NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

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matt5cott
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NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

Post by matt5cott » March 29th, 2020, 4:52 pm

When using either a Pi2JAMMA or RGBPi my image is not stable, moves about a little, sort of a shimmer.

My Mr Driller G board I use for testing works fine, stable image.

Both rasp-pi setups tested on another cab, no issues.

Any suggestions please?
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Re: NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

Post by West » March 29th, 2020, 6:01 pm

Sounds like you might be getting 480i out of your pi rather than 240p. Are you certain your config is set to 240p?

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Re: NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

Post by matt5cott » March 29th, 2020, 7:28 pm

Thanks for replying, this is the config on the Pi2Jamma, the other was borrowed.

It does appear to be set to 240p, I've done nothing afaik to change it from default so that sounds right!

# Pi2Jamma mode --- DO NOT EDIT THIS LINE ---

# See /boot/overlays/README for all available options

force_turbo=1

gpu_mem=256

disable_audio_dither=1
dtparam=audio=on
dtoverlay=vga666
enable_dpi_lcd=1
display_default_lcd=1
dpi_group=2
dpi_mode=87
hdmi_timings=320 1 32 47 17 240 1 2 6 8 0 0 0 60 0 6400000 1 #240p #H-Rate 15.38kHz #V-Rate 60.10Hz
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Re: NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

Post by Sp33dFr34k » March 29th, 2020, 10:12 pm

I have the same thing with the rgbpi, don't think it's a finished product yet as there are many individual issues with them. Can't speak for the pi2jamma though.

I've solved it myself by adding a sync cleaner into the equation, now the image is perfectly stable. So it seems to me the sync is just a little off, and I'm sure it can be solved in the software but I just don't know how.

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Re: NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

Post by matt5cott » March 29th, 2020, 10:33 pm

Sp33dFr34k wrote:
March 29th, 2020, 10:12 MP
I have the same thing with the rgbpi, don't think it's a finished product yet as there are many individual issues with them. Can't speak for the pi2jamma though.

I've solved it myself by adding a sync cleaner into the equation, now the image is perfectly stable. So it seems to me the sync is just a little off, and I'm sure it can be solved in the software but I just don't know how.

Interesting thank you, I'll give that a try then, may I ask which one you're using please?
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Re: NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

Post by Sp33dFr34k » March 30th, 2020, 8:42 am

I'm using one of silverfox0786's sync cleaners.

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Re: NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

Post by matt5cott » March 30th, 2020, 4:22 pm

Sp33dFr34k wrote:
March 30th, 2020, 8:42 am
I'm using one of silverfox0786's sync cleaners.
Many thanks, I'll look at getting one of those or similar then 8-) A quick glance suggests it's not too easy!
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Re: NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

Post by Sp33dFr34k » March 30th, 2020, 9:52 pm

matt5cott wrote:
March 30th, 2020, 4:22 MP
Sp33dFr34k wrote:
March 30th, 2020, 8:42 am
I'm using one of silverfox0786's sync cleaners.
Many thanks, I'll look at getting one of those or similar then 8-) A quick glance suggests it's not too easy!
He's a member here, but I think he resides more often on UK-VAC. It's actually pretty easy, I've used a jamma passthrough, hooked up the cleaner to 5v, ground and sync in/out and off you go :)

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Re: NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

Post by ravepants » April 3rd, 2020, 9:54 am

@Sp33dFr34k I have the RGB-Pi as well, the response i got to using it with a 31kHz monitor and scaler was essentially use retropie! "don't use rgb-pi hardware or software" shame it has a nice UI and the controls work well.

I've just got a retro scaler from irken labs, so i'll hav a play with that, but first try it doidnt output properly, but if you've tried a sync stripper and it worked i'll give that a go as well.

Any idea what signal the RGB-Pi outputs as ATG was reluctant to tell me, i assume its TTL RGBs?

EDIT:

sync stripper/cleaner works to a point with the scaler, so the pi definitely has attenuation issues, i can now see the rgb-pi OS, but games are still janky.

to be continued, oh and if anyone is sitting on the fence about an irkenlabs retro scaler, don't! its amazing.

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Re: NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

Post by matt5cott » April 22nd, 2020, 10:49 pm

Finally got a JAMMA extender today (shipping took a ruddy age) No way was I going to butcher the original harness!

I can confirm as per Sp33dFr34k and ravepants above a LM1881 based sync cleaner worked and the shimmer has now gone 8-)

Thanks! :awe:

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Re: NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

Post by ravepants » April 23rd, 2020, 10:23 am

Hey hey, awesome stuff! Glad it worked out 👍

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Re: NAC, image shimmer using rasp-pi systems - Pi2JAMMA or RGBPi

Post by Sp33dFr34k » April 24th, 2020, 6:31 pm

Nice, enjoy :)

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