G-9000DB adjustments

[scottrt]

I just finished a complete restoration of a G-901DB. It cooperated nicely and the Bias and DC offset were easy to set.

But this has the newer? tuner board.. the one not depicted in the service manual, that has a small daughter card attached to it. On this daugter card are two trimmers, and I was wondering if anybody can tell me what they are for and how to set them/test points to use.

Any other insights for which pots fine tune what on the Tuner board would also be handy.

I tore this baby all apart, then replaced over 300 components.

Here is a link to pics of the process so far:

http://s694.photobucket.com/albums/vv306/scottrt/Sansui G-901DB - G-9000DB/?start=all

Scott T.

 

[Hyperion]

If the second pic is that daughter card then we are talking Dolby level adjustments surely :scratch2:

BTW: 300 components - that is one hell of a strip down...

 

[EchoWars]

Dolby board. The trimmers are for Dolby level adjustment.

When I re-do a G-xxxxdb model, I usually replace the caps simply to forestall any possible failure on this board from affecting the operation of the unit, but I don't generally fool with the Dolby adjustment. No real point to it.

 

[scottrt]

10-4 on the Dolby trimmer. Moot. I will say this is the first time I have heard one of these units. Very robust... and very responsive to each of the control features.. i.e the tone controls and Loudness can really kick it in the pants. The filters are very filtery also.

EW, when researching the Toshiba brand drivers i found them to be uniquely fast for their rating, so I left them alone since they tested very strong and well matched. Do you think this has something to do with the high regard its' sound is held in?

Scott T.

 

[EchoWars]

Topology has more to do with overall sound Q than individual parts...most of the time.

 

[kevzep]

EW, when researching the Toshiba brand drivers i found them to be uniquely fast for their rating, so I left them alone since they tested very strong and well matched. Do you think this has something to do with the high regard its' sound is held in?

Scott T.

They are, 100mhz I think, its tough to find a replacement for those.....

I have found that http://www.littlediode.com/components/home.php
have had them before.....

I have used MJE15033/15032 in their place before, and they seem to perform well, others may disagree. I have not been able to tell the difference in audio quality...
I think they are only 30mhz from memory.....

 

[EchoWars]

Because Sansui uses the tab as an electrical conductor on a bunch of their gear, replacement is a PITA because most all new TO-220's are fully encapsulated. But, you can solder a tiny ring terminal to the collector lead and bend it over to the screw to make a connection.

Not the most elegant solution, but it works.