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hi bobbydigital still in need of some help with a power supply

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BobbyDigital620

New Member
i tryed to start a thread about a 12 volt 50 amp regulated power supply.can't seem to find what is wrong.the voltage go's up and down after about 10 to 15 min.I am hopeing that someone here may be able to help me fix it.it is new i just don't wanna send it back it took a long time to get it here.everything looks intacked on the regulater board no loose solder joints i'm just not shure were to look.please if you think you can help please let me talk with you.
 

varhany

New Member
50-amp power supply

HI: Is there a schematic included with your power supply? Also, what is the brand and model number?
It sounds like a component is failing after heating up for 10-15 minutes. If it's a series pass-transistor type power supply, check the reference voltage supplied to the base of the pass transistor(s). Whatever is supplying the reference voltage may be the problem. Often, they use a small 1-amp regulator IC to supply the reference. If it goes bad, the reference voltage might be unsteady.
Is the voltage changing gradually, or just jumping around randomly?
Is the supply variable? It could be a noisy control pot.
I work with high-current power supplies quite a bit, as I am in the pipe organ biz.
Let me know if I can help.

Jason N-G
 

dr pepper

Well-Known Member
Most Helpful Member
A can of freezer spray sometimes can tell you which component is the offender, you still need some idea where to look though, as Jason says is there a schem?
 

BobbyDigital620

New Member
still in need of some help with a power supply.

Ok Thank You Gentlemen.i am new here and i welcom all that reply.yes i do have the schematic for the power supply.it's a workman PS 35 power supply.i do have some knowledge of the circuit.from day one this is what it has been doing.i don't wish to send it back because it is a free supply the company sent because i am a good customer.i also have another supply thats a 25 amp that works fine i needed to upgrade and the company did me a favor.i just not sure were to look for the problem.i have already tryed checking for cold solder joints.i have smacked the thing before and it came back to life.if someone can help me i would be very greatful.PLEASE all that reply i would look at Thank You so very much. I will be checking the post every day.
 

BobbyDigital620

New Member
I guess your name is Bill hello.i was told from a tech that this supply should give ma 35 maybe 40 amps i am driving 2 2879's in a ham amplifier
 

varhany

New Member
The fact that "smacking" the unit brought it back to life temporarily still suggests an intermittent connection somewhere. If any of the components are socketed, it would be useful to pull each one out (one at a time) and clean the pins on the device and re-insert it.
Cold solder joints: Sometimes I've see a situation where a component wasn't inserted quite far enough for the solder bath to make a good connection. Such a connection might look good from the bottom of the circuit board, but may not be connected firmly to the component. You might try gently pulling on each end of each component with a pair of long-nose pliers (or a hemostat forceps)(WITH THE UNIT DISCONNECTED !!) and see if anything pulls loose.
Failing that, I would probably re-solder every connection on the circuit board (the ol' "shotgun" approach !!).
Good Luck!

Jason
 

BobbyDigital620

New Member
Bobbydigital still in need of some help with a power supply

ok i'm going to try what you said.i just don't see a loose wire or component.i'll keep you informed.
 

BobbyDigital620

New Member
Well still not working i'm willing to send it out but not to far any suggestions?.i guess i dont know what i'm doing!. names and address's are welcom.
 
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