Anyone with experience repairing Harman/Kardon Receivers??

[WndrBr3d]

I'm going to be cracking open my H/K AVR7300 this weekend to attempt to repair an issue I'm having with the power. When I turn on the mains power, the stand-by power button does not light up.

I verified and the unswitched outlet is getting power. Meaning it's not a wiring issue from the mains to the power logic.

When I push the power switch, it should be feeding power to the Standby Transformer. At this point, power should be provided to the NEC CPU which would then control the logic to illuminate the front stand-by power button.

I've looked at the schematics and I can think of only two possible areas of issues:

Because the Stand-By Power button does not light up, I can only assume the following:

1) Stand-By Transformer is Shot
2) If Transformer is OK, verify the voltage regulators are still working
3) If DC probe shows voltage regulators working fine, then the NEC CPU must be borked for one reason or another, which is why it's not triggering the main power relay

Can anyone out there with experience chime in on this?? I have the parts on order from H/K (which were actually very, very cheap). I'm going to crack the case open this weekend and start working on it.

Thanks!!

 

[zildjian]

Can you put a meter in the circuit after the stand by transformer to see if it's the culprit or not? Pending on the layout of the inside, it might be just as much of a pain to get to it to test as it would be to replace it! If you haven't submitted the order yet, just thought that might be one way to rule out that part before ordering it. Post back what you find out; I'm interested to know. I'll work on amplifiers, and they can quickly get over my head, but I avoid receivers altogether, too many other things in there!

 

[WndrBr3d]

Yeah, that was my plan. To just probe those circuit paths. My fear is that the IC is fried, only because it doesn't seem likely that a transformer would up and die.

Since there's no fuse between these parts (which is curious), it's possible that a power surge could have fried the regulators. So we'll see.

The parts from HK (new fuses and new Stand-By Transformer) were only $15. So it wouldn't bankrupt me to repair this, if my suspicions are true.

 

[WndrBr3d]

Just an update on this post

Turns out there was a fuse on the power handling board not listed in the schematic. 800mA/250v fuse. A quick trip to Radio Shack and $2 later, the AVR7300 is alive!

I know I have a post in another part of this forum, but anyone else needing to repair their receiver should take a look at this post in my blog:

http://www.enusbaum.com/blog/2007/11/10/harmankardon-receiver-service-manuals/

I've posted links to every Harman/Kardon Service Manual I could think of. If a Service Manual you need isn't there, please let me know and I'll add it to the list

 

[hifisyd01]

I have a 7200 that wont power on at all. I've never attempted to work on anything remotely resembling this beast, but after reading your post, I'm tempted to crack it open and look for a fuse. Heck, it's out of warranty anyway, so what's to lose? Any advice is greatly appreciated. Thanks in advance.

 

[cbeachwood]

Newbie here...

I found you via Google... (what's new?)

I'm in San Diego (also) and started my search by looking for a place to repair my H/K AVR 225. I get a "PROTECT" message on the display, even with all cables, etc., disconnected. The message stays on for a couple seconds then the unit shuts off. I did open it up and check the five fuses I could easily see, but that's as far as my comfort level goes.

Any help is appreciated!
Clint B.

 

[WndrBr3d]

I have a 7200 that wont power on at all. I've never attempted to work on anything remotely resembling this beast, but after reading your post, I'm tempted to crack it open and look for a fuse. Heck, it's out of warranty anyway, so what's to lose? Any advice is greatly appreciated. Thanks in advance.

Best thing to do is get a multimeter and measure the fuses. The standard resistance should be like 0.2ohms if it's still good. A bad fuse either wont measure or will have a very high resistance (10+million ohms).

 

[WndrBr3d]

I found you via Google... (what's new?)

I'm in San Diego (also) and started my search by looking for a place to repair my H/K AVR 225. I get a "PROTECT" message on the display, even with all cables, etc., disconnected. The message stays on for a couple seconds then the unit shuts off. I did open it up and check the five fuses I could easily see, but that's as far as my comfort level goes.

Any help is appreciated!
Clint B.

This message usually comes up when something is grounded out in the amp or on the binding posts.

Take a look at the service manual for the 225 and see what it says regarding that issue. Might be a quick fix.