Where to get white HP voltage/amp knobs for power supplies? - Page 1
Forum section: electronics / testgear

author: SharpEars
author_rank: Unknown
timestamp: November 13, 2014, 09:48:48 pm
content: I could use some replacement knobs, the little grayish white ones on old digital HP power supplies used to adjust voltage and current, like the two left of center in this image from testequity.com:Is there any place that sells these cheap and preferably in the US?

author: free_electron
author_rank: Super Contributor
timestamp: November 13, 2014, 10:00:50 pm
content: how many do you need ? i need the exact model power supply as there are two shaft diameters of these !i have them brand new ( i just placed an order at the Agilent parts store and i always order spares, so these are not knock-offs but the real deal ! )

author: Electro Fan
author_rank: Super Contributor
timestamp: November 13, 2014, 10:20:23 pm
content: Quote from: free_electron on November 13, 2014, 10:00:50 pmMan, how good is this forum?! Nice work SharpEars on the one post and your wish is granted; very nice service to a fellow EEVer free_electron!EF

author: SharpEars
author_rank: Unknown
timestamp: November 13, 2014, 10:43:20 pm
content: Quote from: Electro Fan on November 13, 2014, 10:20:23 pmLol, I give it three thumbs up!!!

author: SharpEars
author_rank: Unknown
timestamp: November 13, 2014, 10:46:28 pm
content: Quote from: free_electron on November 13, 2014, 10:00:50 pmI could use two of the type that fit the 6554A line. I am not sure if that's enough info to narrow the shaft diameter options. If not, please let me know.I can pay you for 'em via PayPal, so it's all fair and square...

author: free_electron
author_rank: Super Contributor
timestamp: November 14, 2014, 03:22:52 pm
content: lemme see if i can find the service manual of the 6554. -got it.ouch. it is as i feared, they altered the encoders :from the service manual backdating : In T able 5-4:Change Knob (ref RPG) to p/n 0370-1091. Change Optical encoder to p/n 0960-0822. Change PCA Keypad to p/n 5040-3464.In Table 5-6:they ran out of the original encoders ( which are optical and use a stupid little lightbulb) and these were replaced by led driven ones ( the lightbulbs died eventually)but als ot he mounting and shaft changed...so i need some more information :- is the shaft of the encoder metallic or black plastic.- is it round or D-shaped (round with a flat side like the letter D ). ?

author: Rory
author_rank: Frequent Contributor
timestamp: November 14, 2014, 09:51:45 pm
content: I could use one for my HP 6236B power supply too. Round 1/4" shaft.

author: SharpEars
author_rank: Unknown
timestamp: November 14, 2014, 10:34:45 pm
content: Quote from: free_electron on November 14, 2014, 03:22:52 pmThe PS is in the mail at the moment. I'll post the specifics and pics in this thread upon receipt. I didn't realize that there was so much variability in the knobs.

author: free_electron
author_rank: Super Contributor
timestamp: November 14, 2014, 10:49:23 pm
content: Quote from: Rory on November 14, 2014, 09:51:45 pm1/4 inch or 6 mm ? measure it accurately ! these knobs do not have a set-screw and rely on the grip.there are four flavors of this damn thing1/4 round and 1/4 d-shape6mm round and 6mm d-shape..it's gotta be right ...

author: Rory
author_rank: Frequent Contributor
timestamp: November 14, 2014, 11:07:05 pm
content: Quote from: free_electron on November 14, 2014, 10:49:23 pmHP P/N 0370-1099, 1/4" round shaft, and has 2 setscrews. All I really need is the cap. Thanks for helping anyway.

author: free_electron
author_rank: Super Contributor
timestamp: November 14, 2014, 11:24:22 pm
content: Quote from: Rory on November 14, 2014, 11:07:05 pmThose ones i don't have. Too old.

author: nctnico
author_rank: Super Contributor
timestamp: November 14, 2014, 11:37:45 pm
content: Quote from: free_electron on November 13, 2014, 10:00:50 pmI'm wondering about the price. I need a few for a couple of HP power supplies as well but I only see grazy prices on Ebay for old junk.

author: SharpEars
author_rank: Unknown
timestamp: December 03, 2014, 02:22:58 am
content: Quote from: free_electron on November 14, 2014, 10:49:23 pmHi free_electron, I just received my supply. Here is what I am looking for a knob to fit a 6 mm shaft diameter / D-shape pot. The knob itself is 5/8" in height, 7/16" in diameter at its top and about 11/16" in diameter at its bottom with an inset D shaped hole about 6 mm in diameter. The part number is "0370-3238 KNOB 6mm." If you've got the 1/4" ones, they will work too. I tried both sizes from other supplies and the 1/4" ones are just a little more loose, but still function OK whereas the 6 mm ones are pretty snug on the shaft.It's very hard to measure the difference between 6 mm (0.23622") and 6.35 mm (0.25000") with anything short of a vernier/digital caliper, especially since there are part tolerances to take into account and a third of a millimeter is quite small.Here are some pics I took of an HP D shaped 1/4" knob that I borrowed from one of my other supplies, a 6653A:Top/Front view:Bottom view: