Sansui QRS5500 quadrophonic receiver

I hope you mean a QRX, not QRS. They got it at hifiengine, it shows a fuse for the dial lamps, F 01, 5 amps. It also feeds a rectifier for about an 8 volt source that feeds the stereo light, also off the fuse. While at this a ge those lamps may have blown one at a time by now, you would have noticed it.

the cap in the protection, the failure mode is weird. They are usually 10 v olts and sometimes go right across B to E of a transistor so they never cha rge more than like a half a volt. they get leakier and leakier over time. T hey are usually fed by a high value resistor, like 100K or more. I didn't l ook at that part of the circuit but since it is fine, fukit.

Not a badly designed piece. Full comp outputs, current source instead of a bootstrap, DC coupled. Theoretical peak RMS short tem power is 76.5 WPC. Th e rating is 30, so splitting the difference I would say you got about 1.5 d B or so dynamic headroom. It is probably over 3 dB for a couple millisecond s, but in real life not so much.

Tuner is pretty conventional, uses ceramic filters but still a standard rat io detector. No pilot cancel, but all that doesn't mean it doesn't sound go od.

Tone controls OK, filters only 6 dB, don't use the filters. he variomatrix looks like a good thing, like Marantz varimatrix I would guess. You have co ntrol over the L+R attenuatoin in the rear.

I don't see amp strapping in it though, or pre out/main in.

Enough commentary, if it is QRX the manual is at hifiengine.com. It is prob ably ready for the FM to be tweaked, but it might not be so bad. Other than fixing the lights, if all the channels sound good I don't recommend anythi ng. You could go in with an ESR meter and replace caps if you feel like it. Just never short the speaker wires because it has no current limiting at a ll.

Just a hunch here but I remember there were many Sansui models manufactured in that era that had faulty rotary function selector switches. The result was that the panel lights would flicker or go out completely. No amount of switch cleaning would restore them to good health. If you wiggle the function selector switch, do the lights flicker or does the meter function momentarily?

--
David Farber 
Los Osos, CA

r the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were eviden t. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the prot ection board and .that resolved the protect relay problem. Now however ther e is another problem that I never had before. Most of the dial lights incl uding the signal meter light are out and that meter also seems to be inoper ative as well. I never had any trouble with any lighting or the signal mete r on this receiver. This is a big quadrophonic receiver. The switching is d one through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't s ee anything. I Really appreciate any help. Lenny

I think that I know what the problem is. I first sprayed the main selector switch with a silicon based cleaner that contains a mild lubricant, figuring that one of the phenolic wafer sections in the .switch that was switching the power for the lamps perhaps was dirty. This stuff evaporates quickly and it didn't solve the problem. After more fruitless probing, in a last ditch effort I hit all the segments of the switch with No Ox. This stuff is like "Blue Stuff" but a bit more oily. I worked the switch to distribute the material and then powered the unit on. No Ox works wonders with controls and switches but it is some what messy.To my utter dismay I noticed smoke coming off part of the selector switch. (This was probably from the sector that is switching the high current lamp power. I now have to pull the front panel and hope that I then will be able to get a better eyeball of the selector switch. If the section is burned though I don't know what I could possibly do though. A selector switch problem....... My worst fear becomes a reality. Is today the thirteeth by any chance? Lenny

On 6/22/18, Ardell Faul snipped-for-privacy@gmail.com [tv-repair]

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Jump out the switch and see if it blows the 5 amp fuse.

I think 5 amps is a bit much for that type of switch.

Lenny, See my answer on the Yahoo tv-repair group. Chuck

r the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were eviden t. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the prot ection board and .that resolved the protect relay problem. Now however ther e is another problem that I never had before. Most of the dial lights incl uding the signal meter light are out and that meter also seems to be inoper ative as well. I never had any trouble with any lighting or the signal mete r on this receiver. This is a big quadrophonic receiver. The switching is d one through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't s ee anything. I Really appreciate any help. Lenny

? Newer 3 of about 86 Older ? Expand all messages Expand all Print conversation Print Open conversa tion in new window New window Sansui QRS5500 receiver Inbox Unstarred Klem Kedidelhopper Fri, Jun 22, 2018 at 4:32 PM

2 hidden messages ? Show Unstarred snipped-for-privacy@yahoo.com [tv-repair] Sat, Jun 23, 2018 at 2:29 PM Add star Klem Kedidelhopper Sat, Jun 23, 201 8 at 7:39 PM To: snipped-for-privacy@yahoogroups.com Reply | Reply to all | Forward | Print | Delete | Show original I had actually thought of that. It wouldn't be a problem if the lamps were on for each mode. I just wish that I could see the burned section of the switch but it's an impossible jungle of wires.

Two weeks ago before I knew about the lighting problem I picked up a

5500 to use for parts, because my quad section has never worked and I have been thinking that it would be nice to swap a couple o boards and see what happens. So I have a switch however there is no way I'm going to tackle replacing that switch.

I thought o something else. Back in the late 60's and early to mid seventies when VHF TV tuners were built with multisection switches I used to run across a fair number of them that just wouldn't respond to a good cleaning with a silicon based tuner cleaner. Then they came out with "Blue Stuff". As long as you didn't spray it on the neutralizing capacitors it was a miracle of bringing back intermittent tuners to life once again. I So I thought I might try degreasing the switch first and then give it a good cleaning with Blue stuff. and then see what happens. Probably nothing will come of it but it doesn't hurt to try I guess. Lenny

r the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were eviden t. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the prot ection board and .that resolved the protect relay problem. Now however ther e is another problem that I never had before. Most of the dial lights incl uding the signal meter light are out and that meter also seems to be inoper ative as well. I never had any trouble with any lighting or the signal mete r on this receiver. This is a big quadrophonic receiver. The switching is d one through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't s ee anything. I Really appreciate any help. Lenny

Hey guys I really need some more help with this one. It's on the bench and even though I'm working on it my wife is flipping out over the entertainmen t center all torn apart in the living room. But that's a woman for you, can 't appreciate the beauty of a repaired 1974 receiver...

Anyway in looking at the schematic I can see that there is a 6 volt windin g referenced to ground. The blue 6 volt transformer wire goes through a 5 a mp fuse the output of which directly feeds AC to a bunch of lamps in parall el. The output of the fuse also feeds a rectifier and filter which then fee ds DC to some other lamps through some other switches. I just can't make an y sense out of it.

For one thing although I can see a multi pole switch feeding individual lam ps and I'm assuming they are indicators I can't tell for sure which lamps a re for which function, (panel lights or indicators) and so I'm not certain where to jump because I can't tell which lamps would need to powered by AC or DC. Most of the ones that seem to be indicators such as phono, tape, etc . seem to light now and it would be nice to retain that after jumping out w hatever I need to to restore the other lights.

Another weird thing which is also troubling is that every once in awhile th e signal meter seems to illuminate although it doesn't seem like it's fully bright and there is never any signal level response on it. I never had tro uble with that either. Can one of you guys please help me with determining where to "jump" the switch and get all the lamps working? Then I'll have to figure out this signal meter problem. Thanks, Lenny

Lenny, Jumper Pin 02 on F-1483 board to the end of R0118 that goes to PL01. Jumper the B+ end of PL707 to B+ end of PL713. Jumper B+ end of PL 701 to B+ end of PL704. This should allow all lights except for mode ones to light. I'd put a 100 watt light bulb in series with the AC in just in case I screwed up. As a retiree, my mind isn't what it once was. Good luck.

te:

for the protection relay to activate and turn on the speakers I finally t ook it out of service. I recall that it had no other problems that were evi dent. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the p rotection board and .that resolved the protect relay problem. Now however t here is another problem that I never had before. Most of the dial lights i ncluding the signal meter light are out and that meter also seems to be ino perative as well. I never had any trouble with any lighting or the signal m eter on this receiver. This is a big quadrophonic receiver. The switching i s done through the main selector switch and it's a nightmare to get to. A r eal rats nest. Does anyone who has worked on these recall any common proble ms with lighting on one of these? I suspect a ground problem because so ma ny of these lamps are in

ly appreciate any help. Lenny

nd even though I'm working on it my wife is flipping out over the entertain ment center all torn apart in the living room. But that's a woman for you, can't appreciate the beauty of a repaired 1974 receiver...

ding referenced to ground. The blue 6 volt transformer wire goes through a

5 amp fuse the output of which directly feeds AC to a bunch of lamps in par allel. The output of the fuse also feeds a rectifier and filter which then feeds DC to some other lamps through some other switches. I just can't make any sense out of it.

lamps and I'm assuming they are indicators I can't tell for sure which lamp s are for which function, (panel lights or indicators) and so I'm not certa in where to jump because I can't tell which lamps would need to powered by AC or DC. Most of the ones that seem to be indicators such as phono, tape, etc. seem to light now and it would be nice to retain that after jumping ou t whatever I need to to restore the other lights.

the signal meter seems to illuminate although it doesn't seem like it's fu lly bright and there is never any signal level response on it. I never had trouble with that either. Can one of you guys please help me with determini ng where to "jump" the switch and get all the lamps working? Then I'll have to figure out this signal meter problem. Thanks, Lenny

Hmmmm... I would probably drill holes in the backs of all the gauges and ju st globally light up the entire inside of the receiver...

Lenny, I've got about a dozen receivers abandoned from repairs over the yea rs and some of them are quite vintage, although none are quad to my recolle ction. If you want one, stop by next time you're coming through CT and you can pick out what you want.

r the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were eviden t. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the prot ection board and .that resolved the protect relay problem. Now however ther e is another problem that I never had before. Most of the dial lights incl uding the signal meter light are out and that meter also seems to be inoper ative as well. I never had any trouble with any lighting or the signal mete r on this receiver. This is a big quadrophonic receiver. The switching is d one through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't s ee anything. I Really appreciate any help. Lenny

Chuck

First, thank you very much for the power supply jumper information. I hope that I will not have to use it but it is comforting to have it. The reason I say this is because in the interim I tried my Blue Stuff treatment. I spr ayed the switch sections quite liberally and I really worked the switch thr ough all of it's positions.

What I had previously written about the effect that Blue had on the intermi ttent phenoclic switches in the old tuners was not an overstatement. My di splay lamps are all on now and there is no smoke. I guess that I would say that I'm "cautiously optimistic" that I may actually have restored these ta rnished contacts before they actually had a chance to burn.

I've turned the receiver on a few times now since the Blue Stuff treatment and and the display has come on strong without flickering each time. I gues s we'll see.

Now I have to address the other problem with the non functioning signal met er. As I had said it always worked before and never caused a problem. But n ow it just lights up and does not indicate signal.

I really don't see how but could this be some crazy kind of coincidence, or perhaps something associated with the lighting system problem?

The tuner section of the schematic, F-1479-2A shows two meters and one smal l 6V 100ma lamp. Please correct me if I'm wrong but M705 looks like it coul d be the signal level meter and M706 looks like it is connected to the disc riminator output for station centering. Then there is that small 6 volt 100 ma. lamp which is connected off pin 12 of the board. Could that be the ster eo lamp? To troubleshoot the signal level problem would M705 simply get a D C output off that HA1120 chip and through the transistor proportional to si gnal strength? Thanks for any further help. It is very much appreciated. Lenny

Also goes through the switch, usually.

On Wednesday, June 27, 2018 at 3:30:53 AM UTC-4, snipped-for-privacy@gmail.com wro te:

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for the protection relay to activate and turn on the speakers I finally to ok it out of service. I recall that it had no other problems that were evid ent. I had posted this problem at that time and I think that it was Chuck u p in Canada who nailed it immediately. He recommended changing C6 on the pr otection board and .that resolved the protect relay problem. Now however th ere is another problem that I never had before. Most of the dial lights in cluding the signal meter light are out and that meter also seems to be inop erative as well. I never had any trouble with any lighting or the signal me ter on this receiver. This is a big quadrophonic receiver. The switching is done through the main selector switch and it's a nightmare to get to. A re al rats nest. Does anyone who has worked on these recall any common problem s with lighting on one of these? I suspect a ground problem because so man y of these lamps are in parallel but it's so crowded in that area you can't see anything. I Really appreciate any help. Lenny

e that I will not have to use it but it is comforting to have it. The reaso n I say this is because in the interim I tried my Blue Stuff treatment. I s prayed the switch sections quite liberally and I really worked the switch t hrough all of it's positions.

mittent phenoclic switches in the old tuners was not an overstatement. My display lamps are all on now and there is no smoke. I guess that I would sa y that I'm "cautiously optimistic" that I may actually have restored these tarnished contacts before they actually had a chance to burn.

t and and the display has come on strong without flickering each time. I gu ess we'll see.

eter. As I had said it always worked before and never caused a problem. But now it just lights up and does not indicate signal.

or perhaps something associated with the lighting system problem?

all 6V 100ma lamp. Please correct me if I'm wrong but M705 looks like it co uld be the signal level meter and M706 looks like it is connected to the di scriminator output for station centering. Then there is that small 6 volt 1

00ma. lamp which is connected off pin 12 of the board. Could that be the st ereo lamp? To troubleshoot the signal level problem would M705 simply get a DC output off that HA1120 chip and through the transistor proportional to signal strength? Thanks for any further help. It is very much appreciated.

IIRC, the Blue Stuff product contained an actual abrasive along with the b lue schmutz carrier. If the abrasive scoured the contacts into working, I think I'd follow it up with a non residue cleaner to get the blue carrier o ff. I remember the blue carrier thickening into a stiff almost glue like c onsistency over time.

Lenny,

Does the meter work on AM? If it does then either there is a bad connection from VR2 on the F1479 board to the meter or, more commonly, the potentiometer is faulty. If it doesn't work on AM, either the meter coil is open or the wire to ground or the plus wire from the circuit board is open or C 98 is shorted. Hope one of these hunches is correct. Chuck

r the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were eviden t. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the prot ection board and .that resolved the protect relay problem. Now however ther e is another problem that I never had before. Most of the dial lights incl uding the signal meter light are out and that meter also seems to be inoper ative as well. I never had any trouble with any lighting or the signal mete r on this receiver. This is a big quadrophonic receiver. The switching is d one through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't s ee anything. I Really appreciate any help. Lenny

Chuck I put a remote near the antenna and it does respond to AM. I did see it res pond to FM at one point too. But then it didn't seem to after awhile. The t hing is I can't find VR2 that you mentioned. Which meter is the signal met er? Lenny

Lenny, M705. I wonder if the the meter movement is sticky?

r the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were eviden t. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the prot ection board and .that resolved the protect relay problem. Now however ther e is another problem that I never had before. Most of the dial lights incl uding the signal meter light are out and that meter also seems to be inoper ative as well. I never had any trouble with any lighting or the signal mete r on this receiver. This is a big quadrophonic receiver. The switching is d one through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't s ee anything. I Really appreciate any help. Lenny

Chuck I'm embarrassed to say that I think I know what happened. The RF section on this receiver is pretty hot and so for servicing it on my bench I didn't bother connecting the old outside VHF/FM antenna that is now used just for FM, throughout our house. I was getting what I thought was a decent signal in my basement with just a short piece of wire connected to the high side of the 300 ohm terminals. Apparently in spite of the fact that the FM stations I was tuning in sounded OK there must be a signal threshold that must be met before the signal meter will move. With the unit connected to the outside antenna the signal; meter is now working fine. I don't think that there was ever a problem with it. It was more aptly due to "operator head space"

So now I'm at the final stage of this repair. I have owned this receiver for over thirty years now. I originally bought it from the junk man at our town dump who was going to strip it, for 5.00 It has been a great receiver for all this time,however the 4 channel circuitry never seemed to work properly on it. I worked on it, John Del, also a contributor to this thread worked on it as well, but we never seemed to be able to resolve it. So for that time I have lived with it.

A few weeks ago I was browsing Craig's List and found a guy about 30 miles from my house who had one of these for sale. I went out, and looked at it and thought it might need a discriminator alignment, and I picked it up for parts. So today, first I swapped out the 2048 board. I now have output on all 4 channel positions except the first and last, which seems like it should be. I have 4 speakers connected to speaker A front and back terminals. It seems to sound "OK:" but I can hear a very slight "popping" way down in the mud in the rear speakers.

So I was going to swap out the 2047 board, however in spite of the fact that it would fit in the same slot as my original, the board from the donor receiver is totally different. For one thing there are 7 potentiometers on the donor board and only three on my original board. There are also two 8 pin chips on the original board but it seems to be all discrete components on the donor board. So for boards that fit into the same positions in the chassis are these boards forward and backward compatible? After all this I would hate to make a swap and because it was incompatible wind up destroying something. Lenny

Lenny, The board compatibility question I can't answer. Back in the day we never switched out whole boards on Sansuis. Always troubleshot to the component level. Sorry. Chuck

r the protection relay to activate and turn on the speakers I finally took it out of service. I recall that it had no other problems that were eviden t. I had posted this problem at that time and I think that it was Chuck up in Canada who nailed it immediately. He recommended changing C6 on the prot ection board and .that resolved the protect relay problem. Now however ther e is another problem that I never had before. Most of the dial lights incl uding the signal meter light are out and that meter also seems to be inoper ative as well. I never had any trouble with any lighting or the signal mete r on this receiver. This is a big quadrophonic receiver. The switching is d one through the main selector switch and it's a nightmare to get to. A real rats nest. Does anyone who has worked on these recall any common problems with lighting on one of these? I suspect a ground problem because so many of these lamps are in parallel but it's so crowded in that area you can't s ee anything. I Really appreciate any help. Lenny

Chuck I took a leap of faith assuming that if the second 4 channel board fit mech anically it would work electronically. And to my great luck and surprise it did! I'm not sure if I now have two earlier or later versions of the quad boards in there now but they were apparently compatible. And the retrofit w orked quite well too. The very slight "popping" noise that I had previously heard out of the rear speakers was gone, the dead rear channel is restored , and in fact the sound was clean through all the speakers. I have never he ard "4 channel" out of this unit so this is going to be thrilling uncharted waters.

Now I do realize that no one broadcasts 4 channel analog any more and I als o know that sources to reproduce it including any records, or tapes, etc ar e probably few and far between anyway. But I was wondering if you might hav e any information on that?

The guy that I bought the organ donor from included a large plasticized she et with it showing all possible hookups. It also had brief explanations of all controls and their positions and there seems to be a couple of "synth esized" positions that according to this hookup sheet can apparently simula te 4 channel sound. I think that those look like "hall" and "surround". I d o feel like When listening in some of these positions, perhaps I may be ima gining it but the sound does seem to take on a whole new spaciousness to it .

I recall hearing years ago when I first contacted Sansui for a service manu al that the 5500 sold for over 900.00 back in it's hey day. In 1974 I was living in a small apartment over a restaurant with my cat. I wouldn't have been able to afford the carton to pack this in.

So now after all these years I that finally own that has the capability to be used in ways that were not available to me before I don't really know wh at to expect from it. And so I was wondering if you might be willing to com ment on that experience and maybe 4 channel analog in general. Thanks again . Lenny

Lenny,

The Sansui surround system was called QS. It wasn't very successful. I noticed a few QS records on EBay including one by a Chicago folk singer Bonnie Koloc on Ovation records. I bought this album in the early 70s and, if you like poppy folk music, it would make an ideal test record to experience the QS quad experience. Chuck