Hi- Im still batteling with this old GE transceiver ! It is a model MT-33N all tube. I am trying to get it operational again, and I need schematics and manuals, or someone with some know-how about old transcievers ! Please email or post if you might help me out ! I cant get it to receive, and Im not sure it transmits, but the tubes all glow, and relays click when I key the mike.... I dont know how to adjust the plate and all that... Thanks !!! Ryan

Hi,
Chances are high that finding a schematic is going to be tough. You can take a look through here:
http://bama.sbc.edu/
They will not be perfect scans if they have anything.

In general, assuming the output is about 5 watts, make a "dummy load" using a type 47 bulb soldered to a suitable connector for your antenna. It will work for higher outputs, but only up to a point. If the finals are functioning, the bulb will light, and will modulate with your voice. Since you have tube finals, and old vintage materials (assuming no update repairs yet), you may have excessive leakage in the exciter, mixer, and final stages. I would change these over to "Orange drops" or other high quality modern caps.

As for setting bias, check your plate voltage, and then using a databook curve for your output tubes, set grid bias to the optimum potential based on what the curve indicates. Generally speaking, this should keep the radio within the operating limits for the year it was designed. If you are using a Push-Pull output, you need to set up a scope so each output will drive either the vertical, or horizontal deflection on the scope, and final bias tweaks will give you a correctly phased Lisagous pattern.

You may have a situation too, the crystal itself needs to be looked at, and the types that were screwed together were notorious for corrosion on the crystal contact surfaces. Hooking a scope to the output to see what you get will be of benefit in diagnosing what stage is aflicted with bugs.

: Hi- Im still batteling with this old GE transceiver ! It is a model MT-33N all tube. I am trying to get it operational again, and I need schematics and manuals, or someone with some know-how about old transcievers ! Please email or post if you might help me out ! I cant get it to receive, and Im not sure it transmits, but the tubes all glow, and relays click when I key the mike.... I dont know how to adjust the plate and all that... Thanks !!! Ryan

Couple of comments. The transmitter, when working properly will put out about 30 watts. It will blow a #47 in nothing flat. Secondly, it's an FM transmitter so there will be no change in output under moduation.

You can try GE, or I guess it's called Ericsson communications in Lynchburg, VA and see if there is stilla manual available. You will need to know the model numbers of the receiver and transmitter strips.

Transmitter will be an ET-20 something and the receiver will be an ER20 something. Each letter means a different version and there were significant differences between, for example, an ER-20A and an ER-20B.

I had one of them years ago on two meters. Haven't looked at one in a long time and don't have any info on it.

73
Bob Kulow WA2UEH