cia chip blown???

[amiga4001]

I was trying to transfer files with a parnet cable to a A1200 from my 4000.
Parnet could not establish a connection just freezed at waiting for network connection.
So I unhooked it and tried to print with the 4000 which only gives me garbage printing.
Have I possibly blown a cia chip on my 4000?
Are the parallel port not compatible between these 2?
I did't hook anything up while it was powered.
Is there a program to check cia function???
 

[marcfrick2112]

Hello, Here's what Amiga U had to say:
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CIA chips

There are two CIA chips in every Amiga. These handle most of the Amigas communication to the outside world- the serial, parallel, joystick, and mouse ports, as well as the disk drive, keyboard, and timer. If the CIA chips become damaged you may develop problems with these ports that may manifest themselves in a number of ways. These include broken fire buttons on the joystick, disks not being recognised, or the keyboard not recognising presses.

Fortunately, these chips are easy to replace, At least, they are on the A500 and A2000. To see if this is the problem try swapping the two CIA's around to see if one of them is faulty. This may temporarily allow a certain port that you use to work. However, this is only a short term solution and you should replace the CIA chips with new ones at the earliest opportunity. These retail for around £10-20.

To swap the CIA chips you will need to take the Amigas case off and remove the metal shielding underneath. The two CIA's are both 40-pin chips that are marked CIA ODD and CIA EVEN. Simply swap them over, making sure that you have placed them in the right way and replace the case.
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My semi-educated opinion: One CIA chip may be bad, or cable is bad, or cable wired wrong...Built-in Parallel port should be virtually identical on all Amigas....
Hope this helps...

[Ilwrath]

Fortunately, these chips are easy to replace, At least, they are on the A500 and A2000.

Not so easy to replace on an A4000 - they're surface mount.  :-(   (Also, not worth the advice of swapping them.  IF you're going to attempt any repair, might just as well replace 'em with known good or NOS - several places still sell 'em.)

The PARNET cable should work fine between the A1200 and A4000.  Though, unfortunatly, there are a LOT of shoddy PARNET cables out there.  (The plans were freely available as a fairly simple DIY project, and lots of poor-soldering hobbiests made them back in the day...)  If your PARNET shorted internally (or if someone made the modifications to make it work with the A1000 parallel port?), it could have shorted and taken your CIA chip with it.

[amiga4001]

Well sad day here.
The 1200 I had on the other side of the parnet cable has died.
So it is not also my internal paralel port of the 4000 but also my 1200 which has deceased.
Could a defect on one of the cia's in the 1200 caused this as the cable was good(I used it before with no problems).
Also if I would put in a socket for the cia chips(s) would I have a chance of rewakening my 1200?
Which cia would have blown? The on after the parallel port or the one under the diskdrive?
They don't feel warm.
The 1200 is sometimes reacting with a flashing powerlight and sometimes just a steady light.
I tried an other psu.

[Amiga4k]

Just out of curiosity: Was either Amiga connected to a serial device at the time of this tragedy. ParNet can not be used if you had a serial device connect to either Amiga, as some signal lines are shared. I know it will not help you with your situation, but it might answer why it happened.

[amiga4001]

No nothing was connected to the serial port.
Strange though as the parnetcable was known to be good and working.
I didn't used it on the 1200 before the defect.
Only the 4000 had been succesfully tested.
Maybe the 1200 already had an internal error on the parallel port which caused the defect.
Is there any way to prevent these issues with the parnet system?
I mean some kind of fuses on the cable?
Also what do you think can one cia chip on the 1200 cause a total dead computer?
Maybe I'll try socketing one cia chip if I would know which one I should socket.

[Daedalus]

Hmmm... Socketing a CIA on an A1200 motherboard's gonna be extremely tricky, if not totally impossible to the average Joe Electronic. They're not the standard PLCC format, but a much higher density pin layout. You won't get sockets for them, so you'll have to cater for the different layout and socket of a much larger chip. Not worth the effort IMHO given the high probability the board will be damaged further.

[Daedalus]

Sorry, scratch that, just looked at a pic of an A1200 motherboard, and the CIAs are actually PLCC types. My mistake - haven't worked on an A1200 board in years. My comments still stand about the difficulty replacing it though - you'd need access to some pretty serious soldering gear to be able to do that. Good luck with it though! :-)

[patrik]

It's very important to make sure you have a common ground for the computers when using something as shoddy as parnet-cables.


/Patrik