Sansui QS 100: Help Needed for Oscillator and Synthesizer Boards.

[Argou]

Hello all ,
Just sign up !
Im new here and new in the quadrophonic “experience “
I just got this little thing from eBay in Germany to hook it up with my Sansui Au 555a , TU 666 and the SR 525 . Not the great shape but in working condition…

I manage to recap it and replace some bad transistors and upgrade to led kit lamp ….

The results after the recap was like day and night , clear sound from the rear amp no distortion even with all the way up the level set and volume but the surround effect and decoding not that great …..

I know that the vario matrix , later technology and other QS , like the QS 800 can perform better but I think that this one might do better and benefit by readjusting and replacing the trimmers on the oscillator / synthesiser boards (F1357 /F1356) But there are no adjustment mentioned in the the operating/service manual for this boards .
I have contacted the distributor in Greece (they are still open ) but no luck getting informations, same with the Danish distributor, he remembers that the authorised technicians had a service manual of their own only for service in the store …. So nothing there as he has throughout everything since then …..
Only chance is here and yes I took my chances in the “exclusively Sansui forum” too but nothing there either ….
So maybe someone here knows or has serviced in the past one of those and knows the adjustment and the procedure for the oscillator and synthesiser boards

It’s this two boards …..

Thank you in advance for any insight !!!
Cheers
Kostis

 

[Old Quad Guy]

Hello, and welcome to QQ. I added the Help part for your thread title, to get a good response, if this is correct. Thanks.

 

[DuncanS]

Have you seen the manuals and schematics on Hi-Fi Engine? Sansui QS-100 4-Channel Rear Amplifier Manual | HiFi Engine

 

[Argou]

Have you seen the manuals and schematics on Hi-Fi Engine? Sansui QS-100 4-Channel Rear Amplifier Manual | HiFi Engine

Hey Duncan ,
Yes I have those , no information at all about ajustemts for oscillator and synthesizer board ,
Its only references for the bias and the VU meters .....
Cheers
Kostis

 

[Argou]

Hello, and welcome to QQ. I added the Help part for your thread title, to get a good response, if this is correct. Thanks.

Thank you " old quad guy " sorry for the incovinience, still trying to figure out , where goes what !!!
Cheers
Kostis

 

[Sonik Wiz]

Hej Argou!
Nice looking unit you have there. I've had a Sansui QS-1 and QS-500B, both have very similar decoding circuits. While it is good to have things adjusted to best possible I wouldn't be overly concerned about the oscillators & phase modulation circuits. They affect only the rear channels & have nothing to do with separation enhancement. Sansui's main goal with this was to decorrelate the rear sound to "spread it out", to make it a diffused ambient soundfield.

I think my service manual has directions how to do this. I think it required a 1kHz signal source & oscilloscope to observe the phase modulations. The trim pots merely set the oscillation speed to the light bulb / photocell modules for the phase modulation.

 

[Argou]

Hej Argou!
Nice looking unit you have there. I've had a Sansui QS-1 and QS-500B, both have very similar decoding circuits. While it is good to have things adjusted to best possible I wouldn't be overly concerned about the oscillators & phase modulation circuits. They affect only the rear channels & have nothing to do with separation enhancement. Sansui's main goal with this was to decorrelate the rear sound to "spread it out", to make it a diffused ambient soundfield.

I think my service manual has directions how to do this. I think it required a 1kHz signal source & oscilloscope to observe the phase modulations. The trim pots merely set the oscillation speed to the light bulb / photocell modules for the phase modulation.

Thank you Sonic Wiz ,
I did read something that you have post about years back " vario matrix survival guide " ( excuse me if it wasn't you ) I didn't understand much as I'm not even close to technician, it s just my hobby ;

I would be greatfull if you can find your schematic and post the adjustments or if you can write the procedure? Then I can bring the unit to a vintage repair store and do what is needed to be done but them will ask for the prosidure as there is a 3ed trimmer on the oscillator doard , meaning that it's not only just right and left and adjusting the right numbers ( that we don't know even ) bit should be a prosidure too, at least this what my " common sense" says ....
Thank you again for your time
Kostis

 

[Sonik Wiz]

Thank you Sonic Wiz ,
I did read something that you have post about years back " vario matrix survival guide " ( excuse me if it wasn't you ) I didn't understand much as I'm not even close to technician, it s just my hobby ;

I would be greatfull if you can find your schematic and post the adjustments or if you can write the procedure? Then I can bring the unit to a vintage repair store and do what is needed to be done but them will ask for the prosidure as there is a 3ed trimmer on the oscillator doard , meaning that it's not only just right and left and adjusting the right numbers ( that we don't know even ) bit should be a prosidure too, at least this what my " common sense" says ....
Thank you again for your time
Kostis

Hello again.
I have some pics & info I hope can be usefull to you. I have never owned the Sansui QS-100 but as I said I’ve owned both the Sansui QS-1 & QS-500B. I have service manuals on both. Of the two manuals the one on the QS-1 is the most comprehensive & the only one with the Phase Modulator adjustment info.

I see the QS-100 has very similar but not same part numbers as the QS-1.

QS-100
Synth Board = F-1356
Oscillator Board = F-1357

QS-1
Synth Board = F-1327
Oscillator Board = F-1328

All of the adjustment info pertains to the F-1327 / 1328 boards, as does the test points mentioned ( circled numbers ). It will be up to you or your tech to make sure how to interpret this so it pertains to the QS-100 boards so you are not or adjusting the wrong items. You will need to adjust the 3 pots on the oscillator boards as well as the 2 pots on the synth board.

The circuit schematic barely fitted on my scanner bed so I apologize it only contains the section relevant to the phase adjustment. Ignore my hand notations from many decades ago….

Edit: yes I'm the author behind the QS Variomatrix Survival Guide. Good to know folks are still referencing it and thanks to @par4ken for scsnning & posting here!

 

[Argou]

Hello again.
I have some pics & info I hope can be usefull to you. I have never owned the Sansui QS-100 but as I said I’ve owned both the Sansui QS-1 & QS-500B. I have service manuals on both. Of the two manuals the one on the QS-1 is the most comprehensive & the only one with the Phase Modulator adjustment info.

I see the QS-100 has very similar but not same part numbers as the QS-1.

QS-100
Synth Board = F-1356
Oscillator Board = F-1357

QS-1
Synth Board = F-1327
Oscillator Board = F-1328

All of the adjustment info pertains to the F-1327 / 1328 boards, as does the test points mentioned ( circled numbers ). It will be up to you or your tech to make sure how to interpret this so it pertains to the QS-100 boards so you are not or adjusting the wrong items. You will need to adjust the 3 pots on the oscillator boards as well as the 2 pots on the synth board.

The circuit schematic barely fitted on my scanner bed so I apologize it only contains the section relevant to the phase adjustment. Ignore my hand notations from many decades ago….

Edit: yes I'm the author behind the QS Variomatrix Survival Guide. Good to know folks are still referencing it and thanks to @par4ken for scsnning & posting here!

Thank you so much SonicWiz , obviously you are not carrying that nickname for no reason
That is the closer we can get and it’s more than enough , I will make sure to come back in this thread and update with the exact adjustments for the QS- 100 given from my tech and listening impressions after the alignment . It might take a bit before I come back but I will for sure !!! Sonic Wiz you are the hero of the day …. Maybe the year too!!!
Thank you again !
Cheers
Kostis

 

[Sonik Wiz]

Thank you so much SonicWiz , obviously you are not carrying that nickname for no reason
That is the closer we can get and it’s more than enough , I will make sure to come back in this thread and update with the exact adjustments for the QS- 100 given from my tech and listening impressions after the alignment . It might take a bit before I come back but I will for sure !!! Sonic Wiz you are the hero of the day …. Maybe the year too!!!
Thank you again !
Cheers
Kostis

Thanks but I am only one of many here on the forum that if they have the info, they will be glad to help out!

 

[par4ken]

I remember being very intrigued by the phase modulation idea when I first read about it in the mid seventies. I was even thinking of ways to accomplish it. nothing ever came close to an actual project though. I wonder if the oscillator was of a lower frequency if the effect would have been more noticable.

My QS-1 sounds very nice when conceited in a system with closely spaced speakers. In a larger room it doesn't seem to do much of anything. Maybe the small changing phase effect is swamped out by the larger room and it's own reflections.