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sparkos on Marantz 2325

Swapped boards tonight and things are starting to make sense! First thing I found was a jacked up molex connector, where one of the wires was backing out and not making connection! Bingo! Huge find. Then after a drop of super glue to keep that wire in the molex, I swapped boards, and set the dc offset on both boards... no problem. The bias set great on the right side (formerly on the left), but the bias on the left channel (formerly right), still was way too sensitive to set. THEREFORE, it appears at this time all I need is a replacement bias pot. The 25 turn Bourns should be here for the weekend. This hobby can really test a guy! But it is great to know there are people out there to keep us plugging away, probing and pondering until things start to work out!
I may still need help before this is over, but THANK YOU sanjib for all your help thus far!
 
You probably had a problem with the ground wire connection in the Molex connector that was giving the problem with DC offset.
 
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sanjib said:
I hope the new trimmer will fix it otherwise we may need to dig deeper!
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Embarrassing, but I can’t figure how to install the bournes 25 turn ... I used the center lead to where the original pot case went, then 2 outer leads for the other 2 holes, but pot is not responsive at all. Maybe need to reassign leads, but not sure how.

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Now I can't remember how was the original trimmer was installed. But, I never used any wire ( I think you used an external black wire) to short the two pins. I will suggest inserting the pins in holes and solder at the solder side of the board.
 
sanjib said:
Now I can't remember how was the original trimmer was installed. But, I never used any wire ( I think you used an external black wire) to short the two pins. I will suggest inserting the pins in holes and solder at the solder side of the board.
Click to expand...
I did extend length of trimmer middle wire thinking it needed to go to the hole where the OEM trimmer body was. I will remove and swap wires around, but it seems one would need to be extended as the bournes leads are only about 5/16” long.
 
Yes, you need to extend the legs. The two holes on the periphery of the circles are to hold the old big trimmer and they are not connected to the circuit. You have to use the three holes within the circle for the new trimmer.
 
looking at the back side of the board, there appear to be only 2 veins to connect to. While the oem pot only used holes number 1,2,4 and 5,, the hole I marked #3 was unused and there is no solder point for that hole. I have also shaded one vein red and the other yellow. Bournes has 3 legs and this photo shows how I currently have it soldered into place, but it is coming back out since that configuration does not work either. With only 2 veins in the pcb that seem to involve the pot, it seems if I put the middle leg in a hole on one of the veins and then either one of the outer legs of the bournes in the other vein, it should work. Agree? FYI- holes 1 and 5 are where the oem pot outer body was held in place.

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I think the center leg will go to 2, one leg to 1 and the other leg to 4. Have taken out the old trimmer from both channels?
 
Yes, took out trimmer from both channels as they were in bad shape. I will try your thoughts in the next couple of days.
 
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