Problems with recently repaired Amiga A1200

[AmigaBruno]

A few weeks ago, I got my A1200 back after a lengthy complicated repair which took seven months.

Unfortunately, it got damaged in a freak accident which I had no idea could happen. I never put drinks on the same surface as computers. It was rained on through a skylight made by Velux. I had only just managed to get these skylights open with a special tool several months after moving into my flat. I wasn't even sure they were supposed to open. I was in another room which also has a skylight when this happened. There are some walls on the roof near this other skylight which protected it from rain falling on it. This meant I didn't see or hear any rain until I went to the toilet, which was too late. 

The repairer originally said it was badly corroded and basically a write off to anyone with any sense, but that didn't include him! It was badly damaged. It was repaired some time ago, but failed after only about two hours' use, then kept displaying a blank green screen.

Near the end of the seven month repair, he mentioned the Alice chip, RAM chips, and the 74HCT244 buffer chip, as what were causing the display to lose sync and break up. I don't know all that much about electronics, but the Amiga is more specialised anyway. My next project is to attempt to assemble a "Pixel Game Boy" with an 8 x 16 red LED display.

I don't plan to return my Amiga to the same repairer, but if it breaks down again, then I think that may be the end of it anyway. I think I'd just remove the motherboard, then fit a Raspberry Pi running an emulator, so I could at least have the feel of using an Amiga.

My A1200 was working fine when I got it back, but during the last week or so, two faults have come up. It keeps printing the number 6 on the screen. This has happened in more than one program, including saving files in DPaint, and editing programs in Easy AMOS. It often happens when I type the E key. I've also been using Devpac, but I'm not 100% sure now if this problem also occurred there. However, I found I had installed a copy of Wordperfect, then I ran that and found I was able to type in it without any of the number 6 being printed. There's also a problem with the numeric keypad, which includes lots of the number 6 being printed, but some keys on it may not be working at all.

Another problem is the Early Startup screen. I'm using an Amiga 23 pin video to SCART cable. At first, I was depending on this screen to boot up from one or both of my CF cards. Unfortunately, I find that now I can't display it, because it seems to have a lack of sync signal and I can't read it or see where the mouse pointer is! There are also flashes of green. This problem only occurs with the Early Startup screen.

Is there anything I can do to sort out these problems by myself? I can't attempt to desolder or resolder any surface mounted chips. If not, then has anyone had any similar problems which a repairer sorted out in a few weeks, instead of seven months?






 

[Boing-ball]

A few weeks ago, I got my A1200 back after a lengthy complicated repair which took seven months.

Unfortunately, it got damaged in a freak accident which I had no idea could happen. I never put drinks on the same surface as computers. It was rained on through a skylight made by Velux. I had only just managed to get these skylights open with a special tool several months after moving into my flat. I wasn't even sure they were supposed to open. I was in another room which also has a skylight when this happened. There are some walls on the roof near this other skylight which protected it from rain falling on it. This meant I didn't see or hear any rain until I went to the toilet, which was too late. 

The repairer originally said it was badly corroded and basically a write off to anyone with any sense, but that didn't include him! It was badly damaged. It was repaired some time ago, but failed after only about two hours' use, then kept displaying a blank green screen.

Near the end of the seven month repair, he mentioned the Alice chip, RAM chips, and the 74HCT244 buffer chip, as what were causing the display to lose sync and break up. I don't know all that much about electronics, but the Amiga is more specialised anyway. My next project is to attempt to assemble a "Pixel Game Boy" with an 8 x 16 red LED display.

I don't plan to return my Amiga to the same repairer, but if it breaks down again, then I think that may be the end of it anyway. I think I'd just remove the motherboard, then fit a Raspberry Pi running an emulator, so I could at least have the feel of using an Amiga.

My A1200 was working fine when I got it back, but during the last week or so, two faults have come up. It keeps printing the number 6 on the screen. This has happened in more than one program, including saving files in DPaint, and editing programs in Easy AMOS. It often happens when I type the E key. I've also been using Devpac, but I'm not 100% sure now if this problem also occurred there. However, I found I had installed a copy of Wordperfect, then I ran that and found I was able to type in it without any of the number 6 being printed. There's also a problem with the numeric keypad, which includes lots of the number 6 being printed, but some keys on it may not be working at all.

Another problem is the Early Startup screen. I'm using an Amiga 23 pin video to SCART cable. At first, I was depending on this screen to boot up from one or both of my CF cards. Unfortunately, I find that now I can't display it, because it seems to have a lack of sync signal and I can't read it or see where the mouse pointer is! There are also flashes of green. This problem only occurs with the Early Startup screen.

Is there anything I can do to sort out these problems by myself? I can't attempt to desolder or resolder any surface mounted chips. If not, then has anyone had any similar problems which a repairer sorted out in a few weeks, instead of seven months?

The only thing with the faults is down to traces and possibly more problems linking to CIA and Keyboard controller. Unfortunately corrosion can get everywhere and will spread. The mainboard has layers, so even though you will look and possibly not see it, there maybe corrosion underneath or inside layers of the mainboard.

Or it’s simply a fault with the Keyboard membrane, which is a cheap fix by buying a new one for around £26.

I have no idea where you are based, or who you have used before.

If in the U.K? Then try Ian at mutant Catterpillar :  https://www.mutant-caterpillar.co.uk/shop/

If in the EU, then there are others out there who can possibly look at this for you. But again, you have not mentioned who you used before.

If there is damage to the mainboard and you still want to use a stock Amiga, then the alternatives are; A replacement mainboard or get hold of a Re-Amiga board and have the chips transplanted over. Or as you have mentioned try something else.

Amigakit are to release their A600GS soon. So that’s another idea.

[AmigaBruno]

I've found out now that when the Early Startup screen starts going mad I can stabilise it just by pressing the space bar and going into NTSC mode on my PAL Amiga A1200. I can then press the space bar again to get a stable PAL Early Startup screen.

I'm in the UK. I've already said that I don't think there's any point sending it away for repair again. I think it would be finally beyond repair or take so long to repair that there wouldn't be much point. I think that all repair companies are either very small or larger and victims of their own success with a backlog.

As for the keyboard problem, I think I'll have to try fitting a new keyboard membrane by myself, not asking a repair company to do it. This is inconvenient at the moment, but I usually type on a MacBook which has no numeric keypad at all!