9090DB re-cap

Joel_l

Active Member
Hi,

Several years ago I bought a 9090DB on E-Bay. It was in reasonably good condition and worked OK except for noisy controls and dirty contacts on the protection board relay. I used Deoxit on everything and that addressed all the issues. I was going to re-cap it at that time but decided to pass until a later date as everything seemed to work and sound fine. Well, today I decided it was that later date, so I pulled the 9090DB from it's setup and temporarily put another receiver in its place. I'm in the process of pulling the various boards out being slightly annoyed by the amount of point to point wiring that is soldered in at each end, but as it is, it will be OK. I'm taking advantage of the excellent work others have done at identifying replacement caps. I am considering redoing some of the connections with pins and sockets. I figure I can get high quality sockets so that signal path should not be an issue. I'm also thinking about replacing the flex circuit connections at the rear with audio coax and header on the board side. I'll think about this more as I disassemble things. Looks like it should be an interesting project to do.

Joel
 
Good luck,

I told a friend I would rework one he had.
He brought it over to have me get it working and after looking inside, I am SOOOooo glad he cheaped out.

I didn't quote a high enough guess.

LOTS of tight places in there.
 
That is one of the list I have, seems very comprehensive. Thanks for doing the excellent work!

Joel
 
Starting to get things apart. No issues so far. I have all the electrolytic caps saved as a project at Mouser. I am now looking for the caps I'm going to use to replace the tantalums.

Joel
 

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Starting to get things apart. No issues so far. I have all the electrolytic caps saved as a project at Mouser. I am now looking for the caps I'm going to use to replace the tantalums.

Joel

I love to read and learn when someone uses photos with their repair job! :thmbsp:

:lurk:
 
More carnage today. Sometimes the simple things annoy you. For the two filter caps, one had the screw that holds it in easily accessible, the other was inserted from the wrong direction. I will need to get the tuner board out before I can remove it. Had it been inserted from the other direction, life would have been easier.

Joel
 

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More demolition done today. I think I have all the parts out that need to be out. I still may dig deeper and replace the speaker jacks on the back with binding post, but first things first.

Joel
 

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Nice work on the 9090DB Joel. Wish I had the skills to do my 8080DB.. Its never been touched. Will be watching yours! :scratch2:
 
So I ordered most the caps, of course there's always an issue. Biggest problem are the chassis mounted filter caps. Can't seem to find what I want anywhere. There's a Panasonic cap,
ECE-P2AA153HA, I want to use but DigiKey only has one. I should be busy enough for a while, but still need to find something good. I am looking for 15000uF 100V.

Joel
 
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I like this. I did order some Panasonic caps, probably between the Super Through and Gold Tune for ESR and loss tangent. The Nichicons have a much better ripple current rating though I not sure I believe the Nichicon ripple spec. The other thing I notice is the Nichicons are 85C 1000 Hr and the Panasonics are 105C 3000 Hr. I also couldn't find the 100V version so bought the 80V. I figure there is only 50V or so across each cap and the Panasonics are 80V working and 100V surge. I still have time to ponder this more.
 
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Postman brought me some gifts today. I have all the caps and resistor fuses I need for the job now. I will start by bagging up kits for each board.

While I was waiting for caps, I started working on the Dolby board by clearing out all the vias so I can put wire through them and re-solder.

I like the Super Through cap mod, but I do have the Panasonics. Looking at the mod, I think I could do it after the fact easy enough if I'm not happy with the caps I got.

Joel
 

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The work begins. I got all my caps kitted up and ready to go ( I'll have to remember the Mouser feature to make this easier in the future ). I'm starting with the Dolby board, I have all the vias taken care of, ended up clearing and reflowing the holes and seeing that the solder flowed top and bottom. Just started swapping out caps. I'll post some pics when it looks like I've actually done something.

Seems some post to this thread are missing.

Joel
 
Got the Dolby and switch board re-capped except for the two Tantalum caps on the Dolby board. I still need to decide what to do about them. I will start in on the tuner board next.

Joel
 

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Tuner board is done. I did notice that the cap values for C85 and C42 are reversed in V7 of the parts list I'm using. No big deal as I'm using the parts list as a checklist as I change out parts. It looks like Sansui might have used some kind of conformal coating on the boards, cleaning them is a sticky proposition.

Joel
 

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How would you rate the recap on a difficulty scale of 1-10? Just courious because I am looking at getting a 8080db and I believe the 2 to be very similar, and I would like to do a re cap on it as well. thanks
 
That depends a lot on your experience. Removing and replacing the caps is not too bad if you know how to solder. Stripping the chassis can be a handful if you are intimidated by a lot of wiring. For me it is a don't care. In a past life I did avionic repair and installations, gutting complete aircraft and starting over.

Joel

How would you rate the recap on a difficulty scale of 1-10? Just courious because I am looking at getting a 8080db and I believe the 2 to be very similar, and I would like to do a re cap on it as well. thanks
 
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Managed to get the tone board done today also. Pots and switches thoroughly cleaned and deoxit.

Joel
 

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