'51 Zenith Porthole - Page 3 - Videokarma.org TV - Video

Reece · #31 02-08-2010, 05:53 PM

Charlie · #32 02-10-2010, 10:17 PM

Things are getting a little better. I changed most of the smaller capacitors this evening, and a few resistors that were a little tired. The picture has opened up all the way, and high voltage is up to the 10kv as the paperwork says it should be... the other day it only got up to 7kv. The verticle was a bit sensitive, but has calmed down now.

Only bad thing is the audio isn't so great. I'm not really sure how great it was the other night as I didn't even turn it up to a normal listening level. I still have more parts to change, so hopefully that part will get ironed out.

I'm waiting on an order of lytics and some smaller caps to come in... likely wont be here till Friday.

Overall, the picture is looking better. I ran the set for an hour tonight during the news with no problems. Even ran a VHS tape on it... not one bit of tearing across the top!

DaveWM · #33 02-10-2010, 10:20 PM

Very cool Charlie, its getting there

jeyurkon · #34 02-10-2010, 10:28 PM

Good work! I hope my porthole looks that good when I get around to restoring it.

John

wa2ise · #35 02-11-2010, 12:29 AM

Quote:

Originally Posted by Charlie

Things are getting a little better. ...

Only bad thing is the audio isn't so great. I'm not really sure how great it was the other night as I didn't even turn it up to a normal listening level. I still have more parts to change, so hopefully that part will get ironed out.

You've got the hard stuff done.

Audio shouldn't be too difficult to get it working right. One thing to try is to tap the audio signal at the volume control and feed it to a stereo amplifier set (take care to use a coupling cap to keep high voltage out of the stereo). That should tell you if the FM demodulator is working right, and the problem is in the sound audio amp of the TV set. Alternatively, inject some clean audio at the volume control pot and see if the amp works clean.

cwmoser · #36 02-11-2010, 06:04 AM

For audio, the guys at www.AntiqueRadios.com who helped me with restoring my 1950 Zenith Porthole suggested to adjust the BIAS/BUZZ control and the Quadrature Coil. I found that the BIAS/BUZZ control helped get rid of the intercarrier buzzing and adjusting the Quadrature Coil greatly increased the sound volume.

Charlie · #37 02-11-2010, 12:23 PM

Audio issues turned out to be the two funky flat sand resistors under the output tube. I don't have the right values at the moment, so I put some together to get close values and tacked them in place for the time being. The sound is a lot better now.

I ordered a handfull of 5 and 10 watt resistors with my capacitor order... they'll be here soon. I had planned on changing those particular resistors whether or not they needed it since they kinda fall apart if you're not carefull. There's some others under the main chassis... those will be changed as well.

Reece · #38 02-11-2010, 12:36 PM

Looking really good, that's a hot CRT. Does this set have the round/rectangular option switch?

Charlie · #39 02-11-2010, 01:04 PM

Yes... the switch is located behind the flip-down door under the screen.

It's been pretty neat to watch so far. I like it filling the screen, but, you really miss a lot that way. Being that we're now accustomed to seeing the black bars on top and bottom of so many programs these days, watching it in normal mode isn't so bad.

jr_tech · #40 02-13-2010, 06:44 PM

Perhaps a decent gasket on this eBay bezel?

http://cgi.ebay.com/ws/eBayISAPI.dll...%3DI%26otn%3D2

Not affiliated,
jr

Charlie · #41 02-13-2010, 06:57 PM

Looks like the rubber is not included. What is seen on the backside of that bezel is the thin cardboard gasket. The rubber insulator would be behind that... actually attatched to the CRT... it's also part of what sits between the lower CRT front rim and the main chassis and is held in place on the CRT by a long spring. However, thanks for pointing it out.

jr_tech · #42 02-13-2010, 08:15 PM

I asked the seller if he had the gasket and he just responded back "no it went with the chassis, sorry" .

jr

Charlie · #43 02-13-2010, 08:21 PM

Makes ya wonder about the CRT... it could have been a good one.

Tube TV · #44 02-13-2010, 08:24 PM

Great job on the porthole !
One thing I might mention is that I heard one time that JB weld contains some fine metal particals , so you may want to stay clear of it for a insulator ....

marty59 · #45 02-14-2010, 10:02 AM

Ok, I've been thinking about this insulator situation...Having never seen a porthole in person, about what kind of diameter or thickness would be necessary?
What I have done for various projects is take some automotive type vacuum hose and slit it to fit over what you want..plus, it comes in different sizes. You just have to make sure you slit it as straight as possible for a nice appearence.