EEVblog #667 - Agilent 6643A Power Supply Binding Post Hack

Dave shows how to upgrade an Agilent/Keysight 6643A/6642A/6641A system dc power supply to have front panel binding posts.
Sense lines are added to improve the high current accuracy.

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[WhitentonMike]

One option for stabilizing the front binding posts would be to take a peice of non-clad pcb that is large enough to cover the 3 openings and drill 3 binding post holes in it. Stick the posts in and place the pcb on the back side, spin on the lock nuts and done deal. If you were concerned you could hot glue it in place.

[tpolarbeart]

We use the at work for our low current tests, the only difference is ours is the model that goes to 100 volts. These things run 24/7 everyday and I have never seen one break. Pretty good quality

[TheSageDad]

Dave -- perfect use for the 3D printer, make a custom fitting for the front panel cut outs!

[TofranBohk]

The videos I enjoy most on this channel are the ones where you hack things or fix things. :-) Good work!

[BluefanNL]

My 6632A already had the spade lugs. And the PSU is ABSOLUTELY ROCK SOLID! The drift in voltage really needs a 5.5 digit dvm to notice during warmup.

[Mrsrtheflyingmum]

Fill the holes with Epoxy glue (24 Hour type) mixed with cut up FG about 3mm long. Then drill for posts.
This worked well with mine. Good mod on the sense wires that is my next fix. Thanks Dave Thumbs Up!

[YaFunklord]

Just got a 66332A for free at a garage sale and was planning to the same mod when I happened to stumble upon your vid. :)

[tkcl]

Just got my hands on one of these, an older model actually, HP branded 6632A manufactured 1986. It still has the on board connectors for the front panel though. And looking forward to adding front panel binding posts using your video as a guide. Thanks Dave! By the way that things weighs a freaking ton, seriously it is like 40 Lbs.

[BukTeef]

Dave Jones.

He's not just an electrical engineer.

He's a god.

[tomwaters]

Dave. You sir, are a genius. I thoroughly enjoyed that video. Great job!

[waldsteiger]

to keylock the connectors, you would have to drill through the mounting surface into the flat backside of the connector and fit a pin. to make it rocksolid, use at least 2 opposed pins to handle the force symmetrically and fill the cutouts to have a plain mounting surface for the same reason.

[deathcow]

For those front three jacks, I would order a small rectangular 3mm thick aluminum panel from a place like "Front Panel Express". A rectangular panel with screw holes in each of the corners, and the three binding post holes properly keyed to the shape of those Jaycar posts. They can also silkscreen the labels GND, POWER and EARTH or engrave them. They are always fun to receive orders from.

[richfiles]

A quick way to do a flat edge keyed hole when you don't have the tools to easily make such a hole is to drill (in your case, 3) round holes in a piece of PC board, metal, plastic, or whatever you're using. dremel or saw the board so the holes are partially cut through, at the point where you want the flat, then flip the cut piece around, bringing the flat edge against the hole. Secure the two PCB segments and you have a hole with a flat!

[MariaEngstrom]

Why not drill three holes in a bare (copperless) piece of pcb material and use that as a washer behind the binding posts, then you have something firm to tighten them against and they will sit straight. Also, you do not have to mess around with epoxy. 

[JorgeRodriguez-kwpc]

Great video
I did the same mod few months ago in my, my is a different version hp 6632a and it has a connector for the remote sense wire
Also in the diagram there is a mention of a board that got relay to switch sense and load output

[network_king]

That's pretty cool. Did bring up kind of interesting thought though. When they designed that they probably could have made a thing for simple selection of the since. A 3 pin jumper setup would do center to the circuitry, one on each side for front and rear sense. Then they could still mass produce the boards, and if it's a front panel model just change the jumpers. They could even probably play off that and make an after-market front panel with posts, a switch, etc in it. Then the switch could just link onto the jumper headers.

[JCBudro]

I have an HP-branded 6624A that I plan to mod in a similar way but with arduino-controlled relays to switch the output and sense terminals back to the rear panel if needed.

[ab_ab_c]

The mounting holes where the binding posts were installed might be for a metal plate.
The metal plate could be machined (or drilled out carefully with a Dremel tool) to properly mount your binding post form.

[TheEPROM]

Those X2 caps look a lot like the ones used in the BBC Micro that go pop after 30 years (also used in the IBM 5150). I would recommend checking the heath of them or just replacing them, they go with a pop cracel, hiss and lots of smoke.

[icesoft]

There's plenty of room on the front panel for another pair of binding posts or banana jacks for some remote sense connections at which point you could bring the sense lines all the way to your load...