TO THE LEFT!
Take it back now y’all.
With the assistance of Jack Davis (Jackpot Engineering), we got in there and changed out the tube body cooler ring, and the whole thing lived to tell about it…
I didn’t get pictures of the process because my hands were two of the six hoisting parts on and off of the thing, but here was the process:
Remove tube cart, place under chain hoist.
Pluck out tube.
Unbolt input cavity/socket assembly from below, drop it down and remove.
Remove bolts holding secondary cavity to cart legs and remove screws from underneath that hold those four round black vertical standoffs to the top plate of the cart. Hoist the top of the cart up a few inches.
Unbolt and remove grid ring cooler.
Admire the corroded mess.
This looks as if water may have been slowly getting out INSIDE the ring in addition to the externally visible leaks down on the lines feeding it, it was DONE. Please note the heavy coating of black silver oxide. This continued to make itself known throughout the procedure.
This was leak #1 down…….
“Does anyone know the last time the ceramics of the tube were cleaned?”
So, good cleaning of the tube is vital as there’s a BIG voltage gradient across the large white ceramic cylinder, as well as between the filament (innermost two rings) and the next ring up, assuming that’s the ion pump (3.5 KV!)….
I didn’t even realize the very bottom there had a ridged porcelain bushing around it – it looked to me like some kind of dull finish aluminum alloy piece from all the mess stuck on it.
Note the spot where I wiped it with my finger which came away black. I guess this also illustrates where all the air gets sucked out at time of manufacturing – it’s got a center exhaust like a light bulb!
The unglazed part of the bushing appears to just be permanently stained. I even tried Scotch-Brite pads on it. The glazed outside cleaned up perfectly.
And now, time for some massive, ugly cleaning.
Ever had a faux leather case on something or a piece of clothing where the outermost texturized layer of the material started shedding, forming an evil sticky glitter-like flaky substance that sticks to everything and spreads everywhere like the DISEASE of craft supplies itself?! Yeah— imagine that, but made of silver oxide, CONDUCTIVE, and coating most surfaces of the output cavities. Gee, no wonder I was getting cavity arcs in the log every day or so. YAAACK.
Brush, vacuum, brush, vacuum, bleeech.
Finally it was time to put it all back together, at which time I experienced leak number 2 — one of the Hansen couplers blew its o-ring and started spraying water down the back of the tube cart. These things work just like pneumatic line couplers you may be familiar with from air tools, just, big and angry and stuff. You can’t see it well at this angle but there’s a hard nylon ring up inside there followed by a rubber gasket. The rubber gasket had ceased to be, just like any of the Barnstead filter gaskets every time you look at them wrong.
So I left the amplifier running into the combiner load overnight, came back the next day and found a nice puddle of red splooey on the floor below the external glycol piping behind the cabinets. LEAK #3!!!
The source was the mid-body seal of a ball valve that literally would never have been touched since the day the transmitter cooling system was filled up and made ready for the rig to go on air. It’s a valve that’d let you bypass the outdoor heat exchangers and just circulate the Dowtherm glycol solution through the pump/tank unit and the amplifier cabinets. I’ve never seen a ball valve fail this way before. have you? Probably not. IT’S JUST POWERFULLY CURSED OK
COVER WITH J-B WELD, FULL SEND, BYE
Finally, Leak #4 happened on some of the blue hoses at the Barnstead filters, I was so done with this thing I didn’t take a picture, just cut the hose a little shorter and smashed it back onto the fittings, BYESIES
So that’s the tale of FOUR LEAKS on the Harris PisserCD.
Stay tuned for when I attempt a grid scrub / outgassing procedure on this stupid thing which has been last performed probably about when the tube ceramics were last cleaned, which is to say, oh, half a decade ago. -29mA grid current? Ok yeah sure thanks for that. What else is even left on this thing to leak??
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