Quadra 700 Clock Mod

Date: Sun, 6 Jun 1993 01:10:15 -0700 (PDT) From: Guy Kuo <guykuo@u.washington.edu> Subject: quadra-700-clock-mod-145 quadra-700-clock-mod-145.txt Text file for tech folder which describes technique for changing Quadra 700 clock speed. This version includes cooling fan installation, custom speed oscillators, thermal data, caveats regarding socket pins, and performance data. At the time of posting, the author has reports of 33 Q700's modified in this way. Some have been running this way for months without additional cooling. Three machines required cooling for accelerated operation. ---------- This procedure should only be attempted by users experienced in circuit board fabrication and repair. You must desolder a component on a multi-layer motherboard. Such boards are fragile and expensive to repair. This is NOT a good first soldering project. The process voids your warranty. If you are not dissuaded by the above, read on and see how a $5.00 part can bring your Quadra 700 up to Quadra 950 performance. The Quadra 700 has been successfully accelerated by exchanging its CPU clock oscillator for a higher frequency unit. The original oscillator is a 50 MHz unit from which is derived the 25 MHz and 50 MHz clocks used by the 680RC40 processor. Speeds up to 33 MHz are usually attained with new oscillators. Higher speeds are attainable by some individual motherboards. One can reasonably expect to attain 30 MHz. Higher speeds are likely but not guaranteed. There is a small chance that your particular motherboard is incapable of higher speed. Of the 33 Quadra 700's reported to or modified by myself the results are: 35 MHz 2 machines (custom Fox electronics 70 MHz clocks) 33 MHz 17 machines. Two of which reported as unstable until cooling fan added 32.5 MHz 12 machines (had 65 MHz clocks available at low cost) 31.5 MHz 1 machine required cooling fan to operate. Higher speed testing pending. Failed 1 machine failed at 33 MHz. Lower speeds not yet tested 1 machine with a clip on clock oscillator failed at 32 MHz to properly access floppy drive Motherboard destructions: 0 Motherboard damages: 2 episodes of plate through hole damage which the users managed to solder through. Unusual problems: 1 motherboard shorted against the case during reassembly. A piece of paper between the motherboard and case solve the problem. 33 MHz exceeds the manufacturer expected performance of the Newer Technology Variable Speed Overdrive. Newer guarantees 30 MHz as attainable by all. Of the five VSO's in Seattle I know about, 31 MHz has been the recommended speed. Personally, I have run a motherboard with full stability (except 24 bit video) at over 35 MHz. 24 bit video=20 instability at accelerated speeds prompted me to swap motherboards. My second motherboard has a top stable speed of 30.5 MHz with a VSO. 24 bit stability was not attained until I slowed to 30 MHz. This very same moth…