Archive for the ‘RGB Bypass’ Category

Modding PAL TurboGrafx

Freitag, September 30th, 2016

I got some rare NOS TurboGrafx in 50Hz PAL Version.

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What can we do with this kind of PC-Engine

a) Speedup and change it to 60Hz

-Exchange Osscilator X201 to 21.47727Mhz
-cut Pcz80 Pin 15
-Solder wire from Pad pin 15 to Pin 22

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b) RGB bypass for best picture

I took the RGB Signal from C154 to C156 after removing the Kerkos. The wires leads directly to the Hu6260 RGB-Out

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using the rgbbypass PCB

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yellow wire to desoldered PIN 44 from HU6260 (C-SYNC)

I am using an old „french“ pinput from the 90’th. So I have to reroute some cirquits

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Desolder Din and cut GND on Partsside for make standard french Version of Din8 Cable working.

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Cut 5 Din Via circuits and wire as shown here
red audio 2 (right), white Audio 6 left, grey 5V
yellow desoldered Pin 44 from Hudson 6260 CSYNC

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c) Jailbarfix

exchange C137 and C133 to 4,7uf/16V

jailbarfixpalturbografx

 

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d) jap/eng switch

you need to switch 8 wires (15,16,17,19,20,21,22,23). I done it with two  analog switches  MC14551BCP

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NeoGeo AES 3-5 RGB Bypass with THS 3714

Donnerstag, September 1st, 2016

thanks to arcadeTV we have a optimized Version with THS 3714 for NeoGeo AES :-)

-cut left side of the three 6,8k resistors for input rgb input of ths amplifier

-cut the left side of the three 75 ohm resistors for output to the din 8.1

-cut BF for sync output to the din 8.1

the perfect voltage divider values for bypass PCB :

R1,R2,R3=7,51k

R4,R5,R6=2,29k

@ AES 3-5 Mainboard Pin 3 Comp Video and Pin 7 C-Sync are the same on both you will get Comp. Video.

After the modification its is neogeo conform Pin3 comp. Video and Pin 7 C-Sync comming from the THS RGB Bypass PCB

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For some help of solder side

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cable wiring

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