HP Oscilloscope Issue - Page 1
Forum section: electronics / repair

author: AardvarkM31
author_rank: Contributor
timestamp: December 03, 2021, 02:30:14 am
content: I purchased a used HP 54600B oscilloscope. I didn't realize but it was missing the brightness adjustment knob. I seen online that there is some common issue with the brightness of the scope failing. The scope seems to work well and the brightness is fine as it is. Without having the knowledge to pull it apart, does anyone know of a fix for that or similar issue that does involve removing the adjustment switch a a visible clue?

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: December 03, 2021, 10:38:17 am
content: If you can see the stem of the potentiometer in the hole. Just get another knob.Pics of the 54600 show a knob but sometimes these adjustments are just flat screw heads.I do not know what your particular damage might be.

author: oPossum
author_rank: Super Contributor
timestamp: December 03, 2021, 02:58:06 pm
content: The brightness knob is the end of a shaft that extends about 4 inches into the 'scope. The pot it connects to has a D shaft.

author: AardvarkM31
author_rank: Contributor
timestamp: December 04, 2021, 06:03:18 am
content: Howdy Wally,Nope, nothing can be seen in the opening. May have to dig deeper....

author: AardvarkM31
author_rank: Contributor
timestamp: December 04, 2021, 06:08:11 am
content: Quote from: oPossum on December 03, 2021, 02:58:06 pmHello oPossum,So that is what it looks like. Thank you for the picture, I had thought it was a mounted potentiomer and a knob on the outside. That shaft has been removed or is broken inside. Are those parts still even available? Just learning the scope and haven't really realized a problem with the adjustability yet.

author: james_s
author_rank: Super Contributor
timestamp: December 04, 2021, 06:34:46 am
content: I don't know if that part is still available but I'd be kind of surprised if it is still manufactured. It looks like you could fabricate something fairly easily though, some kind of round plastic rod stock coupled to the pot with a piece of rubber tubing ought to work.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: December 04, 2021, 11:15:47 am
content: James has the right idea. You can get clear rubber like tubing from ACE hardware for about 20 cents a foot. It is flexible for liquids but firm enough for this function.I just bought some for my suction on my solder extractor. Comes in several diameters.Craft stores like Michaels probably sell plastic "stock"Harbor Freight sells plastic "welding rods" never used them but they might work.You can heat the end of the clear rubber tube with hot air to make it fit better.

author: oPossum
author_rank: Super Contributor
timestamp: December 04, 2021, 01:45:53 pm
content: No longer available from Keysighthttps://www.keysight.com/my/partDetail/54601-47403

author: george.b
author_rank: Frequent Contributor
timestamp: December 04, 2021, 06:40:14 pm
content: If 3D printing is a viable alternative for you, this might be compatible:https://www.thingiverse.com/thing:4609646

author: james_s
author_rank: Super Contributor
timestamp: December 04, 2021, 08:27:11 pm
content: Oh yeah, look at that. I often tend to overlook 3D printing since the vast majority of what the consumer machines are used for is making useless trinkets but that's exactly the sort of thing that a 3D printed part might actually work pretty well for.

author: CaptDon
author_rank: Super Contributor
timestamp: December 04, 2021, 09:11:19 pm
content: Remember it MUST be a plastic shaft since the brightness pot is a thousand volts below chassis ground!! You could use a metal coupler at the pot end and then a plastic shaft. I have seen FR4 1/4" shafts readily available and TEK uses lots of 1/4" and 1/8" FR4 shafts in their products.

author: oPossum
author_rank: Super Contributor
timestamp: December 04, 2021, 09:51:39 pm
content: Quote from: george.b on December 04, 2021, 06:40:14 pmThe 5462x shaft (top) is a little longer than the 5460x/5464x shaft (bottom) and the hole in the front panel is larger.

author: george.b
author_rank: Frequent Contributor
timestamp: December 05, 2021, 02:58:58 am
content: Quote from: oPossum on December 04, 2021, 09:51:39 pmOh, so much for that idea, then... thanks for pointing that out!

author: oPossum
author_rank: Super Contributor
timestamp: December 05, 2021, 06:42:26 pm
content: Quote from: AardvarkM31 on December 03, 2021, 02:30:14 amJust in case you don't already know this - press the Print/Utility button and then simultaneously press the 2nd and 3rd button under the screen.

author: AardvarkM31
author_rank: Contributor
timestamp: December 06, 2021, 03:09:36 am
content: Thanks, I should be able to facilitate a replacement. Wish I was into 3D printing. Knock that part out easy

author: AardvarkM31
author_rank: Contributor
timestamp: December 06, 2021, 03:11:19 am
content: Yep I think I can!!! Maybe should start a thread for a 3D printed version.

author: AardvarkM31
author_rank: Contributor
timestamp: December 06, 2021, 03:13:15 am
content: Thanks for looking into it. Oh well, day late and a dollar shy..............

author: AardvarkM31
author_rank: Contributor
timestamp: December 06, 2021, 03:19:10 am
content: Howdy oPossum,It looks like some others have beat me to the 3D printer idea. Now I just have to buy the printer and learn how to do itWhat does the pressing those buttons do on the HP oscilloscope?Thanks for your timeOh never mind, I just found out. Outstanding sensed of humour!!!

author: james_s
author_rank: Super Contributor
timestamp: December 06, 2021, 03:51:15 am
content: From what I've seen with some friends of mine that have 3D printers, it's a tremendous amount of screwing around to get it to do anything useful. There are online services where you can have items printed for a fee though, you might look into that.

author: george.b
author_rank: Frequent Contributor
timestamp: December 06, 2021, 11:08:25 am
content: Quote from: james_s on December 06, 2021, 03:51:15 amIn my experience, well, I don't really mind it. Sometimes a part won't come out just right the first time, but I'm probably more at fault than the printer, especially when printing with more finicky materials such as ABS. Buying a 3D printer was worth it for me. For just the one part, though, I agree, looking into a printing service may be a better option.

author: james_s
author_rank: Super Contributor
timestamp: December 06, 2021, 06:53:38 pm
content: 3D printers are for people that want to tinker with 3D printers. 3D printing services are for people that just want a printed part.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: December 06, 2021, 09:02:33 pm
content: I ordered and received "feet" for my Tek 475 scope. They are very nice and made with a 3 D printer.I believe that the fellow who made them needed feet for his scope and then made a bunch to sell as they are known to deteriorate even with good care.

author: AardvarkM31
author_rank: Contributor
timestamp: December 07, 2021, 04:05:52 am
content: Quote from: james_s on December 06, 2021, 03:51:15 amThe empirical data I've collected seem to be that it takes a bit of doing!! Will try that online idea!

author: AardvarkM31
author_rank: Contributor
timestamp: December 07, 2021, 04:09:29 am
content: Quote from: george.b on December 06, 2021, 11:08:25 amYes it does seem to require experience and trials. More than it is currently worth to me. I will see if I can dig up a online site as suggested!