Pilot tv crt
 

Does anyone know what the correct number of the crt for a pilot tv both P1 and P4 .

3KP4 for white and 3KP1 for green

George

Thanks George , would there be other numbers that would work in that set both white or green ?

I dont think so, essentially because I don't know of any other compatible 3 inch CRTs out there.

Now .......... THIS SUNDAY .....!!!!! there is going to be a public auction in Chester, New York :banana: where there will be (2) 3" CRT's offered in a lot. Not terribly far from you! :D I'd take a shot and go for it if you have the time. I think the auction starts around 9AM or so...
-George-

This hobbyist substituted a 3RP1:

http://www.electronixandmore.com/res...lot/index.html

jr

Who was the manufacturer of the pilot tv 37 and what year did the 37 come out.

Well this pilot has issues first no sound but the original field coil speaker was replaced with a permanent magnet speaker that was hooked up and must have worked the voice coil was disconnected and those connections went to the new speaker via the field coil but just have a very low hum. The crt lights but I cannot get a hv reading maybe the probe area for the ground is not ground but rather some place else I don't know. 1b3 tests good it's new but I need to know where to put the ground from the hv probe so I can adjust the feedback ring to set the hv but the ring up or down I get nothing but there is hv. All the rest of the tubes test as new. First turn on it has a pic and after warm up the screen is unstable in different ways maybe that cause along with the hv could be the caps that were put in were ceramic disc where it don't call for those types but nevertheless the set must have worked and this whole set was recapped and they look new and the job that was done was extremely neat and clean better then factory. So if anyone knows these pilot 37 sets I would be open to a few hints, thanks.

Much info here:
http://antiqueradio.org/PilotTV-37.htm

jr

Ok so the hv is acceptable but I have a faint hum in the speaker simply cannot get sound but the video is fine. I checked the discriminator coil and not burned, has video should have sound. I also have a verticle problem the bottom of the screen needs to go down and the adjustment is maxed, verticle size won't stretch top to bottom. B+ voltages look good.

does anyone know if there was 2 schematics for the pilot 37 tv with a ballast and without ? i got the one with the ballast but need the one without if there is one because my pilot dont have the ballast.

You absolutely must put one of those 8.2 volt double-Zener protection diodes
across the CRT filament before running the set just turning it on ... until you protect the CRT filament you absolutely MUST slowly turn it on slowly with a variac (unless somebody has installed a separate power transformer for the
CRT filament.) We don't want any more blown out unobtainium CRTs.

Tim, have you completely recapped the chassis? Also I agree that you need to install some effective method of leveling out the initial surge current to the CRT. There are a couple ways to do it, and you'll really thank yourself later!

Re the audio: seems to be an interruption of the af after takeoff, evidence by the slight hum you're experiencing. So start by making certain you've replaced all paper caps before proceeding. I'm presuming you are getting a video signal to the CRT right now???

Remember, the Pilot TV37 is the Smart Car of early television. Don't expect quality-anywhere-and proceed accordingly. Once you get it working correctly you'll have actually good audio, and a decent picture if viewed thru a magnifying glass and a Scotch (or two) handy.

George

hey George yes it's been completely recapped including resistors and I got the audio working I figured it out and I have a perfect picture but what I'm left will is the vert size is maxed and won't fill the bottom half inch of the screen but 3 caps were put in that are nos, big mistake because they test good but sometimes under load they may change value so that's next for me to check. I get the reason for inrush protection because of the crt heater but this one the heater don't come on fast upon turn on so maybe something was put in already to protect it I don't know I didn't check it. Do you know the voltage or info on what zener to use to protect the heater, and does this Zener go across the heater feed wires. This zener is the glass diode IIRC .

It is not a Zener (though it is based on them) it is a TVS (Transient Voltage Suppressor) diode IIRC. There was a couple great threads on them on ARF's TV forum. On common collected sets it pays (saves you and us time) to search the existent threads for info rather than bugging people to rewrite info that is already out there.

Something that cold would be roughly 400 ohms and progressively come down to around 4 ohms or so as it heats up - maybe 3-5 seconds or so.

This is the diode:

https://www.arrow.com/en/products/p6...ponents#page-1

Ok so I subbed the last 3 caps thinking they were bad but not luck the vert size is maxed and the bottom of the pic is up to far and won't come down to fill the screen. Everything I check from caps to resistors test perfect. Is it at all possible that if alignment was out would it raise the raster from the bottom up a bit like I have going on here?

We need more info on the vertical problem.

There are two different vertical schematics. One in Riders, one in Sams.

Which do you have?

What value HV caps are you using to connect to the deflection plates?

The Sam's circuit is better, and I recommend increasing the capacitance
from .005 uF to 0.02 uF. 3kV ceramic caps in parallel are OK for this,
though the ASC film caps are "officially" better. My set uses ceramics and
has great linearity.

I have the asc caps ,that it shows in the SAMs but what was in there were single ceramic .004 discs so I put the asc caps .005 6kv. I already tried paralleling these caps and didn't work.

Ok here is what it looks like and had the same problem with Motorola sets but caps fixed the problem but this one, I'm lost.

I'd check all the large value megaohm valued resistors and the centering control in the vertical deflection circuit. They are used to set a HV DC bias on the deflection plates. It's possible even if one tests good with the low voltage applied by an ohmmmter it could behave differently when HV is applied in the TV.

Ok there is 4.7 meg I think 2.2 meg all these Meg ohm resistors are new and tested perfect so I'll lift a leg off the verticle size control and test that, I think I already did but that's what I'll do. There is no vert centering control just vert size. I guess even new resistors can behave different with hv present, so I may have to change them to rule them out, thanks

Yes, there is a vertical centering control. It's last on the right on the back. It's R9 - a 2M pot in Sams.

Yes your right I did know there was a vert centering pot my mistake I was thinking something else. Ruled out both size and center pots with others now I'm checking those hi Meg resistors.

Well I subbed the hi Meg ohm resistors around the vert center, size, and tubes. Obviously I am missing something here but wow I went over and subbed everything. I cannot imagine what I'm still missing.

Could be a bad connection to one of the CRT vertcle deflection plates. If only one plate is being driven, the image will be off center just like you're seeing

Did you see the bottom of the screen how much is missing. V14 SAMs shows 225 Vdc but all I'm getting is 115 Vdc on pin 5 measured from pin 5 of v19 so I did that right could this explain not enough voltage. All other voltages are within where they should be. The neg tube tests good and so does the positive tube but I did read that someone put diodes across I think it was 3-4 and 5-6 on the positive tube because of lows voltage.

The plate voltage for V14 comes from the HV power supply divided down by R74 through R78. Could be you have low HV or some of those resistors are off or the 12SN7 is biased wrong and drawing too much current.

I don't have an affective way to check hv on this set but I have an analog meter that goes to 1 kv and when I touch to see what it is it shows 1 kv but then the screen blanks out until I remove the meter probe. I check right off the 1b3 to see the hv. The 12sn7 you refer to is the vert a Amp as being possibly biased wrong? I did the resistance test from the SAMs chart and all were perfect except pin 4-8 of v20 positive rec tube it starts running into the Meg ohm area when it states 120k.

Is there a specific cap in the verticle responsible for timing because there are no Micas like the Motorola tabletop sets. There are 1 .02 and 2 .05 caps at both vert tubes so I'm assuming it's one of the three.

Ok I went over everything can't find anything wrong so I think it's just low hv voltage . The screen is dark even on a second crt I have thats good. The b+ voltage is 130vdc with no diodes put on the 25z6 . Every cap was replaced and the only thing I'm coming up with is that on v17 pin 5 should be - 5.3 Vdc but I'm getting -125 Vdc I even tried another tube same thing and I went over the SAMs and the rider schematic to make sure it's wired right and can find nothing wrong there. A 39k to the 1b3 feedback and it's good there is an 82k also good and the 2 caps at the tube as well both good. There is a cap on the hv oscillator that's good. Tried a new 1b3 too. Strange thing is checking voltages around v17 the screen blanks out dark then comes back after removing the test probe. I do know there are 2 positive points and 2 negative points in this set and I went over the power supply and checked all of that and cannot find anything wrong there. If anyone knows where to go with this pilot at this point I'm all eyes because it looks like I am out of options.

Well the first thing that jumps off the page for me is why. V17 pin5 shows +117 when it should show -5 volts. There is something going on there for sure. When I get home I'll yank out my SAMs and have a look at that see if anything jumps to mind. But I do know that if a circuit is expecting negative potential and it's getting a huge positive there is something wrong in there.

George

I'm sorry I forgot to put negative, so what should be -5.3vdc I'm getting -125vdc. Tim

Aah.. Ok but still way off spec!

George

I'll tell you what I spent hours and hours going over the riders and SAMs and I must be missing something but now I am literally lost because I cannot find what's going on. If the hv is low the the vert and horiz plates won't work right and in this case the vert is missing on the bottom and the size pot is maxed and the picture is dim consistant with low hv. :thumbsdn:

"Note: grid voltage is measured between grid and cathode."

jr

If it used seleniums that could cause low voltages..... I just thought if you didn't mention this already but the replacement capacitors that are 3kv or 6kv maybe they are leaking?

Caps are good and no seleniums , neg tube and positive tube.

Ok my mistake the SAMs didn't show to check that voltage,grid, cathode usually it's ground or otherwise specified. So that voltage is neg 3 volts and SAMs shows 5.6 I believe but rider shows neg 7- 12 volts so this is still low and if the hv was up where it should be then the cry would be much brighter then it is and there would be enough voltage to even out the verticle plates and it would be centered. Went over yet more and still cannot find any mistakes. This set was all redone by someone else and done a very neat job and replaced everything caps, resistors, Micas in the IF and RF but it does have good sound and nice picture but just Alittle more then half and dark so I do think is lacking hv. Even turning the hv adjust on the hv cage brightens Alittle but does nothing for the verticle. These sets have 2 different linearity setups to improve this, 1.2 and 5.6 Meg ohm resistors and using different values for both don't help and has the 2 1500 mmf caps also remove for the other setup still don't help. I guess nothing will unless I can get the correct hv.

Do you have another 25L6 to try? Have you tried swapping the 12SN7s to see if the symptoms change?

jr