Xpantastic!

Well...
 
First, I'm an electrical engineer but not a tech, but I'll do my best.
 
I'm thinking it's something related to the grids for those digits.  That's the mesh that goes between the filaments (the really fine horizontal wires that go the entire lenght of the display) and the phosphor digit-segments.  If they have a problem it affect the whole digit.  Unfortunately, it seems from the schematic that the grid driver chips drive all three display's grids ganged together (e.g. grid 1 from disps 1, 2, and 3 are driven by the same chip driver).  That means it might not be a chip, or you'd have the same digits missing on all 3 displays (do you? did you run the display test in the service page?)
 
It would be interesting to open your OB and hinge down the display board (it's on hinges).  Then see of you can see very tiny wires inside the VFDs running from the pins to the grids for those digits; are they broken?  If so, that's the worst case I suppose, need new displays.  If you have any friends with oscilloscopes, it would be good to check the signals on the grid 4 and grid 25 pins of that display when it's running; are there 55V pulses?
 
I'm also wondering, what brought on the problem on TWO digits simultaneously? (don't thing old age alone would explain the coincidence)
 
Randy

--- On Mon, 8/4/08, Edward Chen <chenedward69@...> wrote:

From: Edward Chen <chenedward69@yahoo.com>
Subject: Re: [xpantastic] Re: Noritake displays on ebay
To: xpantastic@yahoogroups.com
Date: Monday, August 4, 2008, 8:28 PM











Hi Randy,
Thanks much for taking the time to reply.  It is actually two entire digits, I believe the 4th and 25th on the display.
As I am not a tech, are you saying it may be an IC related issue and possibly fixable?
Rgds,
Eddie

--- On Mon, 8/4/08, William Cason <randycason102@ yahoo.com> wrote:

From: William Cason <randycason102@ yahoo.com>
Subject: Re: [xpantastic] Re: Noritake displays on ebay
To: xpantastic@yahoogro ups.com
Date: Monday, August 4, 2008, 8:21 PM









Chenedward69,
 
Are you sure it's not a driver IC problem (the 6118's referenced in the service manual)?
That would be much easier to fix than replacing the VFD!
 
Did you mean two segments of one digit, or two entire digits?
 
Randy

--- On Mon, 8/4/08, chenedward69 <chenedward69@ yahoo.com> wrote:

From: chenedward69 <chenedward69@ yahoo.com>
Subject: [xpantastic] Re: Noritake displays on ebay
To: xpantastic@yahoogro ups.com
Date: Monday, August 4, 2008, 3:57 PM




With my luck my M12 just lost 2 character segments last nite on one 
of the displays. I contacted Armen here in NYC directly knowing he 
is the only one who has stock of the displays what the cost of one is 
and of course he says I would need to bring the whole unit in to get 
it serviced before he can determine a price? WTF? I asked if I can 
just bring the display board and have him just replace the one 
display instead of lugging the whole board in and he said no, no he 
needs the whole unit. When I mention I was out of state and didn't 
want to make a useless trip if the price was out of my range he then 
throws out a quote that it could be $350 - $500?? and also depending 
what else needs serviced?? As I clearly stated to him there was 
nothing else needed to be done besides the one display he says well 
just bring it in and we'll discuss..knowing his shadiness from having 
dealt with him in the past he would have probabaly swap some parts 
out of it to make it defective and then turnaround and jack me up for 
other repair costs. That is why I have no intention of bringing the 
whole unit in and will just avoid him totally. Thought I share 
my .02 experience.

So if anyone has a display for sale please let me know? ;)

--- In xpantastic@yahoogro ups.com, "envia94" <akva@...> wrote:
>
> The value of an Xpander display is easily over 100 EUR ...
>