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Author Topic: Amiga 1200 - screen shifted to left  (Read 275 times)

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Offline TheBRTopic starter

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Amiga 1200 - screen shifted to left
« on: October 08, 2022, 10:29:14 AM »
Hi all,
  I recently purchased an Amiga 1200, I was shown it working and I didn't notice any issue at the time but I may have missed it. It came with a capacitor remap kit from retro something so I installed those whilst I waited for another capacitor to arrive to fix my internal floppy which was also faulty (and I knew about) and install a gotec drive.

Anyway, all appeared to go well but I've noticed the screen is shifted to the left now on my tv, see link for example photos, notice that black bar down the right hand side, even when the TV is set to 4:3 mode, and that there is a similar section missing to the left.

https://imgur.com/a/bLRVwBB

I did wonder if my capacitor change caused this but I don't know for sure, hence the question. Does anyone have any ideas?
 

Offline HGC

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Re: Amiga 1200 - screen shifted to left
« Reply #1 on: October 08, 2022, 10:46:10 AM »
I have my Amiga 1200 hooked up to a Commodore 1084S monitor.  Looks great.  If you insist on using an LCD, get yourself a 15 inch monitor.  They are 4:3 aspect ratio and have a native screen resolution of 1024 X 768.  Remember, the larger the LCD, the higher its native screen resolution will be, and the crappier the picture.  Even if you set your wide-screen TV to 4:3 aspect ratio, the picture will look like crap, because you are not running the TV in its native and recommended screen resolution.  Also, when using an LCD with an Amiga computer, the screen will always be shifted.  This is one of the main reasons why I went back to using a CRT monitor.  They are 4:3 aspect ratio and you do not have to worry about native screen modes.
 

Offline TheBRTopic starter

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Re: Amiga 1200 - screen shifted to left
« Reply #2 on: October 08, 2022, 11:32:59 AM »
Also, when using an LCD with an Amiga computer, the screen will always be shifted.  This is one of the main reasons why I went back to using a CRT monitor.  They are 4:3 aspect ratio and you do not have to worry about native screen modes.

Sorry, new to this old computer, newer TV thing. Are you saying what I am seeing is completely normal and the issue is the TV itself? (It's a really old HD ready plasma). Could you explain why a bit more please (apologies, I know it's a pita just looking to understand the situation) or even link me a page to read up about it. To my mind it seemed like the horizontal sync is off but I'm no expert.

You think if I hook this upto a 15" LCD @ 1024x768 native that'll help and are you using RGB scart or composite?
 

Offline PlatformerZ

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Re: Amiga 1200 - screen shifted to left
« Reply #3 on: October 23, 2022, 11:54:12 AM »
I've used CRT's and 5:4 tft's 17" and 19" either multisync or with a scandoubler and results vary and also change through environmental impact/interference. Your A1200 video out (if it's RGB) probably has a stronger current now with new caps so you could explain the picture that way. I'm using a 5:4 19" NEC accusync atm and I found the best way to center the frame is to use a corresponding screen-mode - in this case Multisync 640x4xx and set the Overscan settings in Prefs. Any screen will have a better time with sizes that compute!
 

Offline AndyFC

Re: Amiga 1200 - screen shifted to left
« Reply #4 on: November 11, 2022, 12:36:29 AM »
How do you connect your Amiga to the TV e.g. Scart, VGA adapter etc?

This thread came to mind when I saw something similar on a TV the other day, not with an Amiga, but with a PowerMac I was trying to recover. My A1200 is connect to a TV via Scart, but the same set also has VGA and HDMI inputs and had connected the G5 to the VGA input. I noticed that sometimes the image was fine, and I could see the left hand side, after a power cycle on the Mac sometimes I'd lose the very left hand side, enough to lost the first three or four characters of the text output. My TV has a setting for pixel clock, and so by going in and choosing it (not even changing it) in the menus, and then exiting, I could see the whole image.

In summary, you might be able to fix it by altering a setting on your TV.
A1200 in DIY Tower. 3.2.1 ROMs, 3.5" HD, CD RW and IDE to SD adapter running off the internal IDE port (using the A4000 4-port IDE adapter from Amigakit), Blizzard 1230-IV, with 32MB 60ns RAM and 50MHz 68882 FPU. 3COM PCMCIA Network card running with Miami DX. https://www.youtube.com/watch?v=1PrGdL6XjmE

MorphOS on PowerMac G5 and ATI 9600 pro