Electronics > Repair
Broken Faders on VideoComp VES-one genlock
<< < (3/3)
Overmann:
Ok, measurements:

2.7 kO
3.8 kO
3.8 kO
3.7 kO
3.5 kO

This makes no sense to me, but perhaps you can derive some meaning from it  :o
 :)
timeandfrequency:
Hello Overmann,

Indeed, we would expect some kind of progression between the different measurements, which is plainly not the case.
Sum is 17,5 kOhms, which is rather far from 10 k. It's actually closer to the next usual fader value (22 k).
And we even have a decrease in values which means negative resistance. But the latter only exists in some active parts, not passive components like a pot/fader.

What are the potential reasons that can explain the values you mesured :
1. External influence / burden
2. Inadequate measuring protocol
3. Defective test equipement


How to manage these issues :

for 1. As you suggested earlyer, isolating the fader (or what is left from the fader) from the board would certainly avoid rigging the multimeter if that is the cause of the weird values. Desolder the fader before making new measurments is the good way to go on.

for 2. Maybe the lateral grey tabs of the resistive element are of high resistance or are fitted for very specific test protocols. So perhaps it is not the best location to put one of the probes. Keep the 'sliding' probe in the middle of the about 3 mm wide resistive track, where the wipers' fingers actually slide. Do not push to hard to avoid damaging the carbon surface.

for 3. As you just bought a new multimeter to perform these mesurement, and therefore have no track record of its' performance, the trust we have in it is rather low. So considering that it might actually be defective cannot be excluded.


Once the fader desoldered, check the total value by mesuring between the two metallic tabs located at each end of the resistive surface. Something between 9 k and 11 k would be in the awaited span. Try this with different faders. Then redo all of the mesurements by following the 'for 2.' protocol.
Overmann:
Excellent. I just desoldered the fader and now the readout from the multimeter mages more sense:

3.0.kO
4.4 kO
6.2 kO
8.0 kO
9.0 kO

The min and max I am able to measure when not focusing on the tabs is 80 O and 10.6 kO. The values are drifting a bit, but these readings are approx. what is shown on the multimeter. It looks pretty linear to me. What do you think? Am I safe to order some of the sliders I've bookmarked below?
timeandfrequency:
Hello Overmann,

Well done ! That looks plainly as a 10 k Ohms linear fader.
You can order the parts you mentionned and proceed with adaptation and replacement.
Navigation
Message Index
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod