So I'm having a hard time figuring out what's wrong with my regulators.
I already replaced the BC550/560, both mosfets, and the 2sk117 on Q104 and q105 positions. Everytime I get no light on the red voltage reference diodes. Using the diode check function on the multimeter the diodes light up so they appear to be ok.
The output voltage never goes above 20V.
I have voltage across R101 and the heatsink gets warm so I have current flowing through the shunt mosfet.This makes me assume that the 2sk117 on the Q102 position is working properly.
This might be quite a dumb question but do I need to have a load connected for the regulator to work correctly?
Here are two pictures of the board.
I already replaced the BC550/560, both mosfets, and the 2sk117 on Q104 and q105 positions. Everytime I get no light on the red voltage reference diodes. Using the diode check function on the multimeter the diodes light up so they appear to be ok.
The output voltage never goes above 20V.
I have voltage across R101 and the heatsink gets warm so I have current flowing through the shunt mosfet.This makes me assume that the 2sk117 on the Q102 position is working properly.
This might be quite a dumb question but do I need to have a load connected for the regulator to work correctly?
Here are two pictures of the board.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
What Merlin said. You can't have a Kelvin four wire output fully open, the Vref and error amp sense circuitry must meet somewhere with the force circuitry. A dummy load is a good way to do that and to evaluate the build as at target load current consumption for heat exchange ability and CCS reserve. That method is pointed out and illustrated in the pdf guide.
Ok, so to make sure I don't make more mistakes, I need to simulate a 50mA load on each rail at 30-32V volts so a 600-640ohm resistor will do.
So reading the manual once again I realized that I never understood that the regulators only work with a load attached. I went through a bunch of new parts and they were probably working just fine all the time.
Positive regulator is working fine with adjustment between 24-40V as projected.
The negative one still has something wrong, I am getting adjustment between 14 and 22V.
I have about 1.35V on R101 and 1.65 on R201, even though they are the same value resistor.
If I replace Q103 for a higher Idss one I should get a higher voltage range for adjustment right?
I used an IRF610A as a replacement for the IRF610 as I destroyed the one that came with the kit.. The data sheets looks pretty similar.
Positive regulator is working fine with adjustment between 24-40V as projected.
The negative one still has something wrong, I am getting adjustment between 14 and 22V.
I have about 1.35V on R101 and 1.65 on R201, even though they are the same value resistor.
If I replace Q103 for a higher Idss one I should get a higher voltage range for adjustment right?
I used an IRF610A as a replacement for the IRF610 as I destroyed the one that came with the kit.. The data sheets looks pretty similar.
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But the negative and positive side complementary mosfets can have different vgs so the 1.35 or 1.65 are not an anomaly. Even same polarity mosfets can have different vgs if not matched, so no worries. You may use a higher value R201 to equalize the currents per side at a point.
If it is not a damage or an oscillation giving you trouble in the negative then it could be a weak Q203. You can see what happens with a higher value R203 also.
If it is not a damage or an oscillation giving you trouble in the negative then it could be a weak Q203. You can see what happens with a higher value R203 also.
R207 is installed yes. I swapped the Q203 for higher one and got a range of voltages starting a 34. I have yet another 2sk117 with a diss value in between. I'll try that one to see if it works, if not I'll have to buy a new resistor for R203 to make a new calculation with the 2sk117 available.
So I finally have the voltage output in the ballpark I want, but it doesn't match the spreadsheet calculations.
I have a 5.22mA Idss Q203, 5k trimpot and 6.8k resistor in the voltage reference, 2 1.9V red diodes. I should have voltage between 24-38V on the output but I'm getting from 18-32. I want 30-32V so this is fine but something is not adding up.
I am having some drift in the Vout as the heatsinks get hotter, is this ok? About 0.5V.
I assume this is normal as the temperature increases the transistors parameters change right?
I have a 5.22mA Idss Q203, 5k trimpot and 6.8k resistor in the voltage reference, 2 1.9V red diodes. I should have voltage between 24-38V on the output but I'm getting from 18-32. I want 30-32V so this is fine but something is not adding up.
I am having some drift in the Vout as the heatsinks get hotter, is this ok? About 0.5V.
I assume this is normal as the temperature increases the transistors parameters change right?
I got the k117 from tea bag in the mini kits so I would assume they are the real deal.
I have about 16V Vdrop on the negative regulator 6k8 resistor. and 19 on the positive one
I have each regulator bolted to a 100x50x40 finned heatsink, this one:
Heat Sink Aluminium Black 100x50x40mm - Audiophonics
After 15 minutes the heatsinks were quite hot, I could put my hand for about 10 seconds before getting too hot. This should be about 50C, I'm waiting on an infrared thermometer
They are all GR yes, some are GR1E some are GR1K.
I have 41VDC feeding the regulators so I am dropping quite a bit of voltage.
I might add a resistor between the raw supply and the regulator on the + and - railw to drop some voltage and make a CRC filter. 38V should be enough for the regulator to work correctly for a 32V output right?
I have 41VDC feeding the regulators so I am dropping quite a bit of voltage.
I might add a resistor between the raw supply and the regulator on the + and - railw to drop some voltage and make a CRC filter. 38V should be enough for the regulator to work correctly for a 32V output right?