Be the first to review this product. The power supplies have a large LCD display and clear buttons to operate the power supply. The power supply is adjustable for voltage, current and power. The models in the PSP series differ mainly in voltage and ampere. The most important specifications are shown in the table below. Maha Powerex chargers are widely used by professionals.
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Welcome, Guest. Please login or register. Did you miss your activation email? This topic This board Entire forum Google Bing. Print Search. No help needed on this one, just hoping to help someone else out. We have about ten of these power supplies.
In the past year, three of these power supplies have failed. They start acting up by the output not turning on consistently. The programmable part of the power supply is though a 9-pin RS connector on the back of the supply. Two of the failed power supplies were 9 years old, with the third failure being a 5 year supply. All of the power supplies had issues with the four capacitors see "four caps.
There were no blown tops on the four caps in the 5 year old supply. Anyway, I hope this helps someone out. JPG The following users thanked this post: Short Circuit , mcinque , Conseils , Wollvieh.
Hi matt6ft9, I just wanted to say thanks very much for posting this! The power board looks incredibly similar to your photos. I've had a look for schematics and things before, so your post and my free time were very well coordinated! I just wanted to check what symptoms you've seen. This supply will sit, seemingly 'resetting' brownout? If you leave it long enough it does tend to startup properly, but then fails to switch on its output Cheers, Attie. Attie: matt6ft9 documents the symptoms he is seeing.
Re-read his post. Replace the 4 caps that matt6ft9 did since you can see that 2 of them are already defective. Then trouble shoot from there.
The day Al Gore was born there were 7, polar bears on Earth. Today, only 26, remain. Thanks JoeO, I was hoping for an expansion on the following: Quote from: matt6ft9 on March 19, , pm. Attie, I was not able to find schematics either. One of the failed supplies would have a relay click several seconds after power up. But, the first symptom was the output not turning on when it should.
If you would hit the output button again, it would come on. Once it progressed to the state of all of the segments on or none the segments on, there was no coming back no matter how long you left it on. If you have an ESR meter, you can use it on some of the large electrolytic caps while they are still in circuit. Here is a table of ESR values you should be reading. NZ Siglent Distributor. In the absence of an ESR tester, a "trusted" capacitance meter might help. This would send up a big red flag for me.
An ESR test would then be only a confirmation of the culprits. Hi matt6ft9, I just wanted to post back and say "thank you very much! You saved me too matt6ft9. The first symptoms was the power supply spontaneously turning off under load. After that it began clicking and the LCD was flickering. Eventually it just wouldn't turn on.
After probing the 15V rail I saw that it was climbing very slowly and eventually when it reached 15V the screen and MCU came back to life this would sometimes take more than a minute. Moments after connecting a load it would die again and the long wait for the 15V rail would start all over. I discovered would die each time the fan turned on, this explained why it would die under load.
Anyways, I found this post and replaced the caps. Conseils Newbie Posts: 3 Country:. I have used these supplies for around 8 years. When purchased, I had a failed unit after a couple of days. Fully expecting the power supply to retire shortly afterwards. Almost 10 years later it seems to be still going strong! I wonder if the original capacitors are either really poor, under rated or over loaded.
With the idea of perhaps fitting a PiZeo to allow Wifi control, http interface and some data logging; together with a small calibration tweak and remembering the dodgy capacitor issue, I popped the lid off for a peek inside again. Sure enough, all the capacitors you identified have a lovely crusty brown exudation on the top!
It still worked seemingly satisfactorily according to my pre calibration check. So maybe my calibration check was bit overkill but what a find, then I came across your lovely post! Ordered some lovely Panasonic replacement capacitors. Thanks for posting. Following from my previous post.. My 'dodgy' capacitors measured and uF. Whilst the previously hacked large 63v RS capacitor measured uF no issue with that one it seems.
They were of course all supposed to be uF nominal. So the brown crusty stuff must be magic smoke related at least ;- Following the repair I measured the heat sink temperature near these capacitors. This was to see if the heat sink was running warmer than might be anticipated, perhaps leading to degradation of the capacitors. As I haven't really run the power supply continuously at full load, to 'stress' the capacitors.
Set at 5. The fan mounted in the unit runs very occasionally for a couple of seconds under this no load condition. You can see the potentiometer that was adjusted on the attached image. Thanks again for posting. Computer PCB After opening it up, C25 and C29 had vented and made brown residue on the lid of the enclosure. I replaced the four caps and the power supply seems functional again.
Another one fixed here. In my case C36, C37 and C19 had too high ESR their capacitance were ok and no brown spots of venting, bulging or other marks of damage. After replacing these three, the supply is working again.
Is there anyone who could share bin file for this uC. Today ive checked - my is blank. I can share bin file for eprom if needed. My is 27C rom is V. It would be even great to get firmware for example PSP just for tests - if will not work correctly.
Regards Greg. Wollvieh Contributor Posts: 14 Country:. Just for the records, there is a schematics file out there, find attached. Just to feed the search engine. The boards may vary over the years. There was an error while thanking. SMF 2. EEVblog on Youtube.
GW Instek PSP-405 Programmable Switching DC Power Supply; 0-40V, 0-5A, 200W
GW Instek PSP-405 power supply