Testing the TK Tar Baby

[TinselKoala]

Well, I've never blown a multimeter (fuses, sure) but I did blow out a HP precision counter one day doing a Mikhailov antigravity electron experiment by twitching the HV control knob the wrong way on one trial... that was a many thousands of dollars goof, but fortunately it was a surplus instrument and nobody cared. And I've blown a thousand dollars worth of mosfets easily, over the years. Did both my expensive NTEs last night, 24 dollars out the window. So screw them, the IRFP450 is better and a lot cheaper.

I also don't use ribbon cable much so I've not experienced that failure mode either.

And the F43's problem happened when I was using the Tar Baby circuit to drive a Tesla Coil.... ordinary "NERD" oscillations don't bother it at all. It was a silly thing to do without paying attention-- I wasn't even monitoring waveforms, just giving it the bipolar pulse juice and sweeping frequencies. What's still puzzling to me is how I could have gotten all that power through the system in spite of the 10A fuse I always use at the battery, which didn't blow. Anyhow, the circuit bounced off the wall of the TC primary's field collapse, power got reflected back to the mosfets, they shorted with a power arc. If Rosemary had only been right about current not going thru FGs ! But she's wrong and the F43 failed by shorting one of the output transistor pairs. It had nothing whatever to do with NERD oscillations or "normal" operation of the NERD circuit or the F43. Any instrument will break if you throw it off a high enough cliff.

I've put a IRFP450 mosfet in the ClassE sstc and it works best, so far. I can get a good Class E waveform, with a cool mosfet, using a 24 volt battery supply and light up NE2s so bright they hurt the eyes, and I can make little smoking RF tattoos on my fingers. Corona is not far away!!

[TinselKoala]

TK,

So you were able to locate a schematic for the F43?  I looked quite a bit, couldn't even find a not for free one for you!

PW

I found a couple of places that have the manual and I'm hoping there's a schematic in there, must call to find out for sure. Another place says they have the schematic set for the "40" series, which includes another couple of variants besides the F43. Interstate must have used the same board for different functionalities, because there's a great section on my board that's unpopulated.
I haven't actually ordered one yet, but it's in the to-do stack, working its way to the top.

[Rosemary Ainslie]

Dear Sean,

Sorry to renege on my previous undertaking - but I've been advised not to contact you by email nor to send you that data. 

Regards
Rosemary

[Rosemary Ainslie]

My dear SeaMonkey,

Thank you.  It's a rare thing for me to find approval on these forums.  Much appreciated.  The more so as one needs to be rather courageous to confront the zealous excess of these posters here. 

It encouraged me to look to your own postings.  Am blown away by your competence in the art.

With the very kindest of regards,
Rosie

[Rosemary Ainslie]

And the F43's problem happened when I was using the Tar Baby circuit to drive a Tesla Coil.... ordinary "NERD" oscillations don't bother it at all. It was a silly thing to do without paying attention-- I wasn't even monitoring waveforms, just giving it the bipolar pulse juice and sweeping frequencies. What's still puzzling to me is how I could have gotten all that power through the system in spite of the 10A fuse I always use at the battery, which didn't blow. Anyhow, the circuit bounced off the wall of the TC primary's field collapse, power got reflected back to the mosfets, they shorted with a power arc. If Rosemary had only been right about current not going thru FGs ! But she's wrong and the F43 failed by shorting one of the output transistor pairs. It had nothing whatever to do with NERD oscillations or "normal" operation of the NERD circuit or the F43. Any instrument will break if you throw it off a high enough cliff.

LOL.  What a load of nonsense.  All of it.  But I've highlighted the most glaring.   

I've put a IRFP450 mosfet in the ClassE sstc and it works best, so far. I can get a good Class E waveform, with a cool mosfet, using a 24 volt battery supply and light up NE2s so bright they hurt the eyes, and I can make little smoking RF tattoos on my fingers. Corona is not far away!!

You're confusing those tattoos with ingrained dirt.  You REALLY need to wash your hands little TK.  And your mouth - while you're at it.

Rosie Pose