Once you have a good CRT change the bad HV wire properly. When that insulation kludge fails on you again a few weeks or months down the road you'll wish you had replaced the wire.

a very dopey looking FBT

http://suzaku.live-evil.org/0717222342.jpg

there were some cracks in the outer " doughnut " that was allowing arcing.
but unlike the ones in the roundies, this one seemed ti be made of tar or something and not rubber.

there was no carbon tracks that I saw, just cracks and so on.

as far as replacing the heater winding, i really don't have the type of wire to do it right now, or really know what to even get to use.

Thinking conservatively, it would be rather foolhardy now NOT TO replace the burned wire now while I have the FBT out of the chassis with it easy to get access to.
Not really knowing what type of wire to get, I made an educated guess.
Copper Core Flexible Silicone Wire Cable Red 10M 32.8Ft (22AWG 40KV)

40KV, well above what this set should generate, 22AWG, should be thin enough for the clearly 2 turns that I see around the core of the FBT, and hearty enough to power the 3A3A/C

Re-post of original FBT photo.

http://suzaku.live-evil.org/0716221404.jpg

You can clearly see 2 turns on the heater winding on the core, should not be too hard to replace with the new wire ordered.


You can also see the crack (cracks) in the FBT outer layer which looks to be made out of some kind of hi temp tar, which was easy to melt with an soldering iron, there was a tendency for corona arcing from these cracks but saw no real carbon, and thought it very risky to try to remove it, so I covered it with several layers of dope.

When the high voltage rectifier winding arced through, I used to cut out the wire and used an EDI solid-tube which was a solid-state replacement for a 3A3/3DB3 or a 3AT2, depending on the set. It was especially important on a Zenith that used resistance wire for the winding.
RCA's seldom needed it because the flyback was replaced before. :D

thought about that, but when I tried the Philips ECG ECG508 / R-3A3 45KV Silicon Rectifier in my CTC-16XL, it self destructed in 90 seconds for some reason.

bit worried about trying one again.

Are those actually silicon? I always suspected they were a selenium stack, and never trusted them.

shango066 also tried one in a roindie, and it fried in 20 min.

so I tend not to trust them.

if anything SS, perhaps this or something like it.
http://hvstuff.com/40kv-1a-high-volt...fier-tesla-ham

I never had one fail, so I don't know if they had a string of silicons or selenium stack. If I knew they were selenium, I never would have used them, knowing that the focus rectifiers were.
I used the EDI brand, not the ECG. :thmbsp:

i did a quick look, but sadly any compatible EDI brands are quite unobtainium.

So the choices fixing it to the original spec, which I will try first, then go with that huge 1A 40kv SS diode later if all else fails.

Turns out that site with the 40kv ss diode is fake, the entire site is nothing but a rip-off.
However, I did find a EDI Solid-Tube R-3DS3 7541 on eBay, a 3DS3 is not compatible, but as a last resort, the SS R-3DS3 can be made to work, as it's well within spec.

There are 82 adjustments on a CT-100. This includes only one channel strip. It includes the six position and tilt adjustments of the yoke, which are
all very criticasl for perfect convergence.

I adjusted every one on my TV, and they all DID make it better! (except the RF on the strips, which were OK.).

In fact I added an 83rd one, one additional adjustment in the color matrix ..
and that really did get it better, even after changing all the fixed resistors to 1% ones.

EDI Solid-Tube R-3DS3 7541 ordered

HV wire will be here tomorrow, FBT coated VERY well with dope and cured, and ready for new wire, I doubt it can arc any more.

one way or another it WILL work.

Here is the link to what could be a useful site to check out a website.
My search was for kalesafe.com and you can see the results. There is a search feature at the top. https://www.scam-detector.com/valida...fe-com-review/

As Tom Petty once said, “the waiting is the hardest part”

Amazon SHOULD bring the new HV wire today, with which I hope to re-wind the newly doped FBT and try again with the 3A3C.

Did a resistance check on it.
http://suzaku.live-evil.org/fbt112.jpg
It all mostly agreed with what SAMS says except fot the one 4.7 ohm reading which was about 10, but I have seen this before, where what they had listed did not match real time with what was in the sets and there was nothing wrong.
Especially when there are 2 different FBTs listed in the SAMS, Hoffman # 033-013000 & 033-012700
both replaced by merit hvo-234c / stancor ho-601c / triad d-304.

And if worst comes to worst and this CRT is no good, ETF does have at least 1 or more that will fit in this thing, :O

The only Hoffman set I worked on, a 23" CTC15 clone. The flyback Sams specified was the wrong one. It was for a 70deg round tube set. It didn't work properly!
A friend worked for a Muntz dealer, so I ordered a flyback from him. Worked great and it was a lot cheaper!
That was about 50 years ago. :sigh:

OK...
this just got a bit stranger.
the replacement FBTs listed in SAMS are FOR the RCA CTC-15 .
was the same one used in the 17?
this is odd
its not SAMS that makes the subs, but merit/stancor/triad right?

The CTC-15 was a roundy the CTC-17 was a rectangular...The deflection angles are different between the two so RCA definitely used different flybacks in the 2 chassis, and I have a hard time buying that Hoffman could have made a roundy fly work in a rectangular set.

Then the list in SAMS must be wrong, just as DJ ran into 50 years ago! :yes::D

The Sams was wrong!

Redone FBT ready to go back in!

http://suzaku.live-evil.org/0719221857.jpg

https://www.youtube.com/watch?v=xos2MnVxe-c
http://suzaku.live-evil.org/0719222043a.jpg

and there is color! dirty! o
http://suzaku.live-evil.org/0719222046.jpg

the repair to the broken pin DID work!

the video is sloppy, prob some weak tubes, many orig ones still in there, but now I know all I need to to move on to the restoration stage,

https://youtu.be/mCyPldcQ9as

first video

I have a question in regard to your Hoffman Colorcaster TV. I looked at the photo of the service adjustments for this set (of which there must have been twenty or more, as I would expect in a 1956 color TV) and saw, to my surprise, a brightness control. My question is this: Why would the brightness control be located on a control panel which has mostly service adjustments, which of course are not to be touched by anyone other than a qualified service technician? Or was there another brightness control wired in parallel with it, the second control being the user brightness adjustment?

In any case, I would think two brightness controls would be one too many for any TV, color or b&w. I could understand this if the second brightness control has a definite function, such as setting the maximum range of the user's control, but otherwise I am at a complete loss to explain this. Most later color sets (late 1960s on) had only one brightness control. Was there something about 1950s color televisions which actually required the sets to have two brightness controls, or was the second control used, as I said, to limit the range of the user's brightness control?

Thank you for any and all information on this, as this TV is the first one I have ever seen (I have never seen a Hoffman TV in person) with a brightness control on a panel normally reserved for service adjustments. I also saw a few other controls on this TV's service control panel which are ordinarily service adjustments only, again to be adjusted only by qualified service technicians. Were these controls wired in such a way as to limit the range of the existing controls? If so, as I said, this is overkill of the worst sort, as most later color sets only had one control for most service adjustments. These controls almost certainly would not be noticed (and should not have been) by the average color TV set owner, anyway, as many color TVs of the '50s and even into the early 1960s had a warning label pasted somewhere on the inside of the TV cabinet, to the effect that service adjustments, tubes and other parts of the set must not be touched except by a qualified TV service technician.

I'm not sure which docs you saw, but this set has only one true brightness control, however I have seen a “ sub- brightness” on some sets, perhaps that's what you saw?

SAMS does list a potentiometer on this to set kinescope bias, but this chassis has a switch for that.
This I can only attribute to the SAMS being for a Hoffman MO# MS-7322 and seems I have a MS-7322 (B), and this one SAMS is the only one there is, and it's close enough.

Sets with an "automatic" color switch of some kind would switch in a set of factory preset controls. Is that the case here?

Not sure, but this thing does seem to be a weirdly modded CTC-15 more than a 17, as I believe the 17 used a 1V2 or the like for focus, and this has SS like the CTC-15.

What ever it is, it does seem to be a Frankenstein creation! A little bit of this, a little bit of that, put into a pretty unique package!

AHHHH! That explains the odd behavior I saw last night!

Turns out that what is stamped out in the back of the chassis for the controls is NOT what they really are, they had stickers to show what they were, but they are long gone, what was marked as CRT bias was really VIDEO PEAKING, which was set in top most setting, and I sort of freaked when I changed it and lost picture and just got a blank raster.

Meaning there may be bad caps or more likely bad resistors, or the switch itself is dirty.

The REAL CRT bias adjustment is indeed a potentiometer, just as the SAMS says, but in a position stamped for something other than CRT bias, and when checked, much to my relief, it was turned 1/3 the way up when it made the video posted yesterday! :)

Sheesh!
You are now officially a member of the guild of electronic archeologists!

Wow... I've been steered that wrong by Sam's before, but I don't think I've been lied to by chassis stampings... That's some 50s B horror movie level cheapness to fix stampings with stickers.

I did find ONE of the stickers that fell off, for top/bottom pincushion.
I did manage to clean up the convergence a bit, will make one more vid before I yank the chassis to haul upstairs to go over it with a fine tooth comb looking for out of spec parts.

It's looking rather well considering it's just been patched together and I did not put the blue lateral/purity assy back on yet.

The whole thing is just too big to bring upstairs, but at least they made it easy to unplug / reconnect the tuner / front controls, just 2 plugs & the IF.

https://www.youtube.com/watch?v=JOuNggMBsEE

2nd video

Looks a lot better!

So far, I have been over 1/3 of the color PCB and i have not found one out of tol resistor yet of the ones the I CAN test w/o removing them from circuit, starting to think that it's not worth checking them at this point any more :O

Recapping 1/2 done (electrolytic)

http://suzaku.live-evil.org/0724220102.jpg

BTW you can embed that picture link so the forum displays it as a picture (the only reason I didn't is the resolution is so high it makes the text too small to read if zoomed out enough to see the whole pic....a lower resolution say 800x600 or 1080HD source image at the URL would fix that).

All you need to do is type this [IMG]linkURL[/IMG] or in the "go advanced" reply page click the square that looks like it has mountains and a sun in it and it will automatically give you the [IMG] BB code.

I've been using Flickr and they give me an over complicated BB code to copy paste that I usually end up editing down so I can arrange my pictures in a neat grid.

Seems that all 3 of these gimmick lights are burned out. :O

Bad design.

NPN switch from the 6.3 fil power through a 1/2 wave rect, lighting up 3 2 volt bulbs through a 6.8 ohm resistor, as long as ALL 3 lamps are OK, all is fine, but if one burns out, then they ALL go because the voltage spikes.

they sell them in packs of 10, not gonna do it, I can get ultra bright yellow LEDs that run at 2-3 volts in packs of 20 cheaper.

Whenever I get a set that someone has converted to LED lamps I reflexively :puke: then switch it back to incandescent it's one of those things that gets under my skin about as bad as a set that someone painted some random ugly color.
I'm pretty well stocked with bulbs thanks to an estate sale of a mid-century EE who had 2 mason jars of spares, but when I use that up I plan to hit up rockauto...When I was doing my 6V 1947 Oldsmobile I had a look at every part they had and found a number of radio bulbs it used for the interior lights were DIRT cheap compared to mouser, and better than bob's capacitor who was my supplier before the estate sale. I think if I browse around 40s cars on rockauto enough I should find almost everything I typically need for consumer electronics.

I really don't mind using LEDs at all, they are cheaper than bulbs, and outlast them.

On second thought, since the source is 6.3v, and the drop across the transistor is pretty much nothing, w/o any bulbs, the switched on output should be about 6-7v so by adding a dropping resistor to ground, like 6-7 ohms should get me the 3.1v needed to use the ultra bright white LEDs, like I used in the GE TV.

Will just have to play till I find the right resistor value.

Trying to picture this. Wouldn't a separate series resistor for each LED make more sense?

The current draw of the old lamps was 3x .06a (180 ma total)
the draw of the 3 LEDS is 60 ma 3x20 ma.
The entire circuit in question is mounted on terminal strips behind where the bulbs go in.
I'm pretty sure all I need to to is add a resistor to gnd at the far side of r160, to keep the voltage about 3-4 volts, the LEDS are pretty forgiving about what you give them, and even if I damage a few while working out the correct value, I have 100 of them to experiment with, and they are small enough to solder into the shells of the old bulbs after the glass has been removed.