Franky Build Help

By NetNomad

Supporter (9)

NetNomad's picture

26-10-2020, 00:02

Hello! I'm working on building a Franky cartridge right now and I ran into some issues. I'm wondering if anyone has run into the same thing or in general has any insight and would be able to help. Here's my board:


I'm configuring it for NTSC composite output and I'm doing the mod to use the SMS crystal. I know it's not the prettiest soldering work, but I can't see any shorts or anything (the ceramic cap in the center that looks shorted on the back is just the angle i took the photo) so I'm scratching my head at where I messed up. VGMPlay detects Franky without an issue, but the audio sounds like a high pitched whine and the video has no color and appears to be out of sync when I choose Franky video in Sofarun. I can change the pitch of the whine with the trimmer capacitor and I can turn the whine into noise with the potentiometer. If you look at the wires on the top left, the yellow wire is composite video out, white wire is audio out, and the black wires are the grounds. Did I wire that up right? I hear the same thing from the audio out and mixed through the MSX. I have it hooked up to an SX-1 Mini+ if that makes any difference. I did enable slot 1 before plugging it in. When I built it and got this result, I went on to do the part of the clock mod that was marked optional where I cut a trace on the front and made a jumper on the back to disconnect the CPULCK signal. Does anyone have any advice? Thank you for reading!

Login or register to post comments

By NetNomad

Supporter (9)

NetNomad's picture

27-10-2020, 02:30


Posting in case someone has the same problems later down the line and finds this thread: the audio trouble and the video trouble ended up being two separate issues. On the left-hand side of the board there's a 100k resistor that you need to omit if you're using an SMS I VDP otherwise you won't get any sound. The video issue was because the clock pin of the video encoder chip wasn't connected to anything, so that blue wire you'll see I added runs from that pin to the SMS VDP's clock out pin (this part is clearly instructed in the manual, I just did a poor job reading it hahaha). The audio is a little crunchy and the video cuts in and out every so often which may be due to weak connections here and there that I'll have to reflow but other than that my Franky cartridge seems to be fully functional!

By jltursan

Prophet (2344)

jltursan's picture

27-10-2020, 09:23

Good work!. Thanks for sharing your experiences! Smile

By Haze

Expert (111)

Haze's picture

27-10-2020, 09:50

Just wanted to say: I ain't building myself a Franky (yet), but thanks indeed for sharing your findings with pictures to boot!

By alexito

Hero (642)

alexito's picture

27-10-2020, 23:54

Thanks for the notes. I build mine following the brasillian MSXPRO Homepage. Because I own already a NTSC Franky (315-5124 and CLOCK feeded from MSX) from Supersoniq Team I always wished a PAL version (315-5246 used) but seems our friends in BRASIL use a different Video STANDARD (SECAM) so I finished my assembly and get a SECAM Video Output with a little Video Noise OUTPUT and a little different colors compared with my NTSC FRANKY but the best of the best is the PLAYSONIQ (with 315-5246 of course) because it count with it's own CLOCK CHIP for Video Sync also the clean VIDEO OUTPUT and the possibility of switching between EUROPEAN(PAL-UK)/AMERICAN (NTSC) via Software. I have Modded my NTSC FRANKY with a SWITCH for get 50/60Hz Video Tweak making some games more appealing to me.
Running Naked in a Field of Flowers

By ducasp

Champion (386)

ducasp's picture

28-10-2020, 00:18

alexito wrote:

Thanks for the notes. I build mine following the brasillian MSXPRO Homepage. Because I own already a NTSC Franky (315-5124 and CLOCK feeded from MSX) from Supersoniq Team I always wished a PAL version (315-5246 used) but seems our friends in BRASIL use a different Video STANDARD (SECAM) so I finished my assembly and get a SECAM Video Output with a little Video Noise OUTPUT and a little different colors compared with my NTSC FRANKY but the best of the best is the PLAYSONIQ (with 315-5246 of course) because it count with it's own CLOCK CHIP for Video Sync also the clean VIDEO OUTPUT and the possibility of switching between EUROPEAN(PAL-UK)/AMERICAN (NTSC) via Software. I have Modded my NTSC FRANKY with a SWITCH for get 50/60Hz Video Tweak making some games more appealing to me.
Running Naked in a Field of Flowers

Brazil is not SECAM at all... Here we use a system named PAL-M, it is 60Hz, use PAL color encoding but NTSC-M line/frame/field format (60 fields per second 30 frames per second 525 lines)... Consider it a NTSC signal with PAL color coding, it made sense for use in Brazil as NTSC color encoding would cause shitty image from RF reception due to reflections caused by our topology and we use 60Hz for AC/Outlets, but nowadays seems like some crazy system. I think that basically the Brazilian Master System uses the NTSC VDP and get the RGB output to encode on PAL signal using a MC1377P IC to get composite output (and doesn't have RGB output capability due to that).

By alexito

Hero (642)

alexito's picture

28-10-2020, 00:56

Thanks for the corrections, Ducasp. Wink

By NetNomad

Supporter (9)

NetNomad's picture

28-10-2020, 02:14

i figured out the issue with the video cutting out! it wasn't the cartridge or how i built it at all i think, the cruddy LCD screen i use as a monitor was the issue. i plugged Franky into a projector and suddenly there were no issues at all. it was nice because i didn't have to fiddle with the video channels and the games are massive on my wall! but getting a CRT in the long run is probably a bit more practical haha. as for the audio being "crunchy" i think that's just me being used to SMS sound on the Mega Drive/Genesis, because that's how i used to play SMS games and i've heard people say that version of the chip has a "sweeter" sound so i guess that's what that means! now that i've been playing games with it for a bit it sounds much more normal

alexito, i've been going through your conversions today and it's been a lot of fun, great work!