Thanks, Todd for all that good information. Yes, let us try a sked sometime on 40 meters.
All my best. Dave, W3ST Secretary to the Collins Radio Association Publisher of the Collins Journal www.collinsra.com ----- Original Message ----- From: "Todd Bigelow - PS" <[EMAIL PROTECTED]> To: <[email protected]> Sent: Wednesday, December 31, 2003 8:28 PM Subject: Re: [AMRadio] Need advice on storing RF power tubes > David Knepper wrote: > > >Todd, you have to be very careful when removing those 75TH tubes, which were > >the original types used in the 30K-1. > > > Uh huh, *now* ya tell me. Actually I broke it a few years back when > simply trying to remove it so I could restore the mod deck. It made me > wanna puke when I realized what just happened, so I stuffed it back into > the chassis and shut the door for a while. Finally found a pair of > replacements back in May. > > >What you need are adapters that slip over the grid pins. These were made by > >Eimac to be used with any of these tubes that had that pin arrangement. > >These caps slipped over the pins and were much more sturdy than the grid > >pins. > > > > > > Well, that was the problem: these caps are some kinda weird, they split > down the center and are held together under pressure on the pin not by > ONE snap ring on top, but also by another beneath it. I'd never seen > them before so I was trying to get the tube out to where I could eyeball > it better. Those snap rings require goofy pliers to remove them, and > it's not the type of thing for the faint of heart to attempt by reaching > under the cap with a mm or less of clearence between the cap and the top > of the glass envelope. > > Today I did the smart thing. After removing the tubes last night with > plate caps and wires still attached (I removed them at the ceramic posts > on the chassis), off we went to see my friend Ray, KC1BT who is a former > BC engineer and has seen, made, and repaired at least one of everything. > He'd never seen this type of cap before either, but his pliers are a lot > better than mine so we prevailed. It was actually easier to slide the > cap off the intact tube with only the top snap clip removed since the > envelope held the pin in place firmly (unlike the one I broke). > > So...now they're sitting in the radio room, waiting to be installed > later tonight. The next step is obtain a crystal for 40M AM and > hopefully to locate the plug in inductor cans for the oscillator and > multiplier plate circuits in the 75M band. The mod 5 differs from the > ham version in that it has two switchable crystal controlled frequencies > with complete tank circuits which each require a combination of 4 coils. > My rig came set up for 6-8 Mcs and 2 - 3.4. Would be nice to find a > complete coil set along with a 310C-2 vfo unit. I traded for a 310B-2, > only to find out it was the wrong unit for my transmitter. Maybe someday > we can work on 40? > > 73, Todd KA1KAQ > > _______________________________________________ > AMRadio mailing list > [email protected] > http://mailman.qth.net/mailman/listinfo/amradio
