I purchased this unit off of ebay. For the first day it worked fine but now the left channel is starting to cut out intermittently. It dosen't do it all the time. Is there anything I can do to maybe clean it. I have sprayed the heck out of it with canned air... but it seems like to no avail. I would like to try and clean it myself. What should I use to clean it and what should I clean?

Where are the pots on this receiver? A picture would help!

Thanks for the help master Sansui man.

Well, lets get some details first.

1) Is the intermittent issue random? In other words, is it totally on it's own - no adjustments or switches causing it to happen?
2) When it happens, it there any static? Or does it just drop the volume?
3) If its just a volume drop, is it to a very quiet level or just a partial drop (e.g. less than half volume)?
4) Is it influenced by any input settings? meaning, does it happen on FM as well as CD's or records?

And, when you cleaned the pots did you only use canned air? Or did you also use Deoxit cleaner?

I don't usually recommend canned air for two reasons; 1) moisture and 2) airborne propellant. #1 is almost always a byproduct of compressing air and #2 is almost always a problem with inexperienced users (no slight intended).

For cleaning I usually stick to Deoxit and alcohol. Both are safe cleaners.

Propellant in the pots is not good - moisture less so.

Paul

1. The intermittent issue is completely random. I make no adjustments whatsoever.

2. There is static when it goes out. When it is out there is still some sound. Like when bass or any type of sound.

3. The volume drops out almost completely with some static.

4. Thus far it has only happened on cd's. That is because I have only used a cd player currently.

I sprayed some deoxit cleaner on the pots. Or at least what I think are the pots. Some has gotten on the circuit board... will this fry the boards? Shoud I let it completely dry before turning the receiver on?

Thanks a million!!!

1. The intermittent issue is completely random. I make no adjustments whatsoever.

OK.

2. There is static when it goes out. When it is out there is still some sound. Like when bass or any type of sound.

It's beginning to sound like either an open resistor, shorting cap or a flaky transistor. Maybe someone else will sign-in here and give us some additional insight.

3. The volume drops out almost completely with some static.

Same as above.

4. Thus far it has only happened on cd's. That is because I have only used a cd player currently.

Can you switch inputs please. Don't use the PHONO inputs first (too large a gain for CD) but you can plug into AUX and TAPE. Try as many as possible. After trying all other inputs, you can set the rear panel gain pot fully counter-clockwise for the PHONO input and try that input - with the volumn control at dead off first - then up gingerly.

It is important to try other inputs before we zero in on any specific repairs.

I sprayed some deoxit cleaner on the pots. Or at least what I think are the pots. Some has gotten on the circuit board... will this fry the boards? Shoud I let it completely dry before turning the receiver on?

It won't hurt the boards. I'd try to get it dry though before powering it up. Here's where your canned air will work well. However, with canned are you must not invert the can, shake the can and do not spray after doing so - wait a couple of minutes. This is to avoid adding propellant to the air. (THose of us with lots of photographic experience already know why :confused: )

The pots will be those round cans immediately behind the shafts. Each will have three wires connected and it's at that location (where the wire join the pot) that you want to insert some cleaner. Anywhere else is just a wast of time. There is a small opening between that point and the metal case.

Paul

So would you recommend that I take to have it looked at? I absolutely love this receiver, so I will pay the repair bill.

Does anyone have any recommendations for repair places in Southeastern Michigan (Detroit Area)?

Thanks for the help Paul.

It's beginning to sound like either an open resistor, shorting cap or a flaky transistor.
Is this an expensive repair?

If you use DeOxit or any other contact cleaner be sure you DO NOT accidently spray any on the tuning capacitor. It will cause you must grief if you do.
>
Beatlefred is an expert on this but I believe I've heard him say that volume cutting out of one channel or the other can be caused by the pre-out switch on the backs of many pieces of Sansui gear. He suggests clearing that switch first.

Can't spell tonight..... 'clearing' should read 'cleaning.'

like what can go wrong if I get it on the tuning capacitor?

Beatlefred is an expert on this but I believe I've heard him say that volume cutting out of one channel or the other can be caused by the pre-out switch on the backs of many pieces of Sansui gear. He suggests clearing that switch first.

Good thought, Bob. I had fogotten about that one.

Fliphandywork:

On the back of the 9090DB next to the Tape 2 DIN plug is a pair of silver "U" shaped jumpers . These are the PreOut/MainIn jumpers - one for each channel. Pull them and re-insert them fully. Test again.

BTW, did you try other inputs? I want to know if this changes the problem.

As for repair costs, I'm not current on that - I do my own. However, there are several AK members close to Detroit (heck, I'm close to Detroit :)) and someone should be able to give you good advice on servicing this unit. DON'T let just anyone touch this beautiful receiver. I'm still waiting for my chance at one!

This classic Sansui equipment is like owning a classic Porsche.

Only cheaper :)

Paul

like what can go wrong if I get it on the tuning capacitor?

Well, not to get you too paranoid. but a tuning capacator uses the AIR between the plates as the dialectric and the rotational position changes the farad values. **If** you get anything other than AIR in between the plates, the capatance is adversley affected and that causes several things to happen;

1) The local oscillator goes off into a new realm that it hasn't visited before,

and

2) The tuning for 88.5 will likely yield 1460 Kcs.

:D

OK, you get the picture. It causes the values to go way off scale. AM and FM will likely not work well, if at all.

Paul

Fixed a lot of ganged caps that someone was sprayed with RatShack cleaner using Electrowash or even IPA.

...so it's not like a fatal mistake.

Would it be a good idea to clean the tuning cap with say, IPA or other non-residue-leaving solvent after blowing one out with compressed air, if there's still some stubborn grime in it?

Just out of curiousity....even though some have suggested a causal link between excessive curiousity and the untimely demise of a statistically significant sampling of the domestic feline population...... :D

TP

I appreciate the compliment Bob, however, when it comes to repairing hi fi equipment I am sure I still have many, many things to learn, so I dunno if I'd call myself anywhere close to an expert at this point in time- but I do plan on my putting my recently acquired vintage Tektronix 475A scope to good use and get into testing, t-shooting, & repairing alot more. My next piece of test equipment I am looking into is a Signal Generator, thinking along the lines of an HP 8640B, but there are alot of sg's to choose from on Ebay so I'll have to eventually decide on which particular one I want.

Ive been spending this whole weekend trying to reorganize all my hi fi equipment- its back-breaking work, just too much stuff and not enough space in this basement! I want to set up my Tascam 48 8 Track machine- that thing weighs well over 80 pounds, feels like its double that though, just trying to lift it and put it in its rack is a major effort. The 48, circa 1987, is one serious Pro multitrack machine! (The Tascam M308 mixing console is huge too!)

As for the cleaing issue- actually, what you are referring to applies to my comments regarding the AU-919 and AU-717, as they both have a slide- switch in the back to connect/separate the pre/power amp sections along with the DC/ac coupled option- this is not the case with the 9090DB which utilizes the jumpers instead.

I suggest contacting the Seller on Ebay about the problem- there was no mention made by the buyer as to whether the Seller sold the receiver to him with the problem made known to him or not, it sounds like it wasnt, but still, wouldnt be a bad idea to let the Seller know and see what he has to say about it. Perhaps if youre lucky, just turning the knobs back & forth might clear it up - while I was reorganizing earlier, I had plugged in my G-7700 which has been sitting unused for a while and noticed that the right channel was distorted- I moved the Volume knob high up (with the Mute switch On of course so as to not go deaf) and then back down a few times and finally the right channel kicked in clear.

B/F

You all should do what my dad did several years ago.
He had a friend at some electronics place who had a vat of cleaner. They just dipped the whole thing. Let it dry and it worked fine.

steve

Would it be a good idea to clean the tuning cap with say, IPA or other non-residue-leaving solvent after blowing one out with compressed air, if there's still some stubborn grime in it? If it tunes stations OK, I'd perhaps blow it out with compressed air and leave well-enough alone.

Well I cleaned the 9090DB with the deoxit cleaner and the left channel is no longet cutting out. So I consider that a success.

Now there is a new problem: The tuner works but only faintly. I have the 9090 running into PSB Image 5T speakers and in order to hear the tuner well I have to turn the receiver almost all the way up. I am not sure if I did something when I cleaned the receiver as I didn't check to see if it worked before cleaning. I would like to correct this problem, but I listen to almost exclusively records and tapes.

Any idea what the problem may be? :dunno:

Thanks in advance!

If the tuner worked before, but now it is faint after all the cleaning and knob/button exercise, stop!

Power down, then reset all button to their off position, especially the tape monitor switches. Reset all tone controls to "0" or flat. Volume control to zero. input selector to aux. Check to see that your FM antenna is still connected properly. Check that the pre/main input connectors (those "U" things) are fully seated in their sockets.

Now power up, check the receiver using a CD on the aux input. If it sounds fine without having to turn it up too much, the preamp and amp are working fine.

Now try the tuner sections, first FM on a typically strong, local station. DO NOT push any buttons yet. If that works ok without the volume control pushed up high, then the FM section of the tuner is working properly. Try the same for the AM side, being sure there is an AM antenna attached or a length of wire hooked to the AM antenna terminal. Again, tune to a local strong station.

If the volume on either the AM or FM section is very weak and requires the volume control to be cranked up, check all signal or switching buttons, one of them is pushed in or out when it shouldn't be.

Usually when the signal is very low, one of the tape monitor switches is pushed in and what you hear is actually the "supposed to be" inaudible crosstalk in the switch.

Hope this helps.

Regards,

Bart