mediatechnology wrote: ↑Thu Oct 01, 2020 7:55 pm
So are your blinky lights working now that you inverted the transistors?
It turns out I wasn't able to use the sot23 transistors upside down, so I tacked to92 TH devices in and that is working better. I haven't really been able to give this project uninterrupted attention, but every time I sit down I find and fix another problem.
Late today I finally powered up my scope and test set for the first time in years to bang some sine waves through it... It took me a half hour this afternoon rooting around in my back lab to find a 1/4" plug to go into the TS-1 output to get a sine wave out.

My audio test bench is in pretty sad shape from neglect and lack of use.
After beer oclock today i found the latest instability... The input pots/attenuators are designed to get their ground from the digital decoder. which isn't connected yet, so they were floating. Tomorrow I will ground all those input trims that should make things more stable.
I still fell lucky, but that stencil/solder paste experiment was a fail... Too much paste in some places and not enough in others.
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But I have other distractions tomorrow, I'm putting new tires on my ride, because the old ones are showing signs of dry rot. That shouldn't take too long.The new tires will be more of a pain in my pocket.

I finally have the mustang running strong like when it was new, but the check engine light is still on. Might be time for some black tape over the check engine light. I checked and the engine is still there.
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I figured out a solution to another different problem... I finally cut holes through a few walls and mounted the air blower to my bathroom ceiling. For summer cooling I just leave it powered up all the time, but last winter for heat assist I had the blower being controlled by the thermostat in my back bedroom. My new solution for winter heat is to run an extension cord inside the 8" air duct feeding the back bedroom. I can plug that in where I did last winter to get thermostatic control. In the bathroom to select between heat mode and cooling mode I will use a 120VAC DPDT relay. When I turn on the wall switch in the bathroom for summer cooling, the energized relay disconnects power from the bedroom thermostat and connects to the bathroom mains power. I have a suitable (30a) relay on order so this will be sorted soon enough. I wasted some time trying to design a solid state circuit to automatically steer the power between the two feeds, but the relay is simple and robust. I don't want to leave behind too many inexplicable systems for the next owner to figure out.

I will only need to label the bathroom wall switch summer/winter.
JR
It's nice to be nice.