DECpc 425SE

Antonio Carlini a.carlini at
Sat Dec 7 12:10:33 CST 2019

On 05/12/2019 14:18, dwight via cctalk wrote:
> With the solder tabs you are not soldering directly to the case, you are soldering to the tab.
> If you try to solder to the case, the electrolyte will evaporate causing excess pressure in the case. This will burst the seal. For a lithium coin cell this can mean a fire.
> As was mentioned, the solder tabs are usually spot welded to the case. The heat is momentary and little pressure is created in the cell.

I've dismantled the machine enough now to get the mainboard out. Right 
behind the cell on the opposite side of the PCB  are expansion memory 
boards. Between those and the PCB is a black square of insulating 
plastic that is tackily glued to the PCB. That lifts up easily enough. 
There are plenty of components on this side of the PCB too. It looks 
like one tab is  right by the label "R337" and the other is between the 
"R346" and "R351" labels. Just in case anyone else ever follows this 
path :-)

I'm going to set it to one side for now and get to the same stage with 
the Acorn A3000 (which looks OK but the battery really has to come out 
now ... it will eventually fail I suppose).

I might as well tackle both at the same time ...

Maybe I'll take photos as I put it back together, sort of "Haynes manual 
in reverse".


Antonio Carlini
antonio at

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