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Garbage Picked 9090db

PK007red

PK007red

New Member
Just garbage picked a 9090db. I brought it home and got the red protection light. This was in someone garage for years and it's dusty as hell. Read a few forum posts here, replaced the no. 34 and 35 1.5k ohm resistors on the power board and she came back to life. I am very excited. I now have a few other issues I need help with. The unit plays both channels only when the mono button is selected. With stereo selected, the right channel is barely audible. I have only tested out the radio receiver, I have not tried the other inputs yet. What could be causing that?
 
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Wow, great save. First, read the DeOxit thread, and the DC offset and you! thread. And I'm certain someone has a glass. Good luck!

Edit - WELCOME TO AUDIOKARMA!

and it sure sounds like a deoxit bath would fix that issue. The mono button is the giveaway.
 
Possible your FM tuner needs alignment and will not lock into stereo. If it plays both channels using a CD player or other source on the AUX or tape inputs, then it's probably just something in the tuner. But dropped channels on other inputs = dirty switches as onwardjames pointed out.

Incredible trash find, BTW!
 
Looking forward to going home tonight and giving it a Deoxit bath. Hopefully it will bring it all back! Never heard of DC offset before, I will check that and report back.
 
I had the exact same model with the exact same symptoms. It had a dead channel. Both speakers played on mono, only one in stereo. Deoxit did not fix it. Hope you have better luck. I was swamped with gear at the time and sold it for $250 to a guy who just had to have it, even with the dead channel. So you are in good shape no matter what goes down.
 
If it plays from both channels when the mono button is pushed but only one channel otherwise, the audio signal for that channel is dropping out in the preamp before the mono button. The most likely reason is dirty controls. It needs to be cleaned.

- Pete
 
image.jpeg She got a good Deoxit bath. Chased a live spider out. I hit everything I could reach. I pulled the front panel off and that gave me a little access to the push buttons. I could get to the volume, balance and the input selector. The good news is that it works on stereo now on both channels but if you mess with the Dolby selector it will go in and out. Looks like I can't get to that without taking the inner front panel off. Any suggestions as to how to get at that? Is it easier to pull the circuit board out below to access it from from the bottom? Oh, I never had a stereo that had a test signal option, without the front panel on you don't know what you are selecting, that thing scared the hell out of me.
DC offset is fine!
 
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The Dolby system on those is a notorious PITA. There should be several old threads about dealing with it.
 
What Sam said. LBPete, who posted above, once tackled that evil Dolby circuit. I read maybe half of it, and immediately wanted to sell my 9090db, lol.

Looking better, keep at it, and perhaps become a subscriber, and post a WTB in Bartertown. SOMEBODY will have that glass.
 
There are literately thousands of these receivers out there that don't have Dolby problems. You just hear about the ones that do. I also think that many people, including myself, make the issues worse by mishandling the board in attempts to repair it.

The biggest issue with the Dolby system is getting the Dolby switch, push buttons and pots clean. You need to take the tuner tray out to get to them. It's held in by 8 screws and then lifts out to expose the top of the lower chassis. Use a quality contact cleaner to clean both sides of the wafers of the Dolby switch. Also spray it inside all the push button switches.

Depending on when in the production run it was built, it will have either ribbon cable or green flex pc boards connecting the array of push switches to the Dolby board itself. The green flex pc boards are very fragile. Try not to flex them.

- Pete
 
LBPete said:
There are literately thousands of these receivers out there that don't have Dolby problems. You just hear about the ones that do. I also think that many people, including myself, make the issues worse by mishandling the board in attempts to repair it.

The biggest issue with the Dolby system is getting the Dolby switch, push buttons and pots clean. You need to take the tuner tray out to get to them. It's held in by 8 screws and then lifts out to expose the top of the lower chassis. Use a quality contact cleaner to clean both sides of the wafers of the Dolby switch. Also spray it inside all the push button switches.

Depending on when in the production run it was built, it will have either ribbon cable or green flex pc boards connecting the array of push switches to the Dolby board itself. The green flex pc boards are very fragile. Try not to flex them.

- Pete
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Pete,

Success! Pulled the 8 screws out to expose the Dolby push buttons. I got them cleaned but still needed to get to the Dolby switch. Pulled the volume switch locking nut off so I could push the volume switch back to allow the push button board to slide back a bit. We were able to get to the Dolby switch wafers from there. Sprayed it down up she went in stereo.

Thanks
 
Glad you were able to reach and clean it. Thanks to LBPete where the entire Dolby headache is concerned. His efforts have advanced many a unit back to life.
 
Welcome to the Land of Trash! I'm a Garbageman of 30+ years and snagged a 9090db out of trash a few months ago. brought it home and when plugged in got really excited till I saw the protection light blinking.
I'm not savvy enough to work on it, especially after taking the case off and looked inside. the case is pretty much wasted, but, all the lights work and input knob works for the switching.
I am on the fence of refurbishing or sell as is, though don't know if it is worth it or what it would be worth.
There is a shop in Eugene Oregon that specializes in these I will contact. Southern Oregon has nobody who wants to do the work that I have found.
Good luck and enjoy!

Opus
 
A 9090DB is worth money in any condition. Post some pictures so we can get an idea of it's condition. It's a great receiver but repairs can get pricey if you don't do the work yourself.

- Pete
 
Opus said:
Welcome to the Land of Trash! I'm a Garbageman of 30+ years and snagged a 9090db out of trash a few months ago. brought it home and when plugged in got really excited till I saw the protection light blinking.
I'm not savvy enough to work on it, especially after taking the case off and looked inside. the case is pretty much wasted, but, all the lights work and input knob works for the switching.
I am on the fence of refurbishing or sell as is, though don't know if it is worth it or what it would be worth.
There is a shop in Eugene Oregon that specializes in these I will contact. Southern Oregon has nobody who wants to do the work that I have found.
Good luck and enjoy!

Opus
Click to expand...
Opus,

If you are looking to part out the 9090db let me know. I could really use the faceplate.

PK
 
I thought I would show the final product. It took 4 months of searching E-Bay to get a faceplate as the glass was shattered on mine. I replaced all the lights. Those front power meter ones are a pain they have a piece of steel between the meters so you can't pull them out the front without desoldering a bunch of stuff. I soldered in a micro plug for the next guy. It went well and it was fun.

Holy Smokes is this thing powerful! My 2 year old Marantz is Blown Away by this beast. On paper they are the same wattage. The Sansui sounds better at all volumes. I run some modern B&Ws and a base giant driver on the Marantz. The B&Ws die under 400Hz so I can't wait to get some vintage speakers for this thing. I have a neighbor who has a pair of AR3a speakers that most likely need to be refoamed (He has two sets I need pick the best ones). He wants to trade for an old jet ski I have.

Are these ARs the way to go, or should I cruse Craig's List for something else.
 

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