开云体育

The big glob under the coil doesn't look good or does the connections through the ceramic under the coil. The solder joint immediately behind the opening in the middle of the ceramic doesn't look good

Steve, did you ever figure out this behavior? My R-4A BFO has identical symptoms to yours. I fixed it by adding a 1K resistor to pull down the Vcc on Q6, but why does the transistor oscillate at 6V

Lead next to the screw bottom left. Looks like a piece is clipped off. -- Richard Knoppow Los Angeles WB6KBL SKCC 19998

What is the voltage on RFC 505? Gary W0DVN

Worked on the VCO board today and founds that the 5 volt regulator is working just fine 5.02 VDC. So am thinking about it trying to decide what I check next. Might make a chart of voltages on the

Folks...for those who have dived into the Final Amp section of the TR-7A, is there a trick to getting to the back of the PA board/removing the heat sink? I have removed all of the mounting screws,

Yes, that is it. In fact, not too difficult to find in my case. Too bad you didn't find the fault in your TR7. These intermittent things can drive you nuts... 73, Dieter DL5RDO Am 29.12.2024 um 23:34

*** I see a cracked solder joint right at the ceramic endpiece. Never did find the similar problem with my TR7 - The PTO would go to 1/10th its normal output, disabling the synthesizer. You'd tap on

Yup Frank Krozel Life Member, ARRL (630) 924-1600 kg9hfrank@...

I had one in a PTO, too! Every now and then, its level was way down and the R4C's sensitivity with it... Hitting on the side of the RX would cure it for a while. But... thou shalt not beat your

Today we had 30 check-ins to the net. We had the following radio's used for the check-ins. TWINS - 5 TR3 = 2 TR4(x) = 5 TR5 = 4 TR7 =7 Next week Bill W9MXQ will be the NCO. 73's, Mark, WB0IQK

Gary & Group, More info- Suspecting that I slagged my finals, I looked in the cage. Saw a fresh solder blob near the base of the choke and a lead popped out from one of the parasitic choke resistors.

Group, I'm looking for a list of bona-fide Drake C-Line repairers. Tnx & 73 Jay W6CJ

Solder connections can develop fractures that are hard to see even with magnification. I had one in a PTO that was only visible from a certain angle, otherwise the connection looked good. "Richard

Yes, by all means, Congratulations on the fix! Sometimes I’ve had that happen to me, too. I wonder if sometimes I scare the radio into working. Mike, WB8VGE www.theheathkitshop.com

Congratulations! Its fairly common for their to be cold solder joints that look fine. Sometimes they show up if you poke around the circuit with an insulated stick like a chop stick. -- Richard

I tried the 6EH7, which is similarly the same pin out with lower gain. Performance of the receiver was seriously degraded. W1ES

The tube has so much gain that it picks up noise like crazy. I can move a metal tool around the base of the third mixer and hear changes in the noise level. Way too sensitive. W1ES

The 6EJ7 is pretty common and can be had for a couple of bucks at a ‘fest or for around $5 at the various tube sellers. I have the advantage of having a fairly nice inventory of tubes used on Drake

I tested contacts, inductance and resistance in all parts used on 40 meters only. While doing so I lifted all leads that might affect the measurements. This brought 40 meters back to life. Miracles