Kenwood PS 50 power supply repair

Рет қаралды 5,022

6 жыл бұрын

My power supply would creep up to about 16vdc while using it with my TS430S. I would adjust vr1 to 13.8vdc and it would be alright for about an hour, then would start creeping or jump to 14, or 15 vdc. When pressing on vr1 the output would go back to 13.8vdc, upon release it would go back to 15 vdc. I cleaned, exercised it and lubed it with no-ox electrical grease. Now it would only go as high as 14vdc. When the board was flexed in the vicinity of Vr1 the output would change, going above 13.8 set point. I pulled the board and re-melted the solder on ALL solder joints. This video shows the test results. I actually tested it for several hours before making the video. It now remains within the specified + or - 0.7vdc of set point. I had originally thought one or more of the transistors where leaking and would need to be replaced. Not today I suppose.
Note: The volt display is a modification I added so I could monitor the output. Drok brand I think.

Пікірлер: 6

@izzzzzz6 4 жыл бұрын

I'm wondering if the pre drive transistor had the furry legs syndrome and the solder cleaned them up a bit, either that or the vr for the voltage regulation was oxidised and it became cleaner? Is it still stable? I had a slightl;y high voltage on a P30 then i was testing it under load with the regulator board unscrewed when i moved it and blew something. Now no voltage on the regulator output transistor and lost my low voltage on the pre drive transistor. Going to check the small glass diode but have ordered new regulator and pre drive transistors, hopefully this and possibly a clean up of the vr might fit her up.

@gixerags750 2 жыл бұрын

hi , is there much difference between the ps50 and my ps30? my power button wont engage anymore and i like the amp meter you have installed. are they very similar? cheers

@gm743633 2 жыл бұрын

30 amps vs 50 amp. Switch might be compatible but not the internals.

@gixerags750 2 жыл бұрын

@@gm743633thanks mate.. i assume that the electrolytic capacitors in these PS are very reliable? while my ps is apart is replacement of large caps necessary in your opinion? cheers

@gm743633 2 жыл бұрын

@@gixerags750 depends on age and how long they have been without power. For electrolytic capacitors they should have power applied for an hour for every month without power. Example would be if the radio had not been used for 12 months then you would turn it on for 12 hours before transmitting. It allows the capacitors to reform oxidation and working voltage limit. If the capacitors are too old (16 years) or are bulging on the ends or sides or leaking then replacement is necessary.

@w9gb 6 жыл бұрын

I have already commented (QRZ and eHam.net), over past 20 years, on how to properly repair the Kenwood PS-xx Amateur Radio linear power supplies. This included the KPS-xx linear supplies sold for LMR Service. forums.qrz.com/index.php?threads/troubleshooting-kenwood-ps-50.359408/ While this DC supply provides Current and Short-Circuit protection, their is NO OVER-VOLTAGE PROTECTION. Modding front panel for Voltage readout was NOT needed. Kenwood No Longer has front panel replacements (You dropped its resale value).