sansui ba 3000

[vigman]

Hot TECH tip FRIDAY...... looking at ANY sansui boards.... big power resistors, connectors or semi's, remove old solder, scrape contact re solder.

 

[Black.Audio.Co]

Hi Sorry to Jump in / hijack the thread but have the same issue. I fully recapped (with Elna Silmic ii) and reflowed the solder (audio note) on all the boards. Ran trouble free for six months then the transistors blew on the left channel. Replaced the Sanken with the Motorola MJ 15024 and 15025 and worked fine for a another three months.

Then got static coming from both channels even with the preamp (CA 3000) disconnected and the gains turned all the way down. Upon checking the technician says the bias was way off fro the earlier setting and does not want to stabilise.

I am at a loss and am replacing all components on the left and right driver boards. Including the transistors and the ceramic caps to the Silver film type.

Please kindly request advice on what to do.....

Thanks in advance.

 

[Tom B]

Hi,
Before you replace "All the components", I would suggest first just replacing the Differential pair transistors (TR01, and TR02) on one of the driver boards to see if this fixes your problem.
From my experience, these transistors can get Noisy, and cause the type of problems you are experiencing which is the inability to stabelize the bias as well as static noise being produced.

Replacing all the components can open you up to more problems in my opinion.

KSC1845FTA fairchild transistors are very nice replacements

 

[musicman999]

Hi,
Before you replace "All the components", I would suggest first just replacing the Differential pair transistors (TR01, and TR02) on one of the driver boards to see if this fixes your problem.
From my experience, these transistors can get Noisy, and cause the type of problems you are experiencing which is the inability to stabelize the bias as well as static noise being produced.

Replacing all the components can open you up to more problems in my opinion.

KSC1845FTA fairchild transistors are very nice replacements

Hi Sorry to Jump in / hijack the thread but have the same issue. I fully recapped (with Elna Silmic ii) and reflowed the solder (audio note) on all the boards. Ran trouble free for six months then the transistors blew on the left channel. Replaced the Sanken with the Motorola MJ 15024 and 15025 and worked fine for a another three months.

Then got static coming from both channels even with the preamp (CA 3000) disconnected and the gains turned all the way down. Upon checking the technician says the bias was way off fro the earlier setting and does not want to stabilise.

I am at a loss and am replacing all components on the left and right driver boards. Including the transistors and the ceramic caps to the Silver film type.

Please kindly request advice on what to do.....

Thanks in advance.

There are some 1313 and 726 transistors on the power supply board which must be changed too. Also on F2513. Use the 1845s and 992s. check your voltages ( especially if both channels are affected). Check your driver and pre driver transistors on the driver board. Check your resistors values...blown outputs on these BA3000 tend to take out a number of resistors too. Make sure your drivers are tight (collector screws) In the diagnostic process you can disconnect F2513 to see if static goes.