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your amp sounds like it is oscillating. You may have a bad parasitic suppressor or two or more.

These amps are know for having problems in the Molex type connectors that connect the primary side of the amp to the primary side of the transformer. They put this connection in so that the power transformer can be removed for shipping. Often times the connections are not durable enough if the...

Depending on the nature of the problem no schematic may be required.

This Emtron use a Chinese tube, It is a tetrode, There seems to be ZERO stateside repair facility authorized by Emtron any longer. The last person who claimed to be authorized died. You need someone that understands Tetrode amps to work on it. They are much different and more difficult to...

Although it is a Heathkit, someone did add the brass washer on the terminal of the 160 meter padding capacitor switch terminal. That washer was in the Al-80A but not in the SB-1000 so somebody went and put that in this 1000.

Put a Mahoney Radio overlay on the panel and be done with it.

Nope. A bad zener diode would not keep it from switching into transmit. All the zener diode does is set the operating bias of the tube. If the zener was shorted the only issue would be higher idle current which is not a big deal it just makes the tubes draw more current when not driven. Make...

That amp should have one high power resistor in series with one leg of its wires going to it from the 120v source. The hi/lo switch simply shorts out the resistor in high speed. In low speed the resistor is in line with the one leg and it slows the fan down. The original design may have had...

That rectifier board looked new in the photo and even if the caps are as old as when that board hit the market, the caps should be good,but you never know. It seems like nothing fits the original build in that amp and you would be at great task to figure this all out not being a technician who...

Yup, you need to determine in the relay is staying on after you unkey the radio, but if what you say that if you turn the amp off the relay recovers then it is indeed remaining energized and that would make the problem in the keying tube circuit.

I've got an SB-200 that has been mono banded for 11 meters works great on SSB at 900 pep output and on AM of course lower output. Has auto key for AM and SSB delay and also can used switchable from radio or foot pedal. All Harbach mods plus soft key. May consider sale.

That is why the grid shunt resistor in an SB-220 is a special fuse type resistor and should be replaced with a similar one when it blows.

OK fine, assuming everything HE did was done right you don't have to go to the primary side of the transformer looking for problems. Your problems are on the secondary side. Your next move is to check out the rectifier and verify right at the take off of the B+ at the PS what the voltage...

There was clearly lots of work done to this amp that was pretty much NG. The intentions may have been good but the execution was all wrong. The original design calls for the correct type of glitch protection and a simple look at the original schematic should suffice to renew the plate section...

The case of you having a storeroom full of these tubes I yield that you have a good reason.

Please tell me how shill bidders get into a bidding war against each other? A shill bid is a bid that is placed on the behalf of the seller to raise the price. A person that is NOT working on behalf of the seller to raise the price is not a shill. There are people who bid on items to raise...

Those TV sweep tubes go for $60 plus new IF YOU CAN FIND THEM. If you have to re-tube one with 10 tubes you will pay $600+ for tubes. Makes no sense. If you have to use more than 2 tubes to make the power you want then you have selected the wrong tube.

With the outrageous price to replace old sweep tubes I can't imagine why people still buy these amps, have them upgraded and re-tubed. I can see someone spending upwards of 400-500 dollars to re-tube and update a sweep tube amp with many tubes in it. There are amps out there which have much...

The spikes are so fast that they really can't do much damage to a thoriated tungsten filament tube.s It is basically a non-issue. And if you are talking about spikes that are 2 to 3 times the full power of the transmitter you certainly will not compensate for that with any loading changes...

Unfortunately I'd rather not discuss "pill" amplifiers. But to answer your question about transceiver overshoot, there is really only one way to see it and that is with a device that can respond to the instantaneous "spike" of power above the carrier level selected. You would need a scope or a...