Hello all. I have a little 2 pill amp that I think is dead as it don't pass RF. It uses some transistors i've never heard of. They are Motorola SRF 866K.... Is there a crossover for these as I cant find them anywhere online.. They are stud mount...
You got me lost there guy!!I can only imagine they used a high current circuit breaker or switch to remotely turn it on and off. I have never seen that board though or that style of cores on the transformer. Do you have caliper or micrometer that is accurate handy to physically measure the dimensions of the transistors?
Well he said it does not have any externals switches and no remote so if you wired it to a battery directly it would be on constantly draining your battery in no time. So you would still want a way to turn it on and off.You got me lost there guy!!
One of the things I always liked about Motorola rf bjt's is how little drive they need for full output.The prefix "SRF" indicated transistors that were special-ordered from Motorola. Generally a part found in their catalog, but selected for a particular final-test result. Not sure how many you had to order to get the house-number marked on it, but there was most certainly a minimum order quantity for that.
Good chance that it's a house-marked type MRF455A. The "A" suffix letter indicates the stud-mount package. The MRF455 without the A is the flange mount with two screw holes for mounting.
This transistor is incredibly easy to overdrive, and usually calls for adding some resistors between the relay and the primary of the input transformer.
73