terminal strip guard for HP 62xxB power supplies STL file - Page 1
Forum section: electronics / repair

author: caiser01
author_rank: Regular Contributor
timestamp: May 22, 2022, 02:52:23 am
content: The HP 6200B and its siblings are great DC bench supplies, and they can usually be purchased for very reasonable money. However they are often missing the red plastic guard for the terminal strip on the rear. While it's not critical for operation, it is nice to have to insure some conductive debris on the bench doesn't accidentally short any of the rear terminals. In the case of the 320V HP 6209B, I would consider the terminal strip guard to be essential for safety.In the zip file attached to this post, you will find an STL file for the terminal strip guard. This should fit any of the HP power supplies that share the form factor of the HP 6200B including the 6201B, 6202B, 6203B, 6204B, 6206B, and 6209B. It may also fit some of the larger supplies such as the 6282A, 6285A, 6286A, and 6291A but I don't have one of these to test fit so beware!I created this drawing based on the original terminal strip guard on my HP 6200B. I also had an HP 6209B that was missing its guard. I took the original guard from the 6200B, measured it, and drew it up in Fusion 360. Then, one of my co-workers printed one with our 3D printer at the office (didn't have red filament so had to be black). I attached it to my guard-less 6209B and it fit perfectly!To secure the new terminal strip guard, I needed some screws and standoffs since those were also missing from my 6209B:pan head slotted screws, 5-40, 1/2 inch long (https://www.mcmaster.com/90283A128/)aluminum unthreaded spacer, 1/4 inch outer diameter, 5/16 inch long, for number 6 screw (https://www.mcmaster.com/92510A443/)The original guard has standoffs pressed into the plastic. This wasn't an option for the 3D printed replacement so I used regular standoffs. You could probably glue the standoffs to the new guard to make it more like the original. I suppose you could also add the standoffs to the 3D design and print everything as one piece.My HP 6209B was also missing some of its original jumpers from the rear terminal strip so I tracked down the appropriate part:Cinch 140J-1 (https://www.newark.com/cinch-connectivity-solutions/140j-1/terminal-block-jumper-2-pos/dp/28F833)Both my 6200B and 6209B were also needing new rubber feet. I found replacements at McMaster-Carr:threaded-stud bumper, 6-32 thread, 1/4 inch high (https://www.mcmaster.com/9541K8/)If anyone tries this out and finds it useful, please share your story below.

author: alm
author_rank: Super Contributor
timestamp: May 23, 2022, 04:55:29 pm
content: Quote from: caiser01 on May 22, 2022, 02:52:23 amI agree that with the supply set to 320V brushing your hand against the output terminals on the back could be quite painful! Thanks for sharing the design and all the part numbers!

author: TimFox
author_rank: Super Contributor
timestamp: May 23, 2022, 05:41:34 pm
content: An unrelated problem with the 6209B supply:I own two of them, which are great for my vacuum-tube hobby.When I got the second one from eBay, I immediately checked it with a DMM, and it worked fine.However, when I connected it to a real circuit, which grounded one side of the supply, it went into current limit.I found an unexpected problem: the circuit board was spaced away from the mounting frame with rubber grommets, one of which was in contact with a trace near a corner of the PCB.The grommet had turned to charcoal, and connected that trace to the frame.Without a ground connection, stuff was "ok".I replaced that grommet with appropriate pieces of PTFE, and the supply worked correctly.I was surprised that -hp- would do that, since there was sufficient space on the PCB to route the trace away from the grommet.

author: caiser01
author_rank: Regular Contributor
timestamp: May 23, 2022, 08:57:26 pm
content: TimFox, that's an excellent tip for something to look for when inspecting a 6209B. I'm going to check the grommets on mine shortly! Thanks!

author: Jeff eelcr
author_rank: Frequent Contributor
timestamp: May 25, 2022, 12:58:02 am
content: I have a 6271B I did something similar to but used clear plastic and 90deg bend top to back(bottom is not exposed) this unit was built in 1976 so may use different parts also.Jeff