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Removing the resin from a security module
#379697 - 11/25/18 03:28 AM
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Hey guys,
I've got a super-rare Victory PCB by Comsoft (NOT Exidy's game also called Victory) which is a Galaxian PCB conversion that has a resin encased security module, and I was wondering what techniques there are to remove the encasement so I can scan the PCB foil pattern and have any custom chips inside dumped? I've already tried heating it with a heat gun and using an Xacto knife but whatever the substance is is still too hard after heating to make that practical, I barely made a dent. I also imagine heating it in boiling water like I've seen done by others wouldn't work any better as I already heated it pretty hot with air.
Any suggestions? The game has been dumped and is already supported by MAME, but whatever encryption method on the encased custom chip I understand isn't entirely understood and I'd like to do whatever I can to preserve this rare bird. I'd like to have enough documented and preserved to make it so if someone was inclined (unlikely) to etch the security PCB and burn the chips they could also convert a Galaxian PCB to be this game, or more importantly repair an existing damaged one. Also the board is not working and overall pretty screwed up, so I'd like to make sure anything custom and irreplaceable is preserved before I start screwing around and trying to resurrect it, thus risking the chance of losing them. It seems to me I've heard paint stripper works sometimes but I've also seen that stuff do a number on the PCB's fiberglass resin too.
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Re: Removing the resin from a security module
[Re: Tornadoboy]
#379698 - 11/25/18 03:46 AM
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You might be better off getting it X-rayed if the resin is too difficult to remove.
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Re: Removing the resin from a security module
[Re: Vas Crabb]
#379699 - 11/25/18 03:49 AM
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Sure, I'll just head down to X-rays-R-Us tomorrow and get it done  lol!
Ok jokes aside, who would I go to to get that done without being thought crazy? Vet? I doubt my dentist would do it, they'd probably risk getting fired for using the equipment for non-patient related stuff, which no doubt would probably be the case with most vets also. Sounds expensive too, and while getting an X-ray might show the foil pattern that in itself wouldn't get the chips identified and dumped, I'd still have to at least partially dig them out for that.
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Re: Removing the resin from a security module
[Re: Tornadoboy]
#379700 - 11/25/18 03:58 AM
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> Sure, I'll just head down to X-rays-R-Us tomorrow and get it done lol!
>
> Ok jokes aside, who would I go to to get that done without being thought crazy? Vet?
> Sounds expensive too, and while getting an X-ray might show the foil pattern that in
> itself wouldn't get the chips identified and dumped, I'd still have to at least
> partially dig them out for that.
The places people go to get X-rays for identifying faulty welds? You don't want to be going to a medical X-ray place - it'd be too expensive and probably not the most suitable setup. People have got a few other PCBs and security modules X-rayed. I haven't been directly involved, so I don't know exactly where they get it done.
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Re: Removing the resin from a security module
[Re: Vas Crabb]
#379701 - 11/25/18 04:00 AM
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Ironically I work on stuff occasionally that is x-rayed for faulty welds, but I've got ZERO chance of getting those guys to do it, or probably even finding out who they are given how anal retentive and overall just plain Orwellian the people I work for are. I'm sure they've got a rule in their holy rule book somewhere that calls it a fireable offense for thinking unapproved thoughts about their vendors or clients.
I remember reading the story of how Pacman Plus was dumped, that guy ended up talking his vet (or was it dentist?) into doing it. But that guy was a LOT more tech savvy than I am and managed to dump the chips by just making educated guesses of the chip's identities and then digging out the needed legs, I'm nowhere near that good, not even close.
I may end up trying paint stripper on it, I need some for another project anyway, but I don't hold out a lot of hope for that idea.
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Re: Removing the resin from a security module
[Re: Tornadoboy]
#379702 - 11/25/18 05:11 AM
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> Hey guys,
>
> I've got a super-rare Victory PCB by Comsoft (NOT Exidy's game also called Victory)
> which is a Galaxian PCB conversion that has a resin encased security module, and I
> was wondering what techniques there are to remove the encasement so I can scan the
> PCB foil pattern and have any custom chips inside dumped? I've already tried heating
> it with a heat gun and using an Xacto knife but whatever the substance is is still
> too hard after heating to make that practical, I barely made a dent. I also imagine
> heating it in boiling water like I've seen done by others wouldn't work any better as
> I already heated it pretty hot with air.
>
> Any suggestions? The game has been dumped and is already supported by MAME, but
> whatever encryption method on the encased custom chip I understand isn't entirely
> understood and I'd like to do whatever I can to preserve this rare bird. I'd like to
> have enough documented and preserved to make it so if someone was inclined (unlikely)
> to etch the security PCB and burn the chips they could also convert a Galaxian PCB to
> be this game, or more importantly repair an existing damaged one. Also the board is
> not working and overall pretty screwed up, so I'd like to make sure anything custom
> and irreplaceable is preserved before I start screwing around and trying to resurrect
> it, thus risking the chance of losing them. It seems to me I've heard paint stripper
> works sometimes but I've also seen that stuff do a number on the PCB's fiberglass
> resin too.
the original set runs in MAME. The decryption function is simple. I don't think there's any point in you sacrificing your PCB. The only weird thing with the game is that the bootleg had a 5th ROM and the original did not, but it's probably just a leftover, the game does not read any data from it.
Code:
void galaxian_state::decode_victoryc()
{
uint8_t *src = memregion("maincpu")->base();
size_t length = memregion("maincpu")->bytes();
for (int i = 0;i < length;i++)
{
if (i & 0x80) src[i] ^= 0x80;
if (i & 0x20) src[i] ^= 0x04;
if (i & 0x04) src[i] ^= 0x40;
if (i & 0x01) src[i] ^= 0x08;
src[i] = bitswap<8>(src[i], 6, 3, 5, 4, 2, 7, 1, 0);
}
}
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Re: Removing the resin from a security module
[Re: Tornadoboy]
#379724 - 11/27/18 10:45 AM
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lol!