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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

If I were wanting to minimize the first excursion of current to a choke or transformer, I would want a switch that closes near the plus or minus crest of the incoming voltage, and not one that

Two the fellow's earlier comment on not using the 5V line, when reworking my 32A, that was the first thing I did - move to SS specifically to idle the 5V line and avoid the risk of the well reported

On Mon, Jul 1, 2024 at 02:15 PM, Paul Christensen wrote: > > > > >”In addition, if you choose the "right" SSR, it will turn-on at > "Zero-Crossing" meaning it will activate when the sine-wave passes

"Zero-Crossing" meaning it will activate when the sine-wave passes zero volts (they're designed that way)." Be careful when using zero-crossing (ZC) SSRs to switch extra-large power transformers. I

That thing was probably a Dampp-Chaser (with two P's). They were used in some receivers and in other equipment to keep moisture out. Just a low power heating element. I don't want to say they are not

About the only way to check drift on AM is to listen to the local oscillator on another receiver. Since the other receiver may not be stable the LO should be beat against a stable oscillator, perhaps

Halden, You're quite right! You have hit on something that is thought to be a cause of certain ON/OFF switch failures in the L-4, L-4B, L-7 amplifiers and the Drake T-4X/TR-4/6 transceivers and

My homebuilt HT-37 uses diode boards in place of the vacuum tube rectifiers so that is definitely an option. My overall supply is not the original Hallicrafters design though. Uses a large TV

It's actually not necessary to restore this transformer.? I just need to not use the 5V winding.? That might be as easy as stuffing a couple diodes into the socket where the HV rectifier used to

oops ? ? edit? all. ?? dumb computer handler , I deleted that first stuff now... motors rely on air FLOW for convection cooling so don't block intended air passages with anything. these

Just a thought here. VPI'ing the entire transformer will reduce its heat dissipating capability. I once painted an electrical insulating varnish obtained at work on the exposed windings of an old

The only problem is that the circuit is inductive so the voltage and current are out of phase with each other, with the voltage leading the current.? Remember "ELI the ICE man"?? At the voltage zero

Cut a plastic milk jug that is just a bit bigger then the transformer so that the transformer can be completely covered.? Under vacuum for 10 minutes should be good enough.Jim Logic: Method used to

Jim I think you mentioned the VPI before. It likely is a good idea for a new transformer, but as the carbon track increases, there is a point of no return, or no restoration. Once the path is bad

Hi Jim, Thanks for the tip on how to make a vacuum chamber!? That sounds quite easy.? There are plenty of industrial vacuum pumps out on ebay that might pump it down faster.? Or, if one has an air