The ALH is a grounded grid linear Amplifier developed by Ameritron using low cost A power triodes. It operates in class AB2 for SSB. I’ve just been asked to fix an ALH by a local. but can’t find a Service Manual download anywhere (a main board layout would be useful). The ALH is rated at watts CW carrier in normal CW or tune. The AL is rated at watts PEP voice, or just over watts carrier.

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AC input power is removed from the transformer when the cover is removed. Lenovo MT Service Manual. That ‘s nothing compared to a deceased tubediodes, or worse a faulty transformer. T he least IMD is produced with that power.

The PA had no additional protection and had not been operational for years. The inductance of the long supply wires can not be ignored. When it first arrived, I installed the tubes, did the meter mod, and got on the air.

I don’t know if there is even a “service” manual available for the ALH. It transmits a clean signal, is easy to tune, and runs well from a VAC circuit, but is easily run on VAC as well.


Faulty Ameritron AL-811H

If the PA is not used for a long time and goes back into operationremove the fuse and let the amplifier an hour long stand idle. As radio amateur time is free and one can modify at random time. I believe it’s asking for troubleand it is better to shorten the RF path by installing an additional 4n7 capacitor at the lower end of L4.

However, it’s as if the Valves are getting no drive on Transmit. After each modification the amplifier was firmly tested and plates never becames red. Skip to main content. The Ameritron amps I’ve seen aren’t poorly made. It is a cheapsimple and proven effective method.

A Pi-Network tuned input matches the A tubes to 50 ohm exciters. Other Ham Radio Equipment.

Faulty Ameritron ALH | QRZ Forums

I am wondering why you say the amp is awfully made. AF6LJAug 1, The suppression of the third- order harmonic is the difference between marker 3D and 4D. More items related to this product. I assume there are no professional repair people around. On the other bandthe SWR will be high and is an internal tuner required for full ouput. This versatile Ameritron feature allows the user to maintain optimum voltages on the tubes and other components to obtain maximum performance and life.


The administrator has the right to edit, move or remove any comment for any reason and without notice. Never attempt to defeat this switch. Ameritron never published service manuals for any of their amplifiers so they don’t exist. I’d recommend this amp and I’ve owned many Check out other reviews on eHam Read full review Verified purchase: Opening the amp and inspecting it showed a connection that was not soldered at the factory.

Free Service Manuals

I used as “earth” serviec screw at the bottom of the anode choke. K9STHAug 2, By submitting a comment, you are declaring that you agree with these rules:. Connect the amplifier to a dummy load and adjust for maximum ouput. Failure to comply with these rules may result in being banned from further commenting.

Used to remove the Amplifier from the RF line while filament and plate voltages are maintained during “barefoot” operation. Turn per band load and plate control clock and anti clockwise and watch if there is any anode or grid current.