benchtop psu problems

[the judge]

while testing my capacitor bank with my psu i noticed a few problems and i don't know if it can be fixed, or if i need to just shell out the +$100 for a new one. its an old bk precision 1630. i was testing one of the capacitors by setting it at 2v 1amp and logging the time it took to charge and working backwards to see the real world capacity. it took shorter than expected and it ended up being 2100f instead of the labeled 2600f. but one thing i noticed is that it stopped charging at 1.84v when it was set to 2v. i hooked up my multimeter and put a 10w 1ohm resistor and the resistor got warm and the voltage didn't flinch. appears to be working so i shrugged it off and hooked up the next capacitor. thats when i noticed the amp meter on the supply was jumping off the scale! it was in current supply mode and set to 1amp so i don't understand how that could happen. i took the case off and i didn't see any loose solder joints or blown components.

 

[KeepItSimpleStupid]

Unless the supply is 4 quadrant, it won't like a voltage applied to it. I did that to a uA723 based supply and I thinkk the only damage was the uA723.

You need to find a schematic. Not free, but found one: http://www.bkmanuals.com/1601-2000.htm

I'd try here first: http://www.bkprecision.com/support/request.html

 

[the judge]

the voltage applied to it is less than it's supplying. it mentions charging a battery in the manual, so i would think this would be the same deal. i got this from my electronics professor, so it has probably been abused by ignorant students.the only thing with a heat sink is 2 3055 and i happen to have exactly 2 brand new 3055. i would contact the manufacturer, but i think it is several decades out of warranty

 

[KeepItSimpleStupid]

With a schematic, it should be easy to fix.

 

[the judge]

this?
https://www.bkprecision.com/downloads/manuals/en/1630_manual.pdf

 

[KeepItSimpleStupid]

No, you have to request the service manual and/or schematic.

 

[the judge]

seeing that i have to pay $17 for the schematic plus shipping and parts, i think i might want to get a new one. any suggestions?

 

[Vgama]

Hello Judge
I hope this could help you.
I know it's not the same model, but could be similar
Best regards and good luck
Vgama

 

[the judge]

thank you, but i don't know what to replace. i'm not sure what would make the amps jump off the scale and nothing looks damaged. i did run it for over an hour and there is no fan on this supply and it did get very hot. a student could have done something screwy with it(when i got it the banana screw terminal colors were all in the wrong place) to damage it but then i don't know what i would have to replace. all of the parts are through hole, so i can replace any part easily, but if i don't know what to replace, i think it might be easier to get a new digital one.

 

[KeepItSimpleStupid]

Look for a shorted diode at the output. CR40 or CR41 in the manual provided. even though it's the wrong one. You can lift a leg and see if the supply will operate. It's there for protection.

 

[the judge]

while looking at the output i saw a rogue bare wire possibly touching something it shouldn't. that may have been it. i will set it back up and see if there are any spikes

 

[the judge]

2 capacitors and 2 hours and it is behaving and i am getting good readings. thank you for your help

 

[KeepItSimpleStupid]

Good job.

 

[MrAl]

Hi,

I was going to say that if you connect a resistor to a capacitor to charge it and the capacitor never charges then it could be very high leakage in the capacitor which could make it work pretty bad.

I had a blown diode in my power supply and it was hidden so i did not see anything burnt when i first looked inside the case. Later i found it and replaced it and everything worked again.