[sdiy] SCI Tom bombs...

[Bob Weigel]

My friends from Portland got off to do some studio work here.  In the 
middle of things the SCI Tom they brought lost memory...they tried to 
reload but I see maybe why that happened..2.5V on the Li cell.

After that though it went totally down.  I'm seeing this rev C board is 
different than the diagrams i got on line.  There is 1) a center tap on 
the connector to ground that isn't shown  2) no LM317..instead we have 
two 7805C regultaors and one 7905.

Now the 5V plus regulator with the heat sink extension on it is getting 
real hot real fast.  50C a few seconds after turning it on and 
climbing.  However measuring with a diode checker I get .9V on both that 
to ground and from ground to the -5V.  The other 5V regulator has more 
like 1.4V drop...all which usually would be NORMAL on a circuit of this 
type.  I replaced the heat sunk regulator anyway and tested and all 
voltages are present and accounted for however still no lights.  I 
pressed on the cpu and got bizarre lights once . Anyway if anyone has 
the real diagram for this model it'd be swell and if anyone has any tips 
even better maybe :-) -Bob

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