Model 1200 bias trimmer

[steve_it]

Hi guys,

I have a model 1200 where the manual says that the R526 bias trimmer must be 1k (actually a wire rheostat), but when I disassemble it I detect a resistance at the ends of about 300 ohms.
Can you tell me what the exact value of the trimmer is? Also, can I replace it with a normal 1w trimmer? Do you have any recommendations on the model to use?

thx

/ste

 

[egellings]

If it's a rheostat, then it has only 2 terminals, a connection at one end of the wire and the wiper. If that's what you have, did you position the wiper to include all of the resistance wire in your measurement?

 

[tonebells]

The second version of this board was 250Ω.

Tony

 

[tonebells]

Look for Marantz 1200 Service Manual Addendum 3500.

Tony

 

[steve_it]

If it's a rheostat, then it has only 2 terminals, a connection at one end of the wire and the wiper. If that's what you have, did you position the wiper to include all of the resistance wire in your measurement?

yes yes I measured it on the sides, but in the post below they say it's 250 ohm so it's fine

 

[steve_it]

The second version of this board was 250Ω.

Tony

ah ok thanks, because on the trimmer there is only the marantz code but you can't trace the value from the code.
can it be replaced with a 500mW ceramic trimmer ?

thx

/ste

 

[tonebells]

I have not need to replace one of these.

Tony