Sansui g5700 and g7700 similarities.

[sansuibutch]

I have recently acquired these receivers. They both semm to work very well but the glue on the power supply has to go. I'm not to familiar with these amps that much but it seems the pre drivers and power supply share the same board? Would it be safe to say the boards in both these receivers are exactly the same, just a couple different value capacitors? Here is a pic of the g7700 board and appears to have a few caps previously replaced (circled ones). I noticed right away since somebody upped the voltage on a couple of them, and the low leakage caps that are on the 5700 board are black on here. It looks like just the biggest caps are different between the two receiver boards. Would this be the case? Seems all the smaller caps should be the same between them. I also read about what a nightmare these board can be in these particular receivers. I'm figuring just replacing the caps and cleaning glue will be as easy as it looks with no I'll effects? Any thought on this? Thank you

 

[sansuibutch]

Sorry for the poor pic and writing. I did it all on my phone.

 

[kevzep]

They are the same F2980 boards, there will be a few minor differences around the bottom of the board as the 7700 has to drive another pair of output transistors.

But, there are two different versions of this board and they are not easily interchangeable, Sansui never documented this in any service bulletin.

I would just blow through and replace all the caps, the relay and the trimmers. I finished a 6700 up yesterday and have another one to do....
Hopefully you have the MY4 02 DC24 relay in yours, I have one of my G7700's which has some miniature Fujitsu thing which has no modern equivalent.

Don't forget to do the F3060 board, replace everything on it as they get ridiculously toasty as you can see in the pic.

This is where I am at. The Glue was terrible on this one.

 

[sansuibutch]

They are the same F2980 boards, there will be a few minor differences around the bottom of the board as the 7700 has to drive another pair of output transistors.

But, there are two different versions of this board and they are not easily interchangeable, Sansui never documented this in any service bulletin.

I would just blow through and replace all the caps, the relay and the trimmers. I finished a 6700 up yesterday and have another one to do....
Hopefully you have the MY4 02 DC24 relay in yours, I have one of my G7700's which has some miniature Fujitsu thing which has no modern equivalent.

Don't forget to do the F3060 board, replace everything on it as they get ridiculously toasty as you can see in the pic.

This is where I am at. The Glue was terrible on this one.
View attachment 1298335 View attachment 1298336 View attachment 1298339 View attachment 1298343 View attachment 1298346

Wow! You are not kidding your glue is pretty bad and that f 3060 board looks like burned toast. Mine looks very good with no signs of heat. Wich is strange because when it's on I can feel the heat off it. I'm thinking the one I had was rarely used or maybe ny is just to damn cold ahahah

 

[kevzep]

Wow! You are not kidding your glue is pretty bad and that f 3060 board looks like burned toast. Mine looks very good with no signs of heat. Wich is strange because when it's on I can feel the heat off it. I'm thinking the one I had was rarely used or maybe ny is just to damn cold ahahah

Yeah you might have a low miles unit, I have seen a lot of these units and they have all been pretty well charred on the F3060 supply board.
I also think the heat accelerates the glue going corrosive as well......

 

[sansuibutch]

Yeah you might have a low miles unit, I have seen a lot of these units and they have all been pretty well charred on the F3060 supply board.
I also think the heat accelerates the glue going corrosive as well......

Ya I think your right about the heat. I will recap the f3060 board after I get these f2980 boards done either way. I dont like doing to much at once, my brain gets fried. Slow and steady wins the race for me hahaha.

 

[sansuibutch]

I don't think either of my boards have that fujitsu relay. You said there not available but id imagine you can replace it with the same one I have no?

 

[kevzep]

I don't think either of my boards have that fujitsu relay. You said there not available but id imagine you can replace it with the same one I have no?

No, different pinout, I had to remote mount a MY2 which was actually not a bad solution.

 

[sansuibutch]

No, different pinout, I had to remote mount a MY2 which was actually not a bad solution.

Gotchya. How did they make that work if the board is the same? Would that be a different production run all together with minor differences to support that relay?

 

[kevzep]

Gotchya. How did they make that work if the board is the same? Would that be a different production run all together with minor differences to support that relay?

The board is different, we know of at least two variants on this board, and that is one of the differences.