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Sansui QRX repair question...

gtx580

gtx580

AK Subscriber
Subscriber
Hello, Im just finishing up reviving a Pioneer SX850 and found a ton of info and help on the Pioneer forum. My next project will hopefully be reviving a Sansui QRX 5500 that I picked up a few years ago. My first questions and concerns are regarding parts lists, known issues,problem boards and such as far as Sansuis are concerned. So I,ll ask. are there replacement parts lists available? Is there a basic troubleshooting route to take with the Sansuis? Do they have known issues that need to be addressed? Any thoughts are appreciated! I,ve done a couple searches on here regarding the QRXs and there doesnt seem to as much info as,say, the older Pioneers. Thanks ahead of time! Chuck
 
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I do Sansui's on a case by case basis, they were always updating and changing things up, so creating those BOM lists from service manuals for Sansui's is very difficult.
Ive done a lot of QRX Sansui's, they are pretty solid, not always easy to access some of the boards, last one I did was a QX7500A, it came up really good, sounded nice enough for me to want to buy one!!

So yeah, just pop the hood and make a list, best way...
 
Kev, thanks for the reply. Do you have a basic procedure as far as working on these? Such as, no relay click would automatically have you rebuilding the power board, then the protection board,etc,etc? On the Pioneers it seems that most issues start with the relay not clicking on and then you just start at the power board,then protection board etc. This QRX 5500 will click on,play for a minute or so,then click off. I,ve only tried it in 2 channel so I,m assuming its an issue with the standard boards,not the 4 channel side,but thats just a guess. I,m not very experienced in these repairs, the 850 was a great platform to learn on, and if the Sansui looks like it could get me in over my head,I may just put it aside until I get a little more experience under my belt. Thanks again!
Chuck
 
I find on these ones, if the amp is in protection, there will be issues with the power amps, I always start with the power amps and work through them, I have found drifted resistors, blown output devices, leaking caps, intermittent bias trimmers among other things.
Every one of the QRX #500 series I have worked on has had issues with the power-amps.
I recap, replace trimmers, look at the resistors in the regulated supplies. NEVER mess with the regulated 25V circuit as the chips in the quad circuit are very sensitive to that voltage, and if it is off, you can damage the chips.
Switches need to be removed dismantled and cleaned.
I also replace all the dial lamps and function indicator lamps.
The last thing I do is align the tuner.
 
Kev, thank you for the help. The output driver board....doing a search in here, I found an old thread where the poster noted that he had the same issues with his QRX-5500 as mine. His relay would kick off after a few minutes but all of his meters were still active. A fellow member replied that if the relay is kicking into protect mode but the meters are still active that the problem is with the output driver board,the one attached to the heat sink, and that a recap would probably be the answer. I think the thread died out after that. Does that make sense? I did pull that board this evening,looks like an easy rebuild. I did note one thing else today.. I hooked up one of my cassette decks to check out my meters and they are functioning even with the relay kicked out. But the relay kicked on and off about 6-7 times before kicking off for good,something its never done without anything being inputted.
I may just rebuild since its an easy one to work on, but thought I would get your thoughts on that board. Thanks again for the input!
 
ok, finally getting around to looking at this qrx 5500. It looks like Ill be starting with a recap of the power board, F1483. My first issue is how to service this board? Can it be carefully lifted up to access the bottom of the board or is there an easier way from the bottom? It looks like some work has to be done to do it that way. Any thoughts would be appreciated! Thanks.
 
gtx580 said:
ok, finally getting around to looking at this qrx 5500. It looks like Ill be starting with a recap of the power board, F1483. My first issue is how to service this board? Can it be carefully lifted up to access the bottom of the board or is there an easier way from the bottom? It looks like some work has to be done to do it that way. Any thoughts would be appreciated! Thanks.
Click to expand...
I know this is an old thread, How did you make out. I just purchased a QRX-5500 and after initial test I noticed my signal meter and fm stereo light other working. Long story short the voltage is not correct and traced back to the caps and tranisitors on the board. Just build a listof parts needed. From what I read you do not need to removed the board, as you can remove the 1482 driver board and heat sink as one component. Unscrew from the back of sink.
 
yup! It came out of the back of the 5500 if I remember correctly. I just went ahead and recapped that board , and that took care of the issue. Its been a few years since that issue but the qrx 5500 is still on my shelf doing back up duty to my SX 850 . If I recall , that was the easiest fix that I had run into , and seeing all the boards in there that are involved in those Quad units I was glad I didnt have to dig further than I did.
 
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