[Coco] MM/1 RTC RIP

[Robert Gault]

Bob Devries wrote:

> hello, MM/1 users (sorry for the bandwidth usage, you coco chaps)
> 
> I just found out that the RTC chip in my MM/1 has died. Actually, it's 
> not the chip, since setting the time will work until the next power 
> down, so it's the battery. The MM/1 uses a Dallas DS1287 integrated 
> clock/battery, *and* it is soldered into the IO board. GROAN.
> 
> What to do?
> I did some googling and came across this:
> http://www.mcamafia.de/mcapage0/dsrework.htm
> 
> This will work, but I still need to desolder the clock chip, or at the 
> very least do a *very* careful job of gringing the relavant parts. Sadly 
> I don't own a dremel tool.
> 
> Does anyone else have experience in this?
> 

Perhaps you can do something analogous to shat I did with a Dallas 
DS1216 clock. This was discussed here not too long ago.

I took a battery, attached two wires to it, and soldered the wires to 
pins 4 and 8 on the clock chip. The clock then worked like new.

I don't know if any pins on the DS1287 go directly to the battery. On a 
DS12885 (drop in replacement) there is a pin for an external battery. If 
your battery is not completely dead, testing the DS1287 leads with a 
voltmeter ought to find if there is a connection.
DS12885 V-Bat pin     package type
      20                SO PDIP
      24                PLCC
      22                TQFP