Before when building superfx repro carts and overclocked carts I was at the mercy of hiring doug to do all the eprom wiring. I never bothered learning to do it myself at first because I thought I could rely on doug and I was busy with other mods. Doug's prices were fantastic and his work wasn't bad but it took months and months for him to get my orders done. It took doug so long to get my commissions done that it was killing my business and I even had a client try to make a paypal claim against me without even consulting me about it. So I stopped hiring doug and decided to learn how to do it myself. Building this stuff myself is the only way I could gaurantee my commissions would actually get done in a timely manner. I've just been so busy with other mods and commissions that I never found the time to sit down and learn what's necessary. Thanks to tiido I recently learned how to desolder and solder surface mount stuff very easily. Doug was using chipquik / solder wick which is expensive stuff and it turns out they're not needed at all. Also doug would throw out the donor cart as soon as anything broke and would order a new one just making the projects take longer.
I built a ghetto probe out of a old s-video cable and taught myself how to probe all 32 connections from the maskrom pins to the gsu 2 cart incase I ever need to repair a trace. Now I can repair a trace if one ever breaks meaning I can pretty much gaurantee your donor will work fine. After probing all of my connections it turned out everything was connected fine anyway but it was still good to learn incase something ever breaks. I broke a few pin connections on some of my early experiment superfx pcbs so now I should be able to easily repair those carts.
The first cart I decided to build is a bit special, it's a winter gold cart which is rare and only released in pal. What makes this cart so special is that it's the only gsu2 cart that came with the most amount of ram and a battery saving circuit. Swapping the lockout chip is easy if you know how to properly desolder / solder surface mount. Doug had stupidly soldered a stunt race fx maskrom onto the pcb. Doug soldered up the maskrom because it's much easier than soldering wires for an eprom so he was obviously just trying to cut corners. Doug also didn't even bother relocating the battery on the pcb. I relocated the battery to the back, desoldered the stunt race fx maskrom, and soldered up wires for an eprom. I then installed a stunt race fx eprom and installed a crystal oscillator to have the gsu 2 running at 32 mhz. Everything runs great, and the cart saves all my data fine.
I havn't installed the pcb into a case yet because I'm still not sure what game I want to make this cart into. Both stunt race fx and starfox 2 use the battery saving circuit but starfox 2 doesn't really need the battery saving circuit since starfox 2 only saves high scores. However stunt race fx has unlocks saved on the battery circuit so I'll probably keep this cart as a dedicated stunt race fx. There's no point in wiring up a socket to be able to change the eprom because as soon as the change the game the sram will get wiped and you'll lose all of your saved data. Really the only reason why it's tempting to make this a dedicated overclocked starfox 2 is because starfox 2 has a much better framerate when overclocked than stunt race fx. Also an overclocked starfox 2 with the ability to save high scores is certainly more rare than a stunt race fx that runs somewhat faster but nothing massive.