For anybody interested in a PD precision supply - there's a 5020 on Ebay here: http://www.ebay.com/itm/252087857361 (I have no connection to this auction, BTW)
5020s are pretty rare. I'm quite a fan of mine.
Any suggested max bids? I am currently at $177 but I have missed several over the last year so I am thinking of going to $233. I am in love with these power supplies.
Anyone want to sell theirs?
Ahh, so you are the one! I was the original bidder. I already have a few PD precision supplies of different vintages & specs, including another 5020. The 5020s seem pretty rare, so I thought I'd bid. I'd already decided not to get into a bidding war on it though.
You are already past what I'd be willing to spend. If you like the look and the precision, you could probably get a lower-specced supply for closer to $100. I got both of my 2005a's for ~$60 shipped. Neither of them were working, but one just needed a new fuse and power cord. The other probably doesn't need much either, but I haven't spent the time to finish troubleshooting it yet.
If you like the precision and the volt/current range, you should be able to pick up an HP6114 on an auction or best-offer. The 6114 doesn't have the nice brushed aluminum aesthetic, but I still find the industrial design pleasing and evocative.
I'll also say that from a human-factors perspective, the dials on the PD precision supplies have a shortcoming, in that the meaning of the inner vs outer knob isn't consistent -- of the two digits handled by the right-hand controls knob sets the least significant digit, while the knob sets the most-significant digit of the two digits handled by the left-hand controls. Yes, there is a logic, but the fact that there are alternative mental models puts an added cognitive burden on the user, which can lead to mistakes. I think the HP 6114's dial controls have less ambiguity.
A few things I've noticed about the 5020 in that listing:
- The top-case isn't as perforated as my 5020, 4010 and 2005a.
- The current and vernier settings knobs are unusual. First, they match, which is odd because most of the 5020 4020 and 4010 supplies I've seen have a 10-turn counting knob for the vernier. Second, they don't look like the knobs used on most PD supplies. They might be replacements, but I've seen similar knobs on one triple output supply. It might be that they are factory original, some of their other later supplies also have different knobs (Bitseeker and I both have TP340a supplies with similar black resin knobs.
- The markings on the precision dials are a plastic appliqué, not the engraved and painted markings seen on most PD precision supplies. My PD5020 is a hybrid. It has engraved markings on the right-hand controls, and plastic applique on the left.
- The meter needle is black, rather than the high-visibility color pink used on most of my PD supplies, including others with that same style of meter. My TP340a, from the mid-1990s, has that same style meter too, but also has black needles on the meters, along with newer, less awesome knobs. It's still a nice, solid supply though.
As for the Vref, definitely not one of their custom ovenized references. Probably an LM399