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CN3 or CN4 (cold solder connection) (CN205 or CN204 A2000).

Problems with left, right or both channels: Internal/external drive not recognized.In the followings tests, a known good drive should be substituted to eliminate the drive as the source of the problem. The most likely causes are:Ĭlean heads and check for excess dust in drive. Printer not working correctly or not working at all.PARALLEL PORT PROBLEMSĪ known good printer should be substituted to eliminate it as the source of the problem. NOTE: Computer will function with no -12 volts but serial port will not work. Incorrect colors (loss of red, green or blue):.Scrambled video loss of composite sync.System locks up when double clicking icon:.Screen breaks up (scrambles) after running for 15 to 30 minutes.Left mouse button and fire button on joystick not working:.EMI 1401 5.1 ohm resistor (supplies 5 volt to mouse).Mouse does not move, left and right mouse buttons okay, joystick okay:.If it is determined that the mouse and joystick are okay, the most likely causes are: R914 1 ohm 1/2 watt resistor A2000 (supplies 5 volt to the keyboard)Ī known good mouse and joystick should be used to eliminate them as the source of the problem.U7 Odd CIA (KBdata Pin 39 – KBclock Pin 40) (U300 A2000).

If the keyboard is determined not to be the problem, the defect is most likely on the main PCB (A500/A2000 motherboard).

If you cannot reset computer, the most probable cause is Q2. The above chips are located on the keyboard.

If the caps lock light on the keyboard is flashing when power up, note the number of times it flashes:.

RAM on motherboard (Check for excessive heat.

If it is too hot to touch, it is bad) (U100 A2000)

Substitute a known good power supply to eliminate it as a possible source of the problem.

Screen goes from dark grey to light grey but does not display Restore screen change to light grey, then workbench prompt.Configure memory: If bad, screen green.Temporary exception processing: If artificial exception occurs, screen yellow.AMIGA TROUBLESHOOTER – PART 2: A500/A2000 POWER UP SEQUENCE