First: thanks for the offer. In fact I am sitting in Europe but I do have a US address for shipping. But: I am a newbie to PD supplies only. I am an electrical engineer myself, so maybe you would like to preserve your supply for a real beginner who needs a starter kit.
But still, I am looking for a DC supply for daily use (I am not satisfied with my current one) and I believe keeping these vintage stuff alive is a good thing (and they also look nice). Your offer is thus interesting to me and I am also willing to pay a reasonable price for it (I am currently searching on ebay).
What modifications have you made on your model? I will have to modify my one anyway because of the different input voltage levels here.
Yes, I was thinking about giving it away as a prize if I ever get around to delivering that presentation on op-amps that I promised last year but have yet to deliver on.
As far as the mods/repairs, the heater coil and thermostat were gone when I got the unit. There were some other minor issues, but nothing major. The heater being out just means that the voltage reference wasn't inside a nice temperature controlled chamber. I rewound the heater with some resistance wire. I didn't want to mess with the mains voltage that was powering the heater, so I have rewired it to the unused phase of the secondary that supplies unregulated DC to the series regulator. The thermostat is just a simple comparator with hysteresis and a MOSFET. It seems to maintain the oven temps with a little better variation than how (I've read) the originals perform, and I am not able to measure any disruption in the output from the heater switching on/off. Of course, my circuit is just a hand-soldered protoboard mounted to the main PCB via some screws, standoffs, and holes I drilled in the PCB. Not pretty, but functional.
If you're OK with voltage adjustment via a potentiometer, there are lots of the older HP supplies like the 6237B on eBay for very cheap. IMHO the nicest "vintage" supplies are the HP 6114A and 6115A. I've repaired and completely refurbished several of these, and I love them and will never part with them
They are really scarce now, but if you're not in a hurry, put a watch on eBay. Unfortunately, there are a few sellers up there with completely ridiculous asking prices and what amount to permanent auctions on these. This tends to mislead the usual eBay surplus scavengers into thinking that's what they can get for the partially functional or physically damaged units that they bought for next to nothing. But if you watch, you can still occasionally find one at a reasonable price, or maybe even talk a seller down by showing him what they actual sell for. The last one I bought I paid $75 (shipped). This is all eBay US, so maybe the situation is different where you are.
There are other good, but inexpensive, supplies out there, I am sure. This might be a good topic for a separate thread on the forum. Another option, if you want a project, is to get one of these old supplies and scrap everything except the chassis, KV divider, and transformer. Building a very good quality series regulator is not very complicated with all the wonderful ICs out there now.