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Tech Bulletin #1 |
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Vectra ES-12 CMOS Battery |
April 27, 1998 |
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| \ | The initial batch
of Flying Faders systems, built in late '88 and early
'89, utilized the HP model ES-12 computer. This computer
model is a 12 MHz '286 system with a 40 MByte MFM hard
drive. Although these systems are extremely durable, we
know that the MFM drives have a finite life. If the MFM
drive should fail, the typical symptom would be either a
drive failure message or lack of boot disk message. If the drive is really dead, only a drive transplant or a new computer will solve the problem. But before these heroic measures are undertaken, a quick check of the CMOS battery is appropriate. (We have had some drives in other products which get stuck and won't spin. We have found that rapidly twisting the drive in the plane of the disk can break free the sticktion and allow the drive to rotate. If you do not hear your drive starting up and spinning when you turn on power, you might pull out the drive and try the twist/spin trick. Do not bang or shock the drive, just rapidly accelerate it in the spin direction. If this restores operation, you are lucky, but you also better look for a long-term solution.) The CMOS battery powers the CMOS RAM memory which holds the Setup information for the computer - hard and floppy drive types being the most critical of this information. If the battery fails, the computer "forgets" the type of disk drive which is installed. When the Boot process starts, the computer cannot access the hard disk. Another symptom is the loss of time and date settings, which also resides in the CMOS memory. When the battery degrades, the performance of the system may become erratic. The battery voltage may change slightly with room temperature or other factors, enabling a clean boot on one day and problems on the next day. To gain access to the battery, the computer cover must be removed. The cover is held in place by three screws through the back panel, one on each side and one at the top and a bit to the right of center. After removing these screws, slide the cover forward slightly to clear the power button and then lift the cover straight up. The ES-12 CMOS battery is located on the front of the power supply chassis in a black molded plastic housing. The red and black leads from the battery terminate on the motherboard below the battery in a Molex-style connector. The voltage of the battery (measured at the connector or at the battery) should be nominally 5V. A significantly lower voltage, indicating a dead cell, should be cause for alarm. (A recent test on an ES-12 yielded 4.87V. We have not determined the voltage threshold for failure.) To remove the battery holder, the plastic bar which actuates the power switch must first be disconnected. Tug the power switch bar forward until it disengages from the switch in the power supply. Lift the free end at the power supply until it clears the power supply and cables, then pull the bar toward the back of the computer to free it from the hole in the front cover. The battery holder is held to the power supply chassis by plastic fingers which stick through holes in the chassis. The fingers are released by sliding the holder up, but the holder is latched in place by the top tab of the holder. This tab has a plastic "bump" which engages a square hole in the power supply. To release the bump, pull the tab at the top of the battery holder toward the front of the computer until the bump clears the hole, then slide the holder up. Installation is done in reverse order. Insert the battery holder fingers into the slots in the power supply chassis and slide the holder downward until the locking tab snaps into place. Feed the power switch bar through the front panel from the back, threading it through any cables, and then engage the back end by pushing the bar into the switch hole. If the battery has been disconnected, the CMOS memory will need to be reloaded. Insert "Auto Install #1" Disk in the floppy drive and turn on power. Hit F1 key to initialize the system. In the Configuration Setup, set 5) Keyboard click off, and in 1) Set
time and date At this point, save and exit the setup. When you finish with Setup, you should not need to reload your Flying Faders software. All Flying Faders PC computers have a CMOS battery which can cause similar problems. Many clone computers use a 3.6V NiCad mounted directly to the computer motherboard. We have seen failures for all types of computers. Martech does carry replacement 3.6V NiCad batteries. If you check your CMOS battery, please pass information to us regarding your findings. Anything you can add to improve the above bulletin will be appreciated by members of the Users' Group. Thank
you |
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