PROPHET64 & MSSIAH Userforum

some details for the mods:

Custom Li-Ion battery pouch attached to locking strap

12v pass through from battery pack, through breadbin and out the top by the LCD mount (no wires, easy disconnect, clean)

color selector switch close to 12V input. Choose Power LED color to suite you mood, can also turn off LED once colors cycle fully if you have not chosen one

Strat guitar boat style output plate wired for stereo trs

Tele style control plate. 2 knobs control volume of dual sids while the switch selects dual sid or mono sid

Hot shoe mount for LCD screen ( would be awesome if someone modded a digital hot shoe to pass power and video to screen when you mounted it, I know some cameras have a sync connection on their hot shoes)

12V power out for LCD screen

Video out for LCD screen

Shortened wires on screen

changed gender of power jack on screen

changed the gender of one of the screen inputs

modded the LCD mount so it can adapt to hotshoes and still be able to position it or angle the screen to your liking

Custom mod grip with 2 pots (next revision i think i will do PCB mounted pots sticking out from the top of the neck to look like tuning heads on a Guitar) The Mod grip can be easily unmounted and has a telescoping "fret board" with locking positions.

Custom transfer logo in C64 font

White keys placed in octave formation

I think that covers most of the current mods. I still want to add 4 pots to the body of the breadbin that would be selectable by 2's (mod grip and body, just body and no mod grip or none with joysticks.

This was built as a performance synth... hopefully now that the mods are almost done I can get to learning the sequencer and such

Last edited by djaudiophile (2011-04-07 03:03:01)

Yes it does! I'm excited about your pot mod and will have to incorporate it. Like I wrote in the description how i would like to revise the mod grip with the pots on a PCB to stick out the necks sides like tuning pegs. Pots that sit on a PCB are also generally smaller bodied and will take up less room in the casing. Awesome work on realizing a definitive way to do the pot mod. I've been waiting to start adding the 4 pots to the body of the breadbin hoping that there was a better way.
You rock!

That is definitely my next purchase. I'm building the Keytar to work with both mssiah and cynthcart. I read somewhere that you could install cynthcart in a switchable rom so that it can always be a part of the system rather than take cartridge space. this would be ideal as I can always have the mssiah cart attached with maybe a switch to kill the cart port.

I haven't heard of anything like that being done.

It's true that Cynthcart requires no extra hardware to run - the cartridge contains just the software on ROM. You can in fact start the C-64 with Cynthcart and remove the cartridge while it's running.

MSSIAH is a good deal more complex. It has lots more going on in the cartridge, and considerably more moving to-and-fro. You could install some sort of switch as you describe, but you'd need to make sure you kill the power to the C-64 before using it. As it happens, I wouldn't attempt such a mod for fear of frying something, especially around the cartridge port.

Do you have a floppy drive? If so, you can download Cynthcart for free (or get someone to put it on floppy for you).

Last edited by InactiveX (2011-04-07 23:58:00)

Oh right. Does the uiec/sd not use the cartdidge port then? If that's the case, it should be OK to add a switch to the power line to the MSSIAH.

Looking at the data, it seems pins 2 and 3 are the +5V. These would have to be disconnected to power down MSSIAH. I don't know if both lines are connected within the MSSIAH cartridge; if they're only connected at one pin then a SPDT switch would work, if connected at both then you'd need a DPST or DPDT switch.

This is all theorising, so do it at your own risk, etc. And any switch should only be flipped when the C-64 is off!

Cartridge port pinout data here.

What power supply are you using? Is it a Commie? Or is that 12V battery the only supply it needs?

Hi djaudiophile !
Incredible live performance synth

It's funny to see that I also started a C64 mod for mssiah and Cyntcarth last year with the same name ! ViCious Oi!
At this time I have my sidX2 working. And my internal power supply from IDE64.org is finally ok !
First I was thinking of use it with both cartridge by switching it with a Datel EX64 expander. But I'm limited in free space because of the MIDI interface (from Nebulah) for the Cynthcart (even if I used a "short" C64C mobo in the breadbin box). So I will use an another C64 for Cynthcart.

I also asked to Josef from IDE64 about a simple 5V switching for two cartridges wired on the C port. He said that it certainly will cause damage to the C64. But it was about 2 cartridges at the same time ! So I don't know about 5V ON/OFF switch...

Anyway if you want I still have a EX64 kit ready to solder somewhere ! But damn it's so big ! Impossible to integer it into a C64 case...

@InactiveX, your pot mod circuit looks great !