Re: Cinematronic HV question

David was kind enough to review my oh so 'artistic' drawings of
schematic markups, and it should be a very easy 'hack' to do. I'll post
my findings once complete. Now if I can only get to it.

I still need to go through those 720 boards, right Jon!

tm

solarfox@texas.net wrote:
>
> On Thu, 20 Jul 2000 17:28:29 -0500, you wrote:
>
> >I've read Zonn's and David Fish's excellent Cinematronics monitor and HV
> >troubleshooting guides. However, I have an 'early' Cinematronics monitor
> >with the discrete HV section that resides on the monitor board itself.
> >The HV has (surprise, surprise) stopped working properly, and while the
> >later gold box HV modules are hard to find, the earlier ones are next to
> >impossible to get.
>
> Ahhh, someone _else_ with a dead "first-generation" Cinematronics
> monitor... I feel your pain. :)
>
> >My tiny mind thinks all it will take is the removal of the now present
> >HV components from the board, and a new set of wires and a molex
> >connector to plug into the Keltron HV box. Is that it, and has anyone
> >done this yet?
>
> I'd been thinking about this as well, actually, and your post prompted
> me to track down some schematic sets for the different monitors, to see if
> it's a feasable swap... Apparantly, there are _three_ different
> Cinematronics monitor designs:
>
> (1) the "SPACE WARS"-style design, which uses the onboard HV section
>
> (2) an "enhanced" version of the above (used in "STARHAWK", and
> possibly one or two others?) which has some additional circuitry in the
> power-supply section. (I'm not quite sure what its purpose is yet, but its
> a significant modification from (1). ) This design also has a 7805
> regulator added, to generate +5V for the logic chips from the +25V input,
> instead of relying on the +5V from the CPU board.
>
> (3) the "Keltron" design, which also has a somewhat different
> power-supply section that's similar, but not identical, to (2).
>
> The DAC and deflection-driver circuits look the same across all three
> designs, except that the "Keltron-style" schematic shows an empty space
> where R122 and R222 used to be... These resistors were paralleled across a
> .1uF capacitor and a 360 ohm, 1W resistor in series, and the whole trio was
> paralleled across the deflection coil, like so:
>
> (warning: ASCII art ahead!)
>
> --------------------------o---------------------
> ! !
> (replace the _'s with ! !
> "1" for the vertical ---o--- !
> deflection circuit ! ! !
> and "2" for the ! ! C_02 !
> horizontal) ! --- 0.1uF !
> ! --- 100V ----
> R_22 \ ! _)
> 1.2K / ! _)
> 1/2W \ \ R_23 _)
> (?) / / 360 ohm )
> ! \ 1W ----
> ! / !DEFLECTION
> ! ! ! COIL
> ! ! !
> ---o--- !
> ! !
> ! !
> --------------------------o---------------------
>
> I can't imagine this has anything to do with the Keltron supply...
> does anyone know what removing the 1.2K resistor from this circuit _does_
> do?
>
> In any case - at _first_ glance, it doesn't look like the Keltron will
> work as a drop-in replacement for the old-style HV section... but, now
> that I have all three schematic sets in one place, I'm going to go through
> them with a highlighter pen and see _exactly_ what the differences are; it
> might actually be do-able with only a bit of tweaking. I'll keep y'all
> posted. :)
> -----------------------------------------------------------------------------
> When they took the fourth amendment, I said nothing because I didn't deal drugs.
> When they took the sixth amendment, I said nothing because I hadn't committed a crime.
> When they took the second amendment, I said nothing because I didn't own a gun.
> Now they've taken the first amendment, and I can't say anything about it.
> -----------------------------------------------------------------------------
> solarfox@DON'TMESSWITHtexas.net (Gary Akins jr.)
> http://lonestar.texas.net/~solarfox
> -----------------------------------------------------------------------------
> ---------------------------------------------------------------------------
> ** To UNSUBSCRIBE from vectorlist, send a message with "UNSUBSCRIBE" in the
> ** message body to vectorlist-request@synthcom.com. Please direct other
> ** questions, comments, or problems to neil@synthcom.com.
---------------------------------------------------------------------------
** To UNSUBSCRIBE from vectorlist, send a message with "UNSUBSCRIBE" in the
** message body to vectorlist-request@synthcom.com. Please direct other
** questions, comments, or problems to neil@synthcom.com.
Received on Wed Aug 2 22:19:15 2000