au717 no right channel.............

[x37tuna]

good monrin everyone........well just to start off..ive been e sprayed.....picked this au717 up on the bay..if anyone saw it it was the one the right channel doesnt come on untill the unit warms up for about ten minutes,,,,well.....its been on for about three hours now cant get a sound out of it...i did do some pokin round..very clean unit...well takin care of...everything looks in order..i did switch the driverboard singles...f 2721,f2722...agian only only the left single comes through.. so i believe that the driver boards are in good shape..just so its clear..i did run the tuner through the aux..then the tuner.tape inputs with no change...i went a little furthter and ran the tuner through the pre out, power amp in section..of course the switch was dirty (cleaned it) and got good sound out of both channels..but of course no pre amp adjustments...so im guessin that the problem is in the pre amp section.. this is a nice unit.just as good if not better then the one im running now...except the one im running now works...lol....even so...mybe someone out there can give a rookie some sdvice on takin the next step in tryin to figure this thing out...i have posted on here before and received a lot of helpfull information...this is a great site...oh yeah i did adjust the offset and bias witch wernt that bad really and both boards hold the adjustment pretty good im around .3 mv on both sides, 0 to .1 on the bias.. that made me feel good.........................

 

[seadzz]

Did you clean the switch in the back of the unit marked "connected/seperated"?

If that switch is funky you can get all sorts of strange goings on.

sdz

 

[x37tuna]

yes i did seadzz...i know about theses switches and that was one of the first things i tthought of...i was hopeing when i bought it that that mite be the case..its kinda funny thuogh like i said in my last post the unit is very clean and all the switches and pots are clean with no scratchieness to them...thanks for the comeback..anymore thoughts out there that mite help?????????

 

[scottrt]

Have you tried it with headphones? Sounds like a bad component on the dreaded F2663 PS/Regulation board. Be patient, the Sansui Lords will chime in here with some more hlpful advice.

'bias' should be set at 20 mv, DC-offset zero'd out. Are you measure Bias at the proper test pins?

Scott T.

 

[Morden2004]

good monrin everyone........well just to start off..ive been e sprayed.....picked this au717 up on the bay..if anyone saw it it was the one the right channel doesnt come on untill the unit warms up for about ten minutes,,,,well.....its been on for about three hours now cant get a sound out of it...i did do some pokin round..very clean unit...well takin care of...everything looks in order..i did switch the driverboard singles...f 2721,f2722...agian only only the left single comes through.. so i believe that the driver boards are in good shape..just so its clear..i did run the tuner through the aux..then the tuner.tape inputs with no change...i went a little furthter and ran the tuner through the pre out, power amp in section..of course the switch was dirty (cleaned it) and got good sound out of both channels..but of course no pre amp adjustments...so im guessin that the problem is in the pre amp section.. this is a nice unit.just as good if not better then the one im running now...except the one im running now works...lol....even so...mybe someone out there can give a rookie some sdvice on takin the next step in tryin to figure this thing out...i have posted on here before and received a lot of helpfull information...this is a great site...oh yeah i did adjust the offset and bias witch wernt that bad really and both boards hold the adjustment pretty good im around .3 mv on both sides, 0 to .1 on the bias.. that made me feel good.........................

It sounds like a preamp problem. What you can do is cross over the pre-out/mail in (LEFT -> RIGHT and RIGHT -> LEFT) with inter-connects and confirm that the LEFT channel now has sound. That will confirm the pre-amp is the culprit.

Then we need a schematic and a signal tracer - you can make one out of a spare interconnect and a 0.047 uF capacitor.

Paul

 

[x37tuna]

thanks agian for the input....i do not have a pair of headphones...that thought did cross my mind..i guess i did read the specs wrong on the bias...will readjust and get back to you on that...im kinda pointing at the dreaded f2663 board myself but we'll see..Mordern......im not quite sure what u want me to do...do u mean me to conect the pre out to the power amp in ?? agian i am a rookie so u mite have to type a little slower....lol.....

 

[x37tuna]

well i reset the bias 20mv +/- 1mv...offset at zero.. it seams to be holding nicely...hooked it up agian, same resaults no right channel.. im not even getting a hint of sound out of it like a weak single,as much as i dont like to say it....dead..got to looking round at the f2663 board and i can see more of the dreaded glue on the board then i care to see..i know this board is one of the harder ones to work on..so im thinkin.. this is a learn as u go type side project... i mite as well take it out and rebuild the thing...any thoughts on why or why not a rookie mite do or not do this.........

 

[seadzz]

That F2663 pcb is the most difficult board to remove in a AU 717. Not impossible but difficult. You will need to desolder several wires so its a good idea to take some pictures or at least take notes on what goes where so you can reassemble the unit correctly.

The symptom does sound like a preamp board could either not be getting its drive voltage from the power supply or could be defective in its own right. Before I took the F2663 out I would be real sure that it and not the preamp was the problem.

sdz

 

[Morden2004]

What I was suggesting you do is connect, using interconnect cables, as follows:

PRE_OUT {LEFT} - > MAIN-IN {RIGHT}
and
PRE_OUT {RIGHT} - > MAIN-IN {LEFT}

That will confirm either that the PREAMP is at fault if sound is now OK on the RIGHT channel speaker or the POWER AMP is at fault if the RIGHT channel speaker is still dead.

Paul

 

[x37tuna]

modern...thanks for your time and input....i did do the pre out... main in thing last night...same resaults..no right channel....got to lookin at the f2663 board a little closer this moring..took some bad pictures...will post them here.. i think they will give u a idea what im lookin at..what im assuming is a transistor is pretty eatin up by the dreaded glue..im assuming that board is split up for the left and right channles, and one side is worse then the other, the way i fallowed the wireing the side that was corroded the worst is for the right channel and the left ones not far behind...let me know what u think.....thanks agian for the time....on a side note..a friend of a friend stopped over yesterday, he heard i was running sansui amps and found he was a aker to...( small world)..anyway hes now looking to run his new jbl's with a sansui amp... seams like hes got a good ear........

 

[Morden2004]

modern...thanks for your time and input....i did do the pre out... main in thing last night...same resaults..no right channel....got to lookin at the f2663 board a little closer this moring..took some bad pictures...will post them here.. i think they will give u a idea what im lookin at..what im assuming is a transistor is pretty eatin up by the dreaded glue..im assuming that board is split up for the left and right channles, and one side is worse then the other, the way i fallowed the wireing the side that was corroded the worst is for the right channel and the left ones not far behind...let me know what u think.....thanks agian for the time....on a side note..a friend of a friend stopped over yesterday, he heard i was running sansui amps and found he was a aker to...( small world)..anyway hes now looking to run his new jbl's with a sansui amp... seams like hes got a good ear........

Kinda fuzzy pics but I would say that you have a driver card re-build on your hands. Just desolder the components and clean off that glue. Check the components you removed for value - replacing all those transistors is not an expensive job. You'll probably want to go ahead and order the transistors and diodes and any failed resistors, and replace the minature electrolytics as well. Shouldn't cost more than $30-$40.

Paul

 

[scottrt]

Check for open resistor on driver board?

So, have we determined then that F-2663 is NOT the problem? By switching L for R the pre-out /main-in and still having a right channel issue have we confirmed that F-2663 is OK, and that the problem is in the right channel output board?

If so, I rmrmber folks talking about about a resistor on this board that opens up....apparntly it was a very common proble, and is the first thing to check for. Hope this helps.

Please someone correct me if I am sending him in the wrong direction!!!!

Scott T.

 

[seadzz]

If you elect to rework the F2663 board you need only unsolder the six wires marked in yellow. The joker that recapped this board was too lazy to remove the glue...if you look close you can still see its there around the new green caps. Sorta half baked in my mind.

Anyway, free up these 6 wires and leave everything else attached (except the quick disconnects) but don't forget to take a clear photo of the wire placement before you remove anything. Worst thing you can do is misswire it and fire up the amp....big sparks will fly I'm 99% sure.

Good luck,

sdz

 

[x37tuna]

agian..thanks to everyone whos takin a intrest in my project..im gonna try tonight to take some better pictures of the board...i am not 100% sure that the f2663 board is the problem.but if u could see through the fuzzyness of my bad pictures it does need the most atention, as far as the driver boards scottrt i did switch the single wires to the boards and got sound out of it, not that there in great shape but at least the single path is not dead in them boards...so if i understand right these f2663 boards are a common problem or should i say the dreaded glue is...my next question is there anyone out there with a parts list of any kind for these boards and where is the best place to get the parts....thanks agian for the input..its monday morning and i gotta go to work, im gonna work on them pictures tonight. will post................

 

[seadzz]

I don't have a parts list but this may help if you are sans a manual. I'll split it into two parts. You can print them out and tape the pages together.

sdz

 

[seadzz]

Here's the rest

sdz

 

[x37tuna]

seadzz thanks for the clear picture...took them wires off, slipped the board out..wasnt bad..got a little clearer pictures out of it...it seams my board is a little different then that one, production thing im sure...any ways i circled the componets that i really cant tell what they are because there rotted away..any help with ideeing these would be a big help...got a list of all the caps no problem there...take a look and see what u guys think....

 

[seadzz]

x37tuna,

I can't see anything on your photo's that is circled. You should be able to match up the components on the board with the scans I posted in #17. Then match that to the schematic.

Sorry I can't be of more help.

sdz

 

[scottrt]

No components go there, if your talking about the 6 points you circled in yellow. Please go to the thread below, and scroll to post # 27. EW has a nice pic of this board after restoration. Hope this helped.
Scott T.
http://audiokarma.org/forums/showthread.php?t=63404&page=2&pp=15

 

[x37tuna]

ok ok ok...i messed up with the pictures...this dam thing getts to me sometimes...lol... thanks seadzz for the downloads not much on the technical stuff but these will be real nice to have...im gonna try agian.. yes agian.. to send them pictures ..maybe i can get it right this time..bear with me and give a rookie a break....ill get it sooner then later.