"Holy smokes, instant gratification... Turned it on and it works almost perfect with only a small tweak of the controls."

Wao! Izzat cool or what. :banana::banana:

Great result. Don't be afraid to give the CRT a mild rejuvenation. I've found that old B&W CRT's respond well and stay that way for a long time.

I did try to rejuvinate it, and it didn't really do anything for it. It's the original Marconi CRT, so I think it's just tired. It tests in the yellow area, it does make a decent enough picture, but you have to crank up brightness to get it to look nice.

I did most of the work back in May, and have been too busy since then to get back to it. Now that it's working, I need to get the cabinet cleaned up and looking nice. I like the way the top comes off the cabinet, exposing all the working parts. One thing I'm not entirely sure about, is how tight to make the band which holds the CRT to the base board. I don't want to overdo it, for obvious reasons.

Tighten it till there's no wiggle or it is too small of a wiggle for anything to work loose.

Tightening a CRT band always causes tightening of a certain muscle in the body!! Especially when the CRT is mounted on lugs only and the whole weight of the CRT relies on the band.

Yep you've got that right! When I did my 25" Motorola colour tv, I marked the worm gear on the band before I took it apart, and it was much tighter than I would have expected glass to take.

This one is more of a strap holding it down, than a band like newer TVs have. It rests on two mounting points, and the strap goes only on the top and sides. I wish Marconi gave me a torque spec in inch pounds, for the retaining screws. I think it's good now, though.

On another topic, I need to find some tubes for the tuner. I sure can't complain about the price of tubes for this TV, the only semi expensive one is the horizontal output, and I have a few of those in my misc. Junk.

I find it interesting how thick the insulating donut is on that flyback HV winding, and the thick strain relief where the anode lead exits is actually functional. Compared to most of our American built flybacks that one looks very robust. It irritates me how so many NOS flys have a crack right where the anode lead leaves the HV winding. Max, do you know what year your set was made?

http://videokarma.org/attachment.php...8&d=1526679734

Most of the parts have a 1958 date code, so I believe 1958 or maybe 1959.

Back to this TV after some time, I wanted something to watch the news on while I'm dealing with the COVID quarantine. I turned it on, and now horizontal refuses to lock properly, and the image looks inverted. Hopefully the better techs here will know what this means by looking at the image. Would appreciate any suggestions. Last time I tried the TV it did show a picture properly.

Try turning down the AGC control....If AGC is set too high you will loose sync, get negative video, and sometimes sound issues.

I started it up cold and it synched fine, but then went out of synch again. This chassis does not have an AGC control, surprisingly, although that idea makes a lot of sense.

Tom, you nailed it - a new 3AL5 AGC detector was the cure, it works properly now.

Another issue it seems to have is weak sound. Low volume, and quite a bit of buzz in the audio. The picture looks great now.

Happy to help.

Does it use a 6BN6 or series string equivalent? If so the buzz control is the first thing to adjust... Assuming fine tuning knob adjustment can't improve the sound.

Here is the tube layout for the set

I already tried a new 3AL5, and a new 3AU6. I do not have handy a 5U8 to try

Do you have a tube tester or a strong 6U8? Has the low voltage lytic on the detector been replaced in recent years?

Another option if you don't have a tester is to check voltages on the tube if the grid is normal or less negative (/more positive) but the plate is higher than normal that indicates a weak tube (DC plate current below normal).

There's also the lazy audiophool method of turn the set down, plug the audio output of your video source into your stereo and turn the stereo up....I tend to favor this even on sets with good sound.

Set was totally recapped in 2018, but project was put on hold so could be an issue there. Suppose could try a 6GH8 for kicks, have no 5U8. Set is series string, so wouldn't be safe to add an input the 3AV6 is weak, and the pentode section of the 5U8 checks okay. Plenty loud with no signal, but barely anything with either a VCR or modulator.

I will check all the voltages in the sound section to be sure. The plate voltages seem okay.

You get two points today.. a 6GH8 cast off from my CTC38 revived the audio, it is loud and strong now. Will have to find a new 5U8. Thanks again!! This strikes me as odd, because the 5U8 tests only slightly weak on my TV7. For all it will cost I'm thinking to maybe just order a set of new tubes for this TV, it seems like a lot of them are marginal. Interestingly, this set has mostly original tubes, but the 5U8 has been changed already, which indicates to me it might be run hard.

Hey Max, I have lots of NOS 5U8 tubes.

Gregb

Hey Greg, good to hear from you.. I will send you a PM