Zenith G2952 "St Regis" porthole restoration

[bandersen]

Thanks. I missed the button switch.

Yes, the 16DP4 fits. They are the same size and deflection angle. 16DP4 is a recommended replacement with the 16EP4.
Room isn't the real challenge though.
The HV metal bar on ceramic insulators needs to be removed and replaced with something that can support the glass CRT at the right height so everything lines up.
I suppose something could be fabricated from wood. Then you'd need to rig up a strap the hold it down.

That aside, I suspect the 16DP4 is even harder to find than a 16EP4.

[John Marinello]

I bought an NOS Rauland 16EP4 off the 'bay years ago, and was shocked what a poor quality tube is was, physically & electrically. The faceplate had a very significant warp to it, good getter flash, but the tube tested completely dead. Original box, warranty card, the works. Shocked that Rauland would even put their name on that POS.

[kvflyer]

Originally Posted by John Marinello

I bought an NOS Rauland 16EP4 off the 'bay years ago, and was shocked what a poor quality tube is was, physically & electrically. The faceplate had a very significant warp to it, good getter flash, but the tube tested completely dead. Original box, warranty card, the works. Shocked that Rauland would even put their name on that POS.

Sounds more like a bait and switch by the eBay seller. I could be wrong but...

[bandersen]

Slowly making progress on the cabinet in this hot, humid, rainy summer.
I got really lucky on the sides. The slopped on paint easily sanded off and the finish underneath is in good condition.

I lightly sanded the old finish to remove the surface oxidation and alligatoring then over-sprayed with semi-gloss lacquer









That leaves the trim around the top and the base.
Or maybe I'll just turn it into a dog bed?

[bandersen]

Flipped the cabinet over and was able to get the speaker board out with out too much trouble.
So much easy to work on the base woodwork now.

It's in quite good condition for a set that was kicked around.

[bandersen]

Just waiting for the weather to cooperate and I'll touch up the front and base.

[John Marinello]

Originally Posted by kvflyer

Sounds more like a bait and switch by the eBay seller. I could be wrong but...

You are wrong

[kvflyer]

Originally Posted by John Marinello

You are wrong

Well, sorry about that, John.

[bandersen]

Finally got a break in the hot humid weather and was able to finish touching up the cabinet after working tonight.

These were taken at twilight so not the greatest quality photos. Miles better than the muddy, painted finish I started with and it's mostly original. Only the top and trim were refinished. The rest only touched up.

Used Mohawk Tone Finish Mahogany on the trim.

[bandersen]

Now there is one thing I'm missing - the volume/power knob.
Does anyone have a spare?

[John Marinello]

Originally Posted by kvflyer

Well, sorry about that, John.

This was back in 2008, when older tubes would pop up more frequently.
Seller auctioned a warehouse inventory of tubes. I got the 16EP4, also a 12UP4, 16GP4, and a 19AP4, all NOS in original cartons with paperwork.

[bandersen]

Just about done with the recap and have some odd issues with the image.
Do not have full width or height.
Image is crushed on the left a bit.
Cannot turn the brightness down very much
Image inverts if I increase brightness or contrast too much

Now that was with the 5AXP4 CRT. So, I popped in the 16EP4 for the first time to see if it had the same issues. It works which is great and has the same issues.
That;s good beacuse that means I can troubleshoot with the little CRT

[bandersen]

Success! The 33K resistor between the brightness control wiper and CRT cathode was measuring close to 500K. Also, the pairs of 100 ohm and 150 ohms resistors on the dual 6BG6 horizontal output tubes were high - more than double in some cases.

Replacing all those great improved the brightness and contrast functionality and cleared up the hor. distortion.

Finally, I unmounted the focus coil from the CRT neck so the 5AXP4 would auto-focus correctly.

Next thing to fix is the power switch which is currently stuck ON.



Bandwidth is pretty good but there is some slight horizontal waviness. Perhaps some 60Hz is leaking in.




This is the focus coil I unmounted by removing three spring loaded screws.

[kvflyer]

Sweet...

[old_tv_nut]

Nice!