View Full Version : Weird `````````````` effect
08-01-2004, 06:14 PM
Okay guys and gals I dunno if this is a hardware or software problem, but before I dismantle this A4000T I want to know if anybody had this kind of nonsense before:
I switched on earlier and the Miggy booted fine but when I went to move the mouse it was frozen. Keyboard also, couldn't CTRL Amiga Amiga. When I reset, I got all sorts of coloured screens, grey, blue, green, red, cycling through then black for 5 seconds then the familiar mutlicolour stripe reboot of the CS MkII. After that, no problem to reset or reboot, but now every now-and-then if I'm working with something that can take keyboard input, I get the ` typing by itself, it keeps on going until the line is full or until I press any key on the keyboard. I've checked and no keys are stuck, all connections into the tower secure.
What the hell is this?
My first thoughts would be that one if the CIA's is a tad flakey, did you just purchase the machine?
08-01-2004, 06:35 PM
he he no, its ironic I was just saying on another thread how somebody blew both my CIAs about 5 years ago and how I had them both replaced, and no trouble from them at all since then.
No, this has been my Amiga all along, since 1996. I hope this isn't a CIA problem. Is this ```````````` a typical CIA problem?
Well I had a similar problem with my A2K, whenever you pressed button one of any device attached to the 2nd user port, the machine would freeze and upon reboot, I would get all kinds of funny screens, if I shut it down again, all would be fine until you pushed button one again. Mind you I did also notice some oddities with the keyboard during normal operation as well. Once I replaced both CIA's the machine was perfect. Not sure how you would fare replacing the CIA's on your A4KT as they are surface mounted, might be a tad costly, so I would examine every other possibility first.
08-01-2004, 08:15 PM
What are the odds that you can do something simple to troubleshoot like swapping out the keyboard with another one. Even if the keys not stuck it doesn't mean a contact can't be triggering on its own.
08-01-2004, 09:34 PM
My A1200's keyboard has a loose connector (a tower keyboard adaptor). Whenever the keyboard loses power for even a fraction of a second it will short and give `````````````````.... Longer, and the caps lock will just flash and the keyboard will refuse to do anything - until I unplug it and replug it, sometimes with a power off needed.
You must have a wobbly connector in there. Secure it and the problem should go away.
Usually that problem comes if you switch data and clk in the keyboard connector, but this time it probably isn't a case of that.
Like said before, check the DIN connector's solder joints on the motherboard and try another keyboard.
08-02-2004, 02:52 AM
Come on gents, give me a little credit, I tried the keyboard. Its not that. In fact it happens even if the keyboard isn't plugged in.
I'm beginning to think this is a software problem
08-02-2004, 04:06 PM
Just got even more weird....I now have the dubious pleasure of seeing the purple screen with the disk, after all these years...
Right, that means I gotta open the old girl up.
I have an A4000T and have seen this problem as well as the purple screen.
First I would try re-seating the daughterboard module for the CPU.
Then - if you have a Cyberstorm installed, re-seat any memory SIMMS -maybe try booting with only one SIMM at a time.
Make sure that the plastic legs under the CPU module go through the holes in the board., There should be a satisying "thunk" when you re-seat the CPU module.
Check or remove any slow motherboard memory - re-seat them.
Usually that problem comes if you switch data and clk in the keyboard connector
Indeed. I got this exact effect when I first accidently had the CLK and DAT lines swapped with my keyboard (http://www.iki.fi/sintonen/tmp/keyb_front_1_s.jpg) hack (http://www.iki.fi/sintonen/tmp/keyb_back_s.jpg).
08-03-2004, 04:44 AM
You guys have been a great help, I dismantled the whole thing and took the CS out and reseated all the simms. So I now have got rid of the weird screens on startup, and also the weird phantom key presses, but I have now swapped one problem for another:
The left mouse button no longer works...interestingly it clicked once when I launched a program from a Toolmanager dock, but hasn't worked again. Tried a different mouse - same deal. This is getting frustrating, chaps. I suppose I had better open it again and run it open (feel which CIA gets hot if any). I dread another CIA being bust.
It would be a shame if I couldn't fix it because I have held onto this Miggy for all these years and have been proud that it all still works.
While I'm checking it again: does anyone know where I can send the mobo to if indeed I do need a new CIA chip?
08-03-2004, 06:24 AM
The mouse problem can be caused by a bad shift register (responsible for data to and from mouse & joystick ports).
The `````` problem is usually caused by either the KB data or KB clock line not working, or one of them being open circuit. A faulty CIA can definately cause this, but so can a few other components in the KB signal lines.
As for repair, if you're on the England side of the planet, then Amiga.fr (France) is a good option. A few places in USA are said to be good, but I can't quote any names off hand.
If you're around Australasia, you can send the bare MB to me in New Zealand for repair. I usually fit SMD sockets when doing CIA replacements so it's much easier to replace them in the field if required in the future.
08-03-2004, 06:47 AM
I think that's a great idea, providing sockets for future CIA chips. If the french guy can't do it, I'll send it to you (assuming I can't find the problem). Can you pm me some contact details and an idea of cost? Weird thing is the joystick button DOES work and I thought that a left button failure is only a CIA problem if the joystick fire button is also dead. Am I wrong about this? If I'm not wrong, any suggestions about what else it can be, because I can't see anything wrong here physically.
BTW the ```````````business has stopped (at least for today).
08-03-2004, 09:00 AM
I had the smae problem with auto input of ````````` and it turned out to be a bad keyboard so a new keyboard solved that problem.
08-03-2004, 09:38 AM
Yup, but my keyboard is being a very good girl. She wasn't responsible for the original ```````````. It happened even with the keyboard unplugged.
Anyway I have made my problem different somehow by dismantling the whole lot....now its all good except for the left mouse button.
Hey, does that mean that it can't be a CIA problem, if the symptoms have changed?
(Reaches for Scully and Mulder's phone number)
vBulletin® v3.8.4, Copyright ©2000-2013, Jelsoft Enterprises Ltd.