I picked up a used HP 6177C Current Source on Ebay for about fifty dollars, plus shipping. Based on the sellers description, I thought it might work right out of the box, but it doesn’t at least not very well.
I’ve started troubleshooting it, but I decided I had a few other incomplete repair projects that were more important, so I’ve shelved it for now, but I thought I’d use this page to collect together some information on it.
The basic details are:
- Adjustable current up to 500mA
- Adjustable voltage limit up to 50v
- Manufactured in ~1984. The design is older, the users manual is dated 1975.
I think some of the Power Designs bench power supplies I have were designed in a similar era, and I must say, from a mechanical point of view, I think the HP is superior.
The chassis seems to be based on a standard design system that can be used for a variety of devices. For example, the HP 6114a and 6115a precision power supplies use a similar, but taller frame and side panels. Even within a given envelope, the frame can be drilled to accommodate various mounting points.
The electrical assembly seems better too. My Power Designs supplies have hand-soldered PCBs, and all the interconnects are soldered. The HP has a sort of daughter card with the big electrolytic capacitors that connects to the main board using an edge connector. The front panel controls and meters are wired to a connector that slips over a line of header pins on the main PCB. The components on the main PCB are wave soldered.
- My initial HP 6177C repair & troubleshooting
- HP 6177C, 81C Operating & Service Manual: This came from an online archive of test equipment manuals, but the page order was completely backwards, so I fixed it. I think the schematics in this manual are more legible than the PDF Keysight makes available for download.
- An EEVBlog forum thread on the HP6177C