Hello Eric and group, I have an old 386 I use for programming. I went to boot it up one night and all I got was "BIOS ERROR" Well long story short it was the dead battery in the potted Dallis chip. After searching around for a replacement I discovered it was going to cost me almost $50 for the part and shipping. All because of a little button battery going dead, I don't think so, time to hack.
Well with a fresh pot of coffee and an exacto knife in hand, I started carefully chipping away at the epoxy. (I placed the chip in a fresh 28 pin socket to protect the pins while I worked.) I soon uncovered the battery and a crystal soldered directly to the missing pins that had been bent upward on the original clock chip. I soldered a short black and red wire to the pins and then to a battery socket salvaged from a old mother board. Slid in a button cell and all is well. I placed the socket and battery in a plastic bag and ty-rapped it to the chip. If I still have it the next time it goes dead, just slide in a new battery and done. I now have the HD information written on the side of the case for quick reload. It took me almost half a day to find the paper file with the information. So if you also have one of these old systems running, take the time right now to write down the HD information from the BIOS screen and keep them handy! Give it a try, 73 Shanon KA8SPW Eric Lemmon wrote: > Don, > > The "on-the-hour" tone is an 800 ms burst of 1500 Hz. I have built a PLL > 1500 Hz tone detector into a Hamtronics WWV receiver, and it works fine- > giving me a relay contact closure exactly on the hour. Unfortunately, that > would only allow me to jam-set the minutes and seconds to zero, and would > not correct an hour error- such as when DST starts and stops. > > I considered dispensing with the voice time announcement completely, and > just broadcast an hourly beep. The problem is that transmitters don't come > up instantly, and most or all of the beep will be missed. My solution to > that problem is to use the on-the-hour pulse to reset a simple countdown > timer that closes a PTT relay at the end of a 59 minute 57 second delay. > The countdown timer will key the transmitter shortly before the hour, > ensuring that it is ready to pass the 1500 Hz beep exactly on the hour. As > soon as the beep detector relay relaxes, PTT goes away, and the repeater > will issue its identity message and return to idle mode. I'm still > tinkering with this idea. The downside is that WWV reception varies with > the time of day and propagation factors, and a decent antenna is required. > > 73, Eric Lemmon WB6FLY > > > -----Original Message----- > From: [email protected] > [mailto:[EMAIL PROTECTED] On Behalf Of Don Kupferschmidt > Sent: Sunday, November 11, 2007 5:43 PM > To: [email protected] > Subject: Re: [Repeater-Builder] Dallas Semiconductor Real-Time Clock (Was > RC-96 Controller Problem) > > Eric, > > I've been toying around with this idea for a couple of years - set the SCOM > 7K clock to atomic standards. As you know, the 7K's are prone to drifting > with their time of day clock. > > The idea is to have a stable WWV signal that "listen" to the top of the hour > > signal. I'm thinking that is a 1000 kHZ tone, but I could be wrong about > that. > > If someone could build a circuit to decode the top of the hour signal from > WWV, you could command the controller, through macros, to reset the clock. > Shouldn't be all that difficult. > > The designers of the new SCOM controller recognized that problem earlier, > and as I am told, have placed a new crystal / circuit in the time of day > clock to address that problem in the 7330 line. > > With all of the 7K's out in the field, if a simple circuit could be made it > would eliminate the drifting problem. > > Don, KD9PT > > ----- Original Message ----- > From: "Eric Lemmon" <[EMAIL PROTECTED] <mailto:wb6fly%40verizon.net> > > To: <[email protected] > <mailto:Repeater-Builder%40yahoogroups.com> > > Sent: Sunday, November 11, 2007 3:27 PM > Subject: [Repeater-Builder] Dallas Semiconductor Real-Time Clock (Was RC-96 > Controller Problem) > > >> Mike and others, >> >> The Dallas Semiconductor "Nonvolatile Timekeeping RAM" found in many >> popular >> controllers, including the Link RLC-1 Plus, is Part Number DS1643-150. >> The >> 11-page datasheet can be downloaded here: >> >> <www.datasheetarchive.com/pdf/1235806.pdf> >> >> Notice that the "-150" indicates 150 ns access time. The replacement >> device >> offered by Dallas/Maxim has either 70 ns or 100 ns access time, and I have >> no idea if the newer device will work properly where a 150 ns device was >> used. >> >> On page 5 of the datasheet is a paragraph entitled "Internal Battery >> Longevity" which states that the device can operate for 10 years in the >> absence of VCC power. When powered as it would normally be in a typical >> application, the note states that the lifetime can be as long as 20 years. >> The battery is not accessible for replacement. >> >> I see that the guaranteed accuracy of the DS1643 clock is within +/- 1 >> minute per month, and there is no capability to tweak the crystal to get >> better accuracy. One of the Hams in my area is experimenting with a >> scheme >> to use a so-called atomic clock to jam-set the correct time once per day. >> With regular synchronism to WWVB, the time announcements will normally be >> no >> more than a second off. Once he gets this idea working, perhaps I can get >> him to write an article about it. I and many other "time-and-frequency >> geeks" think that time announcements should be correct. >> >> 73, Eric Lemmon WB6FLY >> > > > > > > > > Yahoo! Groups Links > > > > >
