Admiral 14R12 Restoration

[Crist Rigott]

Originally Posted by old_coot88

I was gonna suggest essentially the same thing.. incrementally 'walking' the IF adjustments back, while looking for the best rendering of fine detail in the pic, with no ringing or smearing of fine detail. Probably have to re-tweak the Ch 3 osc slug along the way, to keep the fine tuning range centered.

There was a guy on here two or three years ago, a total newbie with a late 40s Dumont (I forget his name. Phil Nelson probably remembers). The guy did an IF alignment totally by eyeball, no instruments, no nothing. But damn if he didn't end up with a perfect pic, just as good as with a full instrument alignment. That might be the way to go with this one.

OK, I'll try walking back the IF and tweaking the CH 3 slug.

I've got a pretty good picture now, I know what you mean by doing it visually. We'll see what happens.

Thanks for the suggestions guys.

[Kevin Kuehn]

Originally Posted by old_coot88

If you want to go the eyeball route and have a frequency counter that'll read 85.25 mc, set the Ch 3 osc slug to that frequency. (A turn or two of wire taped around the osc/mixer tube oughta provide a decent pick up.) With the fine tuning at mid range, the osc wants to be at 85.25 mc for a 24 mc IF. That way, you have a 'target' to walk the IF adjustments toward.

(Ch 3 carrier is 61.25 mc.)

I was hoping you'd explain to us how to do that.

Also a B&K 1076 or 1077 Television Analyst would be really handy right now too. With that he could inject the Analysts IF output directly into the sets IF and manually sweep through 24MC, so he could see exactly where the TV's IF response appears to be optimized for best sound and picture. A very handy and educational tool for anyone planning to stay in the TV restoration hobby.

[old_coot88]

Deleted. My bad. It's the B&K 415 that's the 'gold standard' for learning IF alignments. With a decent scope, it makes doing IF alignment actually fun. https://www.google.com/search?q=b%26...nerator+images

The 1077 Analyst is a stablemate to the 415 and does everything under the sun except IF sweep alignment. Phil Nelson refurbished one not too long ago. http://antiqueradio.org/BK1077BTelevisionAnalyst.htm

[Crist Rigott]

The BK 415 is for the higher freq. IF TV's. It won't work for mine. Later today I'll get back to this chassis.

[Kevin Kuehn]

Originally Posted by Crist Rigott

The BK 415 is for the higher freq. IF TV's. It won't work for mine.

Unfortunately true. And as far as I'm aware there was never a rival service grade unit made for the old 24MC band.

[Electronic M]

Originally Posted by Kevin Kuehn

Unfortunately true. And as far as I'm aware there was never a rival service grade unit made for the old 24MC band.

IIRC the markers on the 415 were crystal based (I need to dust mine off and make it work) so with the right crystals and mods to the sweep section the 415 might be convertible to the older IFs...Could be an interesting project trying to make a 415 mod to switch back and fourth both IF freqs...Though it might be reinventing the wheel.

I recently picked up an example of that EICO generator you were using ($5 at Goodwill)....That makes ~6 pieces of 'as found' IF alignment gear I have sitting waiting for the day I decide to try and teach myself IF alignment...I really need to block off some time for that some summer or winter...

[old_coot88]

Originally Posted by Crist Rigott

The BK 415 is for the higher freq. IF TV's. It won't work for mine.

By golly you're right. I had to look up the specs just to be sure. Amazing that it doesn't cover the old band.

[Kevin Kuehn]

Originally Posted by Electronic M

Though it might be reinventing the wheel.

I looked into that and came to the same conclusion. The correct crystals are very difficult to find, and the project would get very involved before it was all said and done. A better use of time might be to design from the ground up a digital programmable 5 frequency marker generator that could be used as an add on with any of the service grade post marker sweep generators.

[Crist Rigott]

Taking a mini-break from this for a few days. Another quickie project has popped up.

[Zenith26kc20]

Not the first time I heard of "eyeballing" the IF strip. When I was a kid helping at a TV shop, there was a tech that did my Motorola TS905 and a RCA CTC16. Both sets turned out great! Amazed me to watch as he did them. He was a older ham operator who also designed and built a good bit of his gear. As a kid, that shop was a blast!!
I just wish I still had that old Motorola. It's biggest problem was it was huge! My mother was not fond of it in my bedroom. Took up way too much room!

[Crist Rigott]

Besides my mini project this week I worked on getting the back reconditioned. Much to my surprise it really didn't fit too good! I know when I got the TV it was barely on the TV and it really didn't fit so good.

I got to looking and the left vertical brace was installed to the back too high. It contacted the upper left mounting screw boss by a lot. OK, so I relocate the brace to match the good right side. I place the back into the cabinet and it is too high! The cutouts for the upper mounting holes won't line up. Hmm....

I decide to mount the chassis into the cabinet to see where the problem is. Well it looks like the outline of the back is correct, but all the holes, etc are about 1/4 inch high! My guess during manufacture, the blank outline wasn't inserted fully into the jig or machine that drills/punches out the holes! I also thought that there might have been some rubber biscuits that go under the chassis but there can't be because the controls shafts are centered on the cabinet holes.

There is no way to locate the elongated holes that mount the back to the chassis. I run out off the bottom edge of the back.

So I drew up a new back using my CAD program. I double check all the mounting holes to the chassis and to the cabinet. Much, much, better. Of course I have to make a new back now.

I've included some pictures of this whole mess.

[Kevin Kuehn]

Nice job on the drawing. Yes that back design is a bit of a mystery. I wonder if the Masonite actually shrunk to the extent that the top screws pulled the corners off? I also don't understand the need for what appear to be so many extra screw holes, as if that back spent some time on some other cabinet.

[old_coot88]

That looks like the incorrect back. There also needs to be a lot more ventilation holes near the bottom to get a decent draft on them hot tubes.

[Crist Rigott]

It is the correct back. The elongated screw holes and the interlock connector fit perfectly. Also the cutout for the antenna terminals fits perfectly.

Kevin, the extra screw holes in the pictures are for the screws that hold on the 3/4 x5/8 braces which were removed when I was measuring the back. In my drawings, you can see them as dotted lines.

[Kevin Kuehn]

Originally Posted by Crist Rigott

Kevin, the extra screw holes in the pictures are for the screws that hold on the 3/4 x5/8 braces which were removed when I was measuring the back. In my drawings, you can see them as dotted lines.

Ah. Funny how quickly I can forget stuff. I had to go back to where I we originally discuses the set on CL to see what the back originally looked like mounted. Makes sense now that the corner hole were elongated for expansion and contraction, and then the large washers to cover the holes. But I also have to agree that that back doesn't allow for very good ventilation, but since it's spaced out from the chassis at the bottom I suppose it's suppose to work like a convection oven.