17 February 2014

Contents

1. IIgs does not start with Sonic Blaster
2. Maximum 1 MB memory on Q-RAM GS

Problem Log

IIgs does not start with Sonic Blaster

If the Applied Engineering Sonic Blaster card is installed in any slot, the Apple IIgs does not start. The system powers on, but does not chime, and nothing is displayed on the screen.

The 74LS174 on the Sonic Blaster card has failed and is interfering with the reset circuit. Replace it.

Maximum 1 MB memory on Q-RAM GS

When four 1 MB SIMMs are installed on the Pacemark Q-RAM GS board, the maximum system memory is 1.25 MB regardless of how the configuration switches are set.

Some Q-RAM GS boards have been artificially limited to accept only 256 KB SIMMs by cutting a trace connecting ground and pin 27 of the card edge connector (msize). Repairing it restores the card to full functionality.