I didn't breadboard it; I designed the PCB, and did the fine tuning on the PCB itself.

I didn't want to have to re-compensate for the lack of the breadboard parasitics.

I don't blame you there...I'll be doing the same.

Your mileage is going to be different anyway, as with the FT-50B-77 toroid with 10 turns on it, you'll have around 250uH instead of ~220uH, and the 1,000uH will actually be around 1,100uH. If you reduce each by 1 turn, you'll get a good bit closer to what they are supposed to be; right around 210uH and 1,000uH.

I'll reduce them as you suggested. I have a LC Meter, a kit I bought from the internet, but the darn thing did not work from the get-go. Something with the LCD readout. The site did not offer any aid, though I did ask several times. They didn't even return my emails. Haven't gotten around to troubleshooting it.

 

Sgt. ...a quick question for my sanity.
The 15V 1W Zener Diode across the supply of the PWM section of the Desulfator, this is to insure that the 555 does not ever see more than its max rated input voltage...correct? If this is the case then a 14V 1W Zener will substitute without a problem, correct? I do plan to have a trickle-charger with a voltage of aprox. 13.7V connected while running this.

 

Yes, it's just a shunt regulator to keep the 555 supply within limits. You could add a couple of forward biased 1N400x diodes in series with the Zener if you wanted to bump the limit up a bit. If you get too close to your chargers' voltage, you could wind up having excessive current through R3, which limits Zener current. Don't forget, the circuit is generating spikes that hit around 60v. As long as the 555 doesn't see more than 16v across Vcc/GND, you're good to go.

Your circuit seems to be missing stuff - like the MOSFET, the inductors, some caps.... is this a real "el cheapo" version or something?

 

Good info and super-fast response time. Kudo's to you! I just found the 15V 1W Zener, so I'm good to go there now.

Thanks

 

Sgt. The diode in the desulfator, the 1N645-1, for which there are 3. What are the critical parameters?

Will the following part be a decent replacement?
STTH3R02

If not, what do you suggest.

 

That will work fine. Basically, you just need a fast recovery diode with a Vr of 100v or more.

The 1N645 isn't a fast recovery diode; I just had a bunch of them handy from a project I worked on in the 70's so I used them.

 

That will work fine. Basically, you just need a fast recovery diode with a Vr of 100v or more.

The 1N645 isn't a fast recovery diode; I just had a bunch of them handy from a project I worked on in the 70's so I used them.

So the current rating is not critical. 3A is not needed?

Thanks