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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I’ve just been asked to fix an ALH by a local. AC input power is removed from the transformer when the cover is removed.

Ameritron Al-811h 800w Ham Amateur Radio HF Linear Amplifier

W1QJAug 2, I am wondering why you say the amp is awfully made. The drive level is detected to provide a control voltage for the exciter. As radio amateur time is free and one can modify at random time. Your name or email address: Roger, you must be the only person in your area a is willing to tackle ham amplifiers with problems.

No the meters are both OK. Therefore, a sumiere test was done with the two types. Please note that the output in the table is partly achieved by exceeding the maximum grid and anode current.


I don’t know if there is even a “service” manual available for a ALH. The PA had no additional protection and had not been operational for years. Used to remove the Amplifier from the RF line while filament and plate voltages are maintained during “barefoot” operation. Arcing is a momentary short flashover in one of the transmitter tubes.

Faulty Ameritron ALH | QRZ Forums

I soldered this to the spot on the band-switch that hadn’t been soldered, and its been flawless since. The shielding of the cable is only grounded at the side of C Save on Ham Radio Amplifiers Trending price is based on prices over last 90 days.

With this methodthe distance between S1 and C26 changed to a small capacitance in parallel with the servkce capacitor and the total inductance of the coil 10 m is thereby reduced. ALC prevents over-driving of the linear and reduces distortion from excessive drive power. Hopefully it didn’t smoke the meter I’d recommend this amp and I’ve owned many Check out other reviews on eHam Read full review Verified purchase: Service and User Manual.

A Pi-Network tuned input matches the A tubes to 50 ohm exciters. A unique “buck-boost” winding allows adjustment of primary voltages to match a wide range of line voltages centered on and volts. Fast Warm Up Time: A tentative conclusion is that this AL – H does not distort the servicd of the drive stage.


Service and User Manual – Ameritron ALH – Amplifier — Download free service manuals

Register for a free QRZ account. Notify me of new comments via email. However, it’s as if the Valves are getting no drive on Transmit. However, here are photos of the circuit boards, one for the earlier version and one for the later version. On the other bandthe SWR will be high and is an internal tuner required for full ouput.

I’d recommend this amp and I’ve owned many Check out other reviews on eHam Read full review. Other Ham Radio Equipment. It’s a well designed amp at a reasonable price and should provide many seevice of service.

Ameritron never published service manuals for any of their amplifiers so they don’t exist. Because there size s little space was to the valve sockets. 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.