Hey Rocky. I had already used all the steps you listed, BUT, I thought I had done something wrong, so I re-entered everything, and I though I had the same results. When I wasn't getting anything using VGA going to an iPad LCD, I turned my back on it and googled for a couple of minutes, when I turned back around the vga666 board was working, I get video out of my Pi 3B and 4B, but it takes almost three minutes to work? I'm still not getting any on my Pi 2B, which is strange because that was what the vga666 was designed for? So, I thought it might be my interface board, so I hard wired a VGA connector directly to the harness and tested it with the Pi 4 with vga666, and a Power Mac G4 933mhz with a VGA card, both showed the the same results, light screen with washed colors, so it is not the Pi. Then it occurred to me, the early iMac G3 tray loaders combine the horizontal and vertical sync, just like the earlier Macs, that is why all of my iMac color classic conversions had no problems? I suspect that since you are using a slot loader G3, the monitor circuitry is a real multi-sync, especially since it has a VGA output? This is the first time I've ever went from pure VGA output to Mac fixed resolution. What do you think? Just something to chew on. I will definitely post a video in the next three days, this little project has been driving me up the wall, and taking up all my free time, but I refuse to give up:) I built a passive combiner circuit as a long shot, and as I believed, it didn't work, so now I should be getting the parts in for an active circuit in the next couple of days. Oh, by the way, did you know your video is the only one on RUclips showing the Pi being used on a CRT PC display (let alone a G3 iMac) with instructions on how to use the vga666? I'm definitely going to play that up in my video:)
Hi Billy, I tried to reply as best I could in chunks so i've included your original message. Hey Rocky. I had already used all the steps you listed, BUT, I thought I had done something wrong, so I re-entered everything, and I though I had the same results. When I wasn't getting anything using VGA going to an iPad LCD, I turned my back on it and googled for a couple of minutes, when I turned back around the vga666 board was working, I get video out of my Pi 3B and 4B, but it takes almost three minutes to work? Hmm… I don’t have lots of experience with the vga666 board but 3 minutes sounds excessive to me and I doubt it’s related to the OS you’re using. Are you using a stock raspian image? If you’re not, give that a shot just to have a baseline to compare against. I'm still not getting any on my Pi 2B, which is strange because that was what the vga666 was designed for? So, I thought it might be my interface board, so I hard wired a VGA connector directly to the harness and tested it with the Pi 4 with vga666, and a Power Mac G4 933mhz with a VGA card, both showed the the same results, light screen with washed colors, so it is not the Pi. I think the the vga666 board was designed to work with a pi3 so I don’t think it will work with a pi 2 because there are some GPIO lines it needs that are not available on the pi2. I’m sure there’s a way to make it work but it probably isn’t worth looking in to(although it does sound like a nice challenge….). Then it occurred to me, the early iMac G3 tray loaders combine the horizontal and vertical sync, just like the earlier Macs, that is why all of my iMac color classic conversions had no problems? I suspect that since you are using a slot loader G3, the monitor circuitry is a real multi-sync, especially since it has a VGA output? I didn’t know that the tray loaders combined the H & V sync pulses which is curious…….. I’ve found that the slot loader only really works with 3 vertical refresh rates(I have squeezed a couple of others out but it’s not pretty ) so the fact that it can do more than one I guess technically means it’s multi-sync. However, I think to be multi-sync it must be able to handle any frequency withing the range of it’s circuits but I’m not to clear on that.... Was the tube displaying correctly before the mod? Have you passed the point of no return in terms of reversing the mod in order to test with the original guts to make sure the tube is o.k.? This is the first time I've ever went from pure VGA output to Mac fixed resolution. What do you think? Just something to chew on. I will definitely post a video in the next three days, this little project has been driving me up the wall, and taking up all my free time, but I refuse to give up:) I built a passive combiner circuit as a long shot, and as I believed, it didn't work, so now I should be getting the parts in for an active circuit in the next couple of days. You built a passive combiner? That’s really cool. If you can get it to work please make a video because the RGB retro gaming people love that sort of stuff! Also, never give up because I think you’ll get it to work soon! It’s hard to say what’s going on but do you think the mod introduced a voltage change to the RGB cathodes on the tube? Without seeing it, it almost sounds like the gamma is too high now. Maybe try with different gammas with “xrandr” on your pi to see if you get better results. Open a terminal and type “xrandr” and hit return. Xrandr will display a ton of stuff among it the available displays and the display you are currently using. The one you are currently using will have an asterisk next to the refresh rate. Assuming the name is “VGA-1” issue the following command. “xrandr --output VGA-1 --gamma 1:1:1” 1:1:1 represent the R:G:B gamma values and 1:1:1 is standard so you shouldn’t see a change. Issue values below that like. “xrandr --output VGA-1 --gamma .5:.5:.5” Fiddle with that and see if you see any improvement. If you do you might have to adjust your brightness too. “xrandr --output VGA-1 --brightness 1” Oh, by the way, did you know your video is the only one on RUclips showing the Pi being used on a CRT PC display (let alone a G3 iMac) with instructions on how to use the vga666? I'm definitely going to play that up in my video:) Really? That’s insane, I would think lots of people are using the board for CRT monitors. Wow…….. Use the heck out of it! Godd luck
Hi Rocky. Is the Pi also initialising the IVAD board or is there another Pi/Arduino in your G3? Would this be possible? Might be a wacky idea but would be sweet if all you needed was this board and a passive DB15 to iMac connector (not sure on name!)
Hi Luke, In this particular video, the IVAD board is being initialized by the J20 board. The J20 board uses an atmega328p so basically it's an arduino based thing. That said, you can do it with just a raspberry pi and a bit of wiring. Here is a video where I did it with a raspberry pi 3. ruclips.net/video/isjo-4vQxwM/видео.html Here are the wiring instructions and script instructions. github.com/qbancoffee/imac_g3_ivad_board_init#Wiring-Arduino-Uno Hope his helps
@@luke255x The first time I did this was with an emac. It isn't as clean but it works. Afterwards I plan on revisiting my emac hack and making boards for it as well. en.wikibooks.org//wiki/How_to_modify_an_eMac_to_use_as_an_external_monitor The eMac is a nice looking machine and definitely worth the effort. good luck!
great news! I, too, hooked my rpi to my imac g3. gotta say, it's p sick, knowing it won't be going to waste due to dead logic board
Really? Cool!
I would love to see it in action!
Hey Rocky. I had already used all the steps you listed, BUT, I thought I had done something wrong, so I re-entered everything, and I though I had the same results. When I wasn't getting anything using VGA going to an iPad LCD, I turned my back on it and googled for a couple of minutes, when I turned back around the vga666 board was working, I get video out of my Pi 3B and 4B, but it takes almost three minutes to work? I'm still not getting any on my Pi 2B, which is strange because that was what the vga666 was designed for?
So, I thought it might be my interface board, so I hard wired a VGA connector directly to the harness and tested it with the Pi 4 with vga666, and a Power Mac G4 933mhz with a VGA card, both showed the the same results, light screen with washed colors, so it is not the Pi.
Then it occurred to me, the early iMac G3 tray loaders combine the horizontal and vertical sync, just like the earlier Macs, that is why all of my iMac color classic conversions had no problems? I suspect that since you are using a slot loader G3, the monitor circuitry is a real multi-sync, especially since it has a VGA output? This is the first time I've ever went from pure VGA output to Mac fixed resolution.
What do you think? Just something to chew on. I will definitely post a video in the next three days, this little project has been driving me up the wall, and taking up all my free time, but I refuse to give up:) I built a passive combiner circuit as a long shot, and as I believed, it didn't work, so now I should be getting the parts in for an active circuit in the next couple of days.
Oh, by the way, did you know your video is the only one on RUclips showing the Pi being used on a CRT PC display (let alone a G3 iMac) with instructions on how to use the vga666? I'm definitely going to play that up in my video:)
Hi Billy,
I tried to reply as best I could in chunks so i've included your original message.
Hey Rocky. I had already used all the steps you listed, BUT, I thought I had done something wrong, so I re-entered everything, and I though I had the same results. When I wasn't getting anything using VGA going to an iPad LCD, I turned my back on it and googled for a couple of minutes, when I turned back around the vga666 board was working, I get video out of my Pi 3B and 4B, but it takes almost three minutes to work?
Hmm… I don’t have lots of experience with the vga666 board but 3 minutes sounds excessive to me and I doubt it’s related to the OS you’re using. Are you using a stock raspian image? If you’re not, give that a shot just to have a baseline to compare against.
I'm still not getting any on my Pi 2B, which is strange because that was what the vga666 was designed for? So, I thought it might be my interface board, so I hard wired a VGA connector directly to the harness and tested it with the Pi 4 with vga666, and a Power Mac G4 933mhz with a VGA card, both showed the the same results, light screen with washed colors, so it is not the Pi.
I think the the vga666 board was designed to work with a pi3 so I don’t think it will work with a pi 2 because there are some GPIO lines it needs that are not available on the pi2. I’m sure there’s a way to make it work
but it probably isn’t worth looking in to(although it does sound like a nice challenge….).
Then it occurred to me, the early iMac G3 tray loaders combine the horizontal and vertical sync, just like the earlier Macs, that is why all of my iMac color classic conversions had no problems? I suspect that since you are using a slot loader G3, the monitor circuitry is a real multi-sync, especially since it has a VGA output?
I didn’t know that the tray loaders combined the H & V sync pulses which is curious……..
I’ve found that the slot loader only really works with 3 vertical refresh rates(I have squeezed a couple of others out but it’s not pretty ) so the fact that it can do more than one I guess technically means it’s multi-sync. However, I think to be multi-sync it must be able to handle any frequency withing the range of it’s circuits but I’m not to clear on that....
Was the tube displaying correctly before the mod? Have you passed the point of no return in terms of reversing the mod in order to test with the original guts to make sure the tube is o.k.?
This is the first time I've ever went from pure VGA output to Mac fixed resolution. What do you think? Just something to chew on. I will definitely post a video in the next three days, this little project has been driving me up the wall, and taking up all my free time, but I refuse to give up:) I built a passive combiner circuit as a long shot, and as I believed, it didn't work, so now I should be getting the parts in for an active circuit in the next couple of days.
You built a passive combiner? That’s really cool. If you can get it to work please make a video because the RGB retro gaming people love that sort of stuff! Also, never give up because I think you’ll get it to work soon!
It’s hard to say what’s going on but do you think the mod introduced a voltage change to the RGB cathodes on the tube? Without seeing it, it almost sounds like the gamma is too high now. Maybe try with different gammas with “xrandr” on your pi to see if you get better results.
Open a terminal and type “xrandr” and hit return. Xrandr will display a ton of stuff among it the available displays and the display you are currently using. The one you are currently using will have an asterisk next to the refresh rate. Assuming the name is “VGA-1” issue the following command.
“xrandr --output VGA-1 --gamma 1:1:1”
1:1:1 represent the R:G:B gamma values and 1:1:1 is standard so you shouldn’t see a change.
Issue values below that like.
“xrandr --output VGA-1 --gamma .5:.5:.5”
Fiddle with that and see if you see any improvement. If you do you might have to adjust your brightness too.
“xrandr --output VGA-1 --brightness 1”
Oh, by the way, did you know your video is the only one on RUclips showing the Pi being used on a CRT PC display (let alone a G3 iMac) with instructions on how to use the vga666? I'm definitely going to play that up in my video:)
Really? That’s insane, I would think lots of people are using the board for CRT monitors. Wow……..
Use the heck out of it! Godd luck
Hi Rocky. Is the Pi also initialising the IVAD board or is there another Pi/Arduino in your G3? Would this be possible? Might be a wacky idea but would be sweet if all you needed was this board and a passive DB15 to iMac connector (not sure on name!)
Hi Luke,
In this particular video, the IVAD board is being initialized by the J20 board. The J20 board uses an atmega328p so basically it's an arduino based thing. That said, you can do it with just a raspberry pi and a bit of wiring. Here is a video
where I did it with a raspberry pi 3.
ruclips.net/video/isjo-4vQxwM/видео.html
Here are the wiring instructions and script instructions.
github.com/qbancoffee/imac_g3_ivad_board_init#Wiring-Arduino-Uno
Hope his helps
@@rockyhill3 Great info, many thanks. I've got an eMac that desperately needs some work doing on it!
@@luke255x The first time I did this was with an emac. It isn't as clean but it works. Afterwards I plan on revisiting my emac hack and making boards for it as well.
en.wikibooks.org//wiki/How_to_modify_an_eMac_to_use_as_an_external_monitor
The eMac is a nice looking machine and
definitely worth the effort.
good luck!
wow super easy!
Yeah, these guys made a really good product with easy instructions.