Rowe R74 volume wide open

Hello to all,
Working on a Rowe R74. Everything works great except for the volume. It is always wide open. Mute relay has been checked and it works. Volume control cleaned and verified wires are connected. Tried a remote volume control and no change. Verified with the service manual the connections on the rear door are correct.
Thanks for any advice you have!
SteveH

If you don't have a schematic, go here scroll down and D-L it.
http://thearcadeboneyard.com/jukebox_manuals_rowe.php

The area of interest here is Page 11

---BUT There is a connection omitted in the schematic that makes the depicted circuit useless.

Near the middle of the drawing is a line from the "volume control' connection that goes R57 (15ohm) ---The other side of that resistor must be connected to R58 to form a junction with C26 (100mfd) or the circuit will not work. There are other mistakes various Rowe schematics that can drive one nuts if you don't have a grounding in electronics. I guess they didn't proofread these things.

You need to replace the electrolytics and test the diodes in this area along with some associated resistors.

BTW: have you checked for a DC voltage at the volume control terminals. I forget the values, but they are low and vary inversely with volume. That is higher voltage = lower volume. The circuit works by pushing a voltage through a set of diodes to make them conduct thus lowering their resistance and reducing level. Shorts or heavy leakage in this circuit will cause high, uncontrolled level.

It's a really simple circuit and careful rebuilding will get it running.

Rob/NYC

As Rob said--Or--the volume control ( or wires going to it) are shorted--
Ron Rich

Hello steveH,

What number is etched into the printed circuit side of the pre amp board?
Is it R-3788 or R-3805?

Regards
Alan

Alan Hood
ami-man
UK

Thanks guys for all the information! I'll get the schematic and check everything out.

Thanks again for all the information!
Steve