[SignalOne] Progress

[EDWARD SCHUMACHER]

It has been a torturous process but I am finally making some positive progress in bringing SN 00847 back to life. As with the first effort after acquiring the radio, it has been a intense learning experience. Turns out the receiver was not quite dead so it will be possible to troubleshoot. Front end and audio are good so problem may be back at the nefarious Schmidt trigger T/R switch circuit. Finally have the last problems fixed on the display and will also have to figure out the low power out (maybe also related to the T/R switch if that is what is 

going on). Also seems some of the fuse blowing may have been caused by the NOS final. Suspect it may be shorting after warming up awhile so have reinstalled the old tube again.

At this time I would like to know if anyone has had occasion to replace the driver transistors and where to obtain replacements. I have not started checking suppliers yet and do have all the old info from the newsletters. My rig has the TRW at Q3 but the Q4 device is marked K 1013 and does seem to have low output according to my old notes. I have had good luck with the folks at RF Parts, especially for the better Mot dual gate MOSFETs for the front end.

I hope to have the receive completely back shortly and possibly with it the xmit. With the radio on the bench this long, I feel I should go after the Driver board now too so am planning the extra work.


Ed, WA9GQK