log in | register | forums
Show:
Go:
Forums
Username:

Password:

User accounts
Register new account
Forgot password
Forum stats
List of members
Search the forums

Advanced search
Recent discussions
- IrisRam speeds up Iris (News:7)
- RISC OS Users Xmas screenshots 2022 - Michael Grunditz (News:)
- Drag'n'Drop 12i1 reviewed (News:)
- November 2022 News Summary (News:)
- Rougol November talk - Mark Moxon (News:4)
- Informal get together for ...velopers on Saturday night (News:)
- Would you like to share yo...p for our Advent Calendar? (News:)
- Mark Moxon is talking at Rougol on Monday (News:)
- WROCC Newsletter Volume 40:6 (News:)
- WROCC November 2022 Meeting - RISC OS Open (News:1)
Latest postings RSS Feeds
RSS 2.0 | 1.0 | 0.9
Atom 0.3
Misc RDF | CDF
Site Search
 
Article archives
The Icon Bar: General: Fix CMOS power broken track
 
  Fix CMOS power broken track
  MarkieMark (12:55 14/2/2014)
  Zarchos (20:22 14/2/2014)
  apdl (08:53 15/2/2014)
    Zarchos (09:51 15/2/2014)
      MarkieMark (09:58 25/2/2014)
 
Mark Usher Message #123027, posted by MarkieMark at 12:55, 14/2/2014
Member
Posts: 9
Hi all

Powered up last week to find the CMOS battery had leaked. I removed and immediately started the cleanup with a vinegar solution etc. Closer inspection revealed part of a nearby track eaten away on one side of the 470k resistor.

https://dl.dropboxusercontent.com/u/10388542/IMG_0035.JPG

My question is how to fix? I don't have any SMD tools or skills. Can I lightly solder a wire from the 470k to Pin 8 on the 8583T CMOS clock?
________
-Mark
  ^[ Log in to reply ]
 
Xavier Louis Tardy Message #123029, posted by Zarchos at 20:22, 14/2/2014, in reply to message #123027
Member
Posts: 47
Well if you're sure it's the normal connection path I can tell you I resurrected my A5000 (battery leakage issue) simply by soldering a thin wire directly to the CMOS chip.
It's ugly, 'in the air' but as I had used some flux to neatly clean both soldering areas, I'm confident it's definitely fixed.
  ^[ Log in to reply ]
 
David Holden Message #123030, posted by apdl at 08:53, 15/2/2014, in reply to message #123027
Member
Posts: 138
My question is how to fix? I don't have any SMD tools or skills. Can I lightly solder a wire from the 470k to Pin 8 on the 8583T CMOS clock?
Yes, but you'll probably find it easier to connect to the +Ve side of C70.

Alternatively, since soldering to metal that's already been corroded can be difficult, solder a 47R 1/8th watt resistor from the 'upstream' side of the resistor to C70. (Note it's 47R, not 470K as you said).
  ^[ Log in to reply ]
 
Xavier Louis Tardy Message #123031, posted by Zarchos at 09:51, 15/2/2014, in reply to message #123030
Member
Posts: 47
And always use flux on old circuits, whether there's corrosion or not.
It's no luxury.
Flux will always give better soldering, reduce risks of dry joints.
The time spent with the soldering iron head when in contact with the chips will also be reduced to get a clean joint, so it means less danger of burning the chip.


[Edited by Zarchos at 11:42, 15/2/2014]
  ^[ Log in to reply ]
 
Mark Usher Message #123059, posted by MarkieMark at 09:58, 25/2/2014, in reply to message #123031
Member
Posts: 9
Just a note to say thank you to Xavier and David (also for supplying the replacement batteries).

Bought some new solder (with flux!) and soldered a wire from the 47 resistor to pin 8 on the CMOS chip and all is well again. Now just looking for someone with an SMD setup to replace the floppy controller chip on another board!

[Edited by MarkieMark at 09:59, 25/2/2014]
  ^[ Log in to reply ]
 

The Icon Bar: General: Fix CMOS power broken track