Test powerup of my Zenith 1951 TV console

[GaryK]

I got a B&K 440 CRT tester from an eBay seller and tested the picture tube in my Zenith TV Radio Cobramatic console. Although it tests on the low end of good the tube has good cutoff and should produce a reasonable picture. Unfortunately the flyback is bad. The Zenith part number is S-17233 in case anyone here knows of one that might be available.

Here is the youtube video I posted.

http://youtu.be/CsaIEpoIg1A

[John Marinello]

Did you check the fuse? It's not uncommon that these sets lack high voltage, so don't write off the flyback just yet.

[walterbeers]

I wouldn't condemn the flyback either, just yet. Lots of them, the outer coating will break up and crumble off, yet the transformer is still usable. Pull the cap off of the horizontal output tube, and see if you have voltage at the cap lead, and yes also check for a fuse in the horizontal output circuit, probably fusing the cathode of the horizontal output tube. You could have a bad damper, horizontal output, or horizontal osc tube causing the no HV condition, and also one of those could very well have blown the fuse. If the flyback is still usable, break off the loose pieces of coating, and coat it with some high voltage dope, or even maybe use some silicone seal. After watching your video on you tube, I would say that they flyback has at least a 50% chance of being usable.

[GaryK]

Originally Posted by John Marinello

Did you check the fuse? It's not uncommon that these sets lack high voltage, so don't write off the flyback just yet.

Thanks for that thought. Bob Andersen also said that Zenith porthole flybacks often look bad but still work so I have not given up yet.

[GaryK]

Originally Posted by walterbeers

I wouldn't condemn the flyback either, just yet. Lots of them, the outer coating will break up and crumble off, yet the transformer is still usable. Pull the cap off of the horizontal output tube, and see if you have voltage at the cap lead, and yes also check for a fuse in the horizontal output circuit, probably fusing the cathode of the horizontal output tube. You could have a bad damper, horizontal output, or horizontal osc tube causing the no HV condition, and also one of those could very well have blown the fuse. If the flyback is still usable, break off the loose pieces of coating, and coat it with some high voltage dope, or even maybe use some silicone seal. After watching your video on you tube, I would say that they flyback has at least a 50% chance of being usable.

Thank you. I will be delving into the circuitry on this set soon. I have never taken on of these porthole Zenith consoles apart. I wonder if the CRT comes out with the chassis?

[John Marinello]

Slides right out with the chassis.

[Sandy G]

Awrite !! Another Porthole hopefully fixin' to be Woken Up ! Portholes RULE !!

[Kevin Kuehn]

In WI potholes rule this time of year. Nice Zenith set you have there Gary! Hope it can come back to life.

[GaryK]

Originally Posted by Kevin Kuehn

In WI potholes rule this time of year. Nice Zenith set you have there Gary! Hope it can come back to life.

Thank you Kevin. I had one in the early 1960s in my bedroom before I got drafted. I got many hours of enjoyment from watching that old Zenith porthole console. That's why I got the one I hope to restore. Gary

[GaryK]

Originally Posted by John Marinello

Slides right out with the chassis.

Thank you John. I kind of thought it did but as I say- I never pulled the chassis on one of those porthole sets. I have two Zenith porthole sets; The console in question and also a smaller table top set with a brown leatherette cabinet. I had the table top set since the early 1980s and it did work but I had not powered that set for many years now. Gary

[CoogarXR]

Originally Posted by Sandy G

Portholes RULE !!

I resemble that comment

[Sandy G]

Gotten more compliments w/my 1949-50 Zenith 12" Porthole than I have w/all the rest of my stuff, put together. Nothin' shuts up a 2015 wiseass teenager quicker, either.

[cwmoser]

Yes, love seeing Portholes brought back to life.

[GaryK]

Originally Posted by John Marinello

Did you check the fuse? It's not uncommon that these sets lack high voltage, so don't write off the flyback just yet.

I did check the 6BQ6 B+ fuse and it is good.

I checked all the tubes related to HV and horizontal sweep and they all check excellent except for the 6BN6 Synch Seperator. One element tests bad. I suspect this is why I am not getting any HV.

[GaryK]

I cannot pull the chassis yet as I have other work on my bench but I did test the 6BQ6 B+ fuse and all of the tubes related to horizontal sweep. The 6BN6 synch separator tube tests bad on one side so I suspect that is why there is no HV.