Power Supply - Updated recommendations on used equipment - Page 1
Forum section: electronics / beginners

author: MaxBishop
author_rank: Contributor
timestamp: April 01, 2024, 09:25:26 pm
content: Greetings! New member, previous lurker with much respect for the experience in this community. I've been searching the forum for power supply recommendations and frankly, am overwhelmed with the volume of information shared here. I don't know how to narrow it all down. If you can help me and if you have time for yet another power supply recommendation I am most appreciative of your time. I don't know exactly what I'm looking for as I'm not sure what all the power supply options discussed here are.My current project requirements are fairly simple but I would also like to prepare myself for future projects - within reason (budget of around $200'ish). I'm using a Raspberry Pi coupled with some diffuse reflective sensors. The sensors require 10-30v (24v). That is how I ended up here.Based on the information I've managed to process I believe I want something in the 20-30v range, not sure about amp requirements in the future but I've been looking for up to 1 amp and I think I want dual output.One other piece of useful information is I like old, well built stuff especially, if it lends itself to DIY servicing. That said, I don't have anything against new technology if it is the best option.From what I've been able to gather here there are numerous options but what I seem to be gravitating toward is used HP Agilent equipment such as the E3620A or, (for single output) the KORAD KA3005D. Please feel free to share whether you feel I'm headed in the right direction or I've misinterpreted what so many of you have shared.

author: bdunham7
author_rank: Super Contributor
timestamp: April 01, 2024, 09:45:03 pm
content: I have one of these:https://www.ebay.com/itm/156091979590?epid=1300258080It is serviceable (I fixed a half-dozen of them and kept one) and the full service manual is available. The work they needed was very basic--physically broken connectors and parts, a power switch, etc. The guts are pretty reliable. It is OEMed by GW Instek. The quality is OK but it is rather heavy, has a lot of parts and a noisy fan. It doesn't blow up if you attach a battery to it like many modern PSUs. It's reliable and works well, although not super-precise like some of the new ones. 60+ volts at 2.5A (in series), 32V@5A (parallel) or dual 32V 2.5A outputs, plus the 5V output. The arrangement of the connectors is inconvenient with the ground in the middle, but that and the noise are the only real drawbacks.

author: Wallace Gasiewicz
author_rank: Super Contributor
timestamp: April 01, 2024, 09:58:56 pm
content: bdunham7 has a good recommendation. There are lots of units like this in different brands like HP also.Perhaps go to a local Hamfest and see if there is one, they usually go inexpensively.https://www.arrl.org/hamfests-and-conventions-calendarJust put in your state.

author: MaxBishop
author_rank: Contributor
timestamp: April 01, 2024, 10:56:44 pm
content: Quote from: bdunham7 on April 01, 2024, 09:45:03 pmThank you for your feedback! It looks like it would meet my current needs. There appear to be a few of them as well as the HP 3620 available. Do you prefer this brand/model over the HP?

author: MaxBishop
author_rank: Contributor
timestamp: April 01, 2024, 10:59:14 pm
content: Quote from: Wallace Gasiewicz on April 01, 2024, 09:58:56 pmThanks for the tip on Hamfest. As luck would have it there will be an event within walking distance of my childhood home this month. If I don't purchase one before then that sounds like a great option!

author: bdunham7
author_rank: Super Contributor
timestamp: April 01, 2024, 11:01:42 pm
content: Quote from: MaxBishop on April 01, 2024, 10:56:44 pmIsn't the 3620A limited to 25V?

author: MaxBishop
author_rank: Contributor
timestamp: April 01, 2024, 11:18:15 pm
content: Quote from: bdunham7 on April 01, 2024, 11:01:42 pmI believe so. The Tektronix certainly appears to be more powerful.

author: mr ed
author_rank: Regular Contributor
timestamp: April 02, 2024, 06:45:02 am
content: I have 4 hp 62xx power supplies. 6v 2A +/- 20v 1/2A and 24v 3a. Linear, no fan, full service docs. There are higher voltage versions too. Wire wound pots. One has an adjustable crowbar too for independent overvoltage safety Get the newer ones if possible, the hp logo has no blue color. I added leds to the meters. No repairs on any so far, hobby duty. I do rf mostly so switchers are out of the question due to rf noise. Old school Heavy but real nice. Instek would be second choice.

author: MaxBishop
author_rank: Contributor
timestamp: April 03, 2024, 04:40:25 am
content: Quote from: mr ed on April 02, 2024, 06:45:02 amThanks for the tip! More HP models to add to mypossibilitieslist. I read a couple of posts indicating challenges finding Instek schematics. Happen to know if that is common or certain models?