Ameritron AL-811A AL-811H Fuses
WY3A 12 A 250V Fuses 8A 250V Fuses
The Ameritron AL-811A and AL-811H are very reliable HF Amplifiers. I own one of each. But the Chinese made 811A tubes are not very reliable. When one of those tubes goes...it can go with a flash and always takes out a fuse or two...and sometimes blows a protection diode and a meter lamp too. This is very common and has happened to me at least a half dozen times over a dozen years.
In order to figure out which tube went bad...you normally have to take all the tubes out (careful...high voltage!), and test them in the amplifier one at a time. The tube that blows another fuse when you turn the amp on, is the culprit, unless there are other problems. I use the same method to test used 811A tubes I come across. These are plentiful and cheap, because often, when a tube goes bad, hams replace all 4 of them and put the others on the shelf where they stay until the tubes show up at a hamfest or on Ebay. I typically find that for every 4 tubes I get used, one is bad. In any case...
I ended up going through a lot of those fuses
I got tired of running out, so I bought good quantity of the 8 A 250 Volt fuses, 12A 250V fuses, and 1N4007 1000V (meter) protection diodes. I won't run out any time soon; in fact I have more than I need. The trouble with trying to get these retail online, is that the shipping charges high. So...
If you need replacement fuses, or diodes, contact me here. I'll send you (5) for $6.50 postpaid while my supply lasts.
Let me know if you come across a cheap source for those little frosted incandescent meter lamps.
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Bill Patton, WY3AWest Chester, PA