I have a very good friend ( In Germany) who is having trouble with the static deflection on his Pilot 37. Are there any books, manuals or articles that would be helpful for him? (His English is perfect). THANK YOU!!! Frank in OKC

Frank:

Give us an idea of the symptoms; shrunken picture, off center, distorted picture...etc.

He told me a circle is instead egg-shaped. I am going to ask him to join us here...he can tell us better. His name is Manfred Edelmann.. a really neat guy, lives just North of Frankfurt. THANKS! Frank Karner

The Pilot 37, like most early small sets, used electrostatic deflection instead of magnetic deflection. The problem you describe, however, is common to both types of deflection. There are two adjustments that, when set correctly, should round out that egg shape: vertical height and vertical linearity. If these don't do it then there is some problem in the vertical circuit (capacitors, resistors or even a tube). If I remember correctly, the Pilot37 may have the vertical linearity adjustment pot in the middle of the chassis, not on the back.
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Ron

Make sure the coupling capacitors to the deflection plates are correct values and tubular, especially important for the vertical. Also best for horizontal. Should be rated 3KV or better.

Hello,

first of all: Happy Eastern !!

Now to my technical issues: (My technical reference is SAM Photofact Folder for the TV37).

1. I would like to know why there is a connection from R78 (1 MEG, sitting below the FOCUS control) to the plate of V14A ? I would have expected a connection at this point to the B+ supply similar to the circuit arrangement of the horizontal amplifier (V16A+B).
2. A circle within a picture looks like an egg. So, the vertical linearity is bad.
3. I found no alignment opportunity for linearity in the circuitry of the vertical saw tooth generator. Is it not necessary and if not, what's the justification ?
4. I'm not able to center the picture in a right vertical position (By the way: I have replaced all condensers and all resistors above 200Kohm). What could be wrong here ? The horizontal centering works fine.
5. Is there a cheap modulator available which delivers NTSC (60Hz frame rate, 525 lines etc.) in a VHF channel (3 or 4) ?
Actually I use a Modulator from TERRA programmed for NTSC but its frame rate is still 50Hz and not 60Hz (But the audio carrier is 4,5Mhz away from the picture carrier according to NTSC). Could this be the reason for all my problems concerning the vertical linearity issue?

I would appreciate any help, because this TV37 is the first one with electrostatic deflection i have under work. The TV37 is generally running fine (apart from the above mentioned problems) with a 3KP1 to prevent my 3KP4 from damage during restoration work.

Hi manfrededelmann, welcome to the forum. Here are my comments on your questions:

1. That connection provides the B+ for V14A through the divider from HV through the focus control.
2. Yes, the egg means that either the horizontal or vertical amplitude or linearity are off. Did you use disk ceramic capacitors for the coupling capacitors to the CRT vertical deflection plates? They won't work. You must use tubular ones. Otherwise vertical linearity will be bad.
3. There is no vertical linearity adjustment. This is a very cheap set (first set to sell for under $100) and they did not include an adjustment to save money.
4. Do you have identical amplitude signals on the two plates of the vertical output tube? If not, the deflection would not be the same in both directions from center.
5. Cheap modulators are sold by Radio Shack in the U.S. However, what determines the vertical frequency is not the modulator, it is your video signal. if your signal source is 625 lines, the vertical frequency will by 50 Hz. I would think that 50 Hz would work fine with the Pilot

Using a high value plate resistor will increase the gain of the tube. But with a high value plate resistor there is a problem getting a high enough voltage on the plate for the tube to work. Feeding the plate resistor from the high voltage supply allows you to have both a high value plate resistor and enough voltage.

Greetings Manfred.

Study the circuitry around pins 4 and 5 of V14. There were two very different versions of the TV-37 (some say it's TV-37 vs TV-37U). One version has a vertical linearity circuit consisting of two 1500pf capacitors and a 1.2 meg resistor. The other version does not have this circuit. If your set has it, you can adjust your linearity by adjusting the resistor. If your set does not have this circuit, you may add it. A clever person would add a 2 meg potentiometer and create a vert lin control from scratch.

The Rider 2 document (available at the ETF download site) shows a schematic of the circuit. The sams document omits the circuit.

Welcome to the forum.

Also, if your set matches the sams document (lacks the two 1500 pf capacitors) then you can swap R59(b) for slightly different values and affect the vertical linearity that way as well. Again, it would be easy to add a 2-meg potentiometer to adjust for best vertical linearity "on the fly".

Hello together,

I appreciate your help very much. I will realise your advices and report later. Thanks again !

Manfred

Hello again,

in the meantime i purchased a CVID BG-480 Compact AV to AV Composite RCA CVBS Video Converter PAL/NTSC to establish a real NTSC environment for my PILOT TV37U (Thanks for the info: TV37U in contrast to the TV37). Then i have the correct triggering of the vertical saw tooth generator (16,6ms time interval). Once received the converter I will inform you about the results using this device.

Have a nice day !

Manfred

Here's a quick overview of TV37 vs TV37U:

Of course, the obvious:




The screen mask differs:



The 37 tends to have a woodgrain-like painted finish. The 37U tends to be a solid color. Many TV37's have only 5 controls on the back instead of 6:




Decals were put on one letter at a time at first, all at once later.




Front grille was originally held on with bent-metal tabs, later screws.




Chassis layout is almost identical.



Just a couple of differences here.




If you study the Sams schematic vs. the Rider's schematic, you'll see that the wiring was completely overhauled between the two versions. Most notably in the filament string, but also in details such as the vertical linearity circuits I described earlier.

I think the TV-37 should be classified as a 1948 set, the TV-37U as a 1949 set. The Rider schematic is dated 9-21-48. The Sams folder is dated 5/49.

Hello again,

here is the promosed report about progress concerning the problem of vertical linearity:

1. I replaced during the restoration process the condensers C60/C61 by disc ceramic high voltage ones. Anywhere in this forum I read that this type of condensers does not work in this application. I ignored that but I kept this note in mind. Now I replaced these ceramic condensers by MKT condensers...and the vertical linearity was impressive better. The linearity was now sufficient enougth to look to normal stuff. In fact one could say...its done.
But tests with the pattern generator (chessboard pattern) shows still the vertical linearity problem...but as mentioned before a much better vertical linearity was seen.

2. I applied now the frequency converter to have a real NTSC antenna signal (field rate 60Hz). And as expected the vertical linearity was as it should be (the next pulse of the saw tooth generator ends the loading of the respective condenser in 16,6 ms and not in 20ms as in the case of 50Hz).

Many thanks to all the contribution ! The restoration of my first american TV set -off all things a electrostatic one- is successfully completed...and now a SENTINEL 400TV is waiting to be brought back to work.

May be that anybody has a technical explanation why the disc ceramic condensers did not work in case of C60/61. I would appreciate to get any information.

Congratulations Manfred! You have done well! Enjoy.

Frank inOKC

The problem with the capacitors is called saturation. When the applied DC voltage is high, the capacitance is reduced. In other words, the capacitance (ac impedance) is not constant, especially when the voltage is high. It seems that this effect is most pronounced with ceramic capacitors which are much smaller than the tubular types.
You may use ceramics in the horizontal circuits (as the original TV37 capactors were). The higher frequency allows the impedance changes to be far less of a problem.
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Ron

So glad that you were successful. Please enjoy the TV. Your efforts have been rewarded!!!

Manfred, I am very glad that your problem had such a simple solution.

I will make a suggestion- Keep an eye out on Ebay for a Heathkit IG-5240. It is a color/monochrome tv signal transistorized generator. Very compact. Runs on 2 of 9 volt batteries. Bars, both horizontal and vertical, dots as well, colors and so on are all switch selectable. 300 ohm output, so no matching balun needed for the antenna terminals. If the seller has a picture of it working, and it comes with the owner's manual {which of course includes the building instructions}, you are "in the money".

Oh, and the 2 integrated circuits sit in sockets, so things are easy.

There is nothing like having a stable signal source, especially when troubleshooting a problem which gives you an unstable picture on the CRT.

I am sure there are others that do the same thing, perhaps some of the European gear is NTSC compatible. But I bought my Heathkit for $12. Shipping was only $3, but this was not International shipping. There isn't much need for this kind of equipment any more, so prices are usually low.

Enjoy your tv!
John S.

Good Morning!I´m from Sao Paulo/Brazil. I Restored a TV37U Pilot. I made the exchange of capacitors (including high-voltage tubular). I changed a few tubes and more than 30 resistors. I installed a CRT 3KP1 because the original 3KP4 was dead. I have a horizontal image stable, but it remains trembling in the vertical direction. Image does not scroll, just tremble. Does anyone have any suggestions for solving this problem?

Hello! I solved the vertical problem of the TV37U: interference of the transformer adapted for the heater of the CRT and also interference of the DVD player. Now the image is great!