21ax gassy or bad 3a3?

[ohohyodafarted]

Originally Posted by SwizzyMan

Will do later this morning, accidentally pulled a socket pin out of the socket assembly while removing the CRT socket so will have to fix that first. I highly doubt the CRT is gassy if it can survive over 1300 miles of bumpy highways it can survive sitting in the 76 degree house I live in. Anyone have a general idea of how durable the 21axp22 is in terms of taking off the socket and putting it back on plus the bumpy ride home? Also happy New Year to all you folks here!

OK lets use correct terminology. The end of the picture tube has a bakelite "base" with pins. The wires from the chassis has a "socket" that has "terminals" inside of it.

Are you saying you pulled a "PIN" out of the Bakelite "base" on the 21AX or did you pull a "terminal" out of the "socket" that hase wires connected to the chassis.

First, I do not think your 21AX went bad, but that is always a possibility. If your tube is gassy you would probably get the dreaded purple neck glow when you power the chassis up. 10 years ago I purchased a CTC5 Wingate from California. The seller told me it was operational a year prior to when I purchased it. It was shipped to me in Wisconsin and when it arrived the crt was gassy. I am not sure if it was the transportation or temperature changes that made it go gassy but it sprang a leak at the weld line. The usual place that a 21AX leaks is on the heli-arc weld where the front of the tube is joined to the rear funnel. It is very rare for a leak to form where the glass components are fused to the metal parts of the tube. It is even more rare for a leak to happen where the lead wires come through the stem under the Bakelite base.

Normally if a crt is gassy, the filaments will be very dim with 6.3 volts applied. And if you increase the voltage while under test on a tube tester the filaments will usually burn out.

Follow up on suggestions the other posters gave to see if you have focus and ultor voltages. Then see if you have video signals and correct bias voltages at the pins on the crt.

[old_coot88]

Originally Posted by ohohyodafarted

...Normally if a crt is gassy, the filaments will be very dim with 6.3 volts applied. And if you increase the voltage while under test on a tube tester the filaments will usually burn out.

If the tube has gone completely to air, another symptom is quickly apparent:
the cathode end of the neck gets really really hot, immediately. Like too hot to touch. And the heaters may not light visibly, because of being
immersed in a heat-conducting fluid (air). And the heaters pull 'waay too much current since they can't come up to full temperature.
If you put a tester on it, the transformer in the tester may be unable to supply that much current.

[tvdude1]

I sold this set it had very good raster and with a vcr had all 3 good colors but lousy sync. It was fine the night before he picked it up. He is trying to run this old timer with bad filters and waxed caps. I had disconnected a can and jumped it to just make it light up.

[SwizzyMan]

The longest I ran it was for about 4-5 mins this was when I could get a nice bright raster. I noticed an 80uf sprague atom was tacked on to the existing 80uf section in the filter capacitor. That isn't good since the original capacitor could mess with the tacked on 80uf. I also noticed that another filter cap was leaking a bit of PCB infused gunk out of one section. This set needs a nice full recap and that is what I plan on doing before I power up the set again. Will create a separate thread about this set soon. At least I know my 21ax is good!

[holmesuser01]

I'm running, and working on, a CTC-7 with an original CYP22 in it.

When it's warming up, I get a momentary glow of blue in the neck of the CRT just as high voltage comes up. It's always gone before the screen lights.

The 3A3, which is an original with the set glows blue for just a moment around the gap between the plate and cathode.

This set is almost totally original... a total of 2 tubes replaced by me.

Perfectly normal for me over the years.