The SIMM slot is that for the ROM card, when there is one, as opposed to the cache slot next to it for a cache card or a DayStar PowerCache 030 accelerator card (33, 40 or 50MHz). The 33 and 50MHz (2x and 3x multipliers, with the possibility of on-card 68882 FPUs) are the ones to look for for a IIcx.
Did you trawl for past posts in these forums? What you describe about the behaviour with the keyboard power key held down is classic borked PSU stuff.
You can try the 'quick flick' startup. You can remove the power supply and your spanking new 3.67V in circuit battery completely for 5-15min (ie, a hard reset of the MLB and a return-to-taws for the PSU), then replace the PSU and try the power key again, followed by the quick flick if that doesn't work. Finally, you can get another PSU, or try the recommended repair of the (Astec) PSU according to the given link.
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Did you trawl for past posts in these forums? What you describe about the behaviour with the keyboard power key held down is classic borked PSU stuff.
You can try the 'quick flick' startup. You can remove the power supply and your spanking new 3.67V in circuit battery completely for 5-15min (ie, a hard reset of the MLB and a return-to-taws for the PSU), then replace the PSU and try the power key again, followed by the quick flick if that doesn't work. Finally, you can get another PSU, or try the recommended repair of the (Astec) PSU according to the given link.
de