[EMAIL PROTECTED] made an utterance to the drakelist gang ---------------------------------------------------------------------- I am in the process of restoring a TR-3. I've spent a great deal of time trouble-shooting the premixer, but I'm stumped. I'm about ready to throw my hands up and send it out for repair. I'm not too cheap to pay someone to help out with this, but I started restoring this rig to help become more familiar with tube transceivers and analog circuits. I hate to give up.
The radio works well on 20 and 80 meters. On 40 meters, the premixer oscillator runs at 16.3 mhz instead of 20.5mhz. I get no power out. On the 15 and 10 meter bands, the crystals read low by about 100khz. Last night, I poked around with a scope a little more and tweeked the 20m crystal alignment inductor and suddenly the premixer was working. I had precisely 20.5mhz on 40m and the other bands measured correctly too. I found two leads under V3 that looked like they may have been shorted, so I blamed my problems on that. Emboldened with success, I proceeded to run through the alignment procedure. I went through the injection coupler alignment and on to the receiving IF alignment. Then everything went south again. Figuring that maybe I had a thermal issue, I turned the rig off and let is sit overnight. My hope was that this morning I would find the premixer working again. No such luck. I suspect that there may be something wrong with the alignment I did. I've double-and triple checked the steps in the procedure. I've poked around with an insulated tool to see if I could find a bad solder joint or cracked component. I've cleaned the band switch several times. The alignment instructions were written for folks who lacked modern test equipment. Maybe there's an easier and more precise way to align the premixer. If it isn't something I did, then there is something marginal or intermittent in the circuitry. I'll have to admit that my analog background is limited. I can use a scope and I'm comfortable with digital circuits. I have a good scope and know how to use it. I'd appreciate any pointers from the group. I know that Mark (N1VQW) is wrestling with his premixer too, so any tips would probably get double-duty. Thanks in advance Rich KE1EV -- Rich Carter ---------------------------------------------------------------------- Submissions: [EMAIL PROTECTED] Unsubscribe: [EMAIL PROTECTED] - unsubscribe drakelist in body Hopelessly Lost: [EMAIL PROTECTED] - help in body of message Zerobeat Web Page: www.zerobeat.net - sponsored by www.tlchost.net ----------------------------------------------------------------------
