Products > Test Equipment
Lambda LPT-7202-FM Triple Output Power Supply
Chuy:
Hello everyone.
I just got this used Lambda LPT-7202 but it doesn't deliver enough current on all 3 outputs.
I calibrated all 3 voltages and was able to bring the voltage to the maximum value but on the Current calibration, I was short 1 amp even though I rotated the R102. R202 and R302 to the maximum.
The problem is when I connect a load even a small motor or light bulb, the voltage drops down to 3 volts and the motor bearly rotates or the lights barely light up, this happens on all 3 outputs.
I also put a jumper to the V+ and V- to adjust the current to the maximum and it does the same thing.
For example;
I turn on the power supply without load and adjust the voltage to 10 volts with the maximum current then I connect a car light bulb (12 v) immediately the voltage drops to 3 volts and the light bulb bearly lights up.
Gif attached.
I can turn the voltage knob to a higher voltage but it doesn't go up, stays on at 3 volts.
Happens on all 3 outputs.
Any suggestions/advice on what to do?
edavid:
When you connect the lamp and the voltage drops to 3V, what does the current meter read?
Chuy:
About 10ma
Photo attached.
Chuy:
100ma
Correction
alm:
Can you measure the voltage going into the pass transistors (at the collector side) with a scope? I wonder if the filter caps are dry and the regulator is dropping out due to excessive ripple. Also measure the voltage rails for the regulation circuit while you're at it.
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