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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: giZmo350 on October 10, 2017, 02:01:15 AM
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Title should be "Amiga & the Gateway KX2153 21" LCD Monitor" but can't change landing page for some reason.
I was taking my newly acquired naked A500 Rev 6A PAL mobo for a couple of laps using my CBM 2002 monitor and remembered that I have a 390682-01 23pin to 15pin VGA adapter and thought I would connect it to my Gateway KX2153 21" W/S LCD for the heck of it. I was shocked to see that it worked perfectly with games and Workbench 1.3.3. I checked the "info" screen on the Gateway LCD and sure enough it's displaying at 15KHz H and 50Hz V. There is no flicker and some of the games I tried fill the screen vertically and almost horizontally. Workbench looks awesome and nearly filled the screen too. NO artifacts! I looked everywhere on the evilwebs and could not find any specs for this LCD monitor. There may be an Acer equivalent too. The monitor is sold out everywhere I looked. If you can find one, you might get it cheap. I used to sell them for $90.00 NEW in my shop.
So then decided to try it on a naked A1200 mobo. I got a lot of vertical lines but is synced no problem. I retested the A1200 mobo with my CRT and with my Indi AGA MKI scandoubler and they look great. Not sure why the adapter doesn't work as well on the A1200.
Also figured out which CIA chip is bad on my A500 NTSC Rev 3 board (S/N 000784) and got a couple of (listed today) CIA chips for $20.00! Good price for these days I thought. Tested it on my CRT and WOW! How beautiful an NTSC machine screen looks on an NTSC CRT! NO flicker! So I swapped the CIAs back into the naked Rev 3 board and it too looks perfect with games (NTSC doesn't fill the screen vertically) and workbench 1.3.3 on the Gateway LCD. The NTSC mobo displays at 16KHz H & 60Hz V on the KX2153 LCD.
So, seems like the CBM VGA adapter should have worked better on the A1200 with the Gateway LCD but not sure why it didn't. Come to think of it, I may not even need to use the CBM VGA adapter but, that's all I had to connect the Miggy to 15pin VGA - LOL! Thought maybe some others might be interested that the Gateway KX2153 LCD monitor syncs down to 15KHz.
So I had quit a lot of hours of fun and very productive Miggy day! :)
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The vertical lines are probably an artifact of the adapter, I had one of those C= 15 pin adapters and had the same in 31khz modes. You can fix it by (iirc) soldering a resistor between two pins inside, I think there is a doc on Aminet.
Hth.
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Does the Gateway handle PAL and NTSC modes equally well?
I am curious on the modification for the Commodore VGA adapter. I heard something about this years ago but could never find any documentation on it. I searched Aminet and came up dry. Can you provide a link?
Better than that might be this adapter:
http://retro.68k.pl/category/a1200/
I mentioned it on another thread. It being a "buffered" adapter is said to improve the quality and eliminate things like vertical lines. I have heard it requires a PAL Amiga though but have not been able to confirm. No email response yet.
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Does the Gateway handle PAL and NTSC modes equally well?
Well, on the A500 for me it does. PAL, as you may know, just doesn't fill the screen vertically.
I am curious on the modification for the Commodore VGA adapter. I heard something about this years ago but could never find any documentation on it. I searched Aminet and came up dry. Can you provide a link?
After Merc mentioned a resistor hack I searched hi & low and only found references hacking the VGA adapter to work with some obscure hardware but nothing on actually eliminating the vertical lines with an A1200
Better than that might be this adapter:
http://retro.68k.pl/category/a1200/
I mentioned it on another thread. It being a "buffered" adapter is said to improve the quality and eliminate things like vertical lines. I have heard it requires a PAL Amiga though but have not been able to confirm. No email response yet.
I'm not a hoarder by any means, but starting about 15 years ago I would tend to buy anything cheap I thought might be useful. Even back then I could see Amiga prices creeping up (I think I paid $10.00 for the VGA adapter). So, today, I have a bunch of stuff I never even tried - but remember I have! Last week was the first time I tried it out. And, of course started googling all about the adapter and it's uses. I have not seen the adapter you mention but looks damn sweet! Plz let us know when you get a response! :) I tend to only research stuff when I suddenly get a hankering to try something out (like my A2000 stuff). I'm usually the guy that finds cool stuff only after it's no longer available. I have been REAL LUCKY when it came to all my A2000 stuff - especially all the Toaster stuff I have not even put to real use yet. But I'm gonna 'cause I'm retiring this time next year! :laugh1: Ehh, I'm babbling.... + wifey is yelling at me to go to Costco with her.
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Might be a good idea for you to send him a note also (contact link at the top of the page) so he will think there is some interest in his product. :D
Good on your retirement! I hope to be able to do that some day.
I'm not a hoarder by any means, but starting about 15 years ago I would tend to buy anything cheap I thought might be useful. Even back then I could see Amiga prices creeping up (I think I paid $10.00 for the VGA adapter). So, today, I have a bunch of stuff I never even tried - but remember I have! Last week was the first time I tried it out. And, of course started googling all about the adapter and it's uses. I have not seen the adapter you mention but looks damn sweet! Plz let us know when you get a response! :) I tend to only research stuff when I suddenly get a hankering to try something out (like my A2000 stuff). I'm usually the guy that finds cool stuff only after it's no longer available. I have been REAL LUCKY when it came to all my A2000 stuff - especially all the Toaster stuff I have not even put to real use yet. But I'm gonna 'cause I'm retiring this time next year! :laugh1: Ehh, I'm babbling.... + wifey is yelling at me to go to Costco with her.
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I did it!! I finally found the instructions on the banding fix for the Commodore VGA adapter.
It was with a collection of other text files I thought I had lost. Some interesting stuff in there.
I am going to attempt this on a spare adapter I have. It will be really awesome if it does the job as it seems unlikely I will be hearing back from the guy in Poland. This makes me wonder if this "buffered" video adapter is performing some other magic or has just incorporated this fix already.
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Yep those are the same instructions I followed years ago, I remember the mention of the genlock. Good luck!
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Great! So I assume it worked out okay for you? Any chance you can post a photo of your work? I have an idea of what I am going to do but it would be good to see what a completed fix looks like. :D
Yep those are the same instructions I followed years ago, I remember the mention of the genlock. Good luck!
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http://amigadev.elowar.com/read/ADCD_2.1/AmigaMail_Vol2_guide/node015E.html
this link shows a diagram of the 390682-01, (23pin to 15 pin)
Amiga also sold a 390682-02 adapter which was used with the video toaster. The above mod sounds like the change to the -02 version but I do not have 02 version to check.
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Great! So I assume it worked out okay for you? Any chance you can post a photo of your work? I have an idea of what I am going to do but it would be good to see what a completed fix looks like. :D
I'm afraid not, I don't have the adaptor anymore. It did work though, the lines were gone completely.
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Thanks for the adapter info guys & especially jdryyz for finding that document! I'll dig up a 1/4 watt - 100 ohm resister today & give this a try on my A1200... actually I'll run tests after the mod on my A500 PAL, A500 NTSC machines too and post results. :)
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Hmmm, well that didn't work at all on my A1200. :(
I'll have to take a couple of pictures and post to see if I got everything right... 100 Ohms between pin 15 and ground. BRB.
OK here's a pic of the vertical lines, the adapter plugged in and the 100 Ohm mod.
Do I have pin 15 correct? I checked it with a meter to the plug (with a paper clip) labeled 15 to the board.
Ground had a nice thru-hole already on the board which I verified is groung to pin 6,7,8, etc...
(http://www.prolaptopshop.com/AmigaMagic/DL/VGA/vga1.jpg)
(http://www.prolaptopshop.com/AmigaMagic/DL/VGA/vga2.jpg)
(http://www.prolaptopshop.com/AmigaMagic/DL/VGA/vga4.jpg)
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small correction the commodore number is 390682-03..
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The lack of continued info on this "fix" over the years since it was first posted seems odd. If it wasn't for me stumbling onto the text, I would have never found it in a web search. Same is true with the -03 version of the adapter. I did find some on that but not as much as one would expect. Although, I know some people say they do not see the lines. They're very obvious to me, much like your photo.
The inclusion of "AGA" banding in the instructions is somewhat inaccurate as it affects ECS Amigas also. I think that came about only because people started to use the adapter with their AGA Amigas since they could directly connect their VGA multiscan monitors and use the new screenmodes.
I verified you have pin 15 on your adapter. Maybe the choice of ground is not the best?
I was thinking about just using one of the solder points for the screw mounts. That's a ground I'm sure.
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I verified you have pin 15 on your adapter.
Thanks! :)
Maybe the choice of ground is not the best?
I was thinking about just using one of the solder points for the screw mounts. That's a ground I'm sure.
I thought the same thing but I verified that my soldered ground connection is the same as the screw mounts with a meter.
Yeah, this is getting weird... :hammer:
I guess I'll leave the mod in place for now as maybe someone else may chime in with some magical unicorn advice. :lol:
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Thanks! :)
I thought the same thing but I verified that my soldered ground connection is the same as the screw mounts with a meter.
Yeah, this is getting weird... :hammer:
I guess I'll leave the mod in place for now as maybe someone else may chime in with some magical unicorn advice. :lol:
Yeah, we need some more verified cases of this actually working, along with photos. :)
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You know what? I just thought of something... the board is double sided, meaning there are traces on both sides. I only soldered the bottom side. Lemme make a connection to the top ground too... BRB
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I was thinking too. The whole point of this is to eliminate pin 15 from being connected, right? Sending it to ground shorts the connection, per the instructions. I wonder how difficult it will be just to cut pin 15 instead. :D
You know what? I just thought of something... the board is double sided, meaning there are traces on both sides. I only soldered the bottom side. Lemme make a connection to the top ground too... BRB
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OK, that was a bust. So, I took the resistor off and checked for continuity from pin 15 to ANYWHERE on the board and it goes NOWHERE! :confused: Check your adapter for yourself! And Me! :angry: Plus, that diagram that AmiWest posted shows NO pin 15.
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OK, that was a bust. So, I took the resistor off and checked for continuity from pin 15 to ANYWHERE on the board and it goes NOWHERE! :confused: Check your adapter for yourself! And Me! :angry: Plus, that diagram that AmiWest posted shows NO pin 15.
Sorry to hear it didnt work for you, I found my original post on comp.sys.amiga.hardware when I did the hack on my adaptor and I said it didn't happen in NTSC/PAL modes which yours clearly does if it happens on the insert disk screen.
Here's the old post in case it's helpful:
https://groups.google.com/forum/#!searchin/comp.sys.amiga.hardware/ah210@chebucto.ns.ca%7Csort:date/comp.sys.amiga.hardware/ZUR_4-gm810/DI5YUToFYAoJ
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Interesting. A post mentions pin 15 going to pin 18 which is video ground for BLUE according the diagram I have. I wonder why BLUE. If it were to go to a video ground, pin 20 makes more sense since it is not specific to a color.
I dunno. My excitement for this has fizzled. I won't bother getting out the soldering iron just yet.
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Here is the link to the instructions on Aminet:
http://aminet.net/package/docs/hard/MoniAdap
It too differs from the fixes already posted.