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Voltage drop problems with power supply
Hello. I have a homebrew linear 13.8V 20A power supply I have been using
for some years to power an IC-735, a 2M rig and some accessories. The PS has these characteristics: - well filtered (35000uF)22AMP, 21 volt DC output from diode bridge circuit - LM-317 regulator circuit (as per LM-317 datasheets) - MJ2955 NPN feeder transistor from regulator driving 4 - 2N3055 PNP power transistors in parallel - large heat sinks (I don't think heat is a problem) - good air circulation with fan I have the regulator set to 13.7 VDC out. Lately however, I have had some problems with voltage drops: while drawing 20 amps the voltage drops to about 11.3 volts and I have had reports of a rough CW signal as a result. I have tested the reg circuit and even replaced the LM-317 to no avail. I cannot see where the problem lies, unless perhaps the MJ2955 feeder transistor is not working as it should? (I don't yet have a replacement transistor to test that idea, hence this post). Any ideas greatly appreciated. Larry VE7EA -- For direct email remove fake. |
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