Met up with Adam this afternoon - Videokarma.org TV - Video

jpdylon · #1 10-28-2007, 11:53 PM

I took a nice zenith color set and some chromacolor parts off his hands.

I brought my beltron with me to test it on some really weak CRTs he had in every day watcher sets. Results were excellent on all accounts. We even tried an experiment with a near dead 7JP4.

This was a tube that was not visible before in normal light, and could barely be seen in a dark room. After some toying around with a makeshift adapter, we were able to successfully restore a 7JP4 using the beltron. The picture was bright, with good contrast and completely visible even with moderate to high lighting. There was no longer the need to crank the brightness up. Adam said he may post a picture of a screen shot from the tube, so hopefully you'll all get to see the result. Perhaps he will chime in here.

The results were also near excellent with a 16GP4 (?) that had before tested with no emission. A couple of cleaning and restoration attempts brought the emission up to near new ratings.

It was great coming up and seeing his new toys. Adam is a talented guy when it comes to fixing these sets, and I was very impressed with his work --especially on the hoffman set he restored awhile back, and a zenith portable he fixed the cracked CRT mask on. It was a great visit, but I'm all the more happier that we were able to successfully restore a weak 7JP4.

The Beltron does it again......

Tube TV · #2 10-29-2007, 12:36 AM

Sound like the Beltron really done a days work today .
Good to hear

Adam · #3 10-29-2007, 12:59 AM

Here's a pic of that 7JP4 we rejuvinated. I don't have a before pic, but this tube really was too weak to watch except in a dark room. It's good to know something can be done with these electrostatic tubes.

The 16GP4 in the RCA 6T65 barely moved the needle at all on my B&K 420 when I first tested it, it tests good now, but I won't be done with recapping the chassis for another week or so, so we can't see the results yet.

The beltron also brought back to life the 21YP4 in my '54 Westinghouse, which I had already zapped with my B&K about a year ago, only to have it get weak again after a while, and was currently really too dim to watch even with the brightener I had on it. But I was watching it tonight only to loose horiz sync, with the HV to follow a few seconds later, so that set will have to go back on the bench after I get done with the RCA 6T65.

Tube TV · #4 10-29-2007, 01:52 AM

Thats watchable , good to hear it brought it back .

Dan Starnes · #5 10-29-2007, 04:25 PM

Wow,,, that is now watchable for sure, very interesting.
Dan

kbmuri · #6 10-29-2007, 09:34 PM

My Beltron just arrived this morning.
http://cgi.ebay.com/ws/eBayISAPI.dll...m=300160568009
I'm anxious to play with it (after I check it out for bad caps/resistors or whatever else).

I was planning on starting a thread to ask if anyone had an adaptor for the 7JP4. Small world instead. Jordan, would you post a quick pic and description of your adaptor? Thanks.

Didn't Eric H have a Pilot TV-37 with a super-dim 3KP4? Maybe you could help out...

***Eric H*** · #7 10-29-2007, 10:02 PM

Quote:

Originally Posted by kbmuri

My Beltron just arrived this morning.
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Didn't Eric H have a Pilot TV-37 with a super-dim 3KP4? Maybe you could help out...

Yes i do! what do you think Jordan, could you adapt it?

I played around with a couple weak 7JP4's and my B&K 466 last week, I was able to rejuvenate them but not read emission.
This is basically a brute force rejuvenator and the results were disappointing, they worked better for a short time then dropped off to where they were or worse.

BTW, if anyone wants a Beltron there's one on eBay now for only $900

http://cgi.ebay.com/BELTRON-picture-tube-restorer_W0QQitemZ220154071037QQihZ012QQcategoryZ6 1395QQrdZ1QQssPageNameZWD1VQQcmdZViewItem

Even though it "werks like new" He might have a tough time getting that for it since the last one went for $51.

ChrisW6ATV · #8 10-29-2007, 10:14 PM

Especially with a $200 shipping charge.

kbmuri · #9 10-29-2007, 10:16 PM

Yes, the $51 one was mine. Another one just listed:

http://cgi.ebay.com/ws/eBayISAPI.dll...m=300166518672

The $900 one has been listed for a long time. Wonder why...

I'm reading the documents for mine right now. Looks like an interesting tool. Hope I have Jordan's luck with mine.

jpdylon · #10 10-29-2007, 10:19 PM

I will post a pinout of the adapter later along with the procedure I used. It's more or less what the setup manual describes.

Essentially what you need are some clip leads, some wire. Having the socketless adapter with free wires helps alot. You only need 4 leads for the process. Two for the heater, one for the 1st grid, one for the cathode.

If you have a receiving tube manual, you can find the pinout of the tube and connect the clip leads accordingly. Pin designation is clockwise if looking directly at the base.

7JP4:
pin1, 14 : heater
pin2 : cathode
pin3 : 1st grid

I definitely would think it could handle the 3kp4. Most rejuvenators rely on current measurements from the 1st and 2nd grids to facilitate the rejuv process, so they don't work well with the electrostatics because of the deflection plates instead of the 2nd grid (beam accelerator / ultor?). Since the beltron only needs the cathode and 1st grid, it becomes a better candidate for use with electrostatics .

Stay tuned!

jpdylon · #11 10-30-2007, 12:10 AM

You can use the BR-UA adapter if you have it, make one from the socket adapter, or make your own octal to CRT adapter to plug into the beltron directly. My camera is with my father on a trip, but here is a diagram I created:

If you have access to the pinout diagram of your particular tube you can wire it up as I did the 7JP4. I do not have the 3kp4 pinout, sorry Eric.

Here's what I did to restore the tube:

1. Wire it up. If you have the K and G1 leads mixed the short indicator will come on, so check your wiring if this occurs

2. apply AC power to the beltron, set the heater switch to 12, turn down the variable heater voltage control, and plug in your adapter to socket 1. You will see the heater voltage drop when the load is applied. You're shooting for the mark above the 5, which is 6.3 volts. You will need to adjust the voltage as the tube warms up because the heater's resistance will change as it heats up.

3. observe the Green emission meter. A usable tube reads about 70-75ua. A good tube reads 85. In this case Adam's 7JP4 barely registered 40. Depending on the electrical values of the tube this will vary, so it may not be the same for other electrostatic tubes. If its dim or near dark, its probably bad!

4. lower the heater voltage to 5 volts, and change your adapter to socket 2. observe the green cleaning light below the emission meter. Flickering indicates cleaning or short removal. If no light can be seen after 5 seconds, increase the heater voltage using the variable control to 10 volts and no more than that. If the light starts to glow but is not bright, wait 20 seconds. If its bright, wait no more than 10 seconds then proceed to step 5.

5.Turn down the heater voltage to 5 volts and move your adapter to socket 3. Slowly turn the voltage back up to 10 volts and observe the restoration current meter. when it reaches 85ma, press and hold the interrupt button until it falls to 60ma, then release it. If it doesn't get to 85, release it at its highest point. I would not recommend repeating this more than 3 times. Its ok to do it 4-5 times if the current never reaches more than 70ma.

6. Leaving the voltage at 10 volts, go back to socket 2. Leave it for 20 seconds, then turn down the heater voltage back to 6.3 volts and move the adapter to socket 1. Observe your emission results.

kbmuri · #12 10-30-2007, 09:21 AM

Jordan -

Thanks for the info. I'll probably make a dedicated 7JP4 adapter from scratch out of a bad metal octal tube and a spare female 7JP4 socket.

jpdylon · #13 10-30-2007, 11:22 AM

I should also mention that the above heater voltages are for a 6.3 volt heater. If using anything else other than 6.3, I would go 1 volt lower to start the cleaning and rejuv process, and not exceed 65% more than the heater voltage its rated for.

Although the filament is 100% overrated, the combination of the heat generated by over volting the heater and the intense heat surrounding the heater from rejuvenating the gun could cause the heater to fail.

Dan Starnes · #14 10-30-2007, 08:04 PM

I am watching that beltron and a few other rejuventors on ebay right now. This has been a very informative thread.
Dan

refill233 · #15 10-31-2007, 05:24 AM

Better get the Beltron while you can. Check this out if you don't think they are getting high in price.

http://cgi.ebay.com/BELTRON-picture-...QQcmdZViewItem

Don