varying voltage on enermax power supply

[danbob5]

I make bench power supplies out of the old xt supplies and I have found that if I put a 13k resister in series with a 200k pot between pin 1 and ground I can vary the voltage between 12.5 to 14.5. this works on the supplies with tl or dbl494 chips. Well I Got a enermax eg365p-ve supply and the sneaky s.o.b's use a different chip. It has a uc3842mn in it. Has any one tried varying the voltage on supplies with this chip?

danbob5

[Dgtech]

Re: varying voltage on enermax power supply

What else are you varying besides voltage out? Have you checked the ripple? How does this change the output of the PWM chip? Remember, when you gain somewhere, you're gonna lose somewhere. Higher voltage = Lower current. Do you use an oscilloscope or are you tinkering blindly?

[370forlife]

Re: varying voltage on enermax power supply

TL494 is old outdated design for half-bridge (hence it being common on XT designs). Enermax isn't usually cheap, and I think this uses single transistor forward.

Wait, why do you want to ruin a perfectly good power supply?