Anyone here have experence repairing Sony recievers?

[Shawn]

My dad's got an old Sony STR-DE515 receiver that no longer works. It would always overheat and go into protect mode. We'd always just turn it off wait a minute and turn it back on. One day when we turned it back on it remained stuck in protect mode and has been that way since.

Last year I decided to get it out and take a look at it. It looks like one of the integrated circuits got fried (probably a sound processor or something). I looked up the part number and found it was $15 so I said forget it since it's just a prologic receiver and I wasn't 100% sure that replacing that part would fix it. Anyway I just got my hands on a Toshiba HD-A1 HD DVD player which has it's own digital decoder so I could make use of this receiver since it has 5.1 analog inputs.

Basically I'm just wondering if anyone has repaired these receivers before and knows if this sounds like something that would cause the protect mode message. My dad is going to bring it up next month so I can't look at it until then, but I finally got my hands on the service manual.

If I can get it working I think i'm going to wire in a PC fan to help it cool off since it currently doesn't have anything.

edit: Service Manual

 

[The Boston Dangler]

an ic fried? strange, it's usually the caps that go on something like that. yes, a fried ic would kick in protect mode, or kill it outright, but i'm not sure replacing it would solve the problem. now that i think about it, i'm going to guess there's a voltage problem that killed the ic. if you decide to go ahead with the repair, plug the reciever into a surge protector all by itself for a while.

 

[Shawn]

Luckily I wrote down what IC it was. It was Ref# IC701 Part #8-759-326-52 Description IC uPC2581V.

The manual says it's a drive amp.

Does this seem likely? The resistors surrounding it were kinda black too so maybe they are damaged.

edit: Looking at the service manual there are a couple of capacitors in the surrounding area connected to the IC. Maybe they caused the damage. I'll have to wait until I get it before I can investigate further.

 

[Shawn]

block diagram

looks indeed like it controls the receiver's protect mode.

 

[Modelworks]

It looks like its responsible for providing bias voltages to the amplifier.

Is the amplifier using mosfets/transistors ? or is it using an integrated amp ?

If its fets you will need to check each one as well as all associated parts, otherwise you will just likely blow the IC you replace.
I would probably go ahead and replace them anyway, shouldn't cost much.
Replace the resistors if they have any change in color, shows overheating.
be careful, amplifiers generally have some pretty hefty power supplies and the capacitors can remain charged for weeks/months after the receiver is unplugged.

 

[Shawn]

I finally got this thing. I replaced that IC but it still goes into protect mode. It looks like 2 other ICs were bad, IC801 and IC802. They are called "B+ Regulator" and B- Regulator" in the service manual. I'm assuming that they are voltage regulators. I looked up the part numbers and there is only one site that has them and they are $8 each plus shipping. Is there anything else I can use that would be cheaper?

I took a couple of pictures of the board:
http://pics.bbzzdd.com/users/iloveme2/PICT0070.JPG
http://pics.bbzzdd.com/users/iloveme2/PICT0072.JPG