Zenith Porthole 19" H2447R

[John Marinello]

I just picked up another one of those about 3 weeks ago, in remarkable condition.
Tempted to plug it in & see what happens. The "Byron". Yours is the first 19-incher I've seen that uses the angled 6AU6 IF strip, might be an early set. Curious to see if it uses an integrator or a diode. That set should have a 24H21 chassis in it.

[cwmoser]

Originally Posted by John Marinello

I just picked up another one of those about 3 weeks ago, in remarkable condition.
Tempted to plug it in & see what happens. The "Byron". Yours is the first 19-incher I've seen that uses the angled 6AU6 IF strip, might be an early set. Curious to see if it uses an integrator or a diode. That set should have a 24H21 chassis in it.

John, you got an uncanny ability to sniff out the nicest Zenith Portholes.

Carl

[StellarTV]

First signs of life today... and what an interesting set of circumstances.

I recapped the power supply. I noticed that even after bringing the set up slowly on the variac that quad section filter was getting too hot to touch. Brought it up slowly afterward.... okay, I can hear the horizontal oscillator running.... can't hear the vertical oscillator at all and screen is dark.

I used a long screwdriver to check for HV at the 1B3... nope. Voltage at the top of the horizontal output... .nope, nothing. I have a decent multimeter that I've used before to check the raw DC level in horizontal circuits, except this time I made a mistake. I set the multimeter to OHMS instead of DC, touched the probe to the top of the 6DQ6... the multimeter buzzes and lights up from the inside (could see it through the plastic!) and the high voltage comes up on the TV!

So my multimeter is smoked but it seems to have somehow resuscitated the TV... Haha.... My reward was a nice bright raster about 1/3" tall. Glad the flyback is OK.

Originally Posted by John Marinello

I just picked up another one of those about 3 weeks ago, in remarkable condition.
Tempted to plug it in & see what happens. The "Byron". Yours is the first 19-incher I've seen that uses the angled 6AU6 IF strip, might be an early set. Curious to see if it uses an integrator or a diode. That set should have a 24H21 chassis in it.

John, According to the sticker inside the cabinet, it is in fact a 24H20. I don't see that little 3 legged vertical integrator module on this chassis, if that's what you're talking about.

Also, looks like we now have a pair of the same exact TVs! Here is a quick series on the other one I'm restoring, just had the cabinet finished:

[wa2ise]

Hard to imagine this setup doing anything other than going into oscillation. Especially at 45MHz.

[John Marinello]

[QUOTE=StellarTV;3083898]

John, According to the sticker inside the cabinet, it is in fact a 24H20.

The sticker in your cabinet will say "TV Chassis 24H20 & 24H21".

The sticker will say "16GP4A or 19AP4A" for the CRT.

See attached.