Optonica SA-5605 Help

[Juan-Jose]

Hello! I have this beautiful Optonica SA-5605, turns on, clicks out of protection (indicator turns green) but I get no sound.







Called a local tech to take it for repair, and he said that he only does "major brands".

So, I bought the elusive service manual (it is different from the SA-5606) to give it a try but my troubleshooting skills are too bad. I've tried attaching the files for your convenience but keep getting a "The uploaded file is too large" error.

Any help would be much appreciated.

 

[cademan]

Can you show a pic of the rear panel?

Did you just get this?

Check the easy stuff first: Is the tape monitor on? Are the speakers turned on? Does it have "PRE OUT/MAIN IN" capabilities?

 

[Juan-Jose]

It's connected to a pair of working 8 ohms speakers. I've tried each channel (A, B & C): nothing. Not even thru the headphones. I've tried each input (Aux, Phono's and Tape's) with the same sources I use for my current setup. And also the tuner (both AM & FM).

 

[cademan]

Did you have sound before?

 

[Juan-Jose]

Did you have sound before?

I got it as part of an estate sale lot. It was supposed to be working ...but it isn't.

 

[Juan-Jose]

Sharing the service manual here.

 

[cademan]

So no, it never had sound since you got ahold of it.

Make sure both fuses are good.

It's hard to follow the schematic on my tablet and unless someone is there to help in person.........

 

[Juan-Jose]

So no, it never had sound since you got ahold of it.

Make sure both fuses are good.

It's hard to follow the schematic on my tablet and unless someone is there to help in person.........

Both fuses taken out and tested Ok for continuity.




Thanks for helping!

I have multimeter, soldering station, scope, etc... I took an electronics vocational course and worked assisting a navy engineer at a radio station, but that was over 30 years ago and then I switched to computer repair ...so my electronics troubleshooting skills are long gone (if there were any). But I can follow directions. Let know what to check and I'll follow.

Again, I really appreciate any help!

 

[ivandezande]

View attachment 2318095

Both fuses taken out and tested Ok for continuity.

View attachment 2318139
View attachment 2318140

Thanks for helping!

I have multimeter, soldering station, scope, etc... I took an electronics vocational course and worked assisting a navy engineer at a radio station, but that was over 30 years ago and then I switched to computer repair ...so my electronics troubleshooting skills are long gone (if there were any). But I can follow directions. Let know what to check and I'll follow.

Again, I really appreciate any help!

Replace all the fusable resistors.

This has been the problem in all Optonicas I've worked on. They are a lighter color and off the board.

 

[Juan-Jose]

Replace all the fusable resistors.

This has been the problem in all Optonicas I've worked on. They are a lighter color and off the board.

I tested all fusible resistors, all reading within range ...all EXCEPT for R649 which should be 100 ohms but it's reading +2K and looks burnt:

AWESOME! Thank you so much, @ivandezande !

 

[Juan-Jose]

Oops! I overlooked one page, still need to check several other resistors.

 

[ivandezande]

Why test? Replace them. They will fail.

 

[Juan-Jose]

Why test? Replace them. They will fail.

Ok!

 

[ttbccw]

I have a 5605 that I completely went through. I am very familiar with this specific amp.

No sound could be a lot of things. Checking the fusible resistors is a start. They protect each individual board from power problems. If there is a bad one then that might be a clue to follow.
I accidentally shorted the low voltage power supply while taking voltage measurements. I suggest using the test points on the boards so that shorts don't happen. The fusible resistors saved the components on the other boards
The fact there is no sound from the FM/am section is also a clue. The audio goes through so many points, and the tone boards are dense with components.
I'll have to look at the schematics for the 5605...and yes they are different... especially the main amp board.

 

[ttbccw]

Ok, I looked at the schematic. R649 is a fuse for the 29vdc supply from the low voltage power supply. I would test to see if there is 29vdc or so feeding that resistor...Q601 & Q602 in the power supply should be checked for voltages. & C611 & C612

 

[Juan-Jose]

Ok, I looked at the schematic. R649 is a fuse for the 29vdc supply from the low voltage power supply. I would test to see if there is 29vdc or so feeding that resistor...Q601 & Q602 in the power supply should be checked for voltages. & C611 & C612

Readings as requested:
R649 +28.6V
Q601 +28.9V (E) +29.6V (B) +33.6V (C)
Q602 -29.1V (E) -29.7V (B) -36.4V (C)
C611 +28.9V
C612 -29.1V

 

[Juan-Jose]

There are several bad fusible resistors (most of them 100ohms) but, as advised, I've ordered and will be replacing all of them.

 

[ttbccw]

Ok. I think those voltages are correct.
You can definitely replace them, IIRC they are all 100ohm.
Which ones tested open like R649?
The 29+ and 29- from those feed the other boards, and the tuner power supply (on the schematic it's just below this)
If there is a shorted component on one of the boards it would blow the new resistors as well.
I shorted this power supply and it blew those transistors, diodes and the same fusible resistors...R649 & R616

 

[Juan-Jose]

R531 100 OHMS 1/4W <<<BAD
R532 100 OHMS 1/4W <<<BAD
R523 100 OHMS 1/4W <<<BAD
R524 100 OHMS 1/4W <<<BAD
R525 100 OHMS 1/4W <<<BAD
R526 100 OHMS 1/4W <<<BAD
R527 100 OHMS 1/4W <<<BAD
R528 100 OHMS 1/4W <<<BAD
R545 100 OHMS 1/4W <<<BAD
R546 100 OHMS 1/4W <<<BAD
R547 100 OHMS 1/4W <<<BAD
R548 100 OHMS 1/4W <<<BAD
R649 100 OHMS 1/4W <<<BAD
R355 100 OHMS 1/4W <<<BAD
R356 100 OHMS 1/4W <<<BAD
R537 270 OHMS 1/4W <<<BAD
R538 270 OHMS 1/4W <<<BAD
R543 270 OHMS 1/4W <<<BAD
R544 270 OHMS 1/4W <<<BAD

 

[Juan-Jose]

Tested Ok:
R613 1.0 OHMS 1/2W
R647 1.0 OHMS 1/2W
R601 1.0 OHMS 1/2W
R602 1.0 OHMS 1/2W
R563 4.7 OHMS 1/4W
R564 4.7 OHMS 1/4W
R605 4.7 OHMS 1/4W
R606 4.7 OHMS 1/4W
R529 4.7 OHMS 1/4W
R530 4.7 OHMS 1/4W
R533 4.7 OHMS 1/4W
R534 4.7 OHMS 1/4W
R535 4.7 OHMS 1/4W
R536 4.7 OHMS 1/4W
R616 10 OHMS 1/2W