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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: Mizar on October 13, 2012, 07:58:03 AM
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In my A1200 the graphics output has been getting gradually weaker for some time, requiring ever increasing brightness adjustments on the monitor. I'm wondering, when I upgrade to the Mediator PCI expansion and put in a modern graphics card, if that will fully replace the aging Alice and Lisa chips that seem to be wearing out?
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In my A1200 the graphics output has been getting gradually weaker for some time, requiring ever increasing brightness adjustments on the monitor. I'm wondering, when I upgrade to the Mediator PCI expansion and put in a modern graphics card, if that will fully replace the aging Alice and Lisa chips that seem to be wearing out?
No, it wont.
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No. A gfx card in an Amiga acts like a second gfx card. Programs which support it (including Workbench but excluding most games) can be made to display on the gfx card. But the main output remains through AGA, like the early startup menu, the guru meditation and those games and programs which don't support gfx cards or switch off AmigaOS.
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A suspect a quick capacitor change would get your Amiga back nice and bright again....
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No. A gfx card in an Amiga acts like a second gfx card. Programs which support it (including Workbench but excluding most games) can be made to display on the gfx card. But the main output remains through AGA, like the early startup menu, the guru meditation and those games and programs which don't support gfx cards or switch off AmigaOS.
Yeah, that makes sense. Bummer. Just like how using a 31 kHz scan mode you still have to display those same things on a 15 kHz screen with anything that doesn't support the higher scan mode, or that can't be mode promoted.
A suspect a quick capacitor change would get your Amiga back nice and bright again....
Quick? Heh, I wish, but that sounds fairly involved. It'd require knowing which capacitor, disassembling the system to gain access, acquiring an exact replacement component, doing the SMT desoldering and resoldering, and reassembling the system. I've even done SMT work, but not for years, and there's no margin for error if you end up damaging something in the process (overheat or otherwise damage the board or pads while removing and installing). Probably the diagnoses of the exact problem and which component to replace would be the trickiest thing of all.
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In my A1200 the graphics output has been getting gradually weaker for some time, requiring ever increasing brightness adjustments on the monitor. I'm wondering, when I upgrade to the Mediator PCI expansion and put in a modern graphics card, if that will fully replace the aging Alice and Lisa chips that seem to be wearing out?
have you tried with another monitor?
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have you tried with another monitor?
Agreed. If your chips were wearing out, I suspect you'd be seeing other symptoms. It's more likely that your monitor is getting old, especially if it's a CRT. If you don't have another monitor, you could try a different computer attached to that monitor to see if you get the same results.
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I think it was Matt Dillion who said that the Amiga custom chips quit working when the Blue Smoke gets out.
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When you are changing the capacitors change all of them because all are mounted false. There are some websites around with the exact spare part numbers and how to´s.
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In my A1200 the graphics output has been getting gradually weaker for some time, requiring ever increasing brightness adjustments on the monitor. I'm wondering, when I upgrade to the Mediator PCI expansion and put in a modern graphics card, if that will fully replace the aging Alice and Lisa chips that seem to be wearing out?
I also think its the monitor.
The Indivision AGA MK2 will get you the best picture period...
a Samsung SyncMaster 711r might be a good route
http://www.amiga.org/forums/showthread.php?t=62866
or dell 2320
http://www.amiga.org/forums/showthread.php?t=58860&highlight=dell+2320
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I presume he's tested the monitor on another machine, right..? :)
Either way, you will need to change the capacitors at some point. They're the right way round (it's only the A3640 that's not), but they're just very cheap.
There are various people who can do it for you if you want - I'd offer myself but I'm across the pond in the UK.
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Agreed. If your chips were wearing out, I suspect you'd be seeing other symptoms. It's more likely that your monitor is getting old, especially if it's a CRT. If you don't have another monitor, you could try a different computer attached to that monitor to see if you get the same results.
Well, I am seeing other symptoms, actually. I see weird flickering in certain parts of the display sometimes, and the picture has missing blocks in certain places when I drag screens up and down at other times.
My monitor is a CRT, but it's not that old really, and hasn't been used too awfully heavily. Unfortunately, I don't think it's the monitor. The other monitor I have is a 1084S, but it's under a bunch of boxes I'd have to dig it out from under, and try to find some space. So, I was going to hook up another computer to the monitor. That's what I forgot to do... I'll test it tomorrow.
I presume he's tested the monitor on another machine, right..? :)
Either way, you will need to change the capacitors at some point. They're the right way round (it's only the A3640 that's not), but they're just very cheap.
There are various people who can do it for you if you want - I'd offer myself but I'm across the pond in the UK.
Didn't test it yet... will tomorrow. No, I can do the capacitor replacement myself actually. I was basically just saying it'll be hard to find the time. And I didn't know where to get the install info. I think someone mentioned where to get it. (I'll also have to get some fine pitch equipment.)
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I also think its the monitor.
The Indivision AGA MK2 will get you the best picture period...
It's not the monitor, as I suspected (see below). It's either the AGA or the scan doubler maybe. But I'm not sure the scan doubler would have those symptoms. I forget, the Indivision AGA MK2 is a scan doubler, right?
have you tried with another monitor?
Ok, yes I checked the monitor now, with another computer. As I figured, it's fine. It's exceptionally bright, in fact, even when I turn the brightness way down it's still bright. However I have to keep the brightness at the default, 50%, or it's hard to see detail in dimmer pics. This is opposed to 75% for it to be marginally bright enough with the Amiga output, and I used to have it well below the default setting originally.
I'm skeptical the scan doubler could be at fault. For one, it's normally in bypass mode as I'm using a 31 kHz mode, but there's no difference with the problem at whichever frequency, 31 or 15 kHz. That is, unless it could be causing some issue even when it's supposed to just be bypassing... seems unlikely. Also, the strange display anomalies are too specific to parts of the screen for the scan doubler to cause. However, I'm not 100% sure because there is some toasting and very slight melting of the case. As there had been some overheating going on with the scan doubler at certain times, it seems.
I will have to dig out the 1084S from the storage area to further test it. Being as that doesn't require a scan doubler, it should indicate whether the problem is the scan doubler, or that it is in fact the AGA chips.
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Hello, i also noticed the Brightness Problem of PAl Screens when the PCI Library is running. That is no fault of AGA or Flickerfixer or somethimg else. Seems so when switching to GFX mode that less Power goes through the TV Modulator or video Output. I have a Mediator 1200 PCI for a long time and can say, there is a special Trick you can use. If you have a TV Card in your Mediator you can redirect the Pal Output signal to this Board. It is fairly simple, all you must do is to connect the amiga video output Plug (Yellow) to the Tv Card Video input Plug (Yellow) with a normal chinch cable. Then if you run under Picassso 96 you must edit the monitor tooltypes in this way: Find the Keyword "Displaychain" and set it to Displaychain=NO. then find the Keyword "FakeNativeModes" and set it to FakeNativeModes =NO that´s all.
After that start your favourite TV Programm i. E. "SuperTV" or the Elbox TV Programm and set the TV Format=PAL BDGHI and the TV Input to video Source that should it be. I recommend SuperTV because you can set nearly every Parameter you want. The elbox Programm is a little bit tricky.
If you done that start supertv and then start the Application or WHDload game you want and it appears bright and clear in the TV Window or Fullscreen you have set, no extra monitor is needed. Now you can play your old favourite games or apps on a High or truecolor Workbench in full colours without closing WB. At this Moment the wb is simply frozen and the game or app takes over the machine. When you quit, everything is getting to normal and the WB is still fully functional.
This is a small Tip for old Games and applications on expanded Amigas without the need of an extra monitor. Hope this will help you and much fun with playing classic games or apps on amiga.
Greetings,
JoachimA
PS: Excuse my bad english, i am from germany.