel as the mono input.
Actually, don't think I've ever seen Right channel as mono input.....

 

[Snerp]

I used deoxit on the gain pots, the mono bridge switch, and the RCA inputs on the amp. No cigar. I've got another receiver. I'm going to give it a try as pre.

I have confirmed all cables are working as well.

Here's the back of the Kyocera. I'm pretty sure I have it right.

:edit:

No luck with the other receiver. So, as I see it, I have an output or connection problem.

 

[whoaru99]

Since the amp has gain controls, why not turn them all the way down then directly connect your CDP (or whatever) to the amp. Use the gain controls on the amp for volume controls.

 

[Snerp]

Since the amp has gain controls, why not turn them all the way down then directly connect your CDP (or whatever) to the amp. Use the gain controls on the amp for volume controls.

I'll give that a shot when I get home.

I was thinking and there are some on board pots. I'll try a little deoxit on them when I get home. I really wish I could find a service manual so I could set them to the proper value.

I contacted parasound. Maybe they'll be cool and hook me up with one.

 

[Snerp]

Parasound hooked up the schematic and told me to check the fuses. He said the relay will still energize if the 12 amp fuses are toast. Gonna check it out when I get home.

 

[Snerp]

AHHHHHHHH! Someone put a 15A fuse in when it should have been a 12A! Both fuses are bad. Hopefully nothing was damaged...time to get some new fuses.

 

[240sx4u]

That's a bad sign, both that the fuses are toast and they have been replaced by 15amp units.

 

[Snerp]

That's a bad sign, both that the fuses are toast and they have been replaced by 15amp units.

Yep. Pretty cool.

I called radio shack looking for a 12A fuse. The kid tried to tell me volts had to be matched, not amps. I told him it's the other way around.

"Yeah, that's what I thought too before I started working here. But then I learned the truth."

He then tried to sell me a 20A/250V. Maybe he knows the previous owner of this amp. Dumb.

Good news though, I think the 15A fuses are quick blow. Maybe it was just a quick spike and it didn't take anything with it.

 

[runnin']

Check the fuses, but don't just blindly replace blown ones.

Excellent advice, way back on post 3.

 

[Snerp]

Excellent advice, way back on post 3.

Yup.

 

[Snerp]

I've got the fuses on order. Parasound guy told me the power transistors are what would have been damaged. Is there any way I can test them without removing them? I can remove them if not.

 

[cademan]

Were the fuses black? Blackened fuse(s) indicates a short somewhere and you won't want to just replace them blindly hoping that it will work. Make sure the outputs are good before replacing the fuses.

Most of the fuses I have seen in equipment is listed as 250 volt so try to find the 12Amp-250 volt fuse.

 

[Snerp]

Were the fuses black? Blackened fuse(s) indicates a short somewhere and you won't want to just replace them blindly hoping that it will work. Make sure the outputs are good before replacing the fuses.

No, they looked fine, but the filament was burnt. It was a ceramic fuse. I popped it open and took a look. Got 250V slow blow. Confirmed with support that these were the correct replacement.