I am trying to find the right Dallas battery for my 486 motherboard.
The socket has 24-pin holes. So I assume any Dallas with 24-pin will work ?
Originally I put a Dallas 12887A in it but it did not work and is missing some pins.
So I want to try this 12885.
What do you think ?
The 12885 looks funny, is this a fake or knock-off ?
All Dallas chips miss pins, look at all the "NC" pins on the diagram you just posted...
First off, the different Dallas chips are not mutually compatible (other than 1287=12887), so you need to find out what was originally on the board. The manual should say.
Secondly, the DS1285 is an RTC without a battery, so if there's no battery on your board, that one definitely isn't right. That's also why it looks 'funny'.
Thirdly, unless you want to mod new batteries onto old modules, don't buy these things 2nd hand as the included batteries are almost certainly dead. Buy them new form a reputable (online) electronics store.
Finally, what do you mean by " it did not work"?
- it boots up but doesn't hold time settings after power down? If so, it's the correct type of module, just the battery is dead. Mod a new battery onto it or buy a new one that does work.
- it doesn't boot at all? Then it's probably the wrong kind of module (most likely alternative: DS1387 RTC RAMified, which is no longer made, so you need to mod it).
That what I want to find out if it is the Dallas clock that is causing the motherboard not to boot.
So if I put the 12885 in it it should boot just not hold the bios settings right ?
I don't have the original manual and the information I have about this motherboard does not list the Dallas battery type.
I received this motherboard with-out a Dallas battery.
A board that needs a Dallas RTC will only boot with the right one. Certainly you can't use a DS1287 in a DS1387 board or vice versa. I've never tried to stick a DS1285 into a board that needs a DS1287, so it might be compatible - but if it is, then you know it won't boot anyway, as the DS1287 didn't let it boot.
How about posting the information you do have, starting with the motherboard name, or failing that a good high-res picture of your own board (and not some stock pic) so maybe someone can identify it.
That's the right Dallas.
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wrote:All Dallas chips miss pins, look at all the "NC" pins on the diagram you just posted... […]
All Dallas chips miss pins, look at all the "NC" pins on the diagram you just posted...
First off, the different Dallas chips are not mutually compatible (other than 1287=12887), so you need to find out what was originally on the board. The manual should say.
Secondly, the DS1285 is an RTC without a battery, so if there's no battery on your board, that one definitely isn't right. That's also why it looks 'funny'.
Thirdly, unless you want to mod new batteries onto old modules, don't buy these things 2nd hand as the included batteries are almost certainly dead. Buy them new form a reputable (online) electronics store.Finally, what do you mean by " it did not work"?
- it boots up but doesn't hold time settings after power down? If so, it's the correct type of module, just the battery is dead. Mod a new battery onto it or buy a new one that does work.
- it doesn't boot at all? Then it's probably the wrong kind of module (most likely alternative: DS1387 RTC RAMified, which is no longer made, so you need to mod it).
Yes, the battery I was using did not have pins ( 1, 4, 5, 6, 10, 24, 22, 21 ).
So it was missing VCC and some address pins? That's not gonna work, bud.
