09.011 Both of my Disk ]['s come on when booting! How can I fix this?
Description
This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
09.011 Both of my Disk ]['s come on when booting! How can I fix this?
Basically, it sounds like Drive 2 does not know when to stay OFF. There
are three fairly high-probability places where a glitch may cause this to
happen:
1. The 74LS132 on the Disk ][ Controller card may have a blown gate or some
pins may be making poor or no contact. Try unplugging and re-socketing the IC.
This usually takes care of bad contact problems. (Or, you can replace the
74LS132 IC with another 74LS132 or 74132. A 74LS00 or 7400 may work, too.) Also
unplug and re-socket the 9334 and 556.
2. The ULN2003 IC on the Drive 2 main circuit board may have a bad gate or may
have developed some poor pin-to-socket contacts. Remove the drive cover. Unplug
and re-socket the ULN2003 IC. (Replacing a blown ULN2003 should not be too
difficult. Both Mouser and Newark carry the IC.)
3. Drive 2's cable may have developed a short between pins 14 and 16. Mark the
position of the cable at the Controller card and at the Drive 2 circuit board
and unplug the cable at each end. Use an Ohm meter to check for shorts between
adjacent pins. If you find a short between 14 and any other pin you can try
repairing the cable or cutting out line 14 and running a new lead; or you can
get a replacement cable.
___________________________
By: Rubywand
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