Sansui qrx9001 low output.

[kevzep]

ok............by the way........when we did the famous test that blew my last outputs it also blew the fuse in my meter..............I almost started to adjust bias without the fuse being ok.......by chance....I said to myself...'check the fuse in the meter"...and whadya know....blown..............
Anyway I am happy we finally made it this far.......will post pictures of music and audio!

Ohh Yeah......Im not surprised it blew the fuse in the meter......with TR10 shorted it was gonna be all bad.......not surprised it took out TR06 too.....

Well Im really happy for you, and Im glad you didnt give up, thats the thing with electronics, theres always an answer when something has a fault..........it can always be found if you just keep at it....

I bet you feel good now......
Get the Bias and offset done and put your feet up and listen to some tunes!!!

 

[skippy124]

Great result guys, persistance wins through!!

 

[anderslober]

hey kev....I have to ask som'ink.........my RB outputs are not original....they are MJ's...if I put in the originals in again...will I have to do Bias and off-set again? I have gotten hold of some original 746/1115's.............can I just pop them in and thats that?

Will post a couple of pictures....when I have music setup and stuff..............

On another note.......you 2 fellas(trnsfmr/you) showed real "staying power"...even when this rollercoaster was at its peaks and troughs........I can't thank you fellas enough for persistence and PATIENCE...........darn, I learned a LOT!

 

[joekid]

Yes.:lmao::yippy::guitar: what more can I say
Good luck
Joe:wave:

 

[Pepa]

What a marathon !!
Hats off to you guys
anderslober,enjoy in your (now priceless) new Sansui

 

[nosirrah]

Good work gents, this one has been a marathon.:thmbsp:

 

[Trnsfmr]

"The Saga of the Anderslober 9001" a tail of adventure, pain, and conquest


Well, I guess it all works out in the end. It shall now be known on AK as, "The Saga of the Anderslober 9001", a tail of adventure, pain, and conquest.

Be it always known, that on AK, we can fix anything. Because we have just fixed the biggest most complicated that there is. :thmbsp:

Congatulations to you Anders. Kev, you are the master amp guy. Way to hang in there. :yes:

Great fun guys.

 

[Trnsfmr]

hey kev....I have to ask som'ink.........my RB outputs are not original....they are MJ's...if I put in the originals in again...will I have to do Bias and off-set again? I have gotten hold of some original 746/1115's.............can I just pop them in and thats that?

Yes, pretty much whenever you change anything on the output driver board, or the output transistors themselves, you need to check offset and bias. It's just safe to do that. Probably the only thing you could change, that wouldn't affect the settings, believe it or not, would be the input differential pair of transistors. They do not operate in a normal transistor mode, their gain is not important. If I changed them, I would still check offset and bias, just to be safe.

 

[kevzep]

hey kev....I have to ask som'ink.........my RB outputs are not original....they are MJ's...if I put in the originals in again...will I have to do Bias and off-set again? I have gotten hold of some original 746/1115's.............can I just pop them in and thats that?

Will post a couple of pictures....when I have music setup and stuff..............

On another note.......you 2 fellas(trnsfmr/you) showed real "staying power"...even when this rollercoaster was at its peaks and troughs........I can't thank you fellas enough for persistence and PATIENCE...........darn, I learned a LOT!

Yes as Jim said if you change anything in the driver boards or the output section you need to reset the bias and the DC offset......

You could change those outputs if you want but the MJ's are excellent devices and they wont affect the sound, but I can understand you would want to keep it as original as possible........

No problem with the helping, it something I like to do when I can, you are most welcome..........

 

[kc613]

resurrecting the 9001

WAY TO GO!! congratulations you guys, Jim, Kev,Anderslober et al, qrx 9001 warriors. what a read. amazing.

 

[kevzep]

WAY TO GO!! congratulations you guys, Jim, Kev,Anderslober et al, qrx 9001 warriors. what a read. amazing.

Hey, welcome to AK, if you have a Sansui and its needs repairing you know where to come.........

 

[Trnsfmr]

Hey, welcome to AK, if you have a Sansui and its needs repairing you know where to come.........

Yeah, right on. In three or four weeks, and 30 or 40 hours of your time, we can fix anything. LOL

Hey Kev, I feel like I just took the advanced course in amp repair and safe turn on. I really do appreciate your knowledge.

Hopefully Anders will have some pictures to put up tonite. I'd like to see the beast, maybe with him next to it.

 

[kevzep]

Yeah, right on. In three or four weeks, and 30 or 40 hours of your time, we can fix anything. LOL

Hey Kev, I feel like I just took the advanced course in amp repair and safe turn on. I really do appreciate your knowledge.

Hopefully Anders will have some pictures to put up tonite. I'd like to see the beast, maybe with him next to it.

Its actually been a lot of fun, Ive enjoyed working together with you on this project, its good to have two minds working together........although there was a lot of chin and head scratching going on at times......

Well we will have to keep an eye out for the next project :thmbsp:

Yes I'm keen to see the pictures, and we managed to get it sorted before he had to go away on the long trip........

I think we really captured the essence of this forum......its a great place to hang out :yes:

 

[anderslober]

trnsfmr..kev...all yee other good folk..........Unit is out of protection:thmbsp:

Bias=SET=29.9-29.8-29.9-30.1.

DC offset=1.5-1.7-1.5-1.8 . Quite hard to get close to 0v.....fluctuates a bit.

Listenin' to FM 95 Singapore.......no friggin' aerial....crystal clear sound!

One small thing..............left power meter.....not indicating/reacting. All others are good.

 

[Trnsfmr]

Very good numbers on the offset and bias. All you need is a clip lead to pick up all the stations for 100km. Looks really good.

Also, I'm really encouraged and am thinking you're well on your way to being a great tech... because .... there's a little bit of mess on your workbench!!!! Now just nurture that and let it grow, and before you know it, you'll be fixin everything in sight.




IT WORKS!! WE DID IT!!

 

[Trnsfmr]

By the way, try exercising the far right button switch. The meter might come back.

 

[anderslober]

hey trnsfmr..........its great......the "beast' has been playing now for more than an hour. Everything is stable.......the FM is really, really good......I don't have an aerial connected and I can pick up all stations around the island..........

Very few things to go now..........before clean-up and close-up......any ideas on the left power meter? I have tried to follow the electrons........maybe even just 'cold solder'?

But all is good.

(I have another project comin' up.....beaten up sx1250........I'll probably be bustin' your chops with that one too!;-)

 

[kevzep]

hey trnsfmr..........its great......the "beast' has been playing now for more than an hour. Everything is stable.......the FM is really, really good......I don't have an aerial connected and I can pick up all stations around the island..........

Very few things to go now..........before clean-up and close-up......any ideas on the left power meter? I have tried to follow the electrons........maybe even just 'cold solder'?

But all is good.

(I have another project comin' up.....beaten up sx1250........I'll probably be bustin' your chops with that one too!;-)

Your Bias and Offset figures look really good.........
Very pleased to hear the Beast is working........Indeed Sansui boast receiver brilliance.......I listen to a local FM station here quite a bit with my G-9000, sounds great......

Dare I say, there will be a meter drive circuit that may need looking at??????
However, it could also be something simple........

Let me have a look at the schematic......

So whats this, are you trying to drag us over to the dark side with that ..............pioneer sx-1250..............
I will never be turned, Im a Sansui Jedi!!!

 

[anderslober]

trnsfmr......I did trace that brown wire from the meters to the meter board.....massaged it a bit.......still no reaction on the meter...will look and fiddle further..........

kev ...i have looked at schematic......where the heck is that meter circuit? i am staring myself blind on that schematic!

 

[kevzep]

trnsfmr......I did trace that brown wire from the meters to the meter board.....massaged it a bit.......still no reaction on the meter...will look and fiddle further..........

kev ...i have looked at schematic......where the heck is that meter circuit?

The meter driver circuit is on the F-2689 board, which is near the front of the amplifier and to the left......
If you refer to the power output meter adjustment you will see there are four trimmers to calibrate the meters VR01-04, this is the board its on......
There is basically a bunch of diodes and capacitors.....its all driven directly from the speaker outputs.....

You may have an intermittent trimmer, but be careful you dont want to screw up the meter calibration......
Its easy enough to set of you have an oscillator otherwise be careful, what you could do it just tap the offending meters trimmer very lightly with a small screwdriver, and see if you get any movement from the meter, because if its intermittent the tapping might make a connection....

The adjustment instructions are on page 8 of the service manual.....

See how you go.....