Hi Neal, The MRF-901 in case style 317-01 data sheet downloaded free from
http://doc.chipfind.ru/asi/mrf901.htm ... indicates the longer lead is the collector. The input to the GLB preamplifier I have here in front of me leads to the first single helical. The base lead should be closest to (pointing toward) the first helical. The collector lead goes toward the trailing 3 or 4 helical tubes. (number of trailing helical tubes depends on frequency range of operation). I reverse engineered the 224 MHz GLB preamp using a dual gate mosfet. I've got pictures (thank you Joe) of the 2 meter version to reverse engineer the 2 meter mrf-901 equipped preamplifier but have yet to do the formal drawing. It's probably voltage divider biased so volt meter measurements of the collector and base positions without the transistor soldered in place would be something to think about doing if you're worried. The base solder pad (with voltage divider bias) would/should have less voltage versus the collector pad voltage, which unloaded is probably up near the supply (input) voltage. Hope that helps... cheers, s. > neal Newman <cozy...@...> wrote: > Hey guys I have a 2 meter GLB preamp/preselector > where the MRF 901 appears to be shot. > > now the question of the day. which side is the Base of the MRF-901 is it the side with Only 1 helical or does it face the side with the 3 helicals... I think the MRF-901 thsts in there ( which has been replaced a few times. I think its incorrectly installed hence it not working. But the leads were cut. which side does the Long Lead face. > Neal >
