SANSUII BA-3000 PROBLEMS

[pppoffice]

A thought, since there has been a bunch of soldering on wires... I would be VERY suspect of the shielded cables... the center wire insulator is almost a foam, if to much heat is used on the shield it can melt through and give you a nice short to ground, so maybe some passive ohm meter checks might be in order....
AND
I would ( when testing the 2513 ) see that you get signal on the input wires on the correct 2512 pins going into the 2507 , but do NOT have the 2507 in circuit.

I checked all of the shielded cables that go to the 2513 board and there are no shorts. I think that I had mentioned to you that I redid the red cable as the wires were getting all screwed up and could possibly short to each other and now i have also made the same kind of repairs to all of the shielded cables that go to the 2513 board.

 

[vigman]

I need to see a pix of #1 & 2 2507 and I am unclear if you got audio to the speaker out ? ( I bet not )

 

[pppoffice]

I need to see a pix of #1 & 2 2507 and I am unclear if you got audio to the speaker out ? ( I bet not )

No, the sad fact is that I DID NOT get anything to the speaker out. I will have to remove the #1-2507 board to take a picture of it which requires I unsolder the wires to the 2512 board so it will take a minute or so. I will get the pics right now.

 

[vigman]

All of my 2507's have TR-12 ( the little can transistor ) AND have your style resistor board between the bricks
Something is VERY FISHY ! WHAT WIRES do you need to desolder ?? on the 2512 to 2507 ???? That is AFU as well !

 

[vigman]

Just to verify on the 2512 to brick should be see pix

Back connector
twds rear
Yellow
skip
White


No spaces
twos rear
Gray
Orange
Black
Green
Brown
Blue
Red

 

[vigman]

Close up

 

[vigman]

You need this style

 

[vigman]

Minus the smoked resistors

 

[vigman]

So If I understand
The DBT glows on start and goes Dim
You have audio out of the 2513 ( Lets stay with the leader at this point )
Unit comes out of protect
All power supplies are still OK?

 

[pppoffice]

I'm sorry I haven't got back before now but every time i looked at the 2512 board I found another bad trace. So far I have fixe 3 bad traces and I think I have found them all now. After retesting #1 2507 board before pulling it I now have high bias voltage at .25 vdc and I can't adjust it. I have to run to dinner but after I get back I will pull the 2507 board and take pictures of both for you. I just started finding things and thought it was necessary to make the repairs before pulling the 2507 board. I will be back in about 1 1/2 or 2 hours with pictures and more information.

 

[vigman]

.25 DC = 250 mv and you need 20 mv and bias that high will cook things

 

[vigman]

8 pin style


10 pin style

 

[vigman]

This is version of F-2507 ( 8 pin ) with BIAS transistor 2SC984 (genuine NOS Hitachi) included on the board. There is an another version of Driver Board F-2507 ( 10 pin ) for those amplifiers what doesn’t has BIAS transistor on driver board (BIAS transistor is on the power stage of amplifier), so you should know what kind of driver transistor yours Sansui amplifier has because those two type of F-2507 boards are not interchangeable!

 

[vigman]

The schematic fro HI FI engine is for the OLD BA 3K ( 10 pin )
Oh and the 2507 heatsink is not connected to the circuit ( or shouldn't BE ) So the screw for bolting em in is a mechanical connection only !

 

[pppoffice]

All of my 2507's have TR-12 ( the little can transistor ) AND have your style resistor board between the bricks
Something is VERY FISHY ! WHAT WIRES do you need to desolder ?? on the 2512 to 2507 ???? That is AFU as well !

Both of my amps and all of my 2507 boards have 5 wires that are soldered to the bottom of the boards as you will see in the pictures here of the 2507 boards. These 5 wires go thru the square holes in the 2512 board that is even shown in the service manual and then get soldered to the 2512 board to match up with the same colored wires that come from the brick to the 2512 board. That's the way both of my were when purchased and the way they have been kept ever since. I have always wondered why these wires were necessary but I didn't want to change anything from how they were originally. They are a giant pain in my rear as with all the other wired to the 2512 board these just make it more difficult to solder as the 2512 board is so darn busy anyway.

 

[pppoffice]

View attachment 1009426 Just to verify on the 2512 to brick should be see pix

Back connector
twds rear
Yellow
skip
White


No spaces
twos rear
Gray
Orange
Black
Green
Brown
Blue
Red

Yes, that is how I have it. It looks like you have one of the US released amps where you can change the input voltages to 120 VAC.

 

[pppoffice]

View attachment 1009431
Close up

Yes, just like mine. I have this saved on my computer.

 

[pppoffice]

You need this style

View attachment 1009434

No, that is NOT the style 2507 board I have. I have seen these driver boards but I think they were much newer than mine and I think for USA release. I am told there are at least 3-4 different style 2507 boards out there.

 

[pppoffice]

You need this style

View attachment 1009434

None of my 4 best 2507 boards have any smoked resistors. The two I got off ebay had had lots of smoked resistors as the boards show the burn marks.

 

[pppoffice]

8 pin style
View attachment 1009474

10 pin style
View attachment 1009475

Similar but not the same. My original copy of the BA-3000 service manual shows the kind of 2507 boards that I have and all of the transistor part numbers use to match what the service manual shows. I have went to some of the replacement transistors due to nothing but Chinese knockoffs that are crap.