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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: ciVic on March 07, 2012, 07:06:40 AM
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Hi all,
I've bought the 23" Monitor ST2320L from Dell since it can display the good old PAL screens. But when it is connected during startup it crashes my Amigas. I tested it with two A4000D. Both cannot show the Early Boot Screen, they reset in a loop. When I disconnect the monitor they can boot, and then I can connect the monitor and see my good old PAL screen. Can somebody help me? It's not very comfortable to disconnect the monitor on every boot.
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Hi all,
I've bought the 23" Monitor ST2320L from Dell since it can display the good old PAL screens. But when it is connected during startup it crashes my Amigas.
All I can think of is that there is a potential difference (ground loop (http://en.wikipedia.org/wiki/Ground_loop_(electricity))) between the grounding of the amigas and the monitor. Try connecting them both to same grounded power strip and see if that helps.
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Possibly too much load on the sync lines, so the Amigas try to sync to a non-existant genlock.
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Possibly too much load on the sync lines, so the Amigas try to sync to a non-existant genlock.
Sounds possible, but sounds as there is no solution (besides unplugging the monitor)?
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Hi all,
I've bought the 23" Monitor ST2320L from Dell since it can display the good old PAL screens. But when it is connected during startup it crashes my Amigas. I tested it with two A4000D. Both cannot show the Early Boot Screen, they reset in a loop. When I disconnect the monitor they can boot, and then I can connect the monitor and see my good old PAL screen. Can somebody help me? It's not very comfortable to disconnect the monitor on every boot.
Do you have a different 9pin video converter you can try? I somewhat recall that being an issue with some of those adapters... I may be way off base, but its worth a shot.
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@ciVic
Are you using some sort of adaptor in between the RGB port and the monitor? Some adaptors use transistors on the sync lines to buffer them and prevent the Amiga from thinking it had a genlock attached - maybe you need something like this?
If you're handy with a soldering iron, there are schematics for this sort of adaptor on Aminet...
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Unfortunately I only have one adapter. The adapter itself, without a monitor, does not crash the Amiga, but I think that does not mean anything. I could put a transistor on my adapter on my own, but maybe there is one from amigakit or vesalia I could buy? Would be easier. Or maybe I should buy a genlock, then my Amiga has something to sync :laugh1:
PS: For my original Zorro Busboard I have a flicker fixer. Plugged into this card I have no problems.
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Fair enough, maybe you could check the adaptor you have to see if it's connected straight through or if it contains transistors. My bet is that it's just connected straight through (or possibly with resistors on some lines) rather than being buffered.
Just had a look at AmigaKit's website - they don't specify whether their adaptor is buffered, so maybe send them a mail to find out. A quick search of Aminet gave me these: ami2vga.lha and VGA_Hack.lha both use a TTL chip to do the buffering job, which probably works very well and shouldn't be too difficult to build...
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Interestingly, I just encountered the same problem. My adapter is a straight-through pin-to-pin. Plugged between the A2000 and my SR2320L, the machine will fail to start the boot process. At first I thought it was the monitor, but then I tried with another LCD screen I had and got the same result.
This is a commercially purchased adapter - needless to say I am VERY disappointed.
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Yeah, many years ago I had that issue with a particular monitor. Can't remember what make it was now, but it had me baffled for quite a while until I borrowed another monitor which worked perfectly. Buffering the sync lines solved it for me - perhaps it's only the odd screen that has issues, I haven't come across one which caused that issue since then...
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Hi all,
I've bought the 23" Monitor ST2320L from Dell since it can display the good old PAL screens. But when it is connected during startup it crashes my Amigas. I tested it with two A4000D. Both cannot show the Early Boot Screen, they reset in a loop. When I disconnect the monitor they can boot, and then I can connect the monitor and see my good old PAL screen. Can somebody help me? It's not very comfortable to disconnect the monitor on every boot.
It is more than likely the adapter, i use these monitors with the C= silver vga adapter 390682-01 and they all work fine.
These adapters use a 74hct08 chip and ceramic disc cap in them to buffer the signals.
mech
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The VGA adapter I use was purchased from Vesalia and works great. I believe amigakit has them as well, but you'll probably want to email them first.
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The VGA adapter I use was purchased from Vesalia and works great. I believe amigakit has them as well, but you'll probably want to email them first.
Do you know if it also uses the 74hct08? I live in germany, therefore I would buy it at vesalia anyway. Would be great.
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Do you know if it also uses the 74hct08? I live in germany, therefore I would buy it at vesalia anyway. Would be great.
My technical knowledge is basically zero, sorry.
I've used it with an external scan doubler, with a cheap Acer LCD (in VGA mode) and now on the 2320.
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Unfortunately I only have one adapter. The adapter itself, without a monitor, does not crash the Amiga, but I think that does not mean anything. I could put a transistor on my adapter on my own, but maybe there is one from amigakit or vesalia I could buy? Would be easier. Or maybe I should buy a genlock, then my Amiga has something to sync :laugh1:
PS: For my original Zorro Busboard I have a flicker fixer. Plugged into this card I have no problems.
I have the same dell 2320 and the silver adapter from amigakit and my 1200 boots just fine. Hope thst helps
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Here's a trick that sometimes work on PCs.
Although it's not often there are issues with connecting a monitor to a PC, but it has happened to me a couple of times (I work with IT). Mostly on laptops when hooking up to a projector.
So the trick is:
Remove pin nr 9 on the cable, if it's present. I just bend it back and forth a couple of times and then it brakes off.
I've noticed that quite often pin nr 9 is not even present on vga cables supplied with monitors.
So you could also check if you have another VGA cable without pin nr 9 present.
NOTE: I wouldn't recommend removing the pin if the cable is permanently attacked to the monitor, in case you want to return the monitor.
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FYI, I have a SR2320 with sync strainer and it works fine with multiple Amigas.
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@Damiga
I think Pin 9 is just used as a key pin - the entire middle row of pins are normally just grounds for the various signals and are often simply wired together. Seems strange that that might "fix" things, unless it's some very bizarre ground loop or something like that, as Piru suggested earlier...
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Pin 9 is either key or +5V from graphics. If it's even connected through the adapter an EMI is limiting the current to ~100 mA - don't think too high a load is any problem (unless the PSU is critical already).
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FYI, I have a SR2320 with sync strainer and it works fine with multiple Amigas.
Yup, Sync Strainer should resolve most if not all syncing issues with these Dell monitors. Dell almost bought the Amiga technology in the late 1990's. Maybe Michael Dell needs these monitors to sync to 15Khz to use with his Amiga's?
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Hi ciVic,
See http://www.wonkity.com/~wblock/a4000hard/connvga.html
Quote
"Connecting VGA Monitors
VGA monitors can be connected to the A4000; however, since the special circuitry in the Amiga video output can mistakenly identify a monitor as a genlock and thus cause problems, a special cable or adapter is the best way to hook them up.
All this cable really does is buffer the horizontal and vertical sync signals by double-inverting them through a TTL gate. Commodore's DB23-to-HDD15 adapter (supplied with most A4000s) used a 74HCT08 for this, but you can use a 74LS04 or other low-power TTL-level inverters (or other gates wired as inverters or buffers, of course)."
I hope this helps.
Regards, Michael
aka rockape
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Here's a trick that sometimes work on PCs.
Although it's not often there are issues with connecting a monitor to a PC, but it has happened to me a couple of times (I work with IT). Mostly on laptops when hooking up to a projector.
So the trick is:
Remove pin nr 9 on the cable, if it's present. I just bend it back and forth a couple of times and then it brakes off.
I've noticed that quite often pin nr 9 is not even present on vga cables supplied with monitors.
So you could also check if you have another VGA cable without pin nr 9 present.
NOTE: I wouldn't recommend removing the pin if the cable is permanently attacked to the monitor, in case you want to return the monitor.
NOTE I WAS INCORRECT BELOW - IT'S PIN 12 THAT I PULLED TO ELIMINATE EDID
Pin 9 is EDID and basically allows the monitor to provide information to the PC about what modes it supports. Sometimes you can have odd driver or compatibility problems and pulling pin 9 can help.
For example one of my older HTPCs produced a black screen when booting into Windows 7 with the proper video driver installed and connected to an older Panasonic plasma I have. Didn't matter what resolution and/or frequency I had it set to. Pulling pin 9 fixed the issue, but since there is now no EDID I need to be careful setting resolutions because the PC no longer know which resolutions the TV supports.
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Hi ciVic,
See http://www.wonkity.com/~wblock/a4000hard/connvga.html
I hope this helps.
Regards, Michael
aka rockape
Hi rockape,
oh yes, nice link. Sounds easy to make an adapter with two vga connectors and a TTL IC. Thank you!
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@Kremlar
EDID is the data structure, the signal/pin is called Display Data Channel (DDC) and sits on pin 12. The monitor DDC circuitry may however require +5V present on pin 9 to work while not being powered up; some monitors may even require pin 9 power while they're running.
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Doh! You're right. I confirmed it was pin 12 I pulled for my plasma. Not sure why I was thinking it was pin 9.
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tbh dont recommend users "pulling pins" not necessary. Better just to get a real cbm vga adaptor.
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Thanks to all! I built an adapter as described in the link by rockape and it works! Ok, I took my old adapter and soldered the IC into it. Looks a bit clutter, but fits into the original small case.
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Thanks to all! I built an adapter as described in the link by rockape and it works! Ok, I took my old adapter and soldered the IC into it. Looks a bit clutter, but fits into the original small case.
how macgyverish of you :)
good job :)
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Im in the process of making my own cable using this guide:
http://www.wonkity.com/~wblock/a4000hard/connvga.html
However I'm not sure which wires connect to where on the IC (I'm using a 74LS04) I've tried working it out from Civics picture that is posted above but its rather hard to know for sure which wire goes where.
Any help would be much appreciated.
I've downloaded some guides from aminet but they seem to conflicting instructions.
Thanks
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Yup, Sync Strainer should resolve most if not all syncing issues with these Dell monitors. Dell almost bought the Amiga technology in the late 1990's. Maybe Michael Dell needs these monitors to sync to 15Khz to use with his Amiga's?
Hmm I just saw a Sync Strainer listed on US ebay!