Decided to do "a few little things" on the RF deck this afternoon, while reading the mail on 75.
Department of nothing goes smoothly.
Well, let's poke around and see what's what, maybe how the new vacuum variable will fit? At least I didn't drop it.
First let's pull this 70 amp fuse that is JS'd into the spot and looks very much like it goes from B+ to ground. Does it? Really? Uh huh. WTF? Well, that came out ok... we're cruisin now.
(btw, that's a bad sign... wonder if something else got really fried as a result of this little bit of cleverness - time will tell...)
Wait a sec, this nut on top of the ceramic standoff is loose, the strap is loose and it looks like it has been moved so it is like 1/4" from ground. Let's fix that... ummmm... nut spins with the threaded rod, and if I try to spin the nut off with a driver, it twists the strap. Grab the micro pump pliers, grab the nut behind the nut, and 10 minutes later, voila! Take the standoff apart, clean, reassemble, re-route the strap.
QSO is in full swing on 3885.
Wait a sec, there are a whole bunch of other connections that are loose down here too... hmmm...
Ok, well, let's pull the front sub panel with the Loading & Tuning gear train and see what we can see about the front end of the PA area - besides, we'll need to have it out for cleaning & painting, lubing the gear train, getting at the mounting for the new vacuum variable loading cap, and also to move some of the RF parts around, including pulling the big arse mica blocking cap...
First step, gotta remove the set screws from the bellows style coupling of the Tuning cap. Well there are 4 and 3 of them look shiny, like they have been replaced. No prob, we'll hit 'em with some penetrant, select the proper allen wrench, and pop 'em out.
No way. They're no size known to man. Tried the metrics, the US , nothing is exact!! Bizzare. Well I only need to pull a PAIR!!
The QSO has moved down to like 3825 by now... Brent is channel master.
Ok, so how the heck are we gonna get these stinkin' set screws OUT without destroying the bellows coupler??
It's a brass coupler... fwiw.
So, here's the plan... we'll take the next size up allen wrench and with a nice little hand stone of the right size and grit, take it down one face at a time until it
just taps into the allen set screw - then we'll pull it out!
Many iterations later, grind and test, it's just right... I mount the key into a T handled tapping handle for control and torque (keep in mind this is like a 6-32 size set screw here), tap tap tap, into the set screw. TWIST - ahhhh! Out it comes.
Now the next one... Same method... tap tap tap, TWIST.
sssttrrrriiiipppp!!Friggin setscrew is dead soft crap.
I HATE allen set screws!!
what to do now??
The dremel with flexible extension hangs to my right... obviously for good reason... find the right drill, chuck it in, drillllllll, lube with some kero, drilllllllll, lube, drilllllllll, lube, drilllllllllll... etc... the QSO has ended, I move back up to 3885 and 4s, 5s and 9s are heard... take out the little mill/burr mount it in... gonna have to take it flat down to the shaft of the vacuum variable - what's that shaft made out of any how?? would be nice to know when I'm down to the shaft... burrrrrrrrrrrrr, lube, burrrrrrrrrr, lube, burrrrrrrrrrrrr, lube, burrrrrrrrrr, lube,burrrrrrrrrrrrr, lube, burrrrrrrrrr, lube,burrrrrrrrrrrrr, lube, burrrrrrrrrr, lube,burrrrrrrrrrrrr, lube, burrrrrrrrrr, lube,burrrrrrrrrrrrr, lube, burrrrrrrrrr, lube,burrrrrrrrrrrrr, lube, burrrrrrrrrr, lube,burrrrrrrrrrrrr, lube, burrrrrrrrrr, lube... looks good. Twist? no. Pull? no. Wedge? no.
back in with the burr, must have missed some, but it is moving a little, pivoting around the set screw area... burrrrrrrrrrrrr, lube, burrrrrrrrrr, lubeburrrrrrrrrrrrr, lube, burrrrrrrrrr, lubeburrrrrrrrrrrrr, lube, burrrrrrrrrr, lubeburrrrrrrrrrrrr, lube, burrrrrrrrrr, lubeburrrrrrrrrrrrr, lube, burrrrrrrrrr, lube... grab the shaft of the vacuum variable with a thin nosed vise grip, twist the front panel knob, YESH!!!
Ok, now undo the screws holding the sub panel with the gears & knobs, lift out, and yes it comes out!
Nice.
Meanwhile the clock has been rotating...
take the gear/counter assembly off the front panel, remove the set screws from the two knobs, lube gears, twist knobs, all good and smooth!
Ok, why not pull the rest of the knobs from the front panel and see what the paint looks like under it all... find the allen wrench of choice, uh-oh, the setscrews in these knobs are really siezed. Not a good sign. But, we'll finess it, not too much torque - don't want any more stripped ALLEN set screws!!
Let's drop some penetrant down the screws first, yeah.
These are those military style "Raytheon" knobs, black plastic, two set screws.
Bad news after 50 years, steel set screw in an aluminum inner collar.
Wait a bit, clean up the bench a little after the last operation, give the lube some time to work its way in...
<tick tock, tick tock>
Find a really GOOD allen wrench, tight fit... ehhhhhh, pop! Next screw... ehhhhhhh, pop! Ok!
On a roll now! Three more knobs, really at the limit of the wrench's holding power, but they break free... now the last knob! Well... two set screws. Try one... well that one does not want to go, AND it feels like the screw head is giving up - you know that feeling? Those rounded flats??
Try the other one, hope the penetrant works... ok! pop! Back to the stuck one. No way... <ponder>
What the heck to do... don't want to kill the knob, because it is skirted and I don't have any in that style skirted. Oh joy!
The QSO has died down, the band gone into noise and fades... dark outside.
Well, let's take a worn down abrasive cut off wheel, chuck it on the dremel, and make a slit across the set screw, drop in a small screw drive and pull the screw that way! The slit will be on the bottom of the knob anyway, and later we can find a replacement! OK!!
Bzzzzzzzzz... nice slit.
Screwdriver... nice fit.
Twiiiiiisssssst... crack!
End of the setscrew breaks off.
Now no choice, major knob surgery. Take out the model sized hand saw, cut away and remove the section around the set screw, re-cut the slit into solid screw, relube, insert screw driver, Twiiisst! Voila!
Now, let's gently remove the skirt, and reapply it to one of the new knobs... push, push push around the perimeter... ahhh here it comes! CRACK! crud. Ok, we'll use solvent cement and fix it... off it comes.
Solvent cement applied. Find the new knobs... crud they don't have the little lower ring to mount the skirts!!
The End.
Or, why everything takes much longer than it should and 100x longer than you can imagine it in.
_-_-WBear2GCR