The elusive Indextron

[etype2]

Thank you for that information. Until now, I had assumed the CRT used was 5.25 inch because of the 5.25 inch used in their index projector, also the “5” model designation. Does it use one or two photo cells?

[HelloVoltage]

Originally Posted by etype2

Does it use one or two photo cells?

This , specifically from a disassembled xav-u50, has 2 photocells, masked as D901,D902 on Assembley board "N".
The other relavent masking on the board reads :
1-642-164-11




The reverse of that board other components with a soldered shield, which I have not removed. So no other information can be provided about now.

This xav-u50 definitely has caps swapped out, and they are in most of the places I have visually identified leakage on the xav-55n. I will provide photos as possible, and list the masking id's of the obviously replaced caps.

So far , the only difference between the 2 is the replaced caps, an extra power harness for the xav-55n, to facilitate use without diversity unit (I assume). There is also a small board on the bottom side of assembly board "B" on the XAV-U50, which I suspect was a service update. It is secured only with double sided tape, and manually soldered in.

[HelloVoltage]

note 01-14-2022
If any information regarding these 2 models (xav-u50, xav55n) is desired, please post. Disassembly will not liekly be performed once units are functional.

So far:

XAV-U50 Electrolytic Caps visually identified as likely replaced.
Board "A"

C290 16v µf22
C266 16v µf22
C267 16v µf22
C017 50v µf4.7
C039 22v µf16
C241 --------------- pending
C002 25v µf47
C027 10v µf100
c251 50v µf.47
c260 16v µf22
289 SuperCap 5.5v .22F



Board "D1"
c823 25v µf220?
c814 16v µf22
c656 16v µf22
c655 16v µf22

Board "c"
Neck board, no obvious repairs.
__________________


Board "D2"
c514 50v µf3.3
c561 50v µf3.3
c508 25v µf100
C552 25v µf47

Board "B"
C440 16v µf22
c449 16v µf22
c408 16v µf22
c432 16v µf22
c468 35v µf22
c858 16v µf10
c853 16v µf10
c447 6.3v µf22 (has addon board) (XAV-55N assumed to be unmodified has 50v µf2.2 ) Ignore without board details


note:2
Some resistors have also been serviced. at least 1 so far identified as swapped to jumper at "B" R873

[Electronic M]

If you want to help people document everything. Rare stuff like this odds are nobody else is working on now, but someone will find one x months from now and then have tons of questions.

[HelloVoltage]

small update of progress. Was able to get a broken diversity unit. Repaired it and found a cable with similar connectors that didn't take too much effort to modify. the tv functions came to life. Not able to get the composite video-in signal to stablize (or colorize) yet. But almost there.


1-15-2023, after checking packages, I now have 6 XAV-u50 indextron, 1 xav-55n indextron, and 1 xav-u51 indextron. 6 diversty units (also labeled xav-u50 ¿?). 2 original cables, 1 non original made to work.

[rcpilot23]

Well done

I have 2 x Sony Indextron TVs that I still need to send to Andy in USA

[HelloVoltage]

Originally Posted by rcpilot23

Well done

I have 2 x Sony Indextron TVs that I still need to send to Andy in USA

if you mean watchcubes, have 9 working for a wall (3x3 array) project, can also possibly repair for you. If one of yours is white, would trade straight for a working black or working blue.

[HelloVoltage]

the composite cable in post 170 of this thread should be disregarded. I used it in ignorance. The port into which it is inserted is much more complex, hence the thread I started here: http://www.videokarma.org/showthread.php?t=274650

[rcpilot23]

Originally Posted by HelloVoltage

if you mean watchcubes, have 9 working for a wall (3x3 array) project, can also possibly repair for you. If one of yours is white, would trade straight for a working black or working blue.

Mine are blue and black

[HelloVoltage]

I have 9 watchcubes. specifically fir to create an indextron (watchcube) video wall. I haven't found an appropriate (perfect) video for the project though. I do'nt want the presentation to use tubes removed from shells. But those margins.... I have not found an appropriate recording to spread across a margined wall.

[mbates14]

Seems as if Andy has deleted his entire presence here on this forum for some reason or another.

Anyways, has anyone fabricated up a replacement circuit for the CX22011 IC? they are basically unobtanium now and when I went to order one from aliexpress, they said no stock and wanted to charge some obscene amount.

So the only solution going forward is engineering up a replacement front-end for the SMPS side of the watchcube. Anyone ever cross this path yet?

[jhalphen]

Hi to All,
Hi Mbates14,

Found this illustration of the Sony CX22011 PWR control IC in my archives.
Unfortunately, spec sheet searches yield nothing and i've never had a full Sony data sheet, even in 2007.

Also, there is no Theory of Operation in the KVX-370 Service Manual so it's going to be a difficult task to assess what voltages & how many the CX22011 supplies.

Note: this parts search co. claims/MAY have a spec sheet but requires inscription (which i won't do):
https://www.jotrin.com/product/parts/CX22011

Sorry! not to be more helpful,

Best Regards
jhalphen
Paris/France

[mbates14]

Originally Posted by jhalphen

Hi to All,
Hi Mbates14,

Found this illustration of the Sony CX22011 PWR control IC in my archives.
Unfortunately, spec sheet searches yield nothing and i've never had a full Sony data sheet, even in 2007.

Also, there is no Theory of Operation in the KVX-370 Service Manual so it's going to be a difficult task to assess what voltages & how many the CX22011 supplies.

Sorry! not to be more helpful,

Best Regards
jhalphen
Paris/France

Yeah, that's all the same information I had and i could find as well. they are only using one of the two error amplifiers, and they aren't using the HV or LV shutdown protections in this design, either.

Also this chip appears to use a 1.2V reference, which there are very few PWM chips that do.

What cuts a lot of the market is the fact that they are using this in locked-frequency sync mode which again very few available chips can do. the SG3525 was attractive to do this, but it requires a modified feedback network due to the differences in reference voltage, and the other problem I ran into is its a push-pull design. I tried to sum the output using gates but it did not work well with the glitching and phase compensation issues.

I assume they phase-lock the 22011 power supply section for noise reasons, but they also pick off the R/C timing circuit ramp that runs off to the horizontal deflection stage to an extra winding on the yoke. idk if its a pincushion/horizontal parabola circuit or what.

So i put it aside for now, I did find a couple different ICs i can tinker with which have single-ended outputs and can phase-lock.

I attached the insanity that ensued haha. The picture is hard to see because the forum software is still expecting attachments stuck in 1992.

[jhalphen]

Hi to all,
Hi Mbates14,

Thanks! for the reply.
You have well analyzed the PWR circuitry and your engineering skills are far above mine.

Are you sure your CX22011 is dead; i sent one one of my Indextrons to Andy C. and it was a corroded trace under the IC (electrolytic leakage) which caused the PSU malfunction.

Andy left the VK forum for personal reasons.
He's on ARF (Antique Radio Forum) though and signs "AC".
Might still be willing to repair Indextrons.

see this thread for instance :
https://antiqueradios.com/forums/vie...?f=15&t=427760

Best Regards
jhalphen
Paris/France

[mbates14]

Oh its definitely dead, cap goo gets absorbed into the IC and kills it with no output. I just got into indextrons and I have been successful at fixing them with replacement CX22011s. But supply has run out unfortunately.

So its time to engineer a new solution to replace it.