RePCB 2-ASIC (Game Gear)

the repcb is a brand new motherboard i made for the game gear it supports the cleanscreen as the screen (not originals sorry) and any power/audio boards install guide simply transplant your asics, mpu and ext port from the existing console then use either a gameslot or transplant your original cartridge slot over in short solder in the z80, cpu, vdp and install an oem crystal if the custom one is not pre installed (not forgetting to remove the 2 resistors in the black rectangle by the crystal if using oem) connect a gameslot with a known working game (or use the original cartridge connector) using the usb c port on the side, power up the console use headphones to listen for game load, and press the reset button by the usb port to reset the game as initial hot plugging doesn't always load a game once you get game load and are happy its working proceed to test the cleanscreen, power and audio boards one by one in case any of those introduce issues for you install guide here we recommend purchasing a gameslot to go with this so you don't have to transplant your cartridge port comes with game gear repcb motherboard populated with everything except asics, mpu, cartridge slot and ext port brand new power and audio ribbons cleanscreen ribbons solder paste, stencil and spreader to apply solder paste if you want to hot air asics on features self powered no need for power or audio boards for testing simply plug a usb cable and headphones into the ports on board to fully power up and test the console reset button to reset game, useful for bench testing when powering from onboard usb c japan / english toggle switch, accessible from battery compartment when closed up comes with cleanscreen ribbons for solder free cleanscreen install test points and solder pads for all important signals improved audio with tones never heard before thanks to rerouted traces and a new amp and audio filter circuit change out of reset led so we know if asics out of reset power good led for 5v rail supports original crystal and brand new smd crystal new pcb layout for less noise and cleaner power rails, more accurate data transmissions brand new high quality smd components and an improved pcb design fixing any faults found with the original identifying floating pins some common symptoms we see if certain chips or pins are not soldered well will be listed below address pins on cpu caused by a0 and 5v floating on cpu (and possibly d3/d4 pins too) random colors identifying faulty chips as these are brand new boards with all new components pre installed the only problems you could have with your system if it doesn't work using the onboard usb port and headphone jack are defect in the new repcb board itself (not had any yet, so most unlikely) bad gameslot connection (highly unlikely) or original cartridge port bad game to test with (clean the pins or use known working game) bad z80 / cpu or vdp or soldering of them (most likely) as you can see, short of rare exceptions such as bad cartridge slots or games, you are most likely dealing with a bad soldering of the z80/cpu/vdp or the chips themselves are dead as we do more and more of these i am going to start making a table of known failed chips and their symptoms and make a graph of the typical chips that fail and their visual output the number after the faulty chip is the number of times i've personally seen it and can confirm that chip there may be many other reports from other users to back this up too, but that number will only reflect the ones i've directly fixed and tested myself out of reset border screen test audio notes faulty chip yes no cyan no vdp (3) yes yes cyan yes cpu (1) yes yes black yes vram like blocks of corrupt screen pixels vdp (14) yes yes black yes hsync/vsync pulsing like data pins causing random screen garble cpu (2) yes yes black no gg outputs random solid screen color such as black, pink, red, dull green, cyan etc z80 (11) vdp (3) yes yes black yes and no nothing on screen other than black border, or sometimes fully working screen for game load, sometimes only "sega" intro sound, other times full game load z80 (2) yes yes black missing audio channels audio plays but sounds like its missing a lot of notes sega plays normal vdp out of reset the out of reset light below the cpu comes on border cleanscreen is showing the black border (meaning it has pclk/hsync and vsync all valid) but screen remains black screen test turning on screen test switch on cleanscreen shows this color (white = all good, red = missing pclk etc see here ) audio game audio can be heard from headphone port solid color screen one common fault is when the screen powers on but is just a solid color such as black, pink, red, dull green, cyan etc unfortunately, this has been known to be caused by almost any chip including the wram, z80, cpu and vdp it can also be shorts on the data bus, and ultimately seems to be caused when the data bus is corrupt however, this has been known to be the z80 for me now 95% of the time important the solid color screen is basically the games data corrupting although this is typically the z80 it can also be the actual game, dirty pins on the game/slot or a bad slot or shorts on the data bus make sure you have a known good working game and try cleaning it beforehand, and no shorts or floating pins on the data bus on the z80, cpu or vdp if it is the z80 that is bad, it often can also have the "sega" intro sound (and sometimes nothing on screen, sometimes the game), then the game sometimes loading, sometimes not basically intermittent boot and behaviour when it is caused by the vdp i have never observed the game loading bad vdp examples as i come across any visual issues worth noting i will provide examples below here is a failed vdp that gave off vram like errors (noticable blocks of corruption, not single pixel corruption) the list of manufacter codes on the failed vdp chips i will try to remember and list here, to see in future if we spot a common manufacturing date/time or factory where the faulty chips appear more common so far the ones below are known faulty 315 5377 9229k7 (prevents console boot) 315 5377 9214k7 (prevents console boot) 315 5377 9215k7 (prevents console boot) 315 5377 9211ea009 (boots but corrupt graphics) 315 5377 9131e7 (boots but corrupt graphics) 315 5377 9138e7 (boots but corrupt graphics) 315 5377 9121k7 (boots but corrupt graphics) 315 5377 9229k7 (boots but corrupt graphics) 315 5377 9141e7 (visually ok, but audio missing channels)