Carver M500t repairs in Canada?

[Tallman]

I am now rusty at repairing Carver as it has been quite some time since at the bench. My first days learnig were spent at Micron Electronics under the guidance of Chris Bridge, Hamlet and Dave Kitley.

I have since spent time on and off repairing various audio/electrical equipment for family and friends.

I have two Carver M500t amplifiers mono bridged into two Infinity SM152's using a Carver CT-17 Preamplifier. Just tonight after running the system very hard (but not clipping), the one amp zipped down to nothing and I noticed it sounded fine at very low volume but once I increased the gain it would fade out into a noisy distortion. After letting it cool for several minutes, it has returned to normal and operates fine. I am concerned the protection circuit or temperature transistor circuit is stressed on this older unit. I have kept up maintenance on these and thus all transistors have been re-compounded regularly and the bias is spec.

Any recommendations? A schematic would be GREATLY appreciated!

Thanks in advance,

Dave (Tallman)

[anatech]

Hi Stretch!
What a pleasure "talking" with you again. How are things?

I don't know if I have the schematics or not, but you could swing by if you are ever in the area. Just PM me for my whereabouts. As you can see, I am now in Georgetown.

-Chris (from Micron)

[Tallman]

Well hello there Chris. It has been many moons. Last time I saw you it was in that enormous Buick wagon up at my friends cottage installing a dish...

Hope you and the family are well. I will defenitely look you up soon when I'm in the Georgtown area. What are you up to now? Do you do repairs?

What do you make of my dilema?

I still see Ham from time to time at you know where...

Cheers,

Dave

[AMV8]

Hi Tallman

I also have two Carver M500T amps. When I run them I use the Carver 400 preamp.

I has a similar problem with one of my amps. It had me puzzled for a while. I eventually found that when heated up the cover/grill of the amp was twisting and touching some parts of the pcb. When I inserted a silicon pad between the pcb support frame and the cover the problem was cured. It might be worth checking in your case.

I was not able to find a schematic for the amplifier and would be interested if you find one.

Don

[anatech]

Hi Dave,
Yes, I do some service still. It would be great to see you though. You are more than welcome by.

I am retired after an accident, so I am home most of the time. I got rear-ended at highway speed when I was stopped.

You have to understand that Hamlet is not my favorite person. I caught him over-estimating customers, then buying their stuff on the side. Then he fixed and sold those things. I'm sure there were other activities going on that were not in my best interest. Imagine all the people he stole product from by violating their trust. In my mind, he's a sneaky thief and not welcome anywhere near me. The worst kind of person, but he was an okay technician. Not the best, just okay.

Let's just agree not to talk about Hamlet, I would appreciate that you not bring me up in any conversations with him.

What do you make of my dilema?

Come by and we'll find out. You are capable of fixing the amp yourself. More of a visit and we'll peak at your amp. I do not plan to charge you anything. How does that sound? You were always a decent fella, and this is a perk that good people enjoy.

I still see Ham from time to time at you know where...

Well, I'm guessing at Global Semi, but I don't really know for sure. I don't really care either, since I don't trust Jerry's parts. There is another winner, but not as bad as Hamlet. A good match, those two.

Best regards Dave!

-Chris

[Tallman]

Thanks for your input Don. I'll run it (when the family is out!) with the cover off and see. I will let you know if I come across the schematics. FYI, I have schematics for the Carver HR-895 (what a POS). I also have a decent Phase Linear 7000 (cassette deck), 4000 Pre-amp and a Model 700 Series Two (Blown).

Chris,

Very good to connect with you again. I promise to come out soon as long as you don't blow my mind with all your technical talk . Try to remember most of us "normal/average" people have enough challenges just getting the covers off

See you soon,

Tallman (Stretch could be misconstrewed)

[anatech]

Hi Dave,
We should look at your other blown things at some point as well. I could use the schematics on the HR-895. Having repaired a few, I might be able to help. Overheated resistors are the biggest problem with these. That and they are less fun to work on than normal. I can help you on that unit.

Stretch could be misconstrewed

Okay, sorry about that then. Tell me Dave, what were you thinking?

-Chris

[Tallman]

Well, the good news is my Carver's are both fine. The bad news is I've isolated it to the Infinity SM152 left loudspeaker. It seems after things cooled down I can put a fair amount of power into it, it sounds fine but just slightly more and poof, the amp goes into protection...either amp of course.

Would this be a crossover failure? What items can I check? It appears fine visually. Perhaps I will just replace the caps and coils?

Any help appreciated.

Dave

[anatech]

Hi Dave,
Could be a toasted crossover, we can check those parts here on my LCR meter if you want.

Could be a shorting woofer also. Normally you would feel some roughness in the travel of the VC, or hear something rubbing. I'll bet that your eyes and ears in good light might show you what the problem is.

-Chris

[Tallman]

Hallelujah!!

I popped in the new crossover today and everything is GREAT!

FYI they were available at $57CAN a piece...

Dave