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Should not be a sine-wave output unless it is severely overloaded! It is a CMOS logic output so should swing from near ground to it's supply with according to it's spec 4nS rise or fall time. 20Mhz period is 50nS so half period 25nS so at least 20nS of flat waveform should be visible between...
I believe it is a synchronous motor so to change speed you need to change frequency.
However a capacitor start motor is a sort of 2 phase motor, I am not sure there are vfd's that are compatible.
Some of these motors retain the capacitor for normal running & the start centrifugal switch changes...
It's weird, for me on winXP & MPLAB8 I could plug the PK3 in anytime and it would work.
With MPLABX on Linux I have to ensure the PK3 is plugged in before starting MPLABX!
Well you say nothing, component wise but I spy connecting leads, so what is it powered by and what does it connect too, for example the two red wires ?
Ohh that looks like a DC power jack at the top ?
MOSFET ? is that what Q1 is ?
If so looks like part of an SMPS of some kind given L1 but then we don't know whats on the other side of the board so some more pics would be helpful.
1st problem I can spot that may or may not be related is that your pulling up SDA/SCL to 5V yet the micro pins are NOT 5V tolerant! DS1307 will work fine with these pins pulled up to 3V3.
In fact this may be providing a path from your large 3v3 capacitor to DS1307 vcc after powerdown that is...
It's a horrible circuit as sold on Ebay!! I bought one of these modules as they are as cheap as chips (cheaper actually).
Apart from the problems mentioned above I found another interesting one when running without a battery, the Vbat pin is also a threshold voltage for I2C lockout and unless...
The reason the timing is jumping around and the motor sounds rough is your "timing generator" is not synchronized with the mains supply (note the sync signal on pin19 of the micro).
For a simple open loop speed control you could use almost any AC triac control circuit BUT some are DC intended...
As I think was already mentioned it's a Kelvin connected resistor meaning each end has two terminals connected together. I would imagine the outer pins the easiest to probe so just use those. If you have ~30V across one of those resistors it is open circuit and needs replacing, however it may...
One of those two statements is clearly wrong!
I am intrigued by where IC2's power pins are connected as they are not shown on the schematic.
As your gates are sadly punched through is it possible IC2 is connected to the >30V unregulated supply or that U1 is faulty meaning the 12V is a lot...
Ahh not an ultra-linear then and custom selected valves, could be just for matching but also maybe some secret sauce to get more power out of them, for a short time........
I think I see 700V on the anodes,, we certainly used to crank up the volts on EL34's & 807's to get more out of them.
I can only see 8 wires on that trafo. Normally parralell anodes just drive a single primary, the same for screens so the primary should be just 5 wires leaving 3 for the secondary that is quite common for 16 ohm with an 8 ohm tap. Tracing the anodes & screens on the output bottles should reveal all.
IC1 might be faulty destroying the fets through excessive gate voltage, could also be poor handling causing ESD damage to gates & subsequent breakdown. Can you describe exactly how the fets are determined as "blown up" with resistance readings across all 3 terminals ?
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