Last Attempt To Find Tech To Help with Avante - Videokarma.org TV - Video

TinCanAlley · #1 06-03-2021, 03:05 PM

Okay, I've tried all I can to remove the jailbars from my Avante. I need to find someone in the Los Angeles area that can help. If anyone knows of someone that can help, please let me know. If someone can help fix it, I will give them my scope and B&K for their trouble. Both units are in excellent working condition. They've just been sitting around after using them to try and fix my issue. Don't have a use for them anymore.

http://videokarma.org/showpost.php?p...39&postcount=1

zeno · #2 06-03-2021, 06:32 PM

Sometimes I think of this problem believe it or not. It will probably
haunt me till I die.

One thing I wonder about it is had the tripler replaced by an ECG etc.
Somewhere with a scope you should see a big hoz spike then a trail
of smaller & smaller ones as it goes right then the next big spike.
It has to be seen on either the K's or G!, or G2. With zero signal, not even snow it has to be there. Hmm 1000 V boost filter ?

Another sleepless night.

73 Zeno

LFOD !

BTW did you try Shango or Jordan Pier ?

MadMan · #3 06-04-2021, 02:10 AM

Shango?

zeno · #4 06-04-2021, 03:42 PM

Quote:

Originally Posted by MadMan

Shango?

shango066 on Utube.
He is what we call a "character" up here in New Hampster.
BUT he can work with junk & resurrect damn near any pile
of feces. Much to be learned from him, I have great respect
for his talents.

BTW be sure to have food & drink watching him.He can make
a meal out of a potato chip

73 Zeno

LFOD !

TinCanAlley · #5 06-05-2021, 12:24 PM

Quote:

Originally Posted by zeno

Sometimes I think of this problem believe it or not. It will probably
haunt me till I die.

One thing I wonder about it is had the tripler replaced by an ECG etc.
Somewhere with a scope you should see a big hoz spike then a trail
of smaller & smaller ones as it goes right then the next big spike.
It has to be seen on either the K's or G!, or G2. With zero signal, not even snow it has to be there. Hmm 1000 V boost filter ?

Another sleepless night.

73 Zeno

LFOD !

BTW did you try Shango or Jordan Pier ?

I did change the tripler.

I have scoped so many circuits and found ringing, but if you look over some of my previous posts with pics, most said it wasn't an issue. I still think it is in the ABL as that gives a big ringing on the scope and jailbars seem to be a brightness issue. Also, with the inability to get the setup line to appear bright enough to use, I don't know if that is along the same line as the ringing, or????

I love this set, but every time a darker scene comes up, I'm reminded of the issues that still exist.

TinCanAlley · #6 06-05-2021, 12:27 PM

This is what I get on the ABL circuit.

zeno · #7 06-05-2021, 02:52 PM

The ABL runs off the reference pin of the tripler IIRC. Its the pin
with the big resistor & is just above ground to produce a small voltage
that varies with beam current.
With a good CRT as a rule G2 pots start to show a line at abt 1/3.
You need good boost IIRC between 800 & 1000 VDC. If thats OK
look back to to the G1 & K's. A bad boost filter will lower the boost
& leave unwanted crap on it.
I really suspect the tripler. Its the common link between the sets.
There are resistors, caps & diode stacks in them that may vary in
value from the OEM tripler.

enuf fer now, time for a beer. Or 2 or3............

73 Zeno

LFOD !

TinCanAlley · #8 06-06-2021, 04:16 PM

Quote:

Originally Posted by zeno

The ABL runs off the reference pin of the tripler IIRC. Its the pin
with the big resistor & is just above ground to produce a small voltage
that varies with beam current.
With a good CRT as a rule G2 pots start to show a line at abt 1/3.
You need good boost IIRC between 800 & 1000 VDC. If thats OK
look back to to the G1 & K's. A bad boost filter will lower the boost
& leave unwanted crap on it.
I really suspect the tripler. Its the common link between the sets.
There are resistors, caps & diode stacks in them that may vary in
value from the OEM tripler.

enuf fer now, time for a beer. Or 2 or3............

73 Zeno

LFOD !

The way the tripler is in this unit seems a bit different than any I've seen before, but that could just be my limited exposure.

The trippler has an input and an output. The red output goes to the suction style cup on the CRT. That connection at the CRT has a second pink lead that goes from there down to a plastic distribution block. It then breaks out to two more leads. Once goes to the focus and the other attaches somewhere around the flyback and I believe then routes to the CRT socket. I could be a little off here as I haven't opened the set for a year and I won't be for about a week or so.

TinCanAlley · #9 06-07-2021, 06:55 PM

Quote:

Originally Posted by zeno

The ABL runs off the reference pin of the tripler IIRC. Its the pin
with the big resistor & is just above ground to produce a small voltage
that varies with beam current.
With a good CRT as a rule G2 pots start to show a line at abt 1/3.
You need good boost IIRC between 800 & 1000 VDC. If thats OK
look back to to the G1 & K's. A bad boost filter will lower the boost
& leave unwanted crap on it.
I really suspect the tripler. Its the common link between the sets.
There are resistors, caps & diode stacks in them that may vary in
value from the OEM tripler.

enuf fer now, time for a beer. Or 2 or3............

73 Zeno

LFOD !

Okay, so it seems I didn't change the tripler. I remember now, after finding it in a box, that it didn't match what was in the set. The one in the set has an input, ground and output. The replacement has an input, ground, focus, CTL and output. I remember hearing a sizzling sound and it was coming from the plastic piece that is fed off the anode on the CRT and then it feeds the focus and???? Anyway, I found a new one of those and installed it and the noise was gone and I just assumed the tripler was working properly. So if NTE526A isn't the correct one, what is? Or, am I supposed to do away with that plastic piece with all the connections? I've attached a pic of the current setup, but note the plastic piece in the pic is the old one. I couldn't find a current pic. The tripler pic is one I found on the web, but it is the same.

Thanks

zeno · #10 06-08-2021, 02:35 PM

The replacement shown has the focus built in.
It is not a direct replacement at all but could be moused.

The OEM ? in the set uses the divider resistor, the plastic part
with the other big red wire etc.
If you go further with it get the ##'s off the tripler. If a ZENITH
OEM you should find part number 212-141-## on it.
Also be sure that big resistor isnt burned. Bad triplers sometimes
burned it.

73 Zeno

ed857 · #11 06-09-2021, 10:25 AM

Could that be a ECG 500A with the Zenith focus block ( HIDIV 3? )?

TinCanAlley · #12 06-09-2021, 02:52 PM

Quote:

Originally Posted by zeno

The replacement shown has the focus built in.
It is not a direct replacement at all but could be moused.

The OEM ? in the set uses the divider resistor, the plastic part
with the other big red wire etc.
If you go further with it get the ##'s off the tripler. If a ZENITH
OEM you should find part number 212-141-## on it.
Also be sure that big resistor isnt burned. Bad triplers sometimes
burned it.

73 Zeno

I will attempt to find the part number on it this weekend. It seems, according to the service manual, that there are two different units. One with the built-in divider and one with the external. The SM shows the integrated unit, but notes there are two different ones.

So I have choices, I can try to keep it original and find one that uses the external divider, use the one with the integrated divider, or if possible, use the one with the internal divider, but don't use the integrated part and run the external divider.

Thoughts?

TinCanAlley · #13 06-09-2021, 03:02 PM

Quote:

Originally Posted by ed857

Could that be a ECG 500A with the Zenith focus block ( HIDIV 3? )?

According to the service manual, it is 212-142-01. This one is noted as tripler only. The other part number is 212-141-01 and is the tripler with focus bleeder combined. It says to see schematic, but the schematics show the combined tripler, which is not my setup. Either way, most cross-references I can find point to the combined (NTE526A). I did find a site that has a PDF of and old Zenith list of universal triplers and it has (977-46) as the simple tripler replacement. No such luck finding that.

So I either install and ditch the external focus divider, use it with the external divider by ignoring the outputs on it, or I continue my search.

TinCanAlley · #14 06-09-2021, 03:39 PM

Going by this pic I located, I'm going to assume the tripler has already been replace sometime in the past. It doesn't look OEM from '74. Kind of looks like the simple version of the replacement I got a few years ago (NTE526A). Same kind of grey plastic, tan resin and molded bracket.

Also shows the new focus divider I installed.

Oh, and a question.... Is the crap on the leads for the tripler covered with simple RTV, like you'd use for car gaskets, etc.?

damen · #15 06-09-2021, 09:35 PM

About the jailbars, I remember a similar problem many years ago that ended up being a lead dress issue. The yoke and convergence wires had to be kept away from the CRT socket cables, especially the yellow wires.