Duplicating my 16GP4 plea!!! - Page 3 - Videokarma.org TV - Video

Chris K · #31 10-01-2025, 06:20 PM

I PMed Brian. Haven't heard anything yet

bgadow · #32 10-01-2025, 09:45 PM

Just replied, Chris.

Yes, I'll test that tube again...I picked it up a few years ago from a collector who was short on space. Funny, I've now had 3 sets that use that tube and they've all been fine.

Chris K · #33 10-01-2025, 10:50 PM

Thank you so much! I included my email in my return PM message and you’re welcome to send me an email.

Chris K · #34 10-03-2025, 10:55 PM

Unfortunately it looks like Brian’s CRT didn’t wake up after some higher voltage cooking for several hours. So it seems the search is back on. I am going to take the drive to look at the tv Kevin pointed me to this weekend and we’ll see how that goes. Thanks for trying Brian! I just have absolutely dismal luck when it comes to vintage CRTs. I think I’ve had 2-3 decent tubes in about three dozen TVs I’ve worked on

Penthode · #35 10-04-2025, 10:43 PM

Back to the old one again. Did you try running the filament at 8 volts and then test emission?

Chris K · #36 10-05-2025, 07:28 AM

Yes I tried letting it cook for a while but it’s a very very tired tube.

Chris K · #37 10-05-2025, 02:41 PM

The trip to Trenton NJ proved to be very fruitful. The 16GP4 tested very good.

Filament voltage set at 6.3 volts

Cutoff as good as I've seen in any vintage tube in a while.

Emissions with cutoff not zeroed

Emissions with cutoff zeroed

I really can't expect much better than that. Thanks to everyone for your help and a special thanks to Bryan for his generosity and Kevin for his efforts in helping me find this and kicking me in the butt to go get it!!!

bgadow · #38 10-05-2025, 09:31 PM

Really glad you found the good one! (Well, maybe there is another out there...somewhere!) I tried running mine all day at 6, then several hours at 8. Just won't get out of the "bad" range. I could have swore it tested decent previously. Maybe it's getting gassy? Maybe Nick Williams would want to play with it.

Chris K · #39 10-05-2025, 10:24 PM

Did it ever show any cutoff? My Sencore has an auto-restore function that’s the most gentle of the rejuvenation settings. It pulses a 5 second shot of voltage 3 times and has definitely helped with a couple of my weak tubes. When I do visit I can bring it and if you so desire we can try it. The manual states with this function there’s no danger of damaging the filament. I think it just “cleans” but doesn’t boil off any of the surface metal.

Kevin Kuehn · #40 10-06-2025, 12:48 AM

Very glad to hear that went well. Can you tell if it's an original to the set RCA 16GP4A, or some later replacement?

Chris K · #41 10-06-2025, 08:38 AM

Quote:

Originally Posted by Kevin Kuehn

Very glad to hear that went well. Can you tell if it's an original to the set RCA 16GP4A, or some later replacement?

I'll check it tonight. From the looks of it and from a conversation with the owner (single owner since new in 1951) I don't think it's a replacement. He told me about how well he took care of the TV over the years and when he and his family moved to the east coast from the Midwest, how upset he was that the movers had caught one of the side veneers on a moving blanket and delaminated it. This was 30 years ago and other than this and some modest dings here and there, the unit was in very good condition. The small piece of delaminated veneer is still attached and can be easily glued back in place. I'm really really tempted to put my restored chassis in it if only to check out how the CRT performs. My wife likes light colored woods and maybe this will be the working unit in my living room for now while I restore the additional chassis and put it in the darker finish TV.

Electronic M · #42 10-06-2025, 08:39 AM

It's my experience that gassy tubes normally test with excellent emissions (assuming the heater isn't open or about to be open), but on B&K testers where you turn the cutoff up until the meter increases by 2 divisions the cutoff will exhibit "neon bulb" behavior where you get 0 increase then it shoots to the far end of the scale and you can't make it read stable outside of those 2 states. It's distinct enough that I'm confident I can detect an unusably gassy tubes in anything it can test.

Kevin Kuehn · #43 10-06-2025, 11:40 AM

Quote:

Originally Posted by Chris K

I'll check it tonight. From the looks of it and from a conversation with the owner (single owner since new in 1951) I don't think it's a replacement. He told me about how well he took care of the TV over the years and when he and his family moved to the east coast from the Midwest, how upset he was that the movers had caught one of the side veneers on a moving blanket and delaminated it. This was 30 years ago and other than this and some modest dings here and there, the unit was in very good condition. The small piece of delaminated veneer is still attached and can be easily glued back in place. I'm really really tempted to put my restored chassis in it if only to check out how the CRT performs. My wife likes light colored woods and maybe this will be the working unit in my living room for now while I restore the additional chassis and put it in the darker finish TV.

Getting to have that conversation with the original owner is icing on the cake for making the trip. The gentleman is probably delighted their TV went to someone that will continue to care for it. If it's not too much of a pain please post up some pictures for us when you have time.

Chris K · #44 10-06-2025, 01:23 PM

Will do!

Chris K · #45 10-06-2025, 09:03 PM

Amazingly, this is the original CRT! I don't think the owner and his family watched a lot of TV. He's an outdoorsman, a hunter and a boat owner and didn't seem to be the typical couch potato.

I have lots of physical alignment and vertical and horizontal adjustments to do but the picture is sharp. For some reason, photos of these B&W sets look more washed out than they really are.