PPUDigitizer No Signal

[adamcirillo]

I installed my PPUdigitizer into a SMTendo Board + POW Block I was getting no signal, I checked with the multimeter and the lumacode signal was going to ground after unplugging the jst connector I checked on the POW Block and lumacode pin does not go to ground there and after desoldering the PPUDigitizer i checked again with the multimeter and the lumacode signal goes to ground is this correct? this is the install guide i followed from zaxour https://drive.google.com/file/d/1AG7VPhgDjaCZcKff1___guIwyUVKqZ5V/view

[c0pperdragon]

Hi! The lumacode signal from the PPUdigitizer (denoted LUM on the board) should go out through the connector only and should of course not be connected to GND. The GND pad on the PPUdigitizer should indeed be connected to GND near the output connector. Can you send me pictures of your installation? best regards, Reinhard Am So., 3. Mai 2026 um 22:53 Uhr schrieb adamcirillo < ***@***.***>:

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*adamcirillo* created an issue (c0pperdragon/LumaCode#50) <#50> I installed my PPUdigitizer into a SMTendo Board + POW Block I was getting no signal, I checked with the multimeter and the lumacode signal was going to ground after unplugging the jst connector I checked on the POW Block and lumacode pin does not go to ground there and after desoldering the PPUDigitizer i checked again with the multimeter and the lumacode signal goes to ground is this correct? this is the install guide i followed from zaxour https://drive.google.com/file/d/1AG7VPhgDjaCZcKff1___guIwyUVKqZ5V/view — Reply to this email directly, view it on GitHub <#50>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACTIHVFFGFTTJKZ7FMEOX234Y6WUJAVCNFSM6AAAAACYPK5M42VHI2DSMVQWIX3LMV43ASLTON2WKOZUGM3TEOJVGA4DQMY> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[adamcirillo]

This is how I placed it on the board

[c0pperdragon]

That looks good to me, if indeed the orientation of the chip on the other side is correct. But I would be more interested in where the red and the black wires go. As this board is very different from the original NES, the connectors are very different and the wiring must be very specific too, I would guess. Can you check with the multimeter to which pins on the output socket the two wires are connected and if there is any short to unwanted points? Am Di., 5. Mai 2026 um 03:59 Uhr schrieb adamcirillo < ***@***.***>:

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*adamcirillo* left a comment (c0pperdragon/LumaCode#50) <#50 (comment)> PXL_20260503_032047576.jpg (view on web) <https://github.com/user-attachments/assets/e3d7ab91-78eb-45ce-93dc-7081297f7d0c> This is how I placed it on the board — Reply to this email directly, view it on GitHub <#50 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACTIHVASHYN67VD27DX7IX34ZFDHFAVCNFSM6AAAAACYPK5M42VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DGNZVHE4TINZXGA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you commented.Message ID: ***@***.***>

[c0pperdragon]

It is difficult to actually see the soldering on this blurry image, but is the board actually soldered to the pins at all? Am Di., 5. Mai 2026 um 09:05 Uhr schrieb Copper Dragon < ***@***.***>:

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That looks good to me, if indeed the orientation of the chip on the other side is correct. But I would be more interested in where the red and the black wires go. As this board is very different from the original NES, the connectors are very different and the wiring must be very specific too, I would guess. Can you check with the multimeter to which pins on the output socket the two wires are connected and if there is any short to unwanted points? Am Di., 5. Mai 2026 um 03:59 Uhr schrieb adamcirillo < ***@***.***>: > *adamcirillo* left a comment (c0pperdragon/LumaCode#50) > <#50 (comment)> > PXL_20260503_032047576.jpg (view on web) > <https://github.com/user-attachments/assets/e3d7ab91-78eb-45ce-93dc-7081297f7d0c> > This is how I placed it on the board > > — > Reply to this email directly, view it on GitHub > <#50 (comment)>, > or unsubscribe > <https://github.com/notifications/unsubscribe-auth/ACTIHVASHYN67VD27DX7IX34ZFDHFAVCNFSM6AAAAACYPK5M42VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DGNZVHE4TINZXGA> > . > Triage notifications on the go with GitHub Mobile for iOS > <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> > or Android > <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. > > You are receiving this because you commented.Message ID: > ***@***.***> >

[adamcirillo]

I had the board desoldered at that point as I wanted to check where the grounding problem is and also if solder flowed underneath and joined to pins together. Here is some. More photos the POW block has a jst connector and I have to jumper pin to send the lumacode signal to the saturn din connector I used a saturn cvbs cable I got. But the ground for lumacode only had the short, when the ppu digitizer was connected.

[adamcirillo]

also the pins for the jst connecter is next to the 6 pin header ground is closet to the header the further one is luma. here is the link to the smtendo kicad files and schematic i couldn't find anything for the pow block though https://github.com/zaxour/OpenTendo-SMTendo/releases/tag/V1.5

[c0pperdragon]

I really have a hard time understanding what you did any what the actual problem is. This last picture where you measure 188 ohm from lumacode pin to ground is perfectly fine. There is in fact a 180 ohm resistor that is part of the analog output stage need to bring the voltage down to the required levels. Can you install the PPUdigitizer without soldering the two lumacode&ground wires to your specific output circuitry? With an oscilloscope it would be easy to check which signal the board creates. If you have access to a TV with a composite video input, you could directly clip the signals to this input and should get a black&white image with some vertical stripe patterns. If this is there, then the digitizer is working. Am Di., 5. Mai 2026 um 10:35 Uhr schrieb adamcirillo < ***@***.***>:

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*adamcirillo* left a comment (c0pperdragon/LumaCode#50) <#50 (comment)> also the pins for the jst connecter is next to the 6 pin header ground is closet to the header the further one is luma. here is the link to the smtendo kicad files and schematic i couldn't find anything for the pow block though https://github.com/zaxour/OpenTendo-SMTendo/releases/tag/V1.5 — Reply to this email directly, view it on GitHub <#50 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACTIHVFYJGHXRX57CYHBH734ZGRVVAVCNFSM6AAAAACYPK5M42VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DGNZXG4YDEMBVGU> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you commented.Message ID: ***@***.***>

[adamcirillo]

I don't have a tv with composite all i had was the ossc 1.8 and rt4k which i plugged the cable into the green component plug on the ossc from the din connecter and didn't get a signal there. maybe when i was probing i was getting that 188 there and thought it was connecting to ground.

[c0pperdragon]

It is really hard to do any diagnostics without any tools. Still, you could use the multimeter to measure the voltage between GND and lumacode while the PPUdigitizer is running, but without the lumacode and GND wires connected to anything else. This should give you some average voltage (maybe 1V or something) so you can see that it is at least doing something. The next step is to confirm that the OSSC would show a picture with the lumacode signal. Do you have other video sources? Am Di., 5. Mai 2026 um 10:52 Uhr schrieb adamcirillo < ***@***.***>:

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*adamcirillo* left a comment (c0pperdragon/LumaCode#50) <#50 (comment)> I don't have a tv with composite all i had was the ossc 1.8 and rt4k which i plugged the cable into the green component plug on the ossc from the din connecter and didn't get a signal there. — Reply to this email directly, view it on GitHub <#50 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ACTIHVF2RP7CQ724MARFOZ34ZGTTTAVCNFSM6AAAAACYPK5M42VHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DGNZXHAYDANZZHA> . Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub>. You are receiving this because you commented.Message ID: ***@***.***>

[adamcirillo]

i only had the ossc at one point and was using a transcoder to the component output with the nes composite and that worked fine so i know the ossc works. Once my uncle has free time i will go to his place he has an oscilloscope that i can use as i just borrowed the soldering iron from him to do the work.

[adamcirillo]

I also used 28awg wire is that good enough?

[adamcirillo]

I went to my uncles and we checked with the oscilloscope pe we got a 1v peak to peak but he told me the signal did not look right and was wondering if we could get a picture of the waveform to compare I'm still not getting a signal when plugged in the ossc I have check with the Multimeter I get contiunity from the luma pad all the way to the end of the rca jack with 2.1ohms also here is the picture of the board soldered on this time.

[c0pperdragon]

I would be very helpfull if you could send me a picture of your oscilloscope readings.
And 1V peak-to-peak is correct when the output is plugged into some device (TV or some upscaler), otherwise it should be more like 2V.
One more (probably ridiculous) question: How did you set up the OSSC to use the input signal? I always need to first select the proper input using the remote control. Until then, I also get nothing.

[adamcirillo]

With the ossc I was using the av 2 input and plugged into the green input also was using 1.21 firmware and retrorgb Bob's nes lumacode profile he made. tried both rgbs and ypbpr both no signal I tried my retrotink 4k since I can't do composite on my TV I got this signal it's at the mega man 2 menu.

[c0pperdragon]

As you have a Retrotink 4K, this can be used for composite video input (front side yellow socked) to check the lumacode signal. I used my newly arrived 4K to get pictures of the regular analog composite video from the NES (showing the main menu of my flash cartridge) as well as the same thing from the lumacode output. I did not change any settings on the 4K, but just swapped the cable.

As the 4K does no decoding, this shows up as black&white image with stripe patterns.

If this is the same thing, you did with your machine, this picture indeed looks very odd. Could you make pictures of the whole lumacode signal path from the PPUdigitizer board to the input of the 4K showing everything on how you wired this together?
Maybe something is interferring with the lumacode signal and now gives this strange result.