Apple IIc : Logic PCB Bad After IIc Starts By Itself

The system won't boot or exhibits diagnostic RAM failure after turning itself back on about 10 to 20 minutes after it was turned off.

NOTE: This usually occured the first time the Apple IIc was turned and did not occur on all of the power supplys in the serial number range. Most of the power supplys in the serial number range work properly and will not show any of the described symptoms. If the Apple IIc is working properly there is no need to replace the power supply. All of the replacment module power supplys made by TDK have had this problem corrected. Refer to the Apple IIc Technical Procedures for more information on identifying reworked TDK power supplys.
Some TDK Apple IIc power supplies have a problem that causes them to turn back on spontaneously 10 - 20 minutes after the power switch has been turned "OFF". The power supply may have blown the RAM on the logic PCB when it turned itself back on.

To check for this problem locate the serial number/name plate on the power supply. Identify the vendor and date code for the power supply. The information on the plate is in the following order.

(Vendor)
699-0230
CE-0453
(Date Code)
(Serial Number) Japan

If the vendor is TDK, the power supply shows a date code between 8501 and 8526, and displays the problem stated above, replace the power supply and the logic PCB. Be sure to refer to the Apple IIc Technical Procedures for complete information.

If this cure does not resolve the problem, go to the Technical Procedures to obtain a general troubleshooting procedure for this product.
Published Date: Feb 19, 2012