Retron 1 Fami-clone Game Genie actually works...except... IDEAS?

I recently modified my Retron 1 to support Castlevania 3, thanks to ACE.

However, I discovered that the Retron 1 DOES support the Game Genie. If you can remember how many times to push up and down and right and left to input the code based on using the code on the real NES, you can enter a code blind and start a game. The cheats will work.

It seems that the Game Genie is not displayed correctly, as if it is the wrong frequency. I was able to improve the picture by hooking the Retron 1 up to different LCDs, but it seems that the Game Genie is using a non-standard resolution or something that isn't working with the Retron.

My Retron has the 7404 fix for Castlevania 3 and is using a power supply that has an additional 300 milliamps (otherwise same polarity and voltage), to insure proper operation with peripherals.

Does anyone have an ideas? Perhaps someway to filter the video signal while at the Game Genie screen?

What the fork?

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Originally Posted by Drakon

What the fork?

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http://www.youtube.com/watch?v=BNXs9kcFAPI

Retron 1 is a Chinese Nintendo Clone.

Castlevania 3 did not work with it. When you add a 7404 inverter, Castlevania 3 does work with it.

People say the Game Genie does not work with it because the screen is garbled on the Game Genie (not as in artifacts, but as in wrong hertz for the TV). This is the same type of error you get on some Genesis clones on all white screens. However, I've proven that the Game Genie is working with it and if you put the code in, the codes work. You just can't read the Game Genie code screen because it is all flipping around.

I'm wondering if there is a way to filter the screen while you are on the Game Genie menu so that you can read it.

I had that same problem when I tried to get better colors out of my RetroDuo v2.0's NES side, and it appears to be an issue with the video amp. I changed a resistor to bias a transistor on the video circuit to saturate the colors a little on that console and when I would put something bigger than the default 2.2Kohms, the colors looked better, but the Game Genie would seriously desync my TV, which is fairly tolerant of video signals that are off-spec, namely video signals that are stronger than what they should be. Let me see the motherboard on the RetroN1 so I can retrace the video circuit (both sides, please).

First of all, thank you for replying, Ace.

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Originally Posted by Ace

I had that same problem when I tried to get better colors out of my RetroDuo v2.0's NES side, and it appears to be an issue with the video amp. I changed a resistor to bias a transistor on the video circuit to saturate the colors a little on that console and when I would put something bigger than the default 2.2Kohms, the colors looked better, but the Game Genie would seriously desync my TV, which is fairly tolerant of video signals that are off-spec, namely video signals that are stronger than what they should be. Let me see the motherboard on the RetroN1 so I can retrace the video circuit (both sides, please).

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The Retron 1 is identical to the Retro-bit RES internally, and I mean identical. Do you still have your Retro-bit RES? Attachment 6104

I'll try to get better pictures up later today or tomorrow. Unfortunately, I am preoccupied with several issues at present that will make it impossible for me to post anything like that immediately.

The only difference between the Retron 1 and the RES is that they moved the power and reset switches to a different position. PCB and all components are exactly the same.

I do still have my RES, though strangely, your RetroN1 sounds WORSE than my RES. There has to be something different with the audio circuit or the NOAC itself has a slight difference with its raw audio output (the RES just passes its audio through a 10uF capacitor).

But anyways, I can't really help you without looking at the traces on the underside of the motherboard. Get those pictures and I'll be able to take a look at the video circuit.

Here are the photos:
Attachment 6111
http://img707.imageshack.us/img707/6667/photosdia.jpg

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Originally Posted by Ace

I do still have my RES, though strangely, your RetroN1 sounds WORSE than my RES. There has to be something different with the audio circuit or the NOAC itself has a slight difference with its raw audio output (the RES just passes its audio through a 10uF capacitor).

But anyways, I can't really help you without looking at the traces on the underside of the motherboard. Get those pictures and I'll be able to take a look at the video circuit.

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I compared my Hyperkin Retron 1 to a Retro-bit RES and found the following:
Retron 1 PCB markings ---------------------------------------- RES PCB markings
Top (video out) - RF92 2006.9.13 -----------------------------Top (video out)- RF92 2006.9.13
Middle (connector) - ZB324.PCB 2008.5.19----------------------Middle (connector) - ZB324.PCB 2008.5.19
Bottom (pad ports) - FB642.PCB 2007-18 ----------------------Bottom (pad ports) - FB642.PCB 2007-18

All capacitors were also the same brand.

As you say, you probably have a newer or older revision of this hardware that is better than what I have.

My guess is it needs something like the RetroPort included with the RetroDuo Portable in order to fix the audio distortion. The RetroPort is missing a 1.5Kohm pull-down resistor on the audio output which it looks as if the RetroN1 needs as well as although the boards are the same, the NOAC appears to be different than my RES (which is what I consider the Version 1A as later consoles have redesigned box art, and the most recent ones have the RES logo on the console itself).

As for the video circuit, it's identical to the RES. I will retrace it tomorrow and pinpoint any possible locations to weaken the video signal a bit. But I think you could get away with putting a resistor in parallel with the existing resistor behind C4 (this is a pull-down resistor on the amplified video output). Try it and tell me what you get.

Quote:

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Originally Posted by Ace

My guess is it needs something like the RetroPort included with the RetroDuo Portable in order to fix the audio distortion. The RetroPort is missing a 1.5Kohm pull-down resistor on the audio output which it looks as if the RetroN1 needs as well as although the boards are the same, the NOAC appears to be different than my RES (which is what I consider the Version 1A as later consoles have redesigned box art, and the most recent ones have the RES logo on the console itself).

As for the video circuit, it's identical to the RES. I will retrace it tomorrow and pinpoint any possible locations to weaken the video signal a bit. But I think you could get away with putting a resistor in parallel with the existing resistor behind C4 (this is a pull-down resistor on the amplified video output). Try it and tell me what you get.

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Are you saying to add a resistor to the resister that is behind the capacitor marked C4 (at least I think it is a capacitor)? The resistor above C4 is actually labelled R2, and the resistor next to it is labelled R1, however the labels are situated under the resistors so you can't see them in the photo.

I'm confused here. Wouldn't we be trying to increase the resistance (series), not decrease it (parallel)? I'm still not sure what you are asking me to do. I don't want to risk damaging it as I finally have it playing Castlevania 3. Would it be possible for you to draw on the image (photoshop) what it is that you are suggesting rather than me hazardously guessing and destroying my Retron?

Quote:

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Originally Posted by Ace

I had that same problem when I tried to get better colors out of my RetroDuo v2.0's NES side, and it appears to be an issue with the video amp. I changed a resistor to bias a transistor on the video circuit to saturate the colors a little on that console and when I would put something bigger than the default 2.2Kohms, the colors looked better, but the Game Genie would seriously desync my TV, which is fairly tolerant of video signals that are off-spec, namely video signals that are stronger than what they should be. Let me see the motherboard on the RetroN1 so I can retrace the video circuit (both sides, please).

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Why not add a resistor on the video signal to make it stay on sync?

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Originally Posted by Majestic_Lizard

Are you saying to add a resistor to the resister that is behind the capacitor marked C4 (at least I think it is a capacitor)? The resistor above C4 is actually labelled R2, and the resistor next to it is labelled R1, however the labels are situated under the resistors so you can't see them in the photo.

I'm confused here. Wouldn't we be trying to increase the resistance (series), not decrease it (parallel)? I'm still not sure what you are asking me to do. I don't want to risk damaging it as I finally have it playing Castlevania 3. Would it be possible for you to draw on the image (photoshop) what it is that you are suggesting rather than me hazardously guessing and destroying my Retron?

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R2 is a pull-down resistor, and with pull-down resistors, the less resistance there is, the more it attenuates a signal. So yes, I am saying to add a resistor along with the existing resistor at R2. The worst that can happen is that you lose the video feed due to there being too little resistance between the amplified video output and Ground, in which case, you would need to remove the resistor you added on. Try first with a resistor that's about the same value as what's already at R2 in order to decrease the resistance by about half.

What you could do is to experiment by just taking a resistor and touching its leads to R2's leads while you have your RetroN1 powered on with the Game Genie inserted in the console. Keep playing with different resistor values until the video remains synced and doesn't look too dark or oversaturated.

If you're still confused, I'll draw a rough diagram of what to do.

While you're at it, if you want to eliminate the audio distortion, you should add a 1.5Kohm pull-down resistor between the raw audio output and Ground. If you're interested in doing this, I'll show you where to solder this resistor.

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Originally Posted by Drakon

Why not add a resistor on the video signal to make it stay on sync?

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That usually darkens the video signal too much.

Quote:

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Originally Posted by Ace

If you're still confused, I'll draw a rough diagram of what to do.

While you're at it, if you want to eliminate the audio distortion, you should add a 1.5Kohm pull-down resistor between the raw audio output and Ground. If you're interested in doing this, I'll show you where to solder this resistor.

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Yeah, if you could draw the diagram (or simply draw on the photos what I'm supposed to do). That might keep me from shocking the hell out of myself. LOL.

Adding the resistors either didn't do much of anything (it did seem to be slightly more stable gibberish) or caused the picture to stop completely.

Okay. New plan. Do you think there would be a way to add something to the RCA cable between the console and the TV to stablize the signal, just during the Game Genie part? Then I could switch back to the regular RCA cable?

At this rate, I think it's best to just throw in a bigger resistor in place of R1, which I believe is 75ohms. Try values within the 75ohm to 220ohm range until you find a resistor that will not make the video excessively dark and/or oversaturated all while keeping the video output synced when using a Game Genie.

Attachment 6191
Please see my photo and the documentation of the resisters shown below:

Just to make sure we are on the same page here:

R1 is located behind what look like a resistor and is (green, green, black, gold) 55 ohms

R2 is located behind what looks like a ceramic capacitor and is (red, red, brown, silver) 220 ohms

I had to repair my Retron 1. The circuit board behind the cartridge connector is falling apart due to rust.

• 150 ohm resistor - result: Game Genie will start and be readable and you can play a game. When you restart the console there will be no picture. Tried this multiple times with a few different 150 ohm resistors. This is what happened each time.
• 120 ohm resistor + 15 ohm resistor in series - result: Game Genie screen is almost readable, still flips slowly going up and down, some games have no picture.
• 120 ohm resistor + 10 ohm resistor in series - result: Game Genie screen is almost readable, but flips going up and down, so still can't be read
• 120 ohm resistor - result: picture is a little darker than default, Game Genie screen is gibberish, but slightly more stable gibberish.
• 100 ohm resistor - result: basically the same as the original resistor, slightly darker picture, Game Genie screen completely unreadable and may simply be a white screen.
• 82 ohm resistor - result: basically the same as the original resistor, Game Genie screen is just gibberish. (note I do not have, and could not find a 75 ohm resistor)

Unless Ace can figure this out, I'm calling this a dead end.

However, if the Retron is compatible with the Famicom Everdrive that just came out, it should be possible to input Game Genie codes with that.

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