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Sansui 9090DB

Cliff Jones

Cliff Jones

New Member
Hi am new to this forum, so I really hope that I am posting in the correct place. I received this unit, owner says it wasn't playing in stereo, and had to "wiggle' the switch to get it to play sometimes (fixed that problem, with Deoxit). Well it played awesomely and sounded good. So as I was checking why the stereo light would not illuminate when in stereo. I shorted the transistor "TR09" to see if the light would actually and illuminate, well it did. But I paid a price to see it. Now the volume "sound" is way down, can still hear it, but nothing like I could before I made that mistake. Has anyone had this problem before? Thanks
 
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Update: Well when I got home this morning from work. I decided to hook up the "function generator", well the only problem seems to be on the "FM" channel. Aux and phono, and AM seem to play fine. So now I need to check the FM circuit, and to be honest I have never none that. Any hints?
 
Shorting TR09 shouldn't have damaged anything, but it depends on how you shorted it, or if you shorted it to something else. You may have blown TR09 or IC04. Test TR09 with the diode test on your meter. If it's ok, you probably blew IC04.
 
I shorted the emitter to the collector. The owner said this unit had been worked on before.
However I did find this wire floating around, any ideas looks like it is coming from the "push button" board that connects with ribbon cable to the "dolby board"?

Is there a way to test IC04, scope or meter? TR09 tested good.
 

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See the yellow wire at the bottom of the picture.I can't tell if it's the same or not.

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Robisme said:
See the yellow wire at the bottom of the picture.I can't tell if it's the same or not.

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Click to expand...
This looks like the correct wire, but I can't exactly tell where it is landed at. Wouldn't happen to have more clearer picture by chance?
Update: Looks like I found where that wire goes, it goes to F-2694 terminal "K". Volume on "FM" is still weak though, but clear.
 
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Shorting the collector to emitter on the transistor wouldn't hurt anything. All the signals go through the Dolby board on this unit so you need to look at the schematic, see where the one end of the wire connects, then see where it is supposed to go.
 
dr*audio said:
Shorting the collector to emitter on the transistor wouldn't hurt anything. All the signals go through the Dolby board on this unit so you need to look at the schematic, see where the one end of the wire connects, then see where it is supposed to go.
Click to expand...
Thanks, I guess I was trying to be lazy. That is what I did do by the way.
However, I have never troubleshooted the FM circuit on anything, I mostly do amplifier (car amplifier) repair. Trying to expand. Not sure if I have the correct tools to do FM problems.
 
Sorry, I pulled that from a thread I posted in years ago, and I don't have a better one. I think before the photobucket change this pic would get bigger.

Rob
 
Once you get the wire sorted out you will probably have audio. To get FM stereo working is probably just an adjustment. Tune to a known good station, with a proper antenna. Adjust VR04 for the middle of the range where the stereo lamp lights. If it never lights, it either needs alignment or the MPX chip is bad.
 
dr*audio said:
Once you get the wire sorted out you will probably have audio. To get FM stereo working is probably just an adjustment. Tune to a known good station, with a proper antenna. Adjust VR04 for the middle of the range where the stereo lamp lights. If it never lights, it either needs alignment or the MPX chip is bad.
Click to expand...
I believe I have the wire correct. FM volume is still low, no stereo light...have an excellent signal. I know its not the amp, because I can play in "Aux, tape or phono and AM and the unit plays loud. May be chip, only voltage on the 1196 that is really off is pin 1 it has 12 volts on it, and if I am looking at the schematic correctly it should only have about 3.2, or maybe that high is on Pin 2, can t really tell.
 
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