Tech-Master NIB TV Kit #5516

[Crist Rigott]

This morning I scoped out the Horizontal Oscillator to adjust the frequency and to have the waveform peaks match.

Here is the result.



It seems that the vertical hold is pretty touchy. But for right now, I'll address the width issue with a strip and then move on to a full IF/Video alignment. Oh boy.

[Crist Rigott]

I made a "sleeve" using .003" brass shim stock 1" wide and 6" long. I then covered each side with packing tape. I then shoved it in between the CRT neck and the yoke at the top. I figured this would be the place because the horizontal yoke windings are on the top and bottom. I also placed the centering rings back on the neck and in the same position as before. I then connected a clip lead from the sleeve and chassis ground.

Turned on the TV and here is what I got. Wahoo! Now to clean it up and play it for awhile to see how hot it really gets.

[tom.j.fla]

Crist, ya did good. The warning was about causing a AC short through transformer action,mainly current overload. Read up on transformers to learn more on this. By the way did the HV stay up when you did the adjustment. All the best,Tom.J

[Crist Rigott]

The HV went from 14.5Kv to 10.2Kv! I pulled the strip out about an inch and its back up to 11.8Kv. Both voltages produce a very good picture.

Why does that happen?

[tom.j.fla]

The HV drop is caused by the de-tuning of the retrace freq. which is around 75 khz. Suggest reading books on horizonal sweep systems. Books by the late Jesse Dines are very good indeed. All the best,Tom.J

[old_coot88]

Originally Posted by Crist Rigott

The HV went from 14.5Kv to 10.2Kv! I pulled the strip out about an inch and its back up to 11.8Kv. Both voltages produce a very good picture.

Dadburn. L'arn sumpthin new every day. Next question is would a resistor in series with the horiz yoke winding affect the HV.

[Crist Rigott]

Originally Posted by old_coot88

Dadburn. L'arn sumpthin new every day. Next question is would a resistor in series with the horiz yoke winding affect the HV.

We'll see later.

[Crist Rigott]

Well, I just finished an IF alignment.

I followed the procedure as in the Instruction Booklet on page 4. Basically it went like this:

1) Hook up a VTVM - I used my Knight KG-625

2) Hook up a signal generator - I used my Eico 322. I know, I need to get a better generator. Maybe a BK E-200D.
I did use my 6J6 with pin 1 cut off to eliminate any incoming signal.

3) Connect a 3V bias battery

4) Preset all 5 coils either full in or full out.

5) Set signal generator to a specific frequency and tweak a coil to a max reading on the VTVM.

When done, I hooked up my O'scope and Eico 369 Sweep Generator to check the overall response curve. This was the waveform displayed:



Not even close!

So, with my diddle stick in hand, I first set the middle frequency of 24.75MC on the marker and then started tweaking till the marker was near the middle of the hump. A quick check to see if the 50% frequencies were anywhere close. They were not. After a lot of adjusting and getting a feel for which coil did what to the waveform, I ended up with a very decent waveform with the 50% frequencies right on the mark. This only took me several hours of being patient. I can't imagine doing this with the grand kids over!

Here is a picture of what the response curve is supposed to look like:


Here is the pip at 26.4MC:


Here is the pip at 23.1MC:


Here is the pip at 21.9MC:


Overall this alignment went a lot better than the Admiral 14R12 I did a few months ago.

I haven't tried it yet because I have to do the sound alignment next even though I tweaked the coils by ear the other day.

Stay tuned for a report on that.

[Crist Rigott]

I accomplished the audio alignment per the instruction booklet. I then ended up doing it again by ear. Much better.

I reinstalled the CRT, here are some pictures of how it is mounted and secured. The strap works well but the bolt brackets are a bit hooky. But they do the job. My guess on smaller CRT's the brackets would "work" better.

I centered the picture and moved the width sleeve to achieve a very nice picture. I'm playing Walt Disney's "Pollyanna".

[old_coot88]

Verrry nice outcome. Virtually a 'brand new' 1955 TV manufactured on the spot. Man, you handled that alignment like a boss.

Re. the width sleeve, all the ones I've ever seen were not grounded. Just guessing it was assumed there'd be some potential for an arc to ground.

[tom.j.fla]

If you remove the ground connection on brass width adjuster you may get back some of the HV reason you will be getting rid of some stray cap. coupling to ground which will detune the retrace freq. plus get rid of a source of arching. All the best,Tom.J

[Kevin Kuehn]

This is the only kind of width sleeve I've ever encountered(admittedly not many). This particular one was never insulated, which is kind of scary knowing it was slid in between the CRT neck and the yoke, but I believe it was common for the yoke to have an internal paper sleeve when these were used in a production set.

[Crist Rigott]

Originally Posted by tom.j.fla

If you remove the ground connection on brass width adjuster you may get back some of the HV reason you will be getting rid of some stray cap. coupling to ground which will detune the retrace freq. plus get rid of a source of arching. All the best,Tom.J

Ok, I took the ground off. I had it there thinking it would arc over when I touched it.

[Crist Rigott]

Originally Posted by Kevin Kuehn

This is the only kind of width sleeve I've ever encountered(admittedly not many). This particular one was never insulated, which is kind of scary knowing it was slid in between the CRT neck and the yoke, but I believe it was common for the yoke to have an internal paper sleeve when these were used in a production set.

Thanks Kevin. The strip that I'm using seems to work well.

[Crist Rigott]

My CL-90 came in and I installed it between the line and the 10 ohm resistor in the filament string. I installed it with the long leads and in the open. It took the voltage from 117vac to 113vac for the 115vac filament string.



I then installed the 15 ohm 50 watt resistor from the line to the B+ supply. With the resistor installed and the TV plugged in the wall, the B+ is now 132 volts.



Then I installed my speaker disconnect using some RCA phono jacks and plugs.





This pretty much concludes the assembly of the chassis.

The thing that still bothers me is the too wide picture and I had to use the sleeve to reduce it. When using the sleeve the HV is reduced by a fair amount. I really didn't like reducing the HV from 14.5Kv to around 10.5 to 11Kv.