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| SNES/Genesis Konami Justifier: how to determine photo diode/phototransistor? |
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| opt2not:
Why not indeed. :dunno |
| Zebra:
Yup, it's the way to go probably and, if the photo diode is not the issue, the caps on these guns also fail and one of the signs is unreliable registering or not registering at all. Changing out the sensor board should fix that too, as long as it still runs through the original i/o chip. While you are at it, I recommend switching out the lens for a Konami arcade gun lens. The arcade lenses let through way more light and Konami arcade parts seem to fit their home guns. They use the same trigger and same size sensor board etc. At least my Terraburst arcade guns seem to fit Konami PS1 gun parts. I suggest using shielded cable to connect the old sensor board to the new one and not making the wire any longer than is necessary, or you'll create other issues with accuracy. |
| opt2not:
I just remembered, I sold all of my lightguns before moving. So it’s information is good for others to do. I’m out. |
| Metalman1661:
--- Quote from: Zebra on October 11, 2019, 04:47:26 pm ---Why not just use one of the happ universal light gun sensor boards (the 4 wire version). Just solder the 3 sensor legs to the corresponding points on the happ board and mount the happ board inside the gun (using hot glue). I have done that with three guncon 2 guns and one guncon 1 with three different models of time Crisis arcade sensor pcbs. Those photo diodes seem to be mostly universal. I have a lot and they all seem to run on either 3.3v or 5v. --- End quote --- I'm sure this option would work. The problem is this universal Happ board is roughly the same price as the gun itself. These Genesis/Snes Justifiers are only about $30. I was hoping I could figure out the part number of the existing phototransistor and possibly find a suitable alternative (assuming the exact part number is most likely obsolete). I did purchase some potential replacements from Digi-Key and dropped them in and they did not work (TSL235R-LF, TSL257-LF, BPW77NA). Also the actual board the phototransistor is soldered to is very basic. It has just one resistor (1K ohm) and one ceramic capacitor (0.1 uF) . There are wires that run to the main logic board after that. The phototransistor is three legs so that limited my search for suitable alternatives but I am not sure on other details of how the transistor communicates to the logic board. There is a reddit post showing the insides (except the logic board): https://www.reddit.com/r/crtgaming/comments/7n9qws/what_photodiode_or_phototransistor_did_the_konami/ Any insight you can provide is greatly appreciated. |
| Zebra:
You'll find the issue with most light gun problems is that the cost of replacement parts is often close to or equal to buying a whole new gun. There is no real way around that. Perhaps you should just get a new one. You can find used sensor boards on ebay but even then, you have to ask if it's worth the effort: https://www.ebay.com/itm/1-happ-gun-pcb-board-opto-ARCADE-VIDEO-GAME-PART-cf3-25/163884996987?hash=item26284e997b:g:JyMAAOSwYxxdkVF2 You could just buy a replacement photo diode from Betson but I'm not sure if they have a minimum order value: https://www.betsonparts.com/amusement-redemption/arcade-guns/op805sl-photo-transistor-for-betson-imperial-shotgun.html and, you don't really know if the photo diode is actually the issue. It could just as easily be the cap. Using a whole new board should solve most issues. |
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