This article is from the Apple II Csa2 FAQ, by Jeff Hurlburt with numerous contributions by others.
It may be that the fan inside the unit is showing wear. The good news is that replacing the fan is an easy and rewarding task. I knew my fan was starting to die when it sounded like it was wheezing during spin-up. The fan, a Sprite model SU2C7, uses sleave bearings, whose lifespan is determined by the lubricating oil supply in the bearings. When enough of the oil evaporates, metal will grind against metal resulting in heat and resistance that cause the fan to quickly lock-up. Better quality fans use ball-bearings, but Kensington apparently used the cheapest component available. Even among the models with sleave bearings, t he SU2C7 is the least capable. It can only move 18 cubic feet of air a minute (half what a typical PC fan moves) and has a 55,000 hour rating. In looking for a replacement for my dying fan, I chose to use a better model. The Sprite model SU2B1 has the same dimensions as the SU2C7 used in the System Saver and is readily available from Digi-Key corporation. It uses ball bearings for long life (the fan is rated for 73,000 hours) and can move 34 cubic feet of air a minute. The higher quality is readily apparent: the replacement is currently noticeably quieter than the original even though it is moving more air per minute. To replace the System Saver fan, first make sure the System Saver AC power cord is unplugged. Next, you will need to open the case. Opening the System Saver case involves removing eight screws. You can remove the foam weatherstriping along the periphery of the case to expose the screws OR you can poke through/around the foam at each screw hole. The screw access holes are arranged as shown in the following diagram (bottom view of the System Saver):FRONT __________________________________| ________________________________________________________ | | | | | | | * | | | | _____________ | | | | | | Screw holes revealed ------>| | | | | | after removing foam | | | | | Fan | | | | | | | | | | | | | | | | | |_____________| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * | | | |________________________________________________________| | |______________________________________________________________| BACKOnce inside, the fan can be removed by unplugging the power cord that connects it to the circuit board. A grounding wire that is attached by a screw must also be removed. The fan itself is held to the case by two screws. Once you remove the SU2C7, you can replace it with the SU2B1. Now mount everything back together again with the screws. Apply new foam weatherstripping if necessary. The refurbished System Saver is now better than a factory new model! Notice the difference in sound: a quiet hum rather than a load rumble. If you have a lot of cards, you will notice that the inside of the IIGS is a lot cooler too. An upgraded System Saver is a great way to counteract accelerator instability caused by heat. Sources and parts needed: 1) Part: Sprite model SU2B1 (Digi-Key Part No. CR103-ND) Source: Digi-Key Corp. (1-800-344-4536/www.digikey.com) 2) Part: Foam weatherstripping tape (3/8th inch width, 3/16th inch thick) Source: Home Depot (or a comparable hardware store) ---------------------------- By: Louis Cornelio The fan I removed from my System Saver IIgs is the Comaire-Rotron Sprite SU2C1-- 'C1, not 'C7. Actually, out of the case, it seems very quite. Much of the noise seems to be rattle from contact with the plastic case of the SS ... I put down some foam weatherstrip along fan-case contact points and that did the trick! I guess there was a bit of vibraction or something. The fan is stil audible, but only slightly from the air. ---------------------------- By: Rubywand Below are specs, ordering numbers, and prices for several possible System Saver IIgs replacement fans. As you can see, the noise numbers for the sleeve bearing fan models originally used in System Saver IIgs are not bad. The catch is that the numbers are for new units before bearing wear begins to increase noise. If you replace your fan, a ball bearing model is recommended. Digi-Key 800-344-4539 Mouser 800-346-6873 Newark 800-463-9275 cfm = cubic feet per minute of air moved db = measure of noise produced (for a new unit); lower is better Comaire-Rotron Sprite SU2C1 <SS Original> (Digi-Key #CR251-ND, p.234 in Apr-Jun 1998 catalog) 3.14sq. x 1.64 20cfm 27db 6watts 115VAC sleeve bearing $25.38 Comaire-Rotron Sprite SU2C7 <SS Original> (Digi-Key #CR108-ND, p.234 in Apr-Jun 1998 catalog) 3.14sq. x 1.64 18cfm 26db 6watts 115VAC sleeve bearing $25.38 Comaire-Rotron Sprite SU2B1 (Digi-Key #CR103-ND, p.234 in Apr-Jun 1998 catalog) 3.14sq. x 1.64 34cfm 40db 11watts 115VAC ball bearing $35.88 Augusta Tubeaxial (Mouser #432-81552, p.229 in Fall 1997 catalog) 3.15sq. x 1.5 21cfm 26db 9watts 115VAC ball bearing $23.63 Augusta Tubeaxial (Mouser #432-81554, p.229 in Fall 1997 catalog) 3.15sq. x 1.5 26cfm 31db 9watts 115VAC ball bearing $23.63 Augusta Tubeaxial (Mouser #432-81558, p.229 in Fall 1997 catalog) 3.15sq. x 1.5 32cfm 38db 10watts 115VAC ball bearing $23.63 NMB Peewee Boxer type 3115FS-12W-B10 (Newark #46F5098, P.405 in 1998 catalog) 3.1sq. x 1.5 22cfm 36db 6watts 115VAC ball bearing $11.42 NMB Peewee Boxer type 3115FS-12W-B20 (Newark #46F5097, P.405 in 1998 catalog) 3.1sq. x 1.5 27cfm 40db 7watts 115VAC ball bearing $11.42 NMB Peewee Boxer type 3115FS-12W-B30 (Newark #46F5096, P.405 in 1998 catalog) 3.1sq. x 1.5 32cfm 44db 9watts 115VAC ball bearing $11.42