Dallas DS1287 & DS12887 RTC & other DS RTC Chip Repairs

For other Dallas DS chips not in this video: See Update on the bottom of the comments.
Description: The Dallas DS1287 RTC (Real Time Clock) has an internal battery that over time goes bad. Even the NEW ones since they're still NOS (New Old Stock) either won't work long or won't work at all, as the battery life is only supposed to last 10 years.
A friend of has on old PS2 that won't boot up so, he asked me to install a new backup batter to fix his. This video is how I did the procedure.

ITEMS YOU'LL NEED:
1. 3 - 4" OF WIRE, 20AWG OR CLOSE TO IT.
2. Solder.
3. Soldering Iron.
4. Liquid RMA Flux, ie. KESTER 186
5. 90% OR Higher Isopropyl Alcohol to clean solder joints.
6. Acid Brush with 2/3rds top cut off to clean solder joints.
7. Dremel or Rotary Tool of some kind. Harbor Freight comes to mind.
8. Carbide Grinding Tip MED/SMALL for the Rotary Tool.
9. Coin Battery Button Holder Socket.
10. Optional: 1/8" Heat Shrink about 1/4" long any color.

Let's Begin.

UPDATE Procedure for other DS Chips.
1. CAREFULLY; Grind through the epoxy above ALL the pins to find the battery connections.
2. Connect a digital meter to the pins that have a wire attached to find the polarity, that's if it still has some charge left over, most won't.
3. If it has a charge left over, take note of the positive and negative pins!!!
4. If the old battery doesn't have a charge or if the polarity can't be determined with a meter; then gently grind away the sides until you can get the top off.
5. Grind the away the epoxy to expose the battery and hope the polarity is marked on the battery.
6. If the polarity is not marked on the battery but it has a part number on it, you can look up the battery polarity on line.
7. If the polarity or part number is not marked, you're pretty much done for now. Check the forums, or post a question on a forum to find a solution. Or you can purchase a used on on line and try again.
8. Once you have the battery to pin connections and the polarity connect a backup battery as shown in the later part of the video above.
I hope this helps you in your project.
*** Personally I would take the time to use a Dremel and cut away the epoxy & find the pin connections and the polarity on battery.
- You have nothing to loose anyways since it's already a dead chip.
** If the video helped please take the time to give me a thumbs up for the work I put into it. Best Wishes n Blessings Keith Noneya

[EcoGreensFarm]

This was very useful information. Thank you for taking the time to put this video together and share it!

[jimbos-sen]

Just got mine fixed and now I have a fully functional 25mhz 486sx with a 5.25 inch floppy running windows 3.11. Thank you for explaining how to do this so well.

[mattagreen]

Thanks for doing this. Solved a big problem for us and General Motors.

[mariolopez]

Great job!!!! today is August 6 2024 from Spain

[glasslinger]

Note that these are now available NEW (fresh battery) from Mouser or Digikey. Of course you will need to load the program into the new one. When you see the price, get ready to say, "ouch!"

[shawnerz]

I like how cleanly you removed the epoxy from pin 16. I have a Dremel tool (well, Harbor Freight knock off) I'm going to give this a shot tomorrow.

[keith]

Why did you cut the top from bottom on PIN 16? Is it to avoid fast drain of the replacement battery? Thanks for this very detailed video !

[landspide]

Perfect instructions, mine was 12887A pin 16 a little deeper than your case. But worked fine :)

[Kauketchen]

Good job, saved 2 old Pentium 1 Mainboards.

[IT-xwdz]

Thanks! Just fixed my caf superlight 386sx 8 -)

[wojciechszymanowski]

Couldnt You just solder battery to the corresponding legs on the back of the motherboard?
I mean without desoldering the rtc.

[Aerobix]

Does the DS1387 have the same solder points as the DS1287? I have some EISA board which needs a revive.

[IvanLutsV]

Dear Keith,

I'm wondering, if do you know what type of battery is inside in chip? What is weight of lithium there? Unfortunately I can't find this data anywhere(

[ddbb]

I am wondering if you can list the advantages to having the replaceable battery.
Cost?
Availability?
Life?
I can still find the Dallas chip and they will last 5 to 10 years but when removed I still need to send in my realtime board to have the CMOS settings reset. If a Button battery is used will it last 20 years? When the button battery is removed I will still need to send in my board for CMOS settings reset.

[Daveyk]

How bought a Dallas DS1742W-150 Timekeeping Ram?

[JohanTwinsen]

how to remove the chip from the board? do i need to desolder?

[kokomal]

Does it work with Benchmarq bq3287AMT? Thank you for the tutorial.

[vladimirsuhhanov]

Thank you very much, you just saved another one industrial pc that works in production. In additional, you can use plc battery 14250, so you don't need to replace it next 15 years at least.

[Bergwacht]

yes and then solder drips onto the board and it's all over....

[Outofthedust]

This is EXACTLY! what i was looking for! Thanks for saving my old ASUS P/I P55T2P4.