Front End Transistor

[nydxa]

I own 2 996T's in addition to 6 more I maintain for a local volunteer ambulance group. Mine is installed in my vehicle in which a 60W UHF radio is installed. In the ambulances, they have 30W UHF and 25W VHF radios. My 996 and 4 996's in the ambulances have failed with poor sensitivity. The problem that I've verified is that the front end RF amplifier transistor is failing when these are operated in close proximity to a transmitter.

Aside from the cost, a typical 30 day turn-arounds is not acceptable. Uniden will not sell the service manual, so I'm looking for the generic part number for this device. I've installed protective diodes on the remaining radios that have not failed, and so far they are fine. I'm totally capable of servicing the radios. Can anyone provide the generic p/n for this transistor?

 

[jonwienke]

Is the part number not marked on the transistor itself?

Also, which diodes are you using for protection? I assume you're attaching a pair across the inside of the antenna jack in opposite directions?

 

[nydxa]

No markings

No generic number from which I can sub it to something. The diodes were some used in some Motorola commercial gear. I picked up several at a hamfest last year. So far they do the trick. I can't believe that Uniden would design a scanner that could not survive life in a public service vehicle. The next time one fails I replace it with another brand.