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Amigaz
May 7th, 2008, 11:13 AM
Recently got hold of a Commodore desktop pc with a 386DX 33mhz motherboard with symphony chipset made my Peacock
The weird thing is that it has a system clock but there's no place on the motherboard for a battery :confused:
The Ami bios complain that the CMOS battery is low and it refuses to save my bios settings even though I do a warm reboot, can anyone please solve this mystery

Here's some pics of the motherboard, there's no pins for an external battery either

http://img396.imageshack.us/img396/5426/boardwu7.jpg

Here's the clock circuits

http://img395.imageshack.us/img395/9688/clockff4.jpg

kb2syd
May 7th, 2008, 11:14 AM
Just a guess, but the battery is probably built in to the Dallas 1287/1187 clock chip. See:
http://www.mcamafia.de/mcapage0/dsrework.htm

for a possible workaround.

Druid6900
May 7th, 2008, 11:19 AM
You see that black rectangle marked "Dallas" next to the AMI BIOS? That's your CMOS, RTC and battery all built into one.

It's not socketed, so, what you'd have to do is unsolder it, put in a socket and replace it with a DS12887 unit or, if you're a masochist, you could do the external coin battery mod to it. There is a link in one of the threads, just search for DS1287 and you'll probably find it

Amigaz
May 7th, 2008, 11:27 AM
You see that black rectangle marked "Dallas" next to the AMI BIOS? That's your CMOS, RTC and battery all built into one.

It's not socketed, so, what you'd have to do is unsolder it, put in a socket and replace it with a DS12887 unit or, if you're a masochist, you could do the external coin battery mod to it. There is a link in one of the threads, just search for DS1287 and you'll probably find it

Damn, talk about cheap design

Solder? my solder skills go as far as replacing a CMOS battery :(

Amigaz
May 7th, 2008, 11:30 AM
Just a guess, but the battery is probably built in to the Dallas 1287/1187 clock chip. See:
http://www.mcamafia.de/mcapage0/dsrework.htm

for a possible workaround.

Might try doing this work but my solder skills are almost zero

Well, If my soldering goes to hell I have 3-4 spare 386 mobo's , hehe :)

kb2syd
May 7th, 2008, 11:32 AM
Where are you located? If near to someone with good solder skills, you could be in business. If you get the board to me in NJ, I've made this mod several times.

Amigaz
May 7th, 2008, 12:23 PM
Where are you located? If near to someone with good solder skills, you could be in business. If you get the board to me in NJ, I've made this mod several times.

Would appreciate your help but there's a small catch...I'm located in the country with lots of Volvo, Saab cars and Ikea furniture :razz:

kb2syd
May 7th, 2008, 12:24 PM
I'm sure there is someone in California :-) that can help you.

Amigaz
May 7th, 2008, 12:30 PM
I'm sure there is someone in California :-) that can help you.

So there's lots of those things I mentioned in sunny California? ;)

I thought my hints would lead you to Sweden where I'm located :cool:

nige the hippy
May 7th, 2008, 01:26 PM
So there's lots of those things I mentioned in sunny California? ;)

I thought my hints would lead you to Sweden where I'm located :cool:

It kind of did!

If you do get your "dremel" or dentist's drill out, there is a slightly reduced modification to the 1287 I've got away with.
You only need to get to (and separate) the positive terminal of the internal battery ( grind away about 5mm above pin 20) when the bent-up pin is revealed work up & down it until you have an area big enough to solder to, then grind through the highest point to separate the piggybacked lithium battery. Just connect a wire, check with a meter that there are no volts on the wire relative to 0V (i.e. the battery really is disconnected) & if all OK, connect your new battery to that, and any handy 0V on the motherboard. You can solder a lithium coin cell holder (NOT the cell!) to a handy bit of ground plane.

The original mod mentioned elsewhere involves getting to both battery connections, this saves a bit of work & upps the chances of getting it right by 75%!

If you're not handy with a soldering iron, take it to someone who is!

modem7
May 7th, 2008, 05:38 PM
If you decide to take the route of replacing the DS1287 (you find someone with soldering skills), note the following, which is based on previous threads in these forums.

1. The DS1287 and equivalents have a manufacturer specified shelf life of around 10 years.

2. If you source an unused DS1287, the battery within it is either dead, or close to it (because they were made so long ago).

3. If you source a device claiming to be a direct equivalent for the DS1287 (e.g. DS12887, BQ3287):
* Depending on date of manufacture, the battery within it is either dead, or partially depleted.
* As stated by the manufacturer, under some circumstances the device is not a direct replacement.

4. Also, the DS1287 (or equivalent) bought off-the-shelf will be empty of data. The BIOS on some motherboards require that the device be preset with certain data before it is fitted to the motherboard. I think that will be a rare situation.

If you want to read the detail, see thread http://www.vintage-computer.com/vcforum/showthread.php?t=7048

That all sounds negative, but based on the "DS1287" threads you'll find in these forums, there's a good chance that you will able to obtain an equivalent to the DS1287 with some life left in it, and it will work in your motherboard.

Personally, if I had a board with a dud DS1287, I'd be doing the modification where a battery and battery holder end up on top of the DS1287.

Druid6900
May 7th, 2008, 07:31 PM
Based on my experience with the three DS12887s I bought from an outfit in Texas, I believe, when tested with a load battery tester, all three registered a full charge.

Two of them went into Commodore PC-20s and the third went into an IBM PS/2. The IBM required that a jumper be inverted and it worked fine after that. The two in the Commodores worked fine right off the bat and all three are still working fine.

Two 1287s that I pulled off a couple of 386 motherboards that weren't worth repairing (which, of course, I got AFTER I had received the 12887s) show a loaded voltage .2V down from a full charge.

YMMV

modem7
May 8th, 2008, 04:31 AM
The DS1287 was made by Dallas Semiconductor, and that company was bought by Maxim. Maxim have an application note at http://www.maxim-ic.com/appnotes.cfm/an_pk/505 which discusses Lithium coin-cell battery life in products such as the DS12887.

In reference to using battery voltage as an indication of remaining charge, the note contains, "The voltage also remains stable during the battery discharge (Figure 2), so the voltage at the end of life is nearly the same as with a fresh battery. While a flat discharge curve is desirable for backup supply voltage, it does make predicting the remaining electrical capacity difficult."

And the "flat discharge curve" of the Lithium coin-cell battery is mentioned at various web sites.

Interesting application note. The only internal deterioration component they've included in the calculations is 'electrolyte evaporation'. So in Case I, they are indicating that because of electrolyte evaporation, if you keep a BR1632 coin cell at 25 degrees C, it will last 230 years, however, because in this case 1.2uA is being always being externally drawn, the life is reduced from 230 to 10.9 years. Hmmm. So an unused BR1632 put on the shelf and kept at 25 degrees C will still be usable in 200 years time!
Why aren't they factoring in self-discharge (loss because of internal resistance), which is what I presume is why various web sites state that Lithium coin-cell battery shelf life is approximately 10 years. Even some of the Lithium CR2032 batteries I have, have "Best before 2016" printed on the packet.

Druid6900
May 8th, 2008, 09:35 AM
Ok, I'll post to this thread when they die and then we'll know :)

Amigaz
May 8th, 2008, 12:13 PM
Today I got a full AT 386 @33mhz mobo I have bought....guess what...it has that darn Dallas clock/batt chip too...DOH!:hammer:

http://img140.imageshack.us/img140/4334/p1010364rv0.jpg

The little bugger:

http://img140.imageshack.us/img140/9371/p1010366el8.jpg

Have a friend at work who has solder skills...might bribe him to desolder the old chips and solder on the replacements you guys mention?

Thanks for all the advice and tips

btw. this full AT board is huge! can't have been cheap back in the late 80's when I think it was made....have a nice Targa full tower which will be it's new home as a vintage gaming rig for late 80's/early 90's games :)

mikey99
May 8th, 2008, 12:35 PM
But think of the alternative, one of those onboard ni-cad batteries
that has leaked acid all over the board and destroyed it :D



Today I got a full AT 386 @33mhz mobo I have bought....guess what...it has that darn Dallas clock/batt chip too...DOH!:hammer:

Amigaz
May 8th, 2008, 10:17 PM
But think of the alternative, one of those onboard ni-cad batteries
that has leaked acid all over the board and destroyed it :D


Yeah, you're right....that's the Amiga disease, they must have chosen a battery manafacturer with the leakiest batteries

I could live with a dead Dallas clock circuit battery and just change the bios settings after a cold boot but when this crap circuit can't keep my settings after i warm reboot it's very annoying :rolleyes:

dongfeng
May 8th, 2008, 11:54 PM
If you are going to replace it, solder a socket on the board so replacement is easier in the future ;)

Amigaz
September 27th, 2008, 03:15 AM
Update:

Have tested the huge full AT 386 motherboard which seem to work flawlessly but as I suspected the Dallas chip battery is dead
There's a 4 pin header as you can see on the top left on the motherboard...right over the com port heards, wonder if that's an external battery header? not sure if suck a thing exists on a motherboard when you have a Dallas chip..
Haven't found any any information of jumper settings on this beast...on neither Stason.org or any Total Hardware '99 mirro r :(

Tinkerer
September 27th, 2008, 02:07 PM
Many old PC's have the DS1287 in them, many were socketed. I reckon that's something to look for when considering a purchase. The DS1287 is in all the mid-90s Gateway computers I have. Some time back I snagged about 20 of the DS1287s and use them as replacements for the ones that are flat when purchaed. They are all goood pulls from previous computers and I have yet to find a bad one.
You know upon reflection those may indeed be socketed. It's hard to tell by looking as the DS1287 is wider than the socket. I remember thinking the same thing as when I went to pull the first one it was very stubborn.
I have also heard the degradation takes 10-16 years when the battery is on the shelf. Time will tell.
The Northgate 386 SuperMicro board uses the DS1287 and also shows a battery connector @ J1, also a 4-pin header, but I'm not sure how it would be utilized or if it even can be.
Hmm, my 286 showed low battery state the last time I turned it on. It has the the barrrel shaped lithium battery soldered to the board. I better yank that sucker before it starts leaking on me.

paul
September 27th, 2008, 11:01 PM
I was thinking that 386-33 board looked like a DTK that I had bought new at work about 1990 but it's missing the "step" in the board outline (top edge in photo) that you would normally see in a full-AT form factor.

But it does have an external cache so should be fast. The DIP switches must be for setting the start address for the optional proprietary external memory card that would have plugged into that end slot.

The DTK was the board I first tried Linux on, Slackware 1.x. I eventually used it for dial-in PPP access to the company network.

Lastly, the RTC chip looks similar to the SGS-Thomson M48T02 used in my Sun IPC. Apparently, the clock can be stopped to reduce battery drain, something I do before putting mine in storage. It's in a socket but will need the battery hack next time it fails as replacements are apparently no longer available.

Amigaz
September 29th, 2008, 04:30 AM
I was thinking that 386-33 board looked like a DTK that I had bought new at work about 1990 but it's missing the "step" in the board outline (top edge in photo) that you would normally see in a full-AT form factor.

But it does have an external cache so should be fast. The DIP switches must be for setting the start address for the optional proprietary external memory card that would have plugged into that end slot.

The DTK was the board I first tried Linux on, Slackware 1.x. I eventually used it for dial-in PPP access to the company network.

Lastly, the RTC chip looks similar to the SGS-Thomson M48T02 used in my Sun IPC. Apparently, the clock can be stopped to reduce battery drain, something I do before putting mine in storage. It's in a socket but will need the battery hack next time it fails as replacements are apparently no longer available.

Agree that it looks alot like that board but the DTK board also lacked SIMM slots.
Have 4x1mb simm's in mine now...not sure if it can handle 4mb simm's
This board can be used to heat a small room, when I test the board lying flat without a case thw whole board got evenly warm all over the board...must be that it's packed with all of these components.
Have a nice full tower from the same year as the board which I'll fit it in.

Amigaz
October 29th, 2008, 10:57 PM
I was thinking that 386-33 board looked like a DTK that I had bought new at work about 1990 but it's missing the "step" in the board outline (top edge in photo) that you would normally see in a full-AT form factor.

But it does have an external cache so should be fast. The DIP switches must be for setting the start address for the optional proprietary external memory card that would have plugged into that end slot.

The DTK was the board I first tried Linux on, Slackware 1.x. I eventually used it for dial-in PPP access to the company network.

Lastly, the RTC chip looks similar to the SGS-Thomson M48T02 used in my Sun IPC. Apparently, the clock can be stopped to reduce battery drain, something I do before putting mine in storage. It's in a socket but will need the battery hack next time it fails as replacements are apparently no longer available.

Regarding these dip switches...you think they can interfere with the mermory I have installed now in the 4 simm slots?
I've tried different simm's/sizes, it seems I'm limitied to 4mb total ram....if not these dip switches have something to do about it.....

Amigaz
November 1st, 2008, 01:47 AM
^bump^

paul
November 1st, 2008, 03:57 AM
Do you think it even supports 4 MB simms? There must be a reason for needing that memory card.

Amigaz
November 1st, 2008, 01:28 PM
Do you think it even supports 4 MB simms? There must be a reason for needing that memory card.

Nope, the problem is that it won't even recognise XMS configured memory on my DFI Megalith ISA memory card so the switches must be doing something?

Terry Yager
November 1st, 2008, 01:34 PM
Nope, the problem is that it won't even recognise XMS configured memory on my DFI Megalith ISA memory card so the switches must be doing something?

Some mainboards are just picky about their memory type/configuration/etc. Have you tried it with different SIMMs?

--T

QuantumII
November 4th, 2008, 09:29 AM
I did the Dallas chip mod with a coin cell battery a year ago on a Compaq SLT/286 laptop. Still works fine. Just follow the instructions at the beginning of this thread and you'll be fine.

Clas Ohlson has cheap soldering irons you know (You should, you're Swedish :D )

Amigaz
November 4th, 2008, 09:53 AM
I did the Dallas chip mod with a coin cell battery a year ago on a Compaq SLT/286 laptop. Still works fine. Just follow the instructions at the beginning of this thread and you'll be fine.

Clas Ohlson has cheap soldering irons you know (You should, you're Swedish :D )

A friend of mune soldered a socket in which I put a NOS Dallas DS12887 chip :mrgreen:

hey, I'm a "stamkund" at Clas Oholson and Kjell & Co but my soldering skills are non existing, hehe

QuantumII
November 4th, 2008, 09:44 PM
It's good that you got it fixed.

Say, is it hard to get hold of vintage equipment in Sweden ?
In Norway it's not much to brag about. I've been to several flea markets (In the Oslo area) over the year, and not a single PC older than pentium II.:confused:

per
November 4th, 2008, 11:24 PM
It's good that you got it fixed.

Say, is it hard to get hold of vintage equipment in Sweden ?
In Norway it's not much to brag about. I've been to several flea markets (In the Oslo area) over the year, and not a single PC older than pentium II.:confused:

I know, I know... It seems for me that people more or less toss them out or overprice them on sites like Finn.no rather than selling them on flea markets (fleamarkets are also pretty uncommon in Norway). Many people I have met actually assumes that any computer equiptment older than pentium II won't work at all!

Amigaz
November 4th, 2008, 11:27 PM
It's good that you got it fixed.

Say, is it hard to get hold of vintage equipment in Sweden ?
In Norway it's not much to brag about. I've been to several flea markets (In the Oslo area) over the year, and not a single PC older than pentium II.:confused:

Same situation here...in fact the exaxt same situation, anything older than Pentium II hardware is impossible to find.
What you can find easily though is Atari, C64 and Amiga stuff...it's like people have more respect for these computers.
Recycling has been too efficient and if people have anything old they never bothert to sell it and go to the dumpster with it instead :(

QuantumII
November 5th, 2008, 12:12 AM
Yeah.. The recycling really damages this hobby. And what's worse, it's not legal to pick up stuff from the recycling dumpsters outsite the electro stores (I do it anyway)..

Some even destroy everything in the dumpsters to avoid people picking up stuff.

On the positive side, where I work there also is a recycling station. A lot of cool stuff, but almost never vintage. I found a 386 commodore desktop there, but didn't take it.... I still regret it..

Amigaz
November 5th, 2008, 01:39 AM
Yeah.. The recycling really damages this hobby. And what's worse, it's not legal to pick up stuff from the recycling dumpsters outsite the electro stores (I do it anyway)..

Some even destroy everything in the dumpsters to avoid people picking up stuff.

On the positive side, where I work there also is a recycling station. A lot of cool stuff, but almost never vintage. I found a 386 commodore desktop there, but didn't take it.... I still regret it..

Seme here...we have a big recycling plant here with piles of old pc's but the staff are very brute, they give you the "evil eye" even if you look at the stuff, lol :D

Commodore 386 desktop? damn!
Did it by chance have the same chassis as the desktop at the top on this pic?

http://lh5.ggpht.com/_QyE3126ASao/SRF3HrexsmI/AAAAAAAAATI/NLyTCKQd73U/s800/P1010001.JPG

QuantumII
November 5th, 2008, 02:22 AM
It was the same as the bottom one in the picture, a slightly more yellowed case, but the same look.

I recently "rescued" 3x 5,25" floppy drives from the recycling room at work (there are many companies inside the buildings) so I'm hoping that the pc's they came from appear soon as well..

Amigaz
November 5th, 2008, 02:42 AM
It was the same as the bottom one in the picture, a slightly more yellowed case, but the same look.

I recently "rescued" 3x 5,25" floppy drives from the recycling room at work (there are many companies inside the buildings) so I'm hoping that the pc's they came from appear soon as well..

Sure it was a 386 then?

The only Commodore 386 I'm aware of is this model:

http://www.commodore-amiga-retro.com/amiga/car_0108/car1207274.jpg

QuantumII
November 5th, 2008, 02:49 AM
Yes, pretty sure it was. I did pick it up to rescue the floppy drive, but I tossed the rest... I must have been drunk or something.

The bottom one with the CD-rom, what CPU does it have ?

Amigaz
November 5th, 2008, 03:16 AM
Yes, pretty sure it was. I did pick it up to rescue the floppy drive, but I tossed the rest... I must have been drunk or something.

The bottom one with the CD-rom, what CPU does it have ?

You're right, of course it's a 386....these are actualy my own pc's
It's built like a tank like the Amiga 2000 but I wish they had used standard AT components
It has a 386 SX 16mhz CPU in it, 4mb sipp RAM etc

I must suffer from temporary alzheimers disease, hehe

QuantumII
November 5th, 2008, 03:43 AM
What part(s) of the machine is not standard AT ? Does it have it's IDE controller on a ISA card or onboard ?

Amigaz
November 5th, 2008, 04:28 AM
What part(s) of the machine is not standard AT ? Does it have it's IDE controller on a ISA card or onboard ?

Motherboard and case isn't standard AT but their own design "a lá DELL"

QuantumII
November 5th, 2008, 05:05 AM
Motherboard and case isn't standard AT but their own design "a lá DELL"

And IBM and Compaq and Fujitsu Siemens and..

And, where did you get yours ? (the bottom one)

Terry Yager
November 5th, 2008, 02:39 PM
Same situation here...in fact the exaxt same situation, anything older than Pentium II hardware is impossible to find.
What you can find easily though is Atari, C64 and Amiga stuff...it's like people have more respect for these computers.
Recycling has been too efficient and if people have anything old they never bothert to sell it and go to the dumpster with it instead :(

Sweden might well be the most recycle-concious nation on Earth. Nobody ever throws anything away, do they?

--T

Amigaz
November 5th, 2008, 02:43 PM
Sweden might well be the most recycle-concious nation on Earth. Nobody ever throws anything away, do they?

--T

They do, but then it get's recycled :mrgreen:

My 286 PC is actually garbage room find :cool: