Victor 10-51 questions

[streetmechanic14]

Several questions related to these wirewound resistors (assuming that's what they are). They appear to be the same; one is used for the volume control and the other, mounted in a little bracket with a terminal strip, is in the back of machine near the horn elbow. This second one was, I believe, in series with the pickup- I have no idea what its purpose was and it's not in any 10-51 schematic I've seen. Anyway, if they are the simple wirewound units they look like something is definitely wrong: both measure close to 100K ohms. Does anybody know what their resistance should be and what the one in the bracket is supposed to do?
-Dave

[rlb955]

My 10-51 only had the one as the volume control. I have been an electronic repairman for 43 years and this was the only control I have seen like this. The actual resistor is on a thin sheet of non conductive material that is pressed into a slot against the piece that appears to be a wire wound resistor. If you are careful the strips can be pulled out of the housing and can see that the wirewound piece is actually individual pieces of wires. I repaired mine by removing the resistor strip and soldering ten 3.9k ohm resistors to the wirewound strip.

[streetmechanic14]

Your description explains the strange ohmmeter readings I was seeing. I'd like to know more about how you got the unit apart. Was there room enough inside for the ten 3.9K's (quarter-watts maybe)? These things may have been a major headache for Victor; it looks like they gave up on them by the end of 1927.

Funny that I've been seeing this in Electrola schematics for years but until your explanation I never realized it's actually an accurate representation of the gadget.

[rlb955]

Before removing the strip from the housing you will have to unsolder a wire that is soldered on each end cap of the housing. Then the strip can be pulled from the housing be careful each of the windings are individual wires bent around the strip. Discard the paper looking strip that is the resistor. Reinstall the wire strip. I was wrong I used 8-1.5k ohm 1/16 watt surface mount resistors. I laid the resistors flat on the housing and soldered the edge of them to the wire strip.

[JerryVan]

Before you do anything with them, are you certain that they're actually bad?

[rlb955]

I had one on my 10-51 and 8-60 they were both bad. There were areas on both that the conductive coating was missing. I think that is why Victor went to a true wirewound resistor on later versions and machines.

[streetmechanic14]

I had forgotten that the same control was used on the 8-60. The one in my 8-60 works "sorta"- (the signal drops out at points on the control) while the 10-51 control was completely unusable. It's been suggested that the resistance of these units was intended to be logarithmic, a refinement I think Western Electric was already familiar with by 1927. The "Fader" control on WE's double-turntable unit for movie theaters used discrete, hand calibrated resistors- a cost-is-no-object approach Victor probably couldn't justify. Is it possible somebody at Victor or GE designed the carbon resistance element to give some of the log taper effect?

-Dave