Need CBS 410/411 Volumax Parts List

[opacheco]

Courtesy of Chalk Hill Educational Media's Virtual Audio Museum, there's a Recording Volumax (17th picture down the page) and it appears to have a switch to vary the high frequency gain reduction on the unit. Edit: for those who have the schematic it's on the lower right side, labeled S3.

@OKCRadioGuy: The potted module has been a secret for a long time. I've heard of people actually opening them up but I've never seen a disclosure of what components are inside them.

Bill,

I saw the picture and I see this switch to vary the high frequency gain reduction in the schematic too!...but I think this is switch is for select three(3) pairs of limiting diodes conected in the primary of the output transformers in order to create some responses in the peak signal or high frequency special or particular limiting!!...I forgot to mention them in my list of differences between CBS 411 and CBS 420 recording Version;

a pair(2) of 1N970B, CR215
a pair(2) of 1N967B, CR214
a pair(2) of 1713B, CR209


Would be great idea to research for a schematic for this potted CBS Circuit A400388 Dinamic Frequency Compensator too.

Opacheco.

 

[opacheco]

Tap Potentiometer for CBS Volumax 410

Hi again!

In the repair process of my pair of CBS Volumax 410 and found a rare broken potentiometer; this is a CTS XLE-47-1, 500 ohms Potentiometer (according to my CBS service manual). I contacted to CTS for a replacement part but unfortunately this kind of potentiometer is discontinued!!...that part has an electrical tap on which CTS no longer produce.

Do someone here knows where to find a part like this or similar? or how I can do in order find a way to rebuild pots with taps using normal pots and external resistors?

Thanks for any anticipated help!
Opacheco