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In the making of a Namco System 11 Schematics and i need some help

moflih.morad said:
Hi RenierD, sure i have a pdf for the GP-13 board but i cant upload it in here (says file is too large 1mb!), i made a google drive link to it: GP-13 cpu schematics
i hope its useful to you,
BTW whats wrong with your board, am still trying to fix the one i have and am almost there. you can share with me your progress i would be glad to help you out.
good luck
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Awesome, thank you so much

Mine (GP-11) is missing the blue channel. It seems like a common problem, with various potential problem areas.

Tracing backwards from the Blue JAMMA pin, the filter IO shows continuity. I'm currently investigating TR9 and TR10 - blue toggles frantically high and low at R18. Red and green (R23 and R28 ) just toggles high (or low, can't remember).

This is now all on the Mother PCB

What is funny (to me) is that RGB toggles fine as it leaves the CPU board through the big white connector, but when Blue it reaches R18 it starts to toggle differently.

Does it mean there might be a short somewhere? But it there was a short it would either toggle high or toggle low. Or can it be that there is a faulty component?

I managed swob out TR10, but didn't get to TR9, yet.
 

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Blue is back!

I traced the signal back from the Blue JAMMA pin, past the filter, up to TR9 and TR10 on the Mother PCB. I was convinced it was the NPN Transistor at TR10, so I replaced it. Didn't do the trick.

This wasn't very encouraging for me. I then used your schematics and managed to make a turn on the CPU board, figuring out the DAC (the PG11 has a Sony DAC) and the VRAM. All were toggling fine.

I took some time off to think about it. Watched some YouTube videos and tried to understand NPN and PNP transistors and how to test them properly.

If not TR10, it had to be TR9, right? Took both of them off and tested them properly out of circuit. TR9 was dead. Replacement did the trick.

Man, Tekken might be old, but it still looks so pretty =)
 

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Ok, Managed to get an osciloscope to debug my Circuit. My Q202 Transistor appears to be the problem since it outputs less voltage than their similar counterparts even tho the base of the transistor were getting the same input on all 3 color channels.

Before anything, I want to verify which is the correct transistor to get for my board. The schematics made by @moflih.morad said that it's a 2SA1037, however, I don't know where did he got that information.
 
xevilang said:
Ok, Managed to get an osciloscope to debug my Circuit. My Q202 Transistor appears to be the problem since it outputs less voltage than their similar counterparts even tho the base of the transistor were getting the same input on all 3 color channels.

Before anything, I want to verify which is the correct transistor to get for my board. The schematics made by @moflih.morad said that it's a 2SA1037, however, I don't know where did he got that information.
Click to expand...
What is the problem?
 
RenierD said:
What is the problem?
Click to expand...
Disregard that last message, I found the culprit. It's the L203 Inductor. It barely lets a voltage pass.

If anyone knows with what to replace it, I would be deeply grateful.

1724786928125.png
 
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xevilang said:
Disregard that last message, I found the culprit. It's the L203 Inductor. It barely lets a voltage pass.

If anyone knows with what to replace it, I would be deeply grateful.

1724786928125.png
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Ok, After some experiments (and getting my hand on a frequency generator from the '70s), I determined that the inductor used in L201,202,203 has a value of 10uH. Please update the schematics to add this info.


EDIT: The SMD packet code size is 2520, based on the inductors used in the PS1.
 
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