1950s or '60s vintage Zenith TVs, Need some info

[vortalexfan]

A little update:

Still waiting on the tubes that I ordered for my Zenith "Bugeye" TV that I had ordered around Christmas and were supposedly shipped the monday after Christmas, and here it is the middle of the first week of January and I still haven't gotten my tubes yet.

[Tube TV]

The more you need a part, the slower the shipping is.

[vortalexfan]

Well my parts came in today and I got the TV working, mostly, I'm still having some issues with the centering of the picture and the Video and Audio IF are still a little off yet, so I'm still trying to get that adjusted but other than that it is producing a picture from the tuner and some audio but its not very loud audio and the Video IF is still a little off, hopefully when I get that B & K 1070 TV Analyst (which is supposed to come tomorrow) maybe that will help with getting the video and audio IF finalized on the TV.

Also how do you tell which station this TV is on? There doesn't seem to be pointer or anything that points to what the channel selector knob is on on this TV.

[Kevin Kuehn]

On my Bugeye the selected channel is at the 12 o'clock position. Unfortunately the Analyst isn't an alignment tool, It's basically a substitution signal source for trouble shooting the various circuits in a TV, say if you can't get a signal through via the tuner, you can inject directly into the video IF, or video amp to see where the signal is lost . The best way to check alignment is with a sweep generator and oscilloscope to look at the video IF response curve.

[vortalexfan]

Originally Posted by Kevin Kuehn

On my Bugeye the selected channel is at the 12 o'clock position. Unfortunately the Analyst isn't an alignment tool, It's basically a substitution signal source for trouble shooting the various circuits in a TV, say if you can't get a signal through via the tuner, you can inject directly into the video IF, or video amp to see where the signal is lost . The best way to check alignment is with a sweep generator and oscilloscope to look at the video IF response curve.

Oh, ok. Well anyways I know the IF is definitely off on this TV (just like it was on my Meck TV) also how do you adjust the centering rings for a properly centered picture?
I tried adjusting the centering rings on my TV and just about got it centered and then I whacked my hand against something on the picture tube and got a nice jolt off of it.
On mine I noticed that when I would adjust the height and linearity adjustments the screen would go really dark especially towards the top and also something seems to be off with the DC Restoration on this TV because the screen is really dark especially when going through the channels the screen will just go black and then when you settle on a channel then the screen will finally brighten up after about 10 seconds.
Is this normal?

[vortalexfan]

As for the 23" Zenith I got some new bulbs ordered for the tuner and they came in the mail today as well, and unfortunately the lights for the tuner don't seem to trigger on and off correctly because when I have the tuner triggered for the VHF tuner the pilot light doesn't kick on right away and also when the UHF tuner is triggered the pilot light doesn't always turn on for that either.

Also the TV isn't producing a signal for the tuner and I figured out that the Oscillator/Mixer Tube (a 6GJ7 tube) iin the VHF tuner is pretty much dead (which was also what was wrong with the bugeye TV as well) unfortunately I don't have a 6GJ7 tube in my tube stash, nor any of its substitutes.

[Kevin Kuehn]

Originally Posted by vortalexfan

Oh, ok. Well anyways I know the IF is definitely off on this TV (just like it was on my Meck TV) also how do you adjust the centering rings for a properly centered picture?
I tried adjusting the centering rings on my TV and just about got it centered and then I whacked my hand against something on the picture tube and got a nice jolt off of it.
On mine I noticed that when I would adjust the height and linearity adjustments the screen would go really dark especially towards the top and also something seems to be off with the DC Restoration on this TV because the screen is really dark especially when going through the channels the screen will just go black and then when you settle on a channel then the screen will finally brighten up after about 10 seconds.
Is this normal?

Please don't mess with the IF adjustments.

Centering consists of spreading or bringing closer the 2 circular rings along with moving them together. Fiddling with them should give you an indication of the direction you need to go.

There is no DC restoration.

You should be able to get a full snowy white raster with no signal going to the tuner. Your brightness control should be able to take it from bright to complete darkness.

On mine I found the cathode bypass cap(C2) on the 6CM7 vertical output tube really needs to be at least 60uf in order to get decent vertical linearity. I tried a 47uf and that was a no go.

[vortalexfan]

Originally Posted by Kevin Kuehn

Please don't mess with the IF adjustments.

Centering consists of spreading or bringing closer the 2 circular rings along with moving them together. Fiddling with them should give you an indication of the direction you need to go.

There is no DC restoration.

You should be able to get a full snowy white raster with no signal going to the tuner. Your brightness control should be able to take it from bright to complete darkness.

On mine I found the cathode bypass cap(C2) on the 6CM7 vertical output tube really needs to be at least 60uf in order to get decent vertical linearity. I tried a 47uf and that was a no go.

Well on mine the IF Adjustments were already fiddled with, that was part of the reason why my tuner wasn't working right, besides bad tubes.

As far as the full bright snowy raster goes that is a no go, the top part of the screen is completely dark, and trying to adjust the centering rings doesn't affect it any, there is supposed to be a ion trap on this TV but I don't know where it is in reference to the rest of the picture tube, the Sams shows it as being part of the yoke but I don't see anything on the yoke assembly that looks like an ion trap.

Any ideas?

[Kevin Kuehn]

Originally Posted by vortalexfan

As far as the full bright snowy raster goes that is a no go, the top part of the screen is completely dark, and trying to adjust the centering rings doesn't affect it any, there is supposed to be a ion trap on this TV but I don't know where it is in reference to the rest of the picture tube, the Sams shows it as being part of the yoke but I don't see anything on the yoke assembly that looks like an ion trap.

Any ideas?

Ion trap should be out on base end of the neck where most are. What Sams shows is the schematic representation, not physical location. Are you currently running without the ion trap?

Also both of my sets have a width sleeve - a thin piece of brass sheet wrapped around the neck inside the yoke. Moving that in and out of the yoke varies the picture width.

[vortalexfan]

Originally Posted by Kevin Kuehn

Ion trap should be out on base end of the neck where most are. What Sams shows is the schematic representation, not physical location. Are you currently running without the ion trap?

Also both of my sets have a width sleeve - a thin piece of brass sheet wrapped around the neck inside the yoke. Moving that in and out of the yoke varies the picture width.

Well there is an ion trap looking thing on the end of the neck near the base on my CRT but it I try to rotate it or pull it in or out and it wont budge like its stuck or something like that.

And with the base of the CRT already being somewhat damaged I don't want to force anything and risk damaging the CRT any further.

I have a picture posted below showing what I mean.

Also my TV Analyst Came today, and its intact, but I have no idea if it functions or not because I don't have any cables for it yet. I would guess that the probes for this thing could still be bought seeing as B & K is still around and they still make test equipment and probes for them.

[dieseljeep]

Originally Posted by vortalexfan

Well there is an ion trap looking thing on the end of the neck near the base on my CRT but it I try to rotate it or pull it in or out and it wont budge like its stuck or something like that.

And with the base of the CRT already being somewhat damaged I don't want to force anything and risk damaging the CRT any further.

I have a picture posted below showing what I mean.

Also my TV Analyst Came today, and its intact, but I have no idea if it functions or not because I don't have any cables for it yet. I would guess that the probes for this thing could still be bought seeing as B & K is still around and they still make test equipment and probes for them.

The ion trap is the thing with the spring. Remove the spring and the trap should move.
That set was stored in a damp environment, as it shows mildew all over.

[Kevin Kuehn]

Good to hear the B&K showed up. The only cables you need are a shielded 50 ohm BNC cable to alligator clip leads and a couple un-sheilded male pin plugs to alligators clip leads. Those pin connectors are the same as what commonly came with inexpensive VOM meters back in the day. Nothing special about them and I'd be shocked if you don't already have the BNC cable with all the test gear you've told us about.

But before worrying about connecting any signal to the Bugeye, get your CRT sorted out. You don't need any video signal to get a raster.

[Electronic M]

When I first got mine I used a BNC scope probe before making a dedicated BNC to clip lead cable...It worked fine with both.

[vortalexfan]

Originally Posted by Kevin Kuehn

Good to hear the B&K showed up. The only cables you need are a shielded 50 ohm BNC cable to alligator clip leads and a couple un-sheilded male pin plugs to alligators clip leads. Those pin connectors are the same as what commonly came with inexpensive VOM meters back in the day. Nothing special about them and I'd be shocked if you don't already have the BNC cable with all the test gear you've told us about.

But before worrying about connecting any signal to the Bugeye, get your CRT sorted out. You don't need any video signal to get a raster.

I got the TV to give a proper raster but now I've hooked up the TV Analyst to the TV through the Video IF input and it showed the test pattern like it was supposed to but the linearity is way off (the top of the test pattern is really scrunched down and the bottom is normal looking), and when I try to adjust that the screen goes blank and I can't get the screen to come back up.
I figured out the ion trap, it was just stuck in place because it hadn't been moved in years.

Another weird thing is that even adjusting the ion trap there's still a dark spot on the top of the screen when I adjust the linearity and height adjustments.

And yes I did have the correct connectors for this thing, the same connectors I used for my signal generator is the same connector that TV Analyst uses (BNC to alligator clip leads.)

[Kevin Kuehn]

Originally Posted by vortalexfan

I got the TV to give a proper raster but now I've hooked up the TV Analyst to the TV through the Video IF input and it showed the test pattern like it was supposed to but the linearity is way off (the top of the test pattern is really scrunched down and the bottom is normal looking), and when I try to adjust that the screen goes blank and I can't get the screen to come back up.
I figured out the ion trap, it was just stuck in place because it hadn't been moved in years.

Another weird thing is that even adjusting the ion trap there's still a dark spot on the top of the screen when I adjust the linearity and height adjustments.

And yes I did have the correct connectors for this thing, the same connectors I used for my signal generator is the same connector that TV Analyst uses (BNC to alligator clip leads.)

Good you got that working.

Now before you go crazy trying to set linearity on the Zenith... do you have a known good somewhat modern TV you can hook the B&K to, something to verify it didn't get it's own linearity messed up during shipment? It does have linearity adjustments very similar to a TV. And don't mess with them unless you have a TV that you know is very near perfect picture. You can even use the B&K Video out to go into composite video in on a newer TV. Here again it doesn't need to be perfect, you just need a reference so you know what it normally looks like. Everything is relative.