flat assembler
Message board for the users of flat assembler.

Index > Heap > Replacing Dallas RTC

Author
Thread Post new topic Reply to topic
Tomasz Grysztar
Assembly Artist


Joined: 16 Jun 2003
Posts: 7724
Location: Kraków, Poland
Tomasz Grysztar
After nearly 20 years the battery in the RTC clock in my old PC machine (the one I used to write first version of fasm) is definitely dead. I do not mind much, I just enter current date and time every time I turn this computer on, and I see it as a nice throwback to the first generations PCs that had no RTCs.

But if any of you have some experience with replacing such chips or batteries inside them, I'd be interested to hear about it. I do not plan to try any "quick fixes", because this machine is quite precious to me and I prefer to leave it as is and work without RTC over trying anything potentially damaging. Probably the best solution would be to replace this chip with something socketed that would allow easy maintenance in a future.


Description: RTC on the motherboard of fasm's "motherland" PC
Filesize: 189.87 KB
Viewed: 6612 Time(s)

20161030_120923_s.jpg


Post 30 Oct 2016, 11:38
View user's profile Send private message Visit poster's website Reply with quote
revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17279
Location: In your JS exploiting you and your system
revolution
If you can find a replacement part it would probably also have a dead battery inside. Another option would be to place a new compatible SMD chip and an external battery together on a small carrier board. Then cut the existing chip from the mobo (don't try to unsolder it, because without some very expensive gear you won't be able to unsolder the power pins that connect to the internal planes). Glue in your new carrier board and connect some wires. Best it you can use a socket with a 3V Lithium button cell and then you can change it whenever needed.
Post 30 Oct 2016, 11:48
View user's profile Send private message Visit poster's website Reply with quote
Tomasz Grysztar
Assembly Artist


Joined: 16 Jun 2003
Posts: 7724
Location: Kraków, Poland
Tomasz Grysztar
Thanks for the advice about the cutting - I was actually already considering buying some good desoldering equipment, but with my little experience I probably would not make a good use of it anyway. Still, I'm not going to make any decision hastily here.
Post 30 Oct 2016, 12:04
View user's profile Send private message Visit poster's website Reply with quote
sleepsleep



Joined: 05 Oct 2006
Posts: 8903
Location: ˛                             ⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣Posts: 334455
sleepsleep
http://pc-restorer.com/replacing-cmos-batteries-in-old-pcs/

Image
it said socketed RTC chip can be lifted out using a flat screwdriver and replacement pressed back, sure replacement is quite hard to find.

http://www.classic-computers.org.nz/blog/2009-10-10-renovating-a-dallas-battery-chip.htm
change it to use modern cmos battery
Post 30 Oct 2016, 14:20
View user's profile Send private message Reply with quote
revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17279
Location: In your JS exploiting you and your system
revolution
If the existing chip is in a socket then of course there is no need to cut or unsolder anything.
sleepsleep wrote:
change it to use modern cmos battery
Erm Confused Do you mean a Lithium battery?
Post 30 Oct 2016, 14:56
View user's profile Send private message Visit poster's website Reply with quote
Tomasz Grysztar
Assembly Artist


Joined: 16 Jun 2003
Posts: 7724
Location: Kraków, Poland
Tomasz Grysztar
Mine is not in socket, it is soldered in. I tried to select an angle of the photo that would show it.
Post 30 Oct 2016, 15:58
View user's profile Send private message Visit poster's website Reply with quote
shoorick



Joined: 25 Feb 2005
Posts: 1605
Location: Ukraine
shoorick
It is regular 6818 in additional case with battery. It has some pins turned up inside, two of them are connected to the regular CR2032 battery. Long time ago I have "resolved" "time problem" in couple of computers at work: I had split off small parts of plastic one by one to open pins, connected to the battery, disconnected them and soldered two wires with two AA batteries (3V) (more cheap than CR2032 Wink ).
I already do not remember details, maybe they were in socket. Sure, it was working but had no good look. Very Happy
If it is so valuable, I'm sure it is possible to find somebody near you with soldering station to solder it out and put socket instead. Being soldered out, it is not hard to open hidden pins with small file filing oblique along pin from the down side upward. Those pins may have voltage slightly more than 0V.
++++++++++
If you have another 6818 chip, it is possible just to destroy original chip gently to not touch something other on the board, then solder out separate pins one by one. Then restore holes with wooden needle (or I use little drill Ф 0.7 mm), then all other is obvious: put socket and 6818 with turned up battery pins, which are connected to any kind of 3V battery.
Post 30 Oct 2016, 17:35
View user's profile Send private message Visit poster's website Reply with quote
sleepsleep



Joined: 05 Oct 2006
Posts: 8903
Location: ˛                             ⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣⁣Posts: 334455
sleepsleep
i want to ask one question, if the chip is soldered out, after that, you turn on the pc, will the pc functions, like checksum error as usual? or it simply won't boot up to bios and to os
Post 30 Oct 2016, 17:48
View user's profile Send private message Reply with quote
shoorick



Joined: 25 Feb 2005
Posts: 1605
Location: Ukraine
shoorick
I have not tested, but I suppose it should work with checksum error, but it may vary on BIOS
Post 30 Oct 2016, 18:16
View user's profile Send private message Visit poster's website Reply with quote
shoorick



Joined: 25 Feb 2005
Posts: 1605
Location: Ukraine
shoorick
Image

Image
Post 30 Oct 2016, 20:38
View user's profile Send private message Visit poster's website Reply with quote
Trinitek



Joined: 06 Nov 2011
Posts: 257
Trinitek
FYI, that part, the DS12887, is still being manufactured.

http://www.digikey.com/product-detail/en/maxim-integrated/DS12887-/DS12887--ND/956874
Post 30 Oct 2016, 22:33
View user's profile Send private message Reply with quote
revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17279
Location: In your JS exploiting you and your system
revolution
I suggest avoiding anything with an embedded battery*. Do you really want to go through this all again in a few years?

* This includes phones and laptops
Post 30 Oct 2016, 23:20
View user's profile Send private message Visit poster's website Reply with quote
revolution
When all else fails, read the source


Joined: 24 Aug 2004
Posts: 17279
Location: In your JS exploiting you and your system
revolution
shoorick wrote:
two AA batteries (3V) (more cheap than CR2032
You might save a small amount of cash initially but once those AA batteries leak and ruin the mobo then you will be crying. Crying or Very sad
Post 30 Oct 2016, 23:37
View user's profile Send private message Visit poster's website Reply with quote
shoorick



Joined: 25 Feb 2005
Posts: 1605
Location: Ukraine
shoorick
those batteries had long wire and were hanging far from mainboard Wink you know standard computer cases: if there is no expansion card installed, you may keep some bottles of vodka inside. Wink
those years (>10 ago) lithium batteries were costing toooo much here Wink (and now again)
Post 31 Oct 2016, 05:55
View user's profile Send private message Visit poster's website Reply with quote
Display posts from previous:
Post new topic Reply to topic

Jump to:  


< Last Thread | Next Thread >
Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum


Copyright © 1999-2020, Tomasz Grysztar. Also on YouTube, Twitter.

Website powered by rwasa.