Want to trade for a dozen 6BH6? :)

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

Phil Nelson

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

Nostalgia Air lists 6DT5 and 6CZ5 as substitutes

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

http://antiqueradio.org/art/PhilcoF4...tyImproved.jpg

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

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

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)

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.

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.

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

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!

http://antiqueradio.org/art/PhilcoF4626MNewFlyback.jpg

Phil Nelson

Hmm. Differnt supplier, evidently. Ours was the wax version and came sans the frame.
The ones for Predictas were the only replacement flybacks I ever saw supplied that way.
oc

I've heard the same thing from other sources about Predicta flybacks (you only got the windings for a replacement). I think Phil's set takes exception to what we have come to expect with the Predicta name (crappy construction) as it was a top of the line set for them at the time.

Speaking of current measurement, this week I got my hands on an HP 428B DC milliammeter, which gave the same reading as my old Triplett meter, so I guess the Triplett's good enough for government work.

Andy's method worked like a charm. Clip the 428B probe over the HOT lead and measure away. Easy as pie. On this set, the Width control affects the current directly, so I turned it down to around 100ma, which gives reasonable width & picture.

I got the 428B to use on my color roundies, but it has already earned back the few shekels I paid for it, and now I feel better about just letting this Philco play away. After warming up a couple of minutes, it looks fine without the CRT brightener, so I tossed that in a box. Who knows why they put on a brightener in the first place? Maybe that was a quicker solution than diagnosing some peskier issue.

Phil Nelson

I missed something. What exactly was Andy's method?

Kevin

Sorry, the method is just what I said (only too briefly). The 428B is a DC milliammeter whose clip-on probe you can place around the HOT lead to measure the current. Andy C. has mentioned doing this before. I thought I had referenced that somewhere earlier in this thread, but maybe I just imagined that part.

Anyhow, it seems to work, and it's easier than lifting one end of the cathode lead to measure. Perfect for a lazy guy like me.

The manual is at hparchive.com. Talk about your cosmic gizmo. Be the first kid on your block with a second harmonic flux-gate-type magnetometer probe!

Phil Nelson

http://antiqueradio.org/art/HP428BProbeOpen.jpg

That sounds like sumpthin' out of 'Back to the Future'.


:D
oc

Ah... so it's a clamp on amp probe. For a minute there I thought you were just clipping the lead of a convention VOM over the HOT lead and measuring current. I thought maybe somehow with the HV it was jumping through the insulation. :D