Tektronix TDS3012B

[hitecelec]

Hi All

There is a problem with front panel rotary knobs both volts/div as well as time/div
it is functioning randomly it doesnt go in sequence when rotated 10/5/2/1 after 1v/div instead of 500mv some times it switches back to 10V
Similarly the Time/div too behaves randomly

Any clues ?

Regards
Anand

[Jwalling]

Dirt or some other contamination under the encoders, most likely. You have to remove them and clean the PCB pads and encoder contacts.

[hitecelec]

hello jay

Thanks for the inputs

[hitecelec]

Hello jay

if you cut open the 4 places where the rotary knobs are sealed. after cleaning the contact what type of epoxy or glue do you recommend to reseal the knobs

[Jwalling]

I use electronics grade RTV.

[hitecelec]

hello jay

thanks

Anand

[Jwalling]

hello jay

thanks

Anand

Hi
Anand,
You're welcome. BTW, there's a "say thanks" button you can click on... 

[warrjon]

If cleaning the encoder does not work and you still have the issue RS Components has 12 step rotary encoders that you can replace the old ones with.

[Jwalling]

If cleaning the encoder does not work and you still have the issue RS Components has 12 step rotary encoders that you can replace the old ones with.

I believe the encoders were custom made by Bourns for Tek. There's not much that can go wrong with them other than dirt or contamination. I've never seen the contacts on the encoder or the PCB wear out. If cleaning doesn't fix it, likely there's a electronics failure somewhere.