12QP4 base repair
 

I took a gamble on this 12QP4 on eBay. The base had come off and the seller was unable to do more that a basic filament test. I ended up the only bidder at $40.

I appeared to be very well packed (or so I thought)
http://farm6.staticflickr.com/5444/8...d5f33b68_z.jpg

Christmas in May :)
http://farm6.staticflickr.com/5449/8...2b180d7f_z.jpg

Uh-oh. What the heck happened to the pins :tears:
http://farm3.staticflickr.com/2863/8...7a3d5dc8_z.jpg

This is how they appeared in the eBay listing. The seller must have mashed and twisted them while packing it up!
Why go to so much trouble carefully doubled boxing it just to smash the base :rant:
http://farm8.staticflickr.com/7330/8...473272e9_z.jpg

So I set out to carefully unmangle them just enough to test on the off change it might still be good.
Much to my amazement, it didn't just test good, it tested like brand new!
I later noticed a telltale weld on the neck indicating it's been rebuilt.
http://farm9.staticflickr.com/8254/8...8cea6747_z.jpg

I didn't dare try to completely straighten the leads out and stress the glass any more. Instead, I spread some epoxy around the leads and bend them up at a different point in the lead. Then I attached some extension wires and carefully threaded the base back. Before it was on all the way, I smeared around a little Permatex silicone adhesive.
http://farm8.staticflickr.com/7309/8...eb1db74f_z.jpg

http://farm6.staticflickr.com/5460/8...a95480b6_z.jpg

After all that, it's still good :banana:
http://farm8.staticflickr.com/7453/8...5492d6bb_z.jpg

Hi Bob;
You Accomplishments seen to amaze me, more and more !!! :D :D Congratulations !!!!
THANK YOU Marty

Nice save on those wires!
I've grabbed them near the glass with a pair of Needle nose pliers and bent them back in shape above that point so they don't break.

There's probably nothing in old TV restoration as nerve racking as doing this surgery on a CRT.
I had to do it on a NOS 7JP4 to fix a short, first getting the securely glued base off without breaking the nipple or any wires, then trying to get all 12 wires back in, nightmare!

Not that I've done it, but it just occurred to me a way to easily replace a tube base: add extension wires the way Bob did, but make them different lengths. Start with a longish one, then next one in line a little shorter and so around the whole base. Thread in the long one first, easy. Then the next longest, and so around the base. Easier than trying to get all of them the same length in at once. Finally trim off the excess and solder.

Check out the 2nd from last picture above. I did make them different lengths :yes:

: There's very few people that have that amount of inginuity, or patience. :thmbsp:

Good Job , glad you saved it and inspired countless other would-be surgeons

Bob - 12J / KP4 was not available from my source as you may have guessed

Reminds me of a Philco split chassis I sold at the ETF. Found the thing at a thrift with the back off and the CRT socket knocked off and destroyed. I had to unbend the leads coming from the glass and attach wires to thread a new base on. I used long lengths of single strand phono pickup wire of the same length. I could bend them and thread them one by one then slide the base down....Worked like a charm.

So you did make the wires different lengths! I just flat missed it.

that was local to me I passed on it (after it started out on a CL for 400$ or something like that for the whole set). I am glad it worked out for you, I had offered to test it for them for a small fee (I did not want to drive out there for nothing) but they chose not to take me up on it. they sold off an extra CRT the orig CRT and I think the "guts" as the plan was to convert the cabinet to storage, ugh. I just did not have the room for a large project like that. Again Glad it worked out :thmbsp:

I do recall seeing the spare 12QP4 on ebay but didn't bid on it. Assuming this one holds up, I'm very happy to have it because it should work just fine in my new Clifton if needed. Otherwise, it might end up in my Stromberg Carlson TV-12.