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+--- Thread: Turbo Speed for Premium Microbee procedure (/thread-1041.html)
Turbo Speed for Premium Microbee procedure - ChickenMan - 20-06-2026
Thanks to PhilipH for making this 4 page document available. It originally appeared in the Vol7 No7 (Sept '89) SMUG Newsletter, which we dont have.
Written by Tony Ellis in 1989 and explains the simple process to upgrade your Premium Microbee to run at 6.75 MHz rather than the standard 3.375 MHz.
... this upgrade shows how you can upgrade your Premium to have GT stripes - in fact to go twice as fast. As a bonus the speed is controlled by software compatible with the Peter Broughton's software. So if you run 'PB' then changing speed is simple - just use a function key to do the job. In addition, if you have the status line active, it will indicate the current speed setting.
The changes are very inexpensive - in fact you only need a few pieces of wire! MicroBee when they designed the Premium left several chips with spare gates, sections of chips unused, so will take advantage of this fact.
You may have to upgrade your Z80 & PIO chips to a higher speed version to run reliably at the higher speed. I have a Z80B in my 128k Premium when I upgraded mine way back in the '80's.
So in the MbeeTech Repository in the Microbee\Documentation\Articles\Technical folder we placed
turbo_speed_for_premium_bee.pdf