IBM 1620

[Dave G4UGM]

> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of ben
> Sent: 31 August 2015 01:43
> To: cctalk at classiccmp.org
> Subject: Re: IBM 1620
> 
> On 8/30/2015 6:32 PM, Tothwolf wrote:
> 
> > On page 5, they describe 0.0031" 40 AWG magnet wire being reduced to
> > 0.002" after soldering with 60/40 tin-lead solder. That 0.0011"
> > reduction is basically 1/3 of the diameter of the wire. This explains
> > the failures of the enamel wires in CHM's IBM 1620.
> >
> > Copper erosion from tin is something I'd never really given a lot of
> > thought to, but it will certainly be something I keep in mind from now
on.
> >
> But is that the case? Would not heat induced failure be the real case here
as I
> suspect that a amp or two of current is flowing that now very thin thread
of
> wire? Digging though the doc's and a little calculation clear this up.
> Ben.
> 
> 

I seem to remember that 1620 core runs warm, and you have to wait for it to
get warm before the machine comes on-line ... see last paragraph

http://www.angelfire.com/oh3/ebjoew/IBM_1620_Core_Memory.html

Dave Wade