Fixing Zenith CCII Avante 25JC49
 

Hello! As a bit of an intro, I'm Ian in NE Ohio- local to the Zenith console tv that had been on eBay for several months. (eventually picking it up) https://www.ebay.com/itm/204588597529

I've never serviced a CRT before, but have restored a handful of tube radios and amps. Not quite the same high voltages, but I'm well acquainted with things that want to bite. I had decided that I'd like to find a Chromacolor II given their longevity, it might be the last CRT I'd ever need. (Truth be told, I built a Pixelmusic 3000 and also wanted a TV that looked the part, something neat to look at while playing music) https://ctrl-alt-rees.com/2020-11-26...-parallax.html

I never found anything local to me after 5 months of daily checking classifieds, but had been eyeballing this Avante console on ebay, wondering if I'd be happy with a console and be able to figure it out if I made a lowball offer that was accepted. Seller was asking a crazy (to me) $299 for a non-working TV that was missing the remote and (this kills my soul) they sold the base separately to someone who messaged them, so I made a lowball $20 offer explaining why this was such a hard sell, took their $50 counter offer.

The description made mention of the TV flipping the breaker, so when I brought it home, I blew out all the dust and powered the TV up with 60v on my variac. Fortunately, this allowed the TV to stay running, and sure enough, the tripler was arcing to the chassis. Of course there doesn't seem to be any of this tripler available on the internet. For the time being, I dismounted the tripler, found the crack in it, filled it with epoxy, let that cure, slathered that in a coat of RTV silicone, let it cure, and brought the TV up to full power. No more lightning! Between waiting for things to cure, I went ahead and cleaned out all the front panel control pots with contact cleaner and followed with Deoxit F5. I also saw enough threads that said to do it as a matter of course, so I resoldered the long ceramic IC on the 9-89 video output module. (Side notes- the safety capacitor that is always mentioned with CCII tvs was already the replacement orange one, and yes, I shorted the CRT per all the guides out there before getting my hands in there)

To this ignorant mind, the TV seemed to be working pretty good, just vertical size, convergence, probably other things being pretty off. I ordered a set of Philmore trimmer tools off Amazon, they came, seem to be trash & sending back, 3D printed a tool in PETG that seems to fit & work fine.

That brings me to tonight- I was using said 3D printed tool to make some adjustments per the Sams manual (nabbed that free from Cleveland library) using 240p Suite on a Sega Genesis : P

HOWEVER, this being the reason I decided to finally get on here, and get a 'build thread' of sorts started- I've become aware of something in the high voltage area softly making a sizzling bacon sort of noise while running. I couldn't see any arc or corona activity, variac is reporting a constant 1amp draw @120v (I have a cool 50's one with gauges lol) I also can't detect any ozone odor. Any thoughts on this? Thanks for the time!

Discharge the high voltage again and clean the red high voltage lead, the cup that attaches to the CRT, and the glass area surrounding the cup with a clean rag and alcohol. Let dry quite a while. It may also be that the cracked tripler has moisture in it. It will either bake itself dry, or fail again. Time will tell.

One nice thing about most tripplers sets that have a focus tap is they usually obtained focus via a high resistance divider off the HV output and because of that would self discharge the HV better than shorting does... Still doesn't hurt to double check it's discharged after all the times HV has bit me I can confirm it's not dangerous, but is definitely unpleasant.

Post the OEM tripler part # I will check for subs
Format is 212-###-##
Patching old one is not good, only for a test.
Check the CRT focus pin for the arc also. Several fixes. Cross that bridge
if you come to it.

73 Zeno:smoke:
LFOD !

That makes sense, it's probably been cracked open for 40 years. I'll give things a clean.

damen: Maybe that's why I didn't get any audible click when shorting the anode. That was unsettling in that I found myself double checking alligator clips, coming in from different angles, etc : P

zeno: the part number is 212-149 From prior threads, I got the impression that this is an oddball one but it would be nice if there are subs. Duly noted about using the patched one. I'll keep that to a minimum.

Thanks for the replies!

https://picclick.com/Zenith-977-45-T...214479930.html

note sub number. I have no idea who they are !
BTW not in 1978 Zenith parts list. Thats about when they switched
from the common 212-141-## AKA 977-36.

zeno

So far, from past sales, it seems like the box these came in had both numbers printed on it, but the same 212-149 marked part inside. The one in the attached pic sold on eBay in March, so it seems they appear from time to time. Keeping an eye out. Thanks!


I also wanted to add that I found an old thread here where it was said that this cross references to an ECG561. https://www.videokarma.org/showthread.php?t=262454
There is a used one on eBay, but I'm a bit wary that the pins being labeled differently, namely 2 of them labeled FOC instead of one being REF. Could anyone confirm that this correct?

Be careful of that one. It may be for an EFL CRT, that would have 2 focus
terminals. EFL is "extended field lens" or "tri focus CRT" big difference
is it has 3 focus grids. VERY bright & sharp. Came out in H chassii on
high end 17 & 19" sets. 13" & 25 " were added in the L chassis.

Zeno

Thanks for the heads up! I had found the schematic for the ECG model and was going to roll the dice on that one, at least to check it to see if the resistances matched up, but it didn't seem like the seller wanted to negotiate on price. (untested used, $50, not quite the right part was too many strikes IMO)

With the back of the CRT, anode cap, the lead, and the contacts in between cleaned up, things were looking and sounding pretty good today. Quiet, but then the sizzle suddenly came back, slightly at first, accompanied by white lines, and as I was reaching to power the set off, all hell seemed to break loose- almost sounded like blow torch (or an electrolytic capacitor flaming out), the screen went gray. This was in a split second before I had the set powered off and disconnected. Around back, something faintly smelled burned near the HV area.

Annoyingly, I dismounted the tripler again, assuming my patch up job let go, but I can't see anything out of the ordinary anywhere over there. I'll try to source parts before trying anything again. Perhaps also a power supply recap is in order as I understand this is the first time this has been run since at least the early 80's, and I haven't really gone about trying to 'reform' them gracefully/gradually.

Interesting... how old are the first 3 grid focus (2 adjustments) CRT? I see that are used for monitors, also (in person I've seen only last era TV's and monitors using it***).

EDIT, NOTE: ***(since I worked only in the early 2000's with TVs)

Big filer cap was reliable, IIRC I changed a few for white humbars, 24 V
supply. The big oil cap has been trouble of late. If opens pix will pulsate if shorts tosses breaker. Also can run hot first. Quick test is undo one
end & see if pix comes back.
When the tripler goes sometime the focus goes high for a time.
Causes CRT socket to arc. Will hiss, smell, & get discolored at
the focus pin.

Zeno

Good to know. The big multisection caps seem to be usually met with doubts in the context of 30's radios. A part of me has always been a little anxious of those blowing apart and spraying the surroundings with scalding hot tar : P

Near as I can tell, things are ok at the socket (pic attached) I'll follow up when I get some downtime to dig deeper, I'd think something that hissed that loud would leave a mark!

Depends on where it bites

With luck, sometimes this "deposit" can be only superficial; but, this seems to be these esay to open sockets (good to check it's innards).

Starts for now with a simple external cleaning