modem7
10k Member
There's a postmortem at http://www.mcamafia.de/mcapage0/dsrework.htm
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Dallas RTC BIOS Trouble - Compaq SLT/286
- Thread starter Fezzler
- Start date
BillT356
Experienced Member
I have a slt286, with a bad main battery, found the unit would not boot pass the post with the battery installed. Run it on just the AC supply without the main battery installed. That's how I run mine.
Well, the first time I removed the DS1287 chip went great. I clipped the chip legs and used braid to remove solder and cleaned MB well. And my installation was top notch too. Real clean solder job. "Heat the item to be soldered, not the solder" I tell myself.
Now, trying to removed that top notch job and save the chip so I could perhaps do the external battery mod to the DS1287 was a complete disaster. Several of the small hole plating rings and one MB lead actuall came undone. I'm pretty upset. Board now boots to system failure.
I guest I'm screwed and the computer is trash unless some has idea/suggestion.
I sent the company that knowingly sent me bad DS1287 chip a email expressing my disappointment (Bluestar International Components). Who sells an item, then when I report it was dead, send a new one with a note that says, "oh yea, BTW, we have been getting high rates of reports of failed DS1287 chips, here's a new one."
To be clear, I'm new to the moding/refurshing game. I think my soldering skills were okay when the chip was clipped and I could easily heat the remaining solder in the holes. But I think I lacked the experience to get a chip out in tact. What I needed was a 24-pin solder iron so I could heat all 24 at once and remove chip.
Anyway, I guess I've learned something here. Not sure what yet. Very disappointed.
Now, I should just trash the computer but for some reason I get this "it will not defeat me attitude." One thing I likes about this computer it ran DOS 5.0, had a 3 /12 floppy, HD and external 5.25 floppy. Was portable. Nice working hobby computer when working on older computers. I ran DISK22 on in and TDO disk images. You know.
UGH!
Now, trying to removed that top notch job and save the chip so I could perhaps do the external battery mod to the DS1287 was a complete disaster. Several of the small hole plating rings and one MB lead actuall came undone. I'm pretty upset. Board now boots to system failure.
I guest I'm screwed and the computer is trash unless some has idea/suggestion.
I sent the company that knowingly sent me bad DS1287 chip a email expressing my disappointment (Bluestar International Components). Who sells an item, then when I report it was dead, send a new one with a note that says, "oh yea, BTW, we have been getting high rates of reports of failed DS1287 chips, here's a new one."
To be clear, I'm new to the moding/refurshing game. I think my soldering skills were okay when the chip was clipped and I could easily heat the remaining solder in the holes. But I think I lacked the experience to get a chip out in tact. What I needed was a 24-pin solder iron so I could heat all 24 at once and remove chip.
Anyway, I guess I've learned something here. Not sure what yet. Very disappointed.
Now, I should just trash the computer but for some reason I get this "it will not defeat me attitude." One thing I likes about this computer it ran DOS 5.0, had a 3 /12 floppy, HD and external 5.25 floppy. Was portable. Nice working hobby computer when working on older computers. I ran DISK22 on in and TDO disk images. You know.
UGH!
tezza
Veteran Member
Yes, I had a STL286 given to me and wondered why the battery had a piece of sellotape over the battery contacts? I soon found out why. When I removed it the machine wouldn't boot. When I replaced the sellotape so the contacts didn't make contact it was fine.
Actually it wasn't "fine". What I meant was that it eventually booted to DOS on the hard drive but only after going through all the config/BOIS warning messages. The floppy disk is faulty so I couldn't use the diagnostic diskette I downloaded from the Internet. However, in reading this thread it would seem even if I got that working, I'd still have the "dead internal battery" issue to content with.
In the meantime, I use INTERSRV on DOS 6.0 to transfer software to the machine from another DOS Box connected via RS 232 cable. This gives the STL286 another external drive of sorts and works like a charm.
Actually, I'm only ASSUMING the floppy disk is faulty? Perhaps it's got something to do with this battery/bios problem? It's a 1.2MB drive and I know the default bios would think it was 720k. Thing is the drive doesn't seem to spin at all! I would have thought it would have at least tried to access a disk? But maybe I'm wrong?
Druid6900
Veteran Member
Ok, the board, most likely, isn't multi-layered, so, on the holes that you pulled the plate-thrus out of (or ripped the pads off of), get some wire-wrap wire and strip the insulation off, feed enough into the holes so you have about an inch on each side of the board, put the chip back in, solder as normal.
When you are done, scrape a bit of the masking off the lands where you rip the pads off and solder the wire-wrap to the land. This is a "less than 3 seconds heat" operation.
Trim excess wire-wrap wire.
Added later; You might want to do a few turns with the middle part of the wire wrap strand around the pin where there is no feed-thru just to give it some mechanical attachment.
When you are done, scrape a bit of the masking off the lands where you rip the pads off and solder the wire-wrap to the land. This is a "less than 3 seconds heat" operation.
Trim excess wire-wrap wire.
Added later; You might want to do a few turns with the middle part of the wire wrap strand around the pin where there is no feed-thru just to give it some mechanical attachment.
Last edited:
easternpinman
New Member
another SLT 286
another SLT 286
I have bought this machine on ebay, machine started OK , I have changed the time via norton utilities to a current date 2009 , I do not remember the old date from the 80 s or 90 , during machine powered I have removed the battery and messured with a voltmeter it was ok , put the battery back and shut down from the power button, then try to start only on battery, removed AC power , machine has started and displayed the 162 error the same issues as from user Fezzler ,,,,,,,,,,,last message here is quite old I will try contact Fezzler to see how has he ended up this story ,,,,
another SLT 286
I have bought this machine on ebay, machine started OK , I have changed the time via norton utilities to a current date 2009 , I do not remember the old date from the 80 s or 90 , during machine powered I have removed the battery and messured with a voltmeter it was ok , put the battery back and shut down from the power button, then try to start only on battery, removed AC power , machine has started and displayed the 162 error the same issues as from user Fezzler ,,,,,,,,,,,last message here is quite old I will try contact Fezzler to see how has he ended up this story ,,,,
Last edited:
Druid6900
Veteran Member
Try setting the year to 1999 and see if it boots right.
If it does, then just set the date to the correct one using the Date command in DOS.
It's worked for me on a couple of old machines.
If it does, then just set the date to the correct one using the Date command in DOS.
It's worked for me on a couple of old machines.
easternpinman
New Member
hi thanks for replay
tried 1999 . no use I have also run the fix file for cmos battery it sets to CMOS BATTERY : OPERATIONAL but after restart with : ctrl alt del I have the same 162 error
with setup compaq : battery lost power ,,,contact compaq bla bla
and in sysinfo with norton commander
CMOS BATTERY : LOST POWER
CMOS TIME : VALID
tried 1999 . no use I have also run the fix file for cmos battery it sets to CMOS BATTERY : OPERATIONAL but after restart with : ctrl alt del I have the same 162 error
with setup compaq : battery lost power ,,,contact compaq bla bla
and in sysinfo with norton commander
CMOS BATTERY : LOST POWER
CMOS TIME : VALID
Druid6900
Veteran Member
Ok, so much for that.
Another thing I've seen suggested is resetting the CMOS (usually a jumper that you switch from one position to another, but, with Compaq, who knows?)
Is the RTC that you got an actual DS1287 or a DS12887?
Another thing I've seen suggested is resetting the CMOS (usually a jumper that you switch from one position to another, but, with Compaq, who knows?)
Is the RTC that you got an actual DS1287 or a DS12887?
patscc
Veteran Member
battery
battery
Can you measure the voltage of the battery in-circuit ?
patscc
battery
Can you measure the voltage of the battery in-circuit ?
patscc
easternpinman
New Member
I have a RTC DS1287
and the bios battery is inside of this device , it can not be messured from outside
CMOS reset jumper to this old compaq ???????
What is puzzling here is that the machine forgets only time it does not forget the other setting like HDD drive ,,,,,,,,,
I think that in fact machine does not save the new time setting and probably this is because the battery from DS1287 is dead
I have read previos messages about DS 1287 rework on that , probably I will try that
and the bios battery is inside of this device , it can not be messured from outside
CMOS reset jumper to this old compaq ???????
What is puzzling here is that the machine forgets only time it does not forget the other setting like HDD drive ,,,,,,,,,
I think that in fact machine does not save the new time setting and probably this is because the battery from DS1287 is dead
I have read previos messages about DS 1287 rework on that , probably I will try that
Last edited:
patscc
Veteran Member
clock
clock
You are, of course, right. From your post I misunderstood that you had an encapsulated battery in a Dallas RTC. Should have gone back and read the earlier ones.
Have you tried changing any other settings in CMOS to see if it takes the changes ?
If it doesn't take any changes, then either the trace you lifted, or the thru-holes haven't fully been repaired.
If you truly are fed up with it, put it up on the marketplace. I'm sure someone will want to either fix it up or part it out.
patscc
clock
You are, of course, right. From your post I misunderstood that you had an encapsulated battery in a Dallas RTC. Should have gone back and read the earlier ones.
Have you tried changing any other settings in CMOS to see if it takes the changes ?
If it doesn't take any changes, then either the trace you lifted, or the thru-holes haven't fully been repaired.
If you truly are fed up with it, put it up on the marketplace. I'm sure someone will want to either fix it up or part it out.
patscc
dpatten
Experienced Member
I think Dallas 1287 clock battery replacement might be a good topic for an FAQ if someone were to be working on one.
easternpinman
New Member
I have reworked the RTC as in the previous comments from :
http://www.mcamafia.de/mcapage0/dsrework.htm
that was the problem, the inside battery was 0,46 volts so DEAD
I have put new external one and all was OK ,put the setup disk from compaq , clock can be set at current time saved the settings ok and machine was running again, main power battery still works for 15 min wow ! so any dos run has backup power
I have 2 more machines in workshop LT 286 and LTE 286 both needs hard disks I will start a new thread for those ,,,,
http://www.mcamafia.de/mcapage0/dsrework.htm
that was the problem, the inside battery was 0,46 volts so DEAD
I have put new external one and all was OK ,put the setup disk from compaq , clock can be set at current time saved the settings ok and machine was running again, main power battery still works for 15 min wow ! so any dos run has backup power
I have 2 more machines in workshop LT 286 and LTE 286 both needs hard disks I will start a new thread for those ,,,,
linemanduke
Veteran Member
great to here you finally got it. im dealing with one now (1287 not a compaq)
computer says bios is corrupt and i for the life of me can't find the one i battery modded for my ps/2 30 before it died.
computer says bios is corrupt and i for the life of me can't find the one i battery modded for my ps/2 30 before it died.
102-System Board Failure
102-System Board Failure
After successfully repairing one Compaq SLT/286 by patching the Dallas 1287 RTC, I decided to try another.
On this board I had soldered in a low-profile socket. I drilled into a 12887 RTC to expose pins 16 and 20 and they read 3v so I popped the chip in.
UGH. 102-System Board Failure. I think in removing the old Dallas 1287 RTC and sodlering in the low profile socket, I may have damaged motherboard. I did notice that the MB nais were difficult to solder to. I bet that is it.
So do I mess more or trash this old dog?
C~
102-System Board Failure
After successfully repairing one Compaq SLT/286 by patching the Dallas 1287 RTC, I decided to try another.
On this board I had soldered in a low-profile socket. I drilled into a 12887 RTC to expose pins 16 and 20 and they read 3v so I popped the chip in.
UGH. 102-System Board Failure. I think in removing the old Dallas 1287 RTC and sodlering in the low profile socket, I may have damaged motherboard. I did notice that the MB nais were difficult to solder to. I bet that is it.
So do I mess more or trash this old dog?
C~