RE: Audio Reg on Tempest or Gravitar

G'day folks,

Thanks, Ray, for resending out that conversion doc! I have a copy at
home, but I'm not sure if it has survived that last couple months on my
bedstand (given my two toddler's habit of clearing it on a weekly
basis). Sounds like I have everything I need to plug and play Asteroids
Deluxe into my Asteroids cabinet (expect for an extra shield button)!
About the only question I had was, "How can I tell if my Tempest AR II
generates +22v and -22v?" I imagine that because this was the first
color vector game from Atari that it generates many more voltages than
any subsequent game, but I thought I should double check.

While I have everyone's attention focussed on the Atari BW, I thought I
should poll people about what games they've put into their Atari BW
cabinets. Please include what cabinet you started with, what you added
and how you did it (ie. plug and play while swapping control panels,
menuing system and banked EPROMs, etc.).

I know that Kevin Philips added Lunar Lander into his
Asteroids/Asteroids Deluxe. Did Doug Jefferys ever figure out how to
modify Battlezone board sets to play Red Baron? Does Red Baron's
pinouts look anything like Battlezone's pinouts (excluding the control
panel inputs)?

                Steven S Ozdemir
                sso@dsc.com

ps - I have a cabaret Asteroids and caberet Battlezone. The neck of the
Asteroids tube almost points straight down to the ground. Seems like
it'd be funny playing Battlezone in this position, so I imagine I'll be
taking my Asteroids/Asteroids Deluxe set up and moving it to the BZ.
Maybe later I'll add Lunar Lander and Red Baron.

>----------
>From: Ray Ghanbari[SMTP:ray@mayo.edu]
>Sent: Tuesday, November 04, 1997 12:42 PM
>To: vectorlist@goonsquad.spies.com
>Subject: Re: Audio Reg on Tempest or Gravitar
>
>You wrote:
>> > What does Ray do with this supply?
>> >
>>
>> The problem is that Asteroids Uses a Reg/Audio I board, and
>> Asteroids Deluxe uses a Reg/Audio II board. The gains of the
>> audio amplifiers on those boards are different, and it has to be hacked to
>> get them to both operate at the same volume.
>
>Yup, this is what I did, although the details are a little different.
>Asteroids uses a AR board, and AD uses an AR I board.
>
>Here is the write up I did way back when.
>
>Alternative was to mod the output stage on the AD PCB. I tend to not make
>modifications like these to PCBs, since I hate it when others do this stuff
>(heck of a time tracking things down if you have to fix it).
>
>Ray
>
>
>
>Addendum to Asteroids -> Asteroids Deluxe conversion
>
>Ray Ghanbari
>ray@mayo.edu
>4/9/95
>
>NOTE: you are responsible for what you do, not the author or anyone else. Do
>
>not attempt the following conversion unless you know what you're doing and
>are
>willing to take responsibility for the results. 'Nuff said.
>
>Once you rig up your adapter and start playing, you may notice that the sound
>
>is heavily distorted. Fret not, this does not mean that the game is melting
>down! Asteroids (and other Atari vector games) use an auxillarly board to
>provide regulated power, and to provide amplification for sound. The
>Audio/Regulator board in Asteroids Deluxe was the Audio/Regulator I board
>(A/R
>I), while Asteroids had a plain old Audio/Regulator board (A/R)
>
>If you look at the schematics, the only difference seems to be that the A/R
>board had additional circuitry to support an Audio Disable signal. Since
>this
>pin is always grounded in the traditional Asteroids harness, this part of the
>
>circuit is never used. I guess the engineers at Atari decided Audio Disable
>was no longer necessary, so they removed it from the A/R I board, and
>subsequently, the Audio/Regulator II (A/R II) board that was used in
>Battlezone
>and Red Baron (among others)
>
>(As an aside, does anybody know if Lunar Lander used the Audio Disable
>signal?)
>
>Unfortunately, when the Audio Disable circuitry was replaced, the resistor
>network between the two audio inputs and the audio amplifiers changed,
>changing
>the signal amplitude seen by the audio amps. As a result, using the A/R
>board
>with Asteroids Deluxe results in the amplified signal being clipped, leading
>to the heavy distortion that you hear.
>
>There are two ways to fix the problem. The first (and easiest) is to replace
>
>your A/R board with a A/R I board, or preferably, an A/R II board. The
>reason
>to opt for the A/R II board is that the A/R II board added support for
>additional voltage levels, which you will need if you want to play Battlezone
>
>and Red Baron in the same cabinet. Apparently, there are different versions
>of
>the A/R II board available, which are configured to supply different
>voltages.
> Again, if you have a choice, try to find one that provides -5V (7905 voltage
>
>regulator), +12V (7812 voltage regulator), and the standard (?) +22V and -22V
>
>(unregulated). These are the additional voltages that are needed by
>Battlezone. These voltages are segregated on a seperate connector on the A/R
>
>II board, and hence should not require any changes to you wiring harness (the
>
>rest of the board seems to be pin compatible with the A/R board, but you
>should
>double ckeck this)
>
>NOTE: Before you risk your electronics, _ALWAYS_ check the line levels on the
>
>reegulator board, make sure they match the schematics and your wiring
>harness.
>When you finish, repeat the procedure just to be sure.
>
>If you do not have access to a ready supply of A/R II boards, then it is
>fairly simple to modify the audio amplification portion of the A/R board.
>You
>will need the following:
>
>2 1k Ohm 1/4W resistors
>2 0.22 uF ceramic disc capacitors (25V)
>
>First, locate C6 and C15. These are 10uF electrolytic capacitors. If you do
>
>not have the schematics handy, follow the traces on the board. Audio 1 comes
>
>into pin 9 on connector J7, goes through a 10k Ohm resistor, then connects to
>
>the "+" side of C6. Audio 2 comes into pin 8, then into a different 10k Ohm
>resistor, then goes into the "+" side of C15.
>
>Once you locate C6 and C15, replace them with the 0.22uF disc capacitors
>(orientation doesn't matter with ceramic caps)
>
>Next find transistor Q4 and Q6. These are 2N3904's, and are used in the
>audio
>disable circuitry. Again, if you don't have schematics, keep following the
>traces. One leg of Q4 is connected to the "-" side of C6, and one leg of Q6
>is
>connected to the "-" side of C15. Remove these transistors (note that this
>will make the audio disable circuitry ineffective)
>
>You now need to add the 1k resistors. Here is what the final circuit should
>look like (Audio 2 has the same topology as Audio 1):
>
> 0.22 uF
> 10k + | |
> Audio 1 ---\/\/\/\/---|----| |---------[...rest of the circuit...]
>(J7 pin 9) | | |
> |
> |
> /
> \
> / 1k
> \
> /
> |
> |
> |
> -----
> ---
> -
>
>What I did was solder one leg of the 1k resistor to the ground terminal of Q4
>
>(it has a square pad instead of a round pad) and soldered the other end to
>the
>lead on the "+" side of the 0.22uF cap. Do this for both audio inputs. For
>one of the audio inputs, the resistor and cap are close enough that you can
>connect them directly. For the other, I had to use a length of insulated
>wire
>to bridge the components together (double check that nothing is shorting!)
>
>Reconnect the board, and the distortion should be gone...
>
>(Note, as a side effect, the volume level on Asteroids will be lower than the
>
>volume level on Asteroids Deluxe, but that's what the volume control is for
>;-)
>
Received on Tue Nov 4 16:32:01 1997