On Saturday, May 3, 1997 at 12:00:00 AM UTC-7, Zonn Moore wrote:
> On Fri, 02 May 1997 09:31:15 GMT, rlb...@cedar-rapids.net (Rodger Boots) wrote:
> ~ On Thu, 01 May 1997 02:00:51 GMT, zo...@concentric.net (Zonn Moore)
> ~ wrote:
> ~
> ~ >
> ~ >On 29 Apr 1997 15:01:43 GMT, r...@ihgp3.ih.lucent.com (Rick Schieve) wrote:
> ~ >
> ~ >~ In article <5k28gf$h...@drn.zippo.com>, Wade Tsai <ep6...@shellus.com> wrote:
> ~ >~ >
> ~ >~ >A week ago I had asked for information about what might be causing
> ~ >~ >R636 (100 ohm) in my G08 to smoke instantly. It turns out that
> ~ >~ >the deflection transistors that the Zanen kit supplied (3716's)
> ~ >~ >were woefully underrated. All four 3716's shorted out the moment
> ~ >~ >power was applied and took out R636 and a few other components
> ~ >~ >with them.
> ~ >~ >
> ~ >~ >Scounging around the shed, I mananged to dig up four 6259's
> ~ >~ >(which are the original transistors that's used in the G08-003)
> ~ >~ >to replace the fried transistors.
> ~ >~
> ~ >~ I was thinking the other day about the problem of gettting
> ~ >~ replacement transistors that would handle the current. If one of
> ~ >~ the serious double E types out there looked at the circuit I'm sure
> ~ >~ multiple transistors could be used in parallel to share the load.
> ~ >~ A few resistors would need to be added to balance the load between
> ~ >~ the multiple transistors (which is where the EE comes in) but it
> ~ >~ should be do-able and there is plenty of room on the cabinet for
> ~ >~ some extra heat sinks.
> ~ >~
> ~ >~ Any EEs out there looking for something to play with? ;-)
> ~ >
> ~ >About a year ago I answered a post about a universal X/Y monitor. I had
> ~ >nominated the Sega X/Y. (Ok laugh! It won't be the first time!)
> ~ >
> ~ >Really. It's the fastest so it can play all the games, including the Sega games
> ~ >(of course) and Cosmic Chasm, which requires a fast monitor. It's also the most
> ~ >sensitive, so playing the Atari game would require only a resistor divider in
> ~ >front of the monitor as opposed to an amplifier. And last (and maybe least) it
> ~ >is already compensated for the bowing effects of Yoke/Picture-tube
> ~ >non-linearities. This means it'll run Star Wars and other ampliphone type games
> ~ >as is (with the Resistor divider). And with Tempest and other pre-compensated
> ~ >games, one simply removes a resistor from the game board, which is much easier
> ~ >to do than to come up with a WG -> Ampliphone adapter type board.
> ~ >
> ~ >It's disadvantage, compared with the Ampliphones, is that it has lower
> ~ >resolution.
> ~ >
> ~ >The biggest problem with the Sega is the underated Transistors (The second
> ~ >biggest is all the proprietary ICs).
> ~ >
> ~ >To fix the transistor problem you can do just what Rick suggests. Parellel two
> ~ >power transistors for each one currently being fan cooled.
> ~ >
> ~ >Since I have a dead Sega X/Y in the garage, I'll be trying this trick real
> ~ >soon...
> ~ >
> ~ >The thing to do is to get two of each transistor, connect the bases and
> ~ >collectors together. Then connect a resistor from each emitter to the place the
> ~ >old emitter used to go...
> ~ >
> ~ > +-------------------+-----------------> to old collector connection
> ~ > | to old base |
> ~ > | ^ |
> ~ > \ c | c /
> ~ > \| | |/
> ~ > | b | b |
> ~ > |-------------|
> ~ > >| |<
> ~ > / e| |e \
> ~ > | |
> ~ > | |
> ~ > \ \
> ~ > / .39 ohm 1W / .39 ohm 1W
> ~ > \ \
> ~ > / /
> ~ > | |
> ~ > +--------------------+----------------> to old emitter connection
> ~ >
> ~ > (Pretty bad drawing huh?)
> ~ >
> ~ >
> ~ >This is only shown for the PNP transistor, do the same for the NPN's.
> ~
> ~ Most all of these monitor used ONLY NPN outputs. There was a version
> ~ that used a complimentary/symetry output stage (PNP and NPN), but I've
> ~ never heard of anyone ever seeing one of those.
> ~
> And as usual, your right. I was just thinking of the Atari monitors and the PNP
> ASCII drawing looked better than the NPN ASCII drawing...
> -Zonn