Products > Test Equipment
Krohn-Hite 522 DC calibrator.
<< < (5/6) > >>
AndersJ:
Have you replaced the switches?
Good or bad results?
Which switches did you use?

NoisyBoy:
Hi AndersJ,

I did purchased new switches to replace all the existing switches, as the bad contacts created occasional relay clicking inside the unit and jumpy numbers and voltages on the output. 

Since I had the front panel disassembled, I tried the DeoxIT D while waiting for the switches to arrive.  After applying it, I worked each switch about 20 times to each position, it helped quite a bit and eliminated 90% of the problem.  I let it sit for another month for the DeoxIT to penetrate the switches, rotating the switches to different positions a few times a week, and positioning the front panel in various angles for the DeoxIT to flow to various part before reassembly. 

The end result was all the bad contact issues disappeared!  Now it has been five months after the DeoxIT application, the unit is back to operating perfectly!  No bouncy digits at all, no random relay clicking.  I had it completed cleaned, calibrated and adjusted, and it is now well within the spec for voltage accuracy and stability. 

I use it for calibrating DMMs under 6.5 digit, very happy with how well it works.  The part I like most is the power-on light show on the digital display. 

The new switches all came in sealed packaged, I will keep them in the package for now, may be I will need to use it someday. 

It is definitely worth it to restore your unit as it performs much better than what the spec suggests, I hope this helps.
AndersJ:
Hello NoisyBoy,

Thanks for your extensive and detailed reply.
I will definitely attempt a Deoxit cleaning.
I have Deoxit D5.
I hope it works as well as the D you used.

I tried a dissassembly today but it came to a halt when I
only had a 1.5 mm Allen key to remove the knobs.
Seems I will need a 1/16 inch key.
Will find one and try again.

What part number do your (unused) switches have?

NoisyBoy:
The original ITT Jeanrenaud switches is now branded under C&K after the acquisition of C&K by ITT back in 2000.  I did some research and it seems like the proper replacement is what is listed below.  However, since I have not had to actually replace the switches with new parts, I have not verified that it is indeed the proper replacement.  Perhaps someone who has done the actual replacement can chime in.   

RTAP4ES10M25NS
Switch, Rotary, 10 POS, 1 Deck, Fixed Stops, Non-Shorting, 150mA, 60VAC/DC, PC
https://www.digikey.com/products/en?keywords=RTAP4ES10M25NS

For DeoxIT, I used this one
https://caig.com/product/deoxit-d100l-25c/

It is 100% solution vs. 5% on D5, also, the holes on the switch are very small, so the needle applicator will give you a lot more control over spray type for a more precise application, it prevents overspray on the circuit board.

I hope this helps, sorry I cannot give you 100% certainty in the replacement switch.
AndersJ:
Cleaning helped a bit, but I still have intermittent problems.
Switch replacement is the next step.

Has anyone tried the switches suggested by NoisyBoy in the previous post?
Navigation
Message Index
Next page
Previous page
There was an error while thanking
Thanking...

Go to full version
Powered by SMFPacks Advanced Attachments Uploader Mod