Recent TSP repair of E3631A: Encoder Restoration

[idpromnut]

Hi,

I'm hoping Hugoneus sees this, as I would like more details on the encoder cleanup he did on the recent TSP video. Specifically, I have an encoder for a E3648A that seems to exhibit erratic clicks when turned at a constant rate (as if it is "missing" clicks during part of a full revolution). I pulled the encoder apart, and cleaned the contact fingers (it is a mechanical rotary encoder) but I did not have any grease on hand to be able to clean out the contact disk (without risking not being able to put it back together). What type of grease should I use in this case? Is there any specific cleaning product that should be used on the disk other than IPA?  Thanks!

[TheAmmoniacal]

Thumbs up on this, such a bummer he skipped that part! Otherwise a fantastic video as always!

[ElectroIrradiator]

To the top!

[HighVoltage]

A new encoder is only a few dollars and the new types have been improved significantly, as to the point that I never had a failure even after a few years of usage.
Before I used new encoders as a replacement, I opened them up and cleaned them and added new grease.
But they lasted only about 6 to 12 month and then exhibited the same problem again.
 

[free_electron]

it is the stupid grease in the encoder that is the problem ....

pull it apart , then, using a paper kitchen towel dipped in IPA (alcohol) clean that disk and the base of the encoder.

take a small vessel , like a plastic bottle cap : spray a bit of deoxit or contact cleaner in it and dip the disk in this solution. alternately : spray some contact cleaner on a paper towel and then use that to wipe of the disk.

reassemble ( no grease ! ) and enjoy a long life encoder.

[ElectroIrradiator]

A new encoder is only a few dollars and the new types have been improved significantly, as to the point that I never had a failure even after a few years of usage.

Do you have a suggestion for a replacement part and/or an Agilent Keysight part number?

reassemble ( no grease ! ) and enjoy a long life encoder.

Thanks! Sounds easy enough. 

[idpromnut]

Thank you all for the feedback!

I actually found a reasonable replacement on digikey (PN# PEC16-4015F-N0024-ND). I will take some measurements when I get home to see that it will fit etc.

[idpromnut]

So as a followup, that Bourns part from Digikey looks like a perfect fit (mechanically and footprint-wise). The other thing that I'm not sure of is if this 24-pulse per revolution replacement will change the input wheel behavior.

I will pick one up on my next digikey buy and test it out.

[View[+]Finder]

it is the stupid grease in the encoder that is the problem ....

pull it apart , then, using a paper kitchen towel dipped in IPA (alcohol) clean that disk and the base of the encoder.

take a small vessel , like a plastic bottle cap : spray a bit of deoxit or contact cleaner in it and dip the disk in this solution. alternately : spray some contact cleaner on a paper towel and then use that to wipe of the disk.

reassemble ( no grease ! ) and enjoy a long life encoder.

This is still good advice in 2015: I just repaired my E3631A using this method and it works the charm. The only change I made was to lightly spray the metal top piece (nothing attached) with teflon 'dry-lube' and then used an 'air-duster' to guide the teflon into the shaft bearing area. When all dry, reassemble.

[free_electron]

the problem is that little metal particles are being generated when the encoder rotates. this contaminates the grease and it forms a relative low impedance path ( 80 to 100 k ohm.. )
this is enough to screw up the logic levels on the cpu and the encoder goes wonky.

no grease !

[Hugoneus]

Hey, I just saw this.

I think you have already gotten your answer. But I simply opened the encoder, cleaned all the terminals and closed it back up.

[idpromnut]

Hey, I just saw this.

I think you have already gotten your answer. But I simply opened the encoder, cleaned all the terminals and closed it back up.

Yup!  I ended up buying the Bourns replacement; works perfectly!

[diytinker]

I recently replaced the encoder. my professor asked me to record it, just want to share it here, maybe someone else will find it helpful: