On Sunday, March 24, 2002, at 10:36 , Gamba wrote: >> The new >> "cowboy" battery shows 4.65v, tested at the connectors in the Plus, not >> on the battery's ends. >> Eagle > > With Plus turned off, if voltage at pin 8 of PRAM chip is the same as > that > across battery, then that means there is no diode, which means your > previous reverse battery installation could have done damage.
(Gamba, please see note at bottom.) Greetings, all. Be warned: somewhat long (and detailed) post ahead. OK, here's the deal with the Plusses. I have 3 Plusses. Let's give them names to make this easier: 1- Mine 2- Grey's 3- Free "Mine" is the one I had been using for a long while. This is the machine that had the original PRAM battery that went dead, where "dead" means 3.5v or so across the battery terminals. This is the one I recently adjusted with a TV tuner set. Until the "battery incident" the machine was in amazing shape. 4MB RAM. I one time accidentally put the Energizer 523 in upside down in this one because I forgot to look which way was +. Oops. My goof. "Grey's" is the other machine I got back in December. It is the one whose screen didn't work for the longest time. After a bit of fiddling, the screen started working and except for the screen being way out of adjustment, the machine worked fine. When checked last week, I found its PRAM battery at the sub-1v level. 4MB RAM. "Free" is the one I got at a swap meet a few weeks ago. It was the big unknown here. Its screen is out of focus, and its PRAM battery is dead (sub-1v) but otherwise it functions well. 4MB RAM. I put the new PRAM battery into "Mine" upside down because it was mislabeled by the "professional" at Batteries Plus. (Perhaps the US Fed Govt should work to "federalize" Batteries Plus employees?) Anyway, this machine exhibits the problem of inability to switch from LocalTalk to EtherTalk. I took the new battery and put it into "Free" - partially because it was a freebie (and, if killed, nothing lost), and partially to check the machine out. Unfortunately it, too, had the battery placed upside down because of the mislabling on the part of Batteries Plus. This machine also exhibits the problem of inability to switch from LocalTalk to EtherTalk. Here's what I did tonight... I took the battery and put it into "Free" (the correct way this time) and zapped the PRAM on bootup. I booted into 7.0.1 and set the Date & Time. I powered down for ~10 minutes and checked the settings. Looked good. Tried switching to EtherTalk. No dice. Same sequence with "Mine." Battery inserted correctly, boot & zap PRAM, reboot into 7.0.1. Configure Date & Time. Check after 10 minutes of power-off. Looked good. Tried switching unsuccessfully to EtherTalk. Same sequence with "Grey's." Battery inserted correctly, boot & zap PRAM, reboot into 7.0.1. Configure Date & Time. Check after 10 minutes of power-off. Looked good. Tried switching to EtherTalk, AND SUCCESSFULLY SWITCHED. So, my guess is that the inverted battery killed the clock chip, among other things. And who knows what "other things" that might be? Anybody have any idea of whether it's possible to repair those motherboards? Or are they shot, with the rest of the computer useful only for spare parts? Finally, Gamba, I checked pin 8 of the (clearly labeled) "Clock Chip." :) The battery registers approx. 4.6 volts, while pin 8 of that chip registers approx. 3.6 volts. What does that tell you? (This was measured by putting the positive lead to pin 8, and touching the negative lead to the frame.) Sorry for the long post, all. I hope this clears up my recent activities and situations. I'm probably going to pull the "good" motherboard from "Grey's" and put it into "Mine." Eagle -- Compact Macs is sponsored by <http://lowendmac.com/> and... PowerON Computer Services <http://www.poweron.com> REPLACEMENT PARTS in STOCK Drives, CD-ROMs, RAM, Mac OS SW, Power Supply <mailto:[EMAIL PROTECTED]> Support Low End Mac <http://lowendmac.com/lists/support.html> Compact Macs list info: <http://lowendmac.com/lists/compact.shtml> The FAQ: <http://macfaq.org/> Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/compact.macs%40mail.maclaunch.com/> Using a Mac? Free email & more at Applelinks! http://www.applelinks.com
