Konami Justifier replacement light sensor? (phototransistor)

[nintendo2600]

Hello All,

I was going to add links to photos and schematics but I can't get them to load on this forum software, sorry about that, anyhow:

I've been searching and trying to find a working replacement for the Konami Justifier gun's light sensor for months now. I've checked everywhere I could on the internet and it all comes up with dead ends and others trying things that didn't work. I've been told that the sensor could quite possibly be a custom part that is actually a phototransistor with a built in op amp? The part itself is unmarked aside from the die number on the back of it. There is no part number at all. I even took a shot in the dark and put in a service ticket with Konami and when they got back to me it was to sadly say their parts division is closed and they just recomended a 3rd party vendor they are sending people too now. That was only for Arcade parts as well, not specifically for 30 year old console hardware. I've tried many different phototransistors and I even tried building an amp with a LM741 but it must be too slow as it's only 1mhz and it needs something faster? I was told if it is a custom phototransistor with built in amp, it might need something as high as 10Mhz but I personally don't know how to make that circuit or if it would even work.



I was also told that the amp could be inside the custom chip Konami had controlling the gun which is in the handle. The sensor board itself it pretty simplistic with only the sensor, a 1k resistor and a .1uf smoothing cap. I took a shot at contacting the guy who posted the player 1 blue gun to player 2 pink gun mod thinking he might know the solution but was unable to find a proper contact for him from his blog posting. I got a little discourage when his name brought up a more recent google search which it saoid someone with his name and similar credentials in the same area had passed this year.

I have tried many different phototransitors so I can list what DOES NOT work from my experience so far:

LM741 op amp ciruit with a tept5600 series sensor, 1meg resistor in parallel with a 22pf cap & 2k variable resistor does not work

L14G1 (I think I tried this one without success but I've tried so much now I forget if this failed too so this might still be an option)

TSL252R do not work

TSL235R do not work

OPL550 do not work



My ultimate goal was not just to find a replacement for the sensor for broken guns but also to be able to post a DIY method for anyone to build
there own player 2 gun out of something super cheap like a $5 NES Zapper clone as the shell base cause the pink gun is really nothing more
than the sensor and a 6p6c cord attaching to the player 1 gun. I think there is a lot of people who would love to not only be able to fix dead Justifier guns but also be able to build there own 2nd player guns for $10 instead of paying upwards of $100 for an original pink player 2 gun that the marketis now commanding for them.


After so many years I would have thought the solution to this problem would have been long ago posted to the internet
as common know how but alas it's not. I really hope this can be finally put to bed and a working solution can be plastered on the web to overtake all
the old dead ends from others not being able to find a way to make this work.

How is this for a wall of text for a first post!

Know a good replacement for the light sensor in the Justifier gun?

Cheers!

[nintendo2600]

bump.

[nintendo2600]

One last bump at trying to find his info from your user base.

[viletim]

For the benefit of others reading this, the Justifier is a blue/pink gun set for the Mega Drive. Maybe that's obvious to some, but I have this thing and didn't know its name until now.

I have tried many different phototransitors so I can list what DOES NOT work from my experience so far:

LM741 op amp ciruit with a tept5600 series sensor, 1meg resistor in parallel with a 22pf cap & 2k variable resistor does not work

L14G1 (I think I tried this one without success but I've tried so much now I forget if this failed too so this might still be an option)

TSL252R do not work

TSL235R do not work

OPL550 do not work

Are you just trying to fit light sensors at random? There is little in common with these parts.

The Mega Drive joystick port just has simple digital I/O pins, so you know that the sensor must have a TTL output. A voltmeter and a torch will tell you that the output is high in darkness and low when hit by light.

I think the original part is a Sharp IS485E. It's old, Japanese, and in an identical looking package. An electrical equivalent seems to be the OPL531A, but it's physically larger and has a different pin arrangement.

When I pulled apart my second player gun I noticed there was a cracked (dry) solder joint on the modular socket pin that connects to the light sensor. If you have a faulty gun, better check this as it seems more likely than a faulty sensor.

I also found a circuit for a Master System light phaser to Justifier converter project.
http://benryves.com/journal/tags/Konami_Justifier

[basketballer]

I have both the blue gun for the SNES and the pink gun and neither currently work. When I first bought the blue one, I couldn't get it to work, but at some point it did function for a brief time. Now it doesn't work again. I took it apart and did notice poor quality solder joints on the photo sensor but redoing them with a soldering iron didn't fix it. I will try and locate one of those Sharp IS485E sensors and see if replacing it fixes the issue.

[nintendo2600]

I have both the blue gun for the SNES and the pink gun and neither currently work. When I first bought the blue one, I couldn't get it to work, but at some point it did function for a brief time. Now it doesn't work again. I took it apart and did notice poor quality solder joints on the photo sensor but redoing them with a soldering iron didn't fix it. I will try and locate one of those Sharp IS485E sensors and see if replacing it fixes the issue.

So you believe that Sharp IS485E sensor could be a suitable replacement? If so that would be great. I checked digikey but they only have one seller who want to sell them 120k at a time...lol.. I need a couple not a hundred and twenty thousand of them! I hope the places you buy from have sellers that sell them in much smaller quantities. Mouser doesn't have any currently either. Being here in Canada shipping is always a deal breaker from most other countries when buying low quantities of parts cause you might only want a couple bucks worth of parts but the shipping is out of this world being $10 for first class up to $30 for priority. Some sellers refuse to use anything but Priority as too which leaves me without cause I just don't have that kinda cash to piss away.

[nintendo2600]

For the benefit of others reading this, the Justifier is a blue/pink gun set for the Mega Drive. Maybe that's obvious to some, but I have this thing and didn't know its name until now.

Are you just trying to fit light sensors at random? There is little in common with these parts.

I think the original part is a Sharp IS485E. It's old, Japanese, and in an identical looking package. An electrical equivalent seems to be the OPL531A, but it's physically larger and has a different pin arrangement.

When I pulled apart my second player gun I noticed there was a cracked (dry) solder joint on the modular socket pin that connects to the light sensor. If you have a faulty gun, better check this as it seems more likely than a faulty sensor.

Thank you VERY MUCH for your input. How sure are you that the original part is the IS485E?

I also found a circuit for a Master System light phaser to Justifier converter project.
http://benryves.com/journal/tags/Konami_Justifier

With that in mind I actually just modded an SMS Phaser as a player 2 Justifier gun. You follow the same schematic
as converting a blue player 1 gun and just add a momentary switch for the start button. Worked perfectly.

Here is a fool proof numbered diogram for anyone that wants to make one themselves:

[nintendo2600]

I am very happy to come back with a definitive answer to this lingering problem. A 100 percent tested and compatible drop in replacement is the IS485E Enjoy Reviving your dead guns and making new ones everyone! Mystery solved and case closed Super Duper Thanks to the help from Viletim.