The chassis is the 25LC30 and this is about the HV rectifer; not setting cathode current. I don't want to lose interest from the get go due to redundancy. I have been working on getting my horizontal output cathode current down to a reasonable value. I have posted other threads on this set about my search for and find of a new horizontal efficiency coil that I had to re-core. Old news now, but I never felt good about not being able to get 200mA on the cathode.

So the other night I decided to pull the related tubes and check them again. Sure enough I pull the HV rectifier and pin connection 5 comes out with it. There didn't seem to be any solder on it and with hope I popped the tube back in and powered up. I had zero HV. Today I was able to unbolt the cup mount and thus the tube socket and it turns out that #5 and #6 have fallen out due to what looks like some nasty arching. This explains the sound of corona and what to me would be light arching along with raster distortion that I have intermittently heard and seen from the get go, but could never see.

Since some Zenith folks will be here I must add that the Sam's schematic for this circuit confuses me as the diagram says that pins 1 & 12 are used for the heater. What I find is that #s 8 & 12 are what are actually used. By looking at the tube I am guessing that either set can be used. Seems like there would be a standard config. used at the factory.

So, anyway; everyone knows what I will need now (a new socket), but I guess I will have to go make another thread in classifieds and see what I come up with. There is a guy out of Chicago that does great repair videos on YouTube who particularly likes old Zeniths. Perhaps I can get in touch with him as he probably has ten of what I will need complete with 1.5K ohm resistor and ultor/second anode lead. Wouldn't that be great? Just bolt in and solder two wires!:D

Thanks in advance to anyone with thoughts and info. SO, good to see more Zenith threads! I guess a few are finally breaking! LOL

What NO Zenith spare parts laying around out there. No way! I know they are tough, but not that tough..... I just need the rectifier socket; not a flyback.

How about posting a clear picture of what the socket looks like? It's possible something generic is available.

How about posting a clear picture of what the socket looks like? It's possible something generic is available.

+1 - I don't have that chassis, the sams doesn't normally show the socket, so I'm blind without a picture, but have over 200 tube sockets. 3A3, 3DB3, 3AT2, what is the rectifier?

Thanks Findem Keepm! You my friend, are on the ball. Placed the picture someone requested for me and look to have it in your hand!! Wow! Sorry, I thought that I put the rectifer# in this thread, Looks like I didnt; it's a 3AT2. I thought that # the 3AT2 was about all they (Zenith color) used through that era once they had moved away from earlier octal base designs. Great surprise after waiting a few days. I knew someone would be through here eventually, but my read count was climbing with almost no response. I figured there would be people with plenty of these to skim me off one. Should be pretty common really... Hey thanks again!

I have some fine arcing somewhere on my 25LC20 (cannot hear it or smell ozone), your experience will prompt me to examine the sockets, though they are not very accessible!

Picture shows the manifestation of corona on the raster, (note fine focus after I fixed the focus control)

NewVista, you can get the rectifier socket loose through the access door of the high voltage cage if you want to take a look. In my case, I could hear but not see the periodic and very fine arching and resultant distortion on the raster.

I was hoping that someone with more experience with these old color sets might be able to tell us what the symptoms would be with the single (1.5Kohm? I think) resistor mounted on the bottom of the rectifier socket being open. I say again, I had HV until I made the mistake of yanking the tube and the pins fell apart. One came out with the tube (pin 4 unused) and pin 5 dropped down as the resistor mentioned above was burned in two. The crt second anode also connects there (pin 5).

I'm dead in the water until I find an appropriate socket to replace mine which is burned from what I assume to be the arching that I could never see. I say arching, but it was more of a hiss than a snapping and was intermittent as well. But so far not a bit of luck finding someone to sell me one.

+1 - I don't have that chassis, the sams doesn't normally show the socket, so I'm blind without a picture, but have over 200 tube sockets. 3A3, 3DB3, 3AT2, what is the rectifier?

That socket assembly in the pictue looks like the all plastic type that I have heard about. I count 12 pins; same as my 3AT2. That picture is teasing me!:D I sent a PM, but I'm not sure if you got it. Not rushing, just anxious to get this thing going again.

OK, it seems that once again VK members have come to the rescue. This is the best site and group of people that I know of! A member found several old chassis and should be having a socket and sub-chassis sent to me soon. I will post as to what (hopeful) improvements correcting the burnt socket and resistor bring in regards to cooling down my flyback and reducing HO cathode current.

I am almost certain that this set was working with the single 1 watt resistor that mounts on the socket burned in two. I am not certain what the open circuit would cause or if operation would be possible. I am thinking that the open resistor would stop HV from making it to the regulator. There were never any obvious regulation problems; just the hissing that couldn't be seen in a dark room and sometimes distortion in the raster that went with the hissing. I just know that there would have been a heck of a smell and the only smoke ever seen or smelled was WAY before this burned socket became an issue. I am hoping that finding and fixing this culprit will prove to be a great improvement to the set as far as the HO cathode current and fly temp.

That socket assembly in the pictue looks like the all plastic type that I have heard about. I count 12 pins; same as my 3AT2. That picture is teasing me!:D I sent a PM, but I'm not sure if you got it. Not rushing, just anxious to get this thing going again.

I never saw a pic of what you needed - did you ever post a picture? I don't have the chassis, so a pic would be needed. If it is what I think it is, with a compactron socket riveted to the corona can, a Zenith 78-1863 is the part number, IIRC. The can with socket fits into the HV cup, and comes with the flyback. I've never replaced one - most of the arcing that ate HV cups was from a dirty cup or too much HV. The cups I have replaced - mostly ones that arced near the cage, else we cleaned them and put a glop of RTV3145 (yes the acetic acid kind) on the hole.
The pins in the socket (except the one or two that are soldered to the corona can) are replaceable with any pins from a compactron socket.

I never posted a picture because you did in frame #4, but you are holding an all plastic version where mine has the metal sub chassis. I'm not trying to replace pins as the plastic holes are eaten away at #4 & 5. Also, I have a thread in Classifieds where Electronic M posted an exact picture of what I have, but somewhere in all of this someone recommended finding an all plastic version. Frankly, I want what was meant to be in the set.

The arching appears to be contained within the insulating cup. The 1W resistor (across pins 4 and I think 9) is blown in two which perhaps is the cause of the arching which in all appearance seems to be right at pins 4 & 5. All of the burning of the socket and corrosion of the pins is isolated to that area. I wish someone knew more about whether or not the open resistor would or could cause the light arching which perhaps did its damage over time. As I mentioned previously, I am almost certain that I had HV with that resistor open.

Also, I don't know why the socket would come with the fly you only have to solder in the wire loop that goes around the core. It is resistance wire and very thin, so I don't want to lose much, or any if possible.

Here is the picture posted on my Classifieds thread concerning the same subject. I didn't post a pic as I couldn't have posted a better one than this. My fault for causing confusion with two threads, but I didn't want to talk buy or sell here as I was afraid that the thread would get moved, yet I wanted something to be seen in the Vintage Color Television forum that might get overlooked in Classifieds. Sorry. I hope this helps.:D

Yes, that's what I was thinking. I don't have one. Here's a clear picture of one I found on the web. I guess you could drill it out and replace it with a compactron socket. By the EIA code, it matches a socket I have, so nothing special about it, just gotta desolder the pins and drill out two rivets, else find the whole socket and corona ring together - which is what I think you are getting off another chassis...

Cheers,

Indeed I am supposed to get one off of another chassis found by a VK member. The chassis is a year newer and he said that it didn't use the 1W 1.5K Ohm resistor that is soldered across pins 4 & 9 on my set.

A 2W 1.2K Ohm is available, but thus far I have not gotten any input on exactly what this resistor does besides the obvious. As it stands I am a bit scared to lessen the value not knowing what critical role the resistor plays and how a change may adversely effect my rectifier or other components. I DO NOT want to lose my flyback if damage isn't already there from high HO cathode currents.