Found an old tube TV. Want to find out more about it.

[SteveNielsen]

Re: Found an old tube TV. Want to find out more about it.

Pretty cool. I doubt any of the TVs made now will last 50 years.

[Mrx3750]

Re: Found an old tube TV. Want to find out more about it.

I decided to make another video... just because I could...

https://youtu.be/rQiWICi4-3k

And the camera on my phone, for some reason records in a 16:10 aspect ratio, yet scales the video to 1280x720 which is 16:9, resulting in a squashed aspect ratio. It also records in a resolution much lower then 720p, so in this video I've corrected these faults as best I can.

[Mrx3750]

Re: Found an old tube TV. Want to find out more about it.

That remains to be seen whether or not I'm keeping it. That said, the power cord is intact, the casing is not cracked or frayed, and it's interlocked with the chassis, so I don't see a safety issue here.

[stj]

Re: Found an old tube TV. Want to find out more about it.

for safety i recomend a new power cable if your keeping it.

[Mrx3750]

Re: Found an old tube TV. Want to find out more about it.

Turns out I was mistaken about there being a bad tube. All the TV needed was a few tube sockets cleaned with contact cleaner.

Check it out now:
http://youtu.be/n3hg0GpWqVs

How lucky am I to find a 50 year old TV, sitting on a curb, and all it needed to provide a good picture was cleaning pots, switches, and a few tube sockets.

[Mrx3750]

Re: Found an old tube TV. Want to find out more about it.

Err--You cant just switch valves around--Unless they are EXACTLY the same number/type.....
--There are THOUSANDS of Different Type Valves--And many LOOK Nearly Identical to each other--but are NOT interchangeable!

--A set that is basically working--with sound and full frame, then frame-collapse and no sound when two valves are transposed suggests the valves are Different Types to me!!

Switch 'em back to the holes they came from!!

A 6BL8 is a small signal Triode Pentode valve, the same as the Euro ECF80 These are often used as Line Oscillator/Sync Sep valves. Maybe in your set--Its the Vertical Oscillator/Sync Sep. Many UK sets used the PCF80 which is a 9V heater version of your 6BL8 for Timebase and sync sep as well as Video Output.
--Had a short hot life used as video amplifiers in 1960's Bush TV105/125 series....

Calm down. I know what I am doing. I've posted about this TV on Videokarma and I was advised to swap tubes. Also look at the pic I took of the tube sheet. The tubes I swapped are both 6BL8's... This Tv uses three of them, one for horizontal, one for vertical, and V 11 which is for noise and clipping. The V 11 tube is either bad or very weak. I swapped it with the V7 which is the same tube, and lost vertical and sound, which is what V7 controls.

so I need a 6BL8 tube

[Alastair E]

Re: Found an old tube TV. Want to find out more about it.

Err--You cant just switch valves around--Unless they are EXACTLY the same number/type.....
--There are THOUSANDS of Different Type Valves--And many LOOK Nearly Identical to each other--but are NOT interchangeable!

--A set that is basically working--with sound and full frame, then frame-collapse and no sound when two valves are transposed suggests the valves are Different Types to me!!

Switch 'em back to the holes they came from!!

A 6BL8 is a small signal Triode Pentode valve, the same as the Euro ECF80 These are often used as Line Oscillator/Sync Sep valves. Maybe in your set--Its the Vertical Oscillator/Sync Sep. Many UK sets used the PCF80 which is a 9V heater version of your 6BL8 for Timebase and sync sep as well as Video Output.
--Had a short hot life used as video amplifiers in 1960's Bush TV105/125 series....

[Mrx3750]

Re: Found an old tube TV. Want to find out more about it.

Yes I have a DTV box. Feeding this TV a signal is not a problem. And I used to watch Channel 9 before they killed off the analog transmitters.

problem is I need a 6BL8 tube.

[Skiver]

Re: Found an old tube TV. Want to find out more about it.

Man, you are just 3 years too late to watch Channel 9 OTA from Windsor. Do you have one of those coupon converter boxes?

A friend of mine worked for Motorola TV. I think he lasted two years after Matsushita bought them out (Quasar). (Motorola's motto: If you can't beat them, try to unload your unprofitable division on them.) Their color TVs used plug in cards for easy repair ("the works in a drawer, and the drawer in the shop").

Chicago was the hub of the American consumer electronics industry. The private label Warwick and Wells-Gardner; the branded Admiral, Motorola, and Zenith. Our first TV was a Hallicrafters, we had a Webcor record player, later a Wollensak tape recorder.

[goontron]

Re: Found an old tube TV. Want to find out more about it.

one certain TVs the selenium or germanium diode in the vertical hold can fail. i would check that. its usually a metal canned diode, not plastic.

[Mrx3750]

Re: Found an old tube TV. Want to find out more about it.

Swapped V8 with V11

Picture collapsed to a line and no sound. I think I found the culprit.

So I need a 6BL8 tube. They're pretty common on eBay, but no $ to spend on one right now.

Anybody in the Detroit area want to donate a tube?

[SteveNielsen]

Re: Found an old tube TV. Want to find out more about it.

Yeah probably. You know anyone with a tube tester? If you want to then pull the chassis out (taking ALL necessary precautions as others have stated) and post some pics of the underside. Old school `tronics is interesting. To me anyway.

[Mrx3750]

Re: Found an old tube TV. Want to find out more about it.

Okay, swapped V7 and V8 around, and that *almost* stabilized it.

So am I looking at weak tubes, or some electronic component that's drifted out of spec in the last 5 decades

[SteveNielsen]

Re: Found an old tube TV. Want to find out more about it.

Vertical linearity. It is used to adjust and even out the vertical spacing of the picture using a test pattern. The control might be recessed and need a small screwdriver to tweak it. Check horizontal and vertical oscillators V7 and V8. They are the same tube # so you might try swapping them and see if it stabilizes.

[Mrx3750]

Re: Found an old tube TV. Want to find out more about it.

I readjusted the controls, this time paying attention to just what I was adjusting. Vertical and horizontal controls work fine, but I can't get horizontal or vertical to lock in place.

Here's a (crappy) video of it now:
http://youtu.be/2agduuDwDL4

A control on the back is missing a knob. It's labeled 'VERTICAL LIN". Not sure what it does or if it's related to why the image won't stabilize. Perhaps there's a weak tube inside the set.

If it's something easy that I can fix, I might give it a go, but I'm more interested in giving this set to somebody more familiar with tube TV's then trying to restore it myself.

[kc8adu]

Re: Found an old tube TV. Want to find out more about it.

great!
just watch things like the temp of the big cap can behind the transformer and the flyback.
might want to check cathode current of the horizontal output tube.too high and fly runs hot as well as the tube.clean the tuner,controls,ect and enjoy your working antique!

[Mrx3750]

Re: Found an old tube TV. Want to find out more about it.

Way ahead of you. It has a picture but needs cleaning and adjustment. Working on that now.

[stj]

Re: Found an old tube TV. Want to find out more about it.

now you need to feed it wih an anlog signal - got any old games consoles?

or bypass the tuner to feed CVBS into it.

[Mrx3750]

Re: Found an old tube TV. Want to find out more about it.

Hey guess what?



It's alive! (Sorry for the crap picture. The phone that I took the first pictures on... the one with the good camera... yeah it decided to die on me last night, so I had to rush out and buy a cheap phone to get by until I get some money.)

In any case, sound and picture works, and the set seems to be new enough to have mylar caps instead of wax.

[budm]

Re: Found an old tube TV. Want to find out more about it.

love it - hardcore fault diagnosis!!

i knew a guy that used a similar method on digital stuff, he ran it for a few min's and then touched every chip till he burned his finger!

Same way as other people that is trying to find the shorts on the circuit board by forcing current through the board and check for which component gets hot.
I think there is a couple threads here that the guy is trying force 10 or 20A through the board to locate the shorts.