Hi Terry, ?Thanks for the great feedback!
I'll change the BS170s. ?Should I in fact change all four at once or can I mitigate potential rework damage and simply change one at a time and test? Or will this present a potential electrical imbalance of more than one BS170 is blown and risk additional circuit damage?
BS170 sockets sounds interesting but I'm sure that has its pros and cons including proper heat dissipation.
I ordered a couple of HiLetgo LM2596 adjustable DC-DC step down buck power convert module 4.0-40V input to 1.25-37V output with LED voltmeter display.
I do have a 23 year old Astron RS-35M linear power supply (dedicated to my IC-756Pro) sitting under my desk. ?I suppose that I could try that with a buck converter. ?I also have a junk box full of various leftover wall warts / adapters but I suspect that they're not "clean enough" for this application. ?I also have some larger (3.5" x 7.5") flat bricks leftover from old larger laptops that are rated at 19.5 VDC @ 12.3 A. I suspect that the filtering may be somewhat better on these. ?Thoughts?
I looked at the specs on the Alinco that you mentioned. ?That looks like a great supply and something nice to have! The ripple spec is <15mV p-p at rated load. ?I went looking for the ripple spec on the universal adapter that I mentioned in my previous post. ?There were no significant spec details on Amazon but one reviewer did say, "Extremely noisy output, A nice Fluke multimeter will show pretty constant output, but o-scope shows 3V+ AC of noise. 3V voltage swings of noise and ripple that seems to scale a little depending on which voltage state you select. Don't use with sensitive electronics!" ?Please understand that I didn't doubt you. ?I'm simply trying to get to root cause vs. apparent cause. ?I don't want to keep changing BS170s. ?The amazon review above does confirm your suspicion that the Universal PSU may be the problem (along with me pushing it too much with 9+ volts in).
Another temporary option I could try is the solder rework station that I recently purchased has a 0-15 VDC @ 3A supply but I'm not sure how "clean" that is either. ?I may just end up with the Alinco which I could use for other things. :-) ?I still need to build my QCX+ and the 50 watt amp.
Thanks again for the suggestions; they are really appreciated!
73, ?Peter ?W1DAD ?Windham NH
