• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

The 881 F-2436 Driver Board Variant

LBPete

LBPete

Rolling Along
Subscriber
The driver board in the 9010/881 has the same numeric designation as the driver board in the 9090/8080. But it is actually quite different. The two boards in the picture are the 9010/881 board on the bottom and an early production 9090 board on top. There are several major differences. The circuit traces in the top center of the board are completely different. The 9010/881 board has a lot of little diodes as well as a pair of coils. Some of the electrolytic caps are lower voltage values too.

Even though there are at least three variants to the F-2436 board used in the 9090, the basic board is the same. The variations are accomplished by adding/subtracting components using existing holes and traces on the board. That’s not the case with the 9010/881 variant. It is a very different board even though it has the same numeric ID. You can see though that the 9090 board has a –1 added to the F-2436.

- Pete
 

Attachments

  • F2436 variants.jpg
    F2436 variants.jpg
    93.6 KB · Views: 260
Register to hide this ad
I have also noticed these boards in QRX-7001 and QRX-777 units. Same number designation although I can tell by looking at yours that there are different parts. In particular two high wattage ceramic resistors in the spot where there is a PCB silkscreening for the resistor in your photo but the resistors are missing.

One thing about Sansui is that they dont seem to be very consistent!
 
Those resistors are on the back of the board. The 9090 board has one on the front and one on the back.

- Pete
 
P1020285.jpg


Here is the board installed in a QRX-777. It is the -1 variant of the board and parts are shuffled between front back from yours, I guess, because I see a few that dont appear on the top of the one in your photo. The resistor you mentioned as well as a film cap.
 
I just picked up a 9090 on CL that I am restoring. I pulled out the driver board and sure enough, its a 2436-1 with the soldered in glass fuses.

According to the SM there are 8 fusing resistors on here. I ordered the replacements and have them in hand and went to go replace the resistors when I realized this board does not match what is on the SM at all. Worse yet, some of these fuses are the light brown kind and i cant even make out what color some stripes are.

What is a man to do??
 
There is a service bulletin that shows the modification. It calls out the changes made to the original design. There also should be a thread somewhere that talks about the variations to the -1 board.

- Pete
 
Got it - I was able to replace 10 fusing resistors but there is another pair of 150 ohm resistors on this board that I do not have replacements for. Looks like its time to run to radio shack.

Thanks Pete!
 
Paul, I've posted scans of many offset/bias adjustement procedures in various threads. These images are all stored on the AK server so they can be linked to any thread. Maybe we need an offset/bias sticky that links to all those images. I'll put something together.

- Pete
 
I need clear photos of the duplex (front and back side) plate f-2436, therefore mine 9090 returned fix from it without the same one. the technician dad and the equipment was returned lacking the part. for the project of sansui, they are some doubts. debtor.
 
The F-2436 board used in the 881 is very different from the F-2436 board used in the 9090. They are not interchangeable.

- Pete
 
You must log in or register to reply here.
Back
Top Bottom