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Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: AmiJIm on October 27, 2013, 05:48:37 PM

Title: A1200 Short circuited pin 150 -12v with pin 149 +12v repair
Post by: AmiJIm on October 27, 2013, 05:48:37 PM
Hello there,this afternood i was installing the acard scsi to ide to CF adaptoer to my blizzard 1230-iv scsi and the metal shield touched to pins of the blizzy.the pin 150 which is actually -12v and pin 149 which is +12v.a line was burnt from pin 150 to a capacitor near CIA .The amiga 1200 powers on OK , but it freezes moments after i use the mouse.I resolder the trace ,still same problem.Is the CIA to blame,shall i replace them or there must have be done some more damage and i shall buy a new motherboard?Also i noticed that the big black barrel capacitor near the cia has enlarged itself,can this problem be because i need to recap my mobo?what shall i do and where i could find CIA chips?
thank you .
Title: Re: A1200 Short circuited pin 150 -12v with pin 149 +12v repair
Post by: Zac67 on October 27, 2013, 06:34:37 PM
If a capacitor has a bulged cap or 'wet' feet it needs to be replaced. Can't guarantee that it solves the problem tho...
Title: Re: A1200 Short circuited pin 150 -12v with pin 149 +12v repair
Post by: gertsy on October 27, 2013, 09:18:48 PM
Id replace the one cap first. Then if that doesn't fix it send it to a professional to attempt to repair and replace all the caps, if they find the problem.  Alternatively you could source a used or refurbished A1200 for probably close to the same price of the repairs and postage. I know it doesn't help but I have thick insulation tape on the edge of the shielding next to the edge connector.
Title: Re: A1200 Short circuited pin 150 -12v with pin 149 +12v repair
Post by: AmiJIm on November 22, 2020, 08:42:37 PM
After  some years of inactivity and having changed the caps by a professional , the blizzard was not working.It would lock up after 4 minutes of usage.Every time.It turns out that all i had to do was to remove the E123C and E125C as per Ians instructions and now the amiga works like new.Note than back in 1994 when i bought new the A1200 and the blizzard 1230iv it was working with the resistors in place.Salute!