Converting a Gravitar to Black Widow?

lastlight

Well-known member
Joined
Aug 25, 2015
Messages
388
Reaction score
376
Location
Calgary, Alberta, Canada
I really doubt I'm going to find a Black Widow I can trade for my Gravitar. I'm interested in people's thoughts regarding converting it to a Black Widow. My intention was to modify the game internals as needed and replace the CPO and marquee. I wouldn't cover up the Gravitar sideart as this machine will be in the middle of a row and the Black Widow sideart isn't that great in my opinion anyways.

I don't know much yet on how to change the internals but I don't expect to be able to toggle between games. Is doing any of this acceptable within the community? I mean Black Widows were Gravitars... it almost seems ok in my mind.

Interested in people's thoughts. Also how hard is this conversion? Is it just some ROMS and I can modify the existing CP to house the Wicos? Due to costs I can't see myself trying to find a BW CP since I have the Wicos already. But if it's criminal to hack the harness and CP up I could be convinced to.
 
Could always go for a vector labs kit to play Widow, Gravitar and Lunar Battle.
http://www.vector-labs.com/index_grav.html

Also, check with Troy (takeman) if he has any extra Widow panels. Rather than hacking up a Gravitar panel, have one of each and use the kit to play whatever game you swap the panel to. It take 5 minutes (if that) to change over those panels. Harness needs to modifications, it's all done from the control panel side.

Otherwise swapping the board is just a rom swap between Gravitar <---> Widow.
 
The formal Atari documentation for doing the conversion is in Atari document TM-252, see here:

http://antelopearcade.com/files/Arcade Manuals/GRAVITAR_BLACK_WIDOW_RETROFIT-TM-232.pdf


If you have a Gravitar cab, with a Gravitar harness, you need to add a few extra wires to the harness, to accommodate the extra CP controls signals used for BW. (Note that if you have or get a Space Duel harness, it already has the extra wires, which makes converting a SD to BW a little easier.)

Modding the PCB consists of replacing the ROMs, plus you can do a set of optional mods to the audio circuitry, which changes the sound a bit, to accentuate the higher-pitched sounds of BW. These are optional, but IMO it doesn't really sound right if you don't do them, as it sounds too muted. Here's a quick summary of the mods, from my own notes (which are taken from the doc above, and are also discussed in the thread below):

Audio mod summary for converting Gravitar to BW:
http://forums.arcade-museum.com/showthread.php?t=364464

- Change C27 from 1000pF to 100pF (increases LPF BW, to play higher sounds)
- Remove C28 (1000pF) (disables LPF, to play higher sounds)
- Remove C34 (0.22uF) (disables LPF, to play higher sounds)
- Change R46 from 10k to 22k (changes mixing of the two pokey audio outputs)
 
I really doubt I'm going to find a Black Widow I can trade for my Gravitar. I'm interested in people's thoughts regarding converting it to a Black Widow. My intention was to modify the game internals as needed and replace the CPO and marquee. I wouldn't cover up the Gravitar sideart as this machine will be in the middle of a row and the Black Widow sideart isn't that great in my opinion anyways.

I don't know much yet on how to change the internals but I don't expect to be able to toggle between games. Is doing any of this acceptable within the community? I mean Black Widows were Gravitars... it almost seems ok in my mind.

Interested in people's thoughts. Also how hard is this conversion? Is it just some ROMS and I can modify the existing CP to house the Wicos? Due to costs I can't see myself trying to find a BW CP since I have the Wicos already. But if it's criminal to hack the harness and CP up I could be convinced to.

Do not hack the Gravitar panel. Gravitar is desirable same as Black Widow.
 
Also, another easy thing you can do is get a Space Duel CP, and add a pair of sticks to it. This allows you to play BW, SD, and Gravitar, with one CP, if you have a SD board. I did this with my SD, as spare SD CP's are super easy to find.

Biltronix has excellent docs explaining in detail how to build CP wiring adapters for the different games, for a SD CP:

http://www.biltronix.com/space_duel_black_widow_adapter.html

http://www.biltronix.com/space_duel_gravitar_adapter.html


This is just one way to go, but having the details figured out and documented saves a lot of the work.
 
Thanks for all the information.

So consensus seems to be against ruining a good Gravitar CP but modding a Gravitar Board is ok? I already didn't like the idea of hacking that CP however I have no intentions of making this a Gravitar again.
 
I've got a couple of those Space Duel to Gravitar CP adaptors I made a few years ago still laying around if anybody is interested.

Kudos to Biltronix and I even sent him a few bucks when I sold some.
 
Modding the PCB is reversible. Modding the CP, not so much. So, yes.

I totally understand the thinking there. But I have a new CPO already from Scott for Gravitar and was going to replace it already. So it's some holes in a piece of metal (still could be reversed technically).

I'm not going to modify the CP. I will wait until I have the funds to do this 'more properly' thanks for the input guys.
 
Modding the PCB is reversible. Modding the CP, not so much. So, yes.

You'd be against someone redoing their sideart as part of a conversion as well? I really am just asking out of curiosity I'm not arguing with anything you've said. Like I said my plan would be to leave it intact since it won't be seen.
 
Back
Top Bottom