Sansui g-6000 no phono

Chriswashere

Active Member

• Aug 30, 2015

• #1

Hi,

I just picked up a beautiful sansui g-6000 today and have encountered some problems. This receiver works great besides having no phono section at all.The pots got a good dexiot bath (which brought back the right channel) but the phono still fails to have any output at all .

Before digging into it does anyone know of any common failures with the phono section? If anyone could point out problem spots on the schematics that would be great.

Thanks !

 

avionic

" Black Knights "------- F-15 " Wizard "

Subscriber

• Aug 30, 2015

• #2

Does the tone controls seem to work or the headphones ? Might have and issue with the +/-30 power supply. They share the same 30v supply.

 

Chriswashere

Active Member

• Aug 31, 2015

• #3

avionic said:

Does the tone controls seem to work or the headphones ? Might have and issue with the +/-30 power supply. They share the same 30v supply.

Click to expand...

Thank you for your response. The controlls and headphones work great with everything besides the phono.

On board resistor r-46 seems to have a way higher resistance than it should . It will not read with a multimeter but with a resistor/transistor tester it reads as 43.79k ohms.

 

avionic

" Black Knights "------- F-15 " Wizard "

Subscriber

• Aug 31, 2015

• #4

R45-R48 should read 100Ω..

 

Chriswashere

Active Member

• Aug 31, 2015

• #5

Yes I am aware of that.They are most certainly bad in this case .


I will replace them and get back with my findings .

 

avionic

" Black Knights "------- F-15 " Wizard "

Subscriber

• Aug 31, 2015

• #6

Hmm..R46 possibly explains the right channel not working.

 

Chriswashere

Active Member

• Aug 31, 2015

• #7

Well both channels were not receiving any power. I did just found some resistors (all tested within spec) and installed them in the receiver . Before powering up the caps inline with the resistors will get tested but other than that it's about ready .

It will surely need to be slowly brought up to voltage with a variac though .

 

Chriswashere

Active Member

• Aug 31, 2015

• #8

As of right now it seems that the sansui is alive and well.


Now if anyone has this problem they can look at this thread and get a good start on repairs.

 

avionic

" Black Knights "------- F-15 " Wizard "

Subscriber

• Sep 1, 2015

• #9

Awesome..

 

ghazzer

Senior Member

• Sep 2, 2015

• #10

It is really great that you were able to find, and repair the problem so quickly.

Were the DC offset and bias settings OK? Nothing heating up so far?

I suspect that the trimmer resistors are the original single turn, white & light blue. I suggest that you replace them with Bourne style, multi turn pots before attempting any adjustment. The originals get very brittle after ~40 years and tend to crack open when adjusted. This can cause a runaway condition in the bias circuits, and will quickly take out the output transistors.

Enjoy - - -