MCI 600 Dim Levels

[pinebox]

Hello, I have a client with a JH600 that has an overreaching dim, to the point they thought it was cutting the signal this whole time. There is no trim pot for the dim level anywhere in the circuit, but looking at this schematic, I am thinking of putting a trim resister in place of  R11 and R81 to adjust the 2Meg down to an agreeable level of signal loss. Is this the correct way of going about it? Or does someone have a better idea or experience? Thanks

 

[JohnRoberts]

yup. 10k/2M is -46dB so dim indeed...

I am too lazy to go back and look at what I did last century, but my guess is a trim pot on the PCB that a tech could access to trim, but even that trim pot could not be turned down more than -40 dB.  :

JR

 

[iampoor1]

Yes that seems right. Maybe a 20k resistor in series with a 500k trim pot? Then the nominal dim level could be set. I would think it would be somewhere between -10db and -20db, depending on your clients taste hehe!

 

[pinebox]

Thank you both for confirming I'm on the right path, cheers!