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Probably a good idea if you have questions about something else in this set :-) 73, Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana. Sent from [Proton

Our records show having replaced a few of these over the years.? BM and the buffer.? Almost sounds like it qualifies for common failure analysis. The 2n4427 has unique properties, not easily

Yes, can cap was already replaced before I got this radio. He didn't put a new can style in it, he used individual caps. This tread is very long now. The original problem is solved with the baked

Ciao Ho sostituito i vecchi filtri originali nella mia r-4c anni fa, e sia i 500 che i 250 Hz hanno una perdita di circa 6 dB... Ho acquistato la stessa coppia di filtri da Noble Radio... NESSUNA

It is my intent to do so. Steve Wedge, W1ES Time flies like an arrow. Fruit flies like a banana.

AFAIK,? the R4C used a different tap on? (I think) the IF section, to increase the gain when using the CW filters, due to their higher, inherent insertion loss. On a similar note,? years ago, I

Rob wrote: " Note that aligning T-7C that appears in S/N 21,000 and above is critical and should be peaked on the narrowest bandwidth filter." Cool...mine is 26xxx (loaded with your mods btw) so will

Please publish your results.? ?They will be very helpful to the group 73 K1NR

Hi Craig, Any crystal or multiple crystals in a filter can degrade, increasing the insertion loss that can also degrade the passband shape. The original insertion loss spec for all the R-4C filters

If it were me, I might go the mechanical/non-solder approach. ?Using something like a Fahnestock (sp?) clip or other device for the connection. ?Back in the day there were several RF amp tubes that

That works, John.? But, muffler cement is about the same thing and much easier to obtain as any auto parts store has it for sale in toothpick type tubes. Lee, w0vt

I have used something like cast iron stove cement and pretty sure I used regular solder..?? It worked on a 6146 I recall. John K5MO

I might add, use Muffler Cement and not regular epoxy.? Epoxy can't handle much heat.? The muffler cement used will be the last time the cap will ever come loose again. Lee, w0vt

I'd try a tiny bit of laquer thinner on the end of a toothpick to try to free that wire. Don't envy that challenge. - Jerry, KF6VB

Similar to Lee, but I just use my normal solder. Never had an issue after but… I never had a tube that hot (I guess). Frank Krozel KG9H Life Member, ARRL (630) 924-1600 kg9hfrank@...

It could work; however I'd be a bit scared of melting the surrounding shellac/varnish/? with it. Also, I don't have a hot air rework gun. I _think_ I can solder it if I can get a bit of the wire

First off, I glue the cap back on the tube with Muffler Cement sold in a toothpaste tube at a local Auto parts store.? Then I use normal electrical solder.? I have never had my re-soldering on a

I’m looking for anyone’s experience in successfully soldering an anode high voltage cap-contact on a final tube. ?Particularly, being that the typical maximum bulb temperature of the tube is 500

How about low-temperature solder paste? Then hit it with a hot air rework gun with the smallest tip. - Jerry, KF6VB

Donnie, testing today with an R-4, which has only one 6HS6 -- the pre-mixer. I tested 5 tubes in the socket: 6HS6, 6AH6, 6AU6, 6BA6, and the Russian 6J5P. There was no difference in the AGC set point