Help with my Region Mod

[PigInTheMud]

I tried to create several region selector chips for my American Turbografx console. The system turns on but the problem is that only static shows up on both settings of the switch. Neither American nor Japanese games will show up. There is I turn the system on.

Here is a video that I posted of what is wrong.

Things that I know are not the problem:
[ul][li]ICs (NTE4551B) are not burned out thanks to 16-pin sockets[/li][li]Wire gauge and length; I've tried various types of wire such as PATA wire and Tinned copper wire from Fry's[/li][li]The console itself works everytime I reconnect the legs.
[/li][/ul]I used the following:
- Rosin-Core Solder with silver bearing
- Solid Copper Wiring or PATA wires
- Rosin Soldering Flux
- NTE4551B IC
- 16pin IC socket
- Sub-Miniature SPDT slide switch

I've checked the wires over and over again and everything appears to be connected correctly.

[SignOfZeta]

Can you see anything through the static? That doesn't look like a problem that would usually have anything to do with a mod. A botched mod usually shows a screen that is black or green, same as a dirty HuCard slot. Your system isn't putting out video, that's a different situation.

Somehow your mod is interfering with parts of the console that have nothing to do with the HuCard. Are you maybe causing problems with where you are getting the power for the IC?

[PigInTheMud]

I cannot see anything through the static.
I attached the 5v wire to the last leg and the ground wire to the leg that was not cut between the other wires.


None of the wires are touching by the way. If you would like me to take more photos, I can

[SignOfZeta]

You got you power and ground from the HuCard socket?

Hm...I'm not sure if that is the cause of you problem, but I didn't do that with mine.

[PigInTheMud]

You got you power and ground from the HuCard socket?

Hm...I'm not sure if that is the cause of you problem, but I didn't do that with mine.

I never thought of connecting the ground and 5volt anywhere else. Where did you connect yours?

[SignOfZeta]

I don't really remember, and it was a Duo R, so the exact placement wouldn't apply anyway.

What I probably did, knowing me, was find someplace on the board with the required voltage (can't remember if it was 5V or what) that was as close to the main power supply input as possible. The ground probably just got soldered or screwed to some random place on the board that is a ground, or the shielding. There are all sorts of places to ground on a system like this.

[pcenginesales]

The 10uf capacitor on the HuCARD port board is a great source for voltage+ground. It connects at the positive end to the 5V source and at the negative direct to ground. If it helps I always use that and I've never once had trouble with interference.

If it also helps I would use different coloured wire for the mod as it helps with troubleshooting. It's very easy to wire these wrong. I've done it multiple times. You can be scratching your head forever if you don't code the wire. I tend to buy a multicore cable with thin gauge wire in it for mine.

[PigInTheMud]

The wires are coded with really tiny letters that I wrote on them. But could you use a photo to show me where the Capacitor is? I am unable to find any that supply 5v and 10 microfarads

[pcenginesales]

Oops sorry - it's on the Japanese systems near the HuCARD slot. If it's not on the US models then I don't know of a comparable source, I wouldn't use the pins on the hucard slot though if only for potential of shorting thanks to the pins bending easily once cut.

[PigInTheMud]

F the IC mod. I just did the 8pdt switch mod. It worked first try and was a heck of a lot easier to do. My advice to everyone is to just completely forget that IC mod.

[SignOfZeta]

Mine works perfectly, first try, but I didn't make the chip myself or anything. I just bought it from D-Lite.

[cpsystem3]

I just built one of the region mod PCB's this past weekend, and installed it no problem on my Duo-R. I used the HuCard port for +5v and GND (grabbed a small wire, made a loop, soldered it very close to the PCB).

I used the guide(s) posted here (used the schematic from the german link, it was easier to read):
http://www.mmmonkey.co.uk/console/pce/region.htm

First thing to do is pull out your multi meter and verify that +5v is coming into the circuit you just built, and actually getting to both chips (same with ground). I verified my ground by measuring resistance from a common ground on the PC Engine's PCB back to the GND on the region mod PCB. Verified the 5v by measuring from GND to 5v on the IC's Vcc pin. 2nd step, double check EVERYTHING with your multimeter, especially looking out for bridges and open circuits (and of course accuracy on the wiring). Finally, make sure that your region mod PCB is not shorting anything out inside your TG16. I insulated the bottom of mine with electrical tape before I hot glued it in its final position.

Another thought- verify the datasheet of your NTE chips versus a MC14551B datasheet. Sometimes the NTE cross references are *very close* matches, but not 100% identical. I suppose its possible the chip(s) your using aren't compatible (which wouldnt' be the end of the world since you socketed them).

Whoever actually suggested using an 8pdt switch is a moron. There's an additional EIGHT wires to solder on doing that approach (24 total!). Talk about a birds nest of wires... The PCB mod is clean, and the parts are dirty cheap.

Good luck!