Teac AG-D8900 Protection Relay Audio Cut Out Problem

[MrBlahman]

Hi All,
First time poster, so I hope this is the right place. I've been having trouble with my Teac AG-D8900 receiver cutting out randomly. When the audio cuts out or back in I hear what I believe is the protection relay clicking. Some observations:

1) Normally when things are working I can press the speaker on/off button on the front panel to enable or disable the speakers. Doing this makes the same click I hear when it cuts out on its own.

2) When cut out, pressing the aforementioned on/off button makes no click. Turning the power off and back on results in a click for the power, but no click 5 seconds later as would normally happen.

3) A light whack to the receiver brings the audio back with 99 percent reliability...until it cuts out seconds or minutes later. (It used to be hours or days) It sometimes comes back on on its own, and I've also heard the relay click on and off in rapid succession a few times.

Anyway, my first thought was to replace the relay in question, but then I realized it could be a voltage issue or any number of other things. Could someone chime in with any thoughts or suggestions on how to proceed? I'm hoping someone with more knowledge on the subject could point me in the right direction. Thanks!

 

[NAD80]

Hello MrBlahman. Welcome to AK. Sounds like a bad solder connection. Since giving the unit a whack brings it back. Does it happen faster as it heats up?. The Service Manual is at HiFi Engine.com. The unit looks like thru hole and surface mount parts.

 

[MrBlahman]

NAD80,
Thanks for the reply and sorry for the delay in getting back to you. It does indeed happen faster as it heats up. Thanks for the heads up on the service manual - I grabbed a copy, but unfortunately it doesn't have much in the way of troubleshooting steps. It's obviously designed for someone who knows what they are doing, unlike me!

Anyway, I finally got the courage to diassemble the unit. Visually the relay solder joints look perfect but I'm going to reflow them anyway and report back.

 

[MrBlahman]

Update: Success! I decided to just replace the relay instead of reflowing it. (Ordered a replacement on eBay a ways back.) It's now back to normal, and whacking it does not cause the relay to open as it did before. I also cycled it by turning the speakers on and off from the front control panel about 50 times, which before about half the time the relay would get stuck open. I won't be 100 percent confident about it until I've used it for a week or two without any drops, but things are looking good thus far. I will update here if not.

 

[quietchannel]

Hello MrBlahman,
I have the same receiver and it has recently developed the exact issue you describe here—every aspect of your original post. Mine’s never had a single other issue with close to 25 years of daily use.

I’m checking in to see if your fix has held up. And to ask what the replacement relay part number is, if you know it.

Thank you for sharing your process and results with us!

Robert

Update: Success! I decided to just replace the relay instead of reflowing it. (Ordered a replacement on eBay a ways back.) It's now back to normal, and whacking it does not cause the relay to open as it did before. I also cycled it by turning the speakers on and off from the front control panel about 50 times, which before about half the time the relay would get stuck open. I won't be 100 percent confident about it until I've used it for a week or two without any drops, but things are looking good thus far. I will update here if not.

 

[goodolpg]

Robert,
MrBlahman was last seen:

Aug 7, 2017, the day he made the post you quoted.

Hopefully some other AK'er can offer you some help.
Good luck.

 

[quietchannel]

I had the same issue and same fix. Replaced the speaker protection relay and all is well!

For anyone else who might have the same problem sometime in the future. . .

There are two relays, one which is part of the power supply, and then the one in question: a larger blue rectangle on the lower circuit board (near the back of the enclosure). As mentioned above, it's the same one that you hear engage/disengage when you click the front panel "speaker" on/off button.

The replacement part number is "OSA-SS-212DM3," and it is available from Mouser Electronics for under $3, plus shipping:
https://www.mouser.com/ProductDetail/?qs=0cdP5f6kAtEiMOwqJ5Ourw==

I paid less than $10, had the part in 2 days, and everything was up and running within one hour. Disassembly and reassembly took most of the hour but wasn't too bad.

You'll just need a soldering iron, solder, desoldering wick, and phillips head screwdriver (with a somewhat long, maybe 4 inches? shaft, to get down into the tall main heatsink).

In my opinion, this receiver is very much worth the $10 and hour of effort. It has served me well for over two decades, with no other issues!

Good luck!