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Halden, your investigation is interesting and detailed. IMO, the DC [resistance only case, ignoring all inductances] is the extreme limit which won’t be reached. Inductance does not go away,

I suppose one could use a zero-crossing SSR in series with a TRIAC.? TRIACs turn off when the current is at zero.? One would have to turn the TRIAC on before or at the same time as turning on the

HaldenTo answer your last question first, hysteresis causes the core to be magnetized.? The strength of the magnet in the core is dependent on where in the AC cycle the lagging magnetic field stopped

Thanks, all, for the comments and lessons! It seems we're converging on using zero-crossing transformers that are capable of switching whatever current the transformer would draw if only the winding's

I am also going to the Sussex hamfest? I can bring it there also.

I also have a complete HT-37 for parts or repair, untested unless someone wants me to variac it up. $100 in Middletown / Goshen NY deliver within 20 miles ________________________________ Sent:

Thanks Don.? That makes sense! 73/jeff/ac0c alpha-charlie-zero-charlie www.ac0c.com

Shipping would probably $50+. I'm in Southwest Ohio near Cincinnati.

If it includes shipping we have a deal. 73 Dave [email protected]> wrote:

Is $100 fair for a parts unit.? No finals. Shipping would be extra of course.

If you are definitely going to part it out, I'd like the relay. Thanks K4ZDH

That's right in the "zone" I measured mine with a Bird 43 at the input (250W slug )? and one on the output (1000W slug) into a Bird 500W load. With the power supply wired for 120, it did about 500W

What do you want for the HT-37.? We have a few HT-37 owners in the area that might rest better at night knowing there is a spare parts unit nearby. 73 dave wa3gin

Thanks Rick! With 40W drive it's making ~500W per the drake meter and a dummy load. Meter is within about ~10% of reality. I'm happy. Just need to get the relays set up for RF and bias switching. 73,

Let me know what you need.

No they were for drift . used to keep the vfo section warm to cut down drift check the manual. Dampp-Chaser's were used in some gear . 73 Tony WA4JQS

I have been buying my SSR's from eBay.? Most of them were for around $10 each.? I bought 4? OPTO22? 240A45 models for $40 a few months ago and they were all new old stock as were the 240A25's I've

Rick, Great info, especially the selection table based on transformer KVA rating. I’ll order a few of the Opto22-120D10 SSRs and give it a try. For others on the list, here’s the noteworthy part

Jeff, as a guess, your likely insulation breakdown was enough to continue building a carbon track between windings even though the 5v was isolated; and must have eventually destroyed the T-T [turn to