PS2521G PSU calibration - Page 1
Forum section: electronics / testgear

author: james_s
author_rank: Super Contributor
timestamp: March 21, 2020, 06:29:16 am
content: I recently picked up a Tek PS2521G PSU, mixed feelings on it so far as it's clearly a rebadged GW Instek and doesn't feel very Tek-like inside, however it is quite a capable unit and seems to work well. When I got it there were weird issues which I believe were down to the DS1220 NVRAM being old and tired. I ran through the whole calibration routine and it seems to be working just fine now, however there is one issue I ran across while calibrating channel 3. I got to step CL2F which involves setting the trimpot, VR401 in this case, and the issue I have is the table in the calibration procedure specifies 7.00V however the pot only provides a range from about 6.3V to 6.7V. I ended up setting it to 6.5V and ran through the rest of the procedure and it *seems* to work just fine, it will deliver 5.0A into the current shunt without difficulty, the channel 3 output can be set to 6.5V which is the max that the firmware accepts, odd to me that it will even go that high since it says 0-6V.Do I have a problem lurking? Should the voltage go all the way up to 7V like the table says or is that a typo? Outputs 1 and 2 are consistent, the table says to set the trimmer to give 21.0V on each of those outputs and that is also the max limit that the firmware allows those outputs to be set to.

author: siggi
author_rank: Regular Contributor
timestamp: March 21, 2020, 04:58:13 pm
content: Hey James,I went through this process with my PS2520 a few years back and I don't remember any trouble following the script. Reading through the procedure, I don't see that it mentions adjusting VR401 for 7V output - I see 6.5V. This is page 65 in the document from Tek's website:https://download.tek.com/manual/061412402.pdf.in the performance verification section it does mention setting the OVP to 7V for channel 3, but that's a whole different kettle of wax.Siggi

author: james_s
author_rank: Super Contributor
timestamp: March 21, 2020, 05:26:16 pm
content: Oh hey that's a whole different doc than I found, looks like my guess of 6.5V was actually correct and this thing is working fine now. I see there are some typos in that one too though, for the PS2521 all three outputs say to adjust VR601 which is obviously not right.Now I just need to do something about that obnoxious fan, it makes a whole lot of noise without even moving a great deal of air, if I'm running several pieces of equipment at once the fan noise becomes unbearable. I ordered a Noctua fan with similar max flow and then I might try to make a controller with sensors on the heatsink sections, I already need to regulate the 24V fan supply down to 12V for the replacement fan anyway.

author: siggi
author_rank: Regular Contributor
timestamp: March 21, 2020, 07:29:50 pm
content: Quote from: james_s on March 21, 2020, 05:26:16 pmYeah, between the atrocious UI, the fact that it displays only one channel read-back at a time and the fan noise, this is IMHO a power supply only a mother could love.

author: james_s
author_rank: Super Contributor
timestamp: March 21, 2020, 11:10:21 pm
content: I mean it does have the advantage of being more powerful than most bench supplies, two outputs that will do 0-20V at 2.5A and another that does 0-6V at 5A is a good bit of juice. The 50 stored memory configurations also allows one to quickly configure it for a specific task, but if I could only have one power supply I don't think this would be it. The old Heathkit triple power supply I'm using on the bench currently shares the same problem of only monitoring one channel at a time, in fact it has only one meter so it can't even monitor voltage and current at once but unlike the various power supplies I've built, at least that can do dual tracking.Not sure if the PS2521G will get a permanent home on my bench or not. It performs well but with that much space they could have done so much better, using smaller displays and more of them to monitor everything at once. Regarding the rest of the UI, I think I still prefer analog knobs, this is the only PSU I've ever used where I had to read the manual to figure out how to operate it.