Valentine's gift (or is it a shameless trick?)

[wa2ise]

So how's it holding up? Hoping its

[marty59]

Maybe this model Philco is picky about Vertical tubes like our Barber Pole models and you have to go through a bunch of 'em to find some that perform well enough to correct that linearity issue.

[Phil Nelson]

It's holding up so well that I have gone on to the next project. Miss America plays all day long to entertain me in the shop until we decide where to put the set.

The linearity is just bad enough to be annoying. I have replaced practically every resistor in the vertical section, even the two on pins 9-10-11 of the yoke socket.

Swapping tubes is a good idea. I tried subbing the 12AU7 but don't have a 6CM6 (vertical out) on hand. I went on a treasure hunt and found many odd & wonderful tubes -- why do I have two dozen 6BH6s? -- but no 6CM6 or equivalent. May as well order one.

I was a little disappointed in the bass response and even thought of hotwiring a new tone control. Then I put the back cover on and, duh, the bass sounds fine.

Phil Nelson

[miniman82]

I could swear I have a 6CM6 in the garage, I'll go look.

[Robert Grant]

Originally Posted by Phil Nelson

Yes, if I move the horizontal hold left while retaining sync, the picture moves left very slightly, and so does the line. The line is also minimized when I adjust the fine tuning for less sharp detail.

When that photo was taken, I was receiving a broadcast from my in-house transmitter (Blonder-Tongue agile modulator) on rabbit ears. Haven't looked for the phantom line using another source yet, but I'll do so tomorrow.

Meanwhile, I'm glad I decided to pull the safety glass and do some cleaning. The inside of the glass was almost as grubby as the CRT face. I have never seen a screen & glass quite this dirty.

Phil Nelson

I wish I had a picture of the Zenith 16C21 I trashpicked as a teenager 31 years ago - it had an almost opaque coating of sepia cigarette "tar" almost 1/8" thick - took a whole roll of paper towels to wipe it off. That and replacing the 1K3 and it was as good as new - best low-VHF TV DX set I ever had!

[Phil Nelson]

Originally Posted by miniman82

I could swear I have a 6CM6 in the garage, I'll go look.

Want to trade for a dozen 6BH6?

Seriously, if you find one, send me a PM.

Phil Nelson

[wa2ise]

Too bad it's not 6CL6, I have a bunch of those.... Only one letter off.

[Eric H]

Nostalgia Air lists 6DT5 and 6CZ5 as substitutes

[Phil Nelson]

Originally Posted by marty59

Maybe this model Philco is picky about Vertical tubes like our Barber Pole models and you have to go through a bunch of 'em to find some that perform well enough to correct that linearity issue.

I tried a couple of new 6CM6 tubes and now I can get closer.



Re-centering the vertical also helps (duh). Strange yoke gizmo, by the way.

Horizontal linearity ain't perfect, but with no linearity adjuster I think I will call this good enough. The next project is already underway.

Here's the usual gabby article:

http://antiqueradio.org/PhilcoF4626MTelevision.htm

Thanks for the advice.

Phil Nelson

[miniman82]

Didn't find that tube, BTW. Looks good to me!

[old_coot88]

Originally Posted by Phil Nelson

.

Here's the usual gabby article:

Phil, your gabby articles are far and away the most entertaining, engaging and informative of any out there. I always settle into one of your resto sagas knowing it's gonna be enjoyable to the utmost.
Bill(oc)

[DaveWM]

indeed the gabbfest is good, as is the consistant style (tube layout etc..).

I have been using the cut off the can and leave the base intact approach lately as well on sets where I dont want to spend a lot of time on.

I use a bone saw style for the cutting, seem them on those late night infomercials, the receprocate and you can plunge cut direct into the can with very little access. A bit pricey though...but fast.

[TerrySmith]

Would it hurt to add a 10 ohm resistor on the HOT cathode? It would make it easy to check cathode current using ohm's law, 100ma = 1v. FWIW I do this on each of the output tubes on all HI FI amp builds, makes bias checks easy.

[Phil Nelson]

Interesting idea. I have also heard of adding a 250ma fuse lamp there.

http://www.videokarma.org/archive/in...p/t-13637.html

The fuse adds protection and the lamp is a poor man's current meter -- adjust for lower brightness.

Phil Nelson

[Phil Nelson]

Originally Posted by old_coot88

Interesting too will be to see if the new fly is same as the Predicta's. That is, the replacement consisting of only the primary windings and 'tire'. You have to reuse the whole frame and core and the paper spacers between the 'C' halves since they determine resonance.

I'm still debating whether to leave the repaired flyback alone (works fine, so far) or install the new one (hey, what else did I buy it for?).

This looks like a pretty complete replacement. It's physically smaller and it has different insulation. No wax -- yay!



Phil Nelson