Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!watmath!clyde!cbatt!cwruecmp!neoucom!wtm From: wtm@neoucom.UUCP Newsgroups: comp.sys.apple Subject: Re: IIe Problem Message-ID: <376@neoucom.UUCP> Date: Mon, 2-Feb-87 10:12:34 EST Article-I.D.: neoucom.376 Posted: Mon Feb 2 10:12:34 1987 Date-Received: Tue, 3-Feb-87 06:45:53 EST References: <8701231438.AA15408@mitre-bedford.ARPA> <703@bucsb.bu.edu.UUCP> <5152@reed.UUCP> Organization: Northeastern Ohio Universities College of Medicine Lines: 80 Summary: I wish they'd put a better power supply in the darn thing! I've experienced all sorts of weird problems with Apple II series comnputers. At last count, the labs I take care of had somewhere between 15 and 20 II II+ IIe and //e computers of various rev levels and motherboards. I've learned a few things that are power problem related: 1. Memrory extenders that attach to the motherboard via umbilical cord to steal the refresh signal are real power hogs. Those old 4116s really guzzle power. These boards are often enough to push a system with a marginal power supply over the edge. 2. The integer basic firmware card, or rather in a few of our cases the applesoft firmware card with its power-hungry ROMs can push a system over the edge too. A few of our firmware cards are so old that they have (non erasable) PROMs on them rather than mask programmed 2316s. 3. Occasionally, the little decoupling capacitors between +5 and ground (and other voltages too) short out. This doesn't happen very often, but it can be a real annoyance to find one when it does! You need a milliohm meter to track down the short. 4. I always wondered why the heck Apple didn't get Astec to drill some holes in the aluminum case of the power pack. A little air circulation in there sure would help things out. It's not like a few small holes would encourage us to electrocute ourselves or pour liquid in. Without air circulation in the power supply, the benefit of a "system-saver" type fan doesn't achieve full benefit. 5. I suspect that Apple didn't used to pre-burn the ICs they used or the computers either. I've had three II+ plus computers blow a 74LS... IC within a few hours of being turned on for the first time. I have to admit that the level of quality control on E series has been much better. 6. On II+ plus computers that are operated 8 hours a day for 5 days a week, we've been averaging about 1-1/2 years on the lifetime of the power pack. 7. You can tell when a power pack is about ready to poop out, as it will occasionally emit high pitched chirps at random intervals. This is probably related to overloading of the switching regulator caused by partial failure of the output filter capacitor. Often the failure mode of the supply is that the filter cap shorts out due to elevated temp in the case, which thenm overloads the switching transistor and blows it out. In general, this means that if your power supply quits, you might as well toss it out, as there are likely multiple things wrong with it. 7a. There is often a conspicuous delay at power-on without even the lamp on the keyboard coming on; sometimes the supply will suddenly turn on as much as ten minutes later. Again, here the output filter capacitor is suspect. 8. I've been replacing the power packs in our apples with one that Jameco sells. So far they seem pretty reliable, and we haven't suffered any failures in the replacement packs, even on systems without add-on fans. The replacement power packs also have nice big vent slots to encourage air circulation and keep heating down. I have to be fair to Apple. With their more recent products, the hardware has been much better put together and seems to be more reliable overall. Now, my main disagreement with apple is that the user should treat the system as a black box. I'm glad that I got a chance to get to know apple in the old days when the machines came with honestly informative manuals. My favorite example is the manual that is packed with the sytem; the prodos filer manual that spends about 120 pages dwelling on the filer in excruciating detail, yet never even bothers to mention what the commands that can be typed directly into prodos are. Apple has gotten a little better with the user manuals on the latter versions of the //e in that at least there is cursory coverage of the fundamental prodos commands. Bill Mayhew Division of BAsic Medical Sciences Northeastern Ohio Universities' College of Medicine Rootstown, OH 44272 USA phone: 216-325-2511 (wmt@neoucom.UUCP ...!cbatt!neoucom!wtm)