Re: When it rains, it pours...

["Bill Garber" <willy46pa@comcast.net>]

"Steven Hirsch" <snhirsch@gmail.com> wrote in message EtydnV9istmxaJHSnZ2dnUVZ_tOdnZ2d@giganews.com">news:EtydnV9istmxaJHSnZ2dnUVZ_tOdnZ2d@giganews.com...
> On 01/10/2012 09:26 PM, mwillegal wrote:
> 
>> Could be a ground or power supply issue.  Check input voltage levels.  With
>> power disconected, compare resistance between power and ground for each
>> power supply input with a good board and your board - don't expect exact
>> match, but it should be in similar range.  Check power off resistance
>> between various ground points on the motherboard and power supply ground.
> 
> 
> Both the primary system AND my backup GS (mis)behaved in the same manner with 
> the LittlePower connected.  The voltages look fine, but I'm thinking it may 
> not provide a solid ground reference. That would account for the Disk 3.5 
> current waveform emerging from the speaker, and may also explain the freezeups 
> with the Phonenet transformer.  I'll bet that looks like a relatively 
> low-impedance load and may push the ground-bounce over the edge.
> 
> When I'm a little fresher tomorrow, I'll put a scope on the rails and find out 
> what's going on.  This is all just speculation at the moment.
> 
> All of this merriment is peripheral to the original instability of the first 
> GS, which happened with the Innerdrive power supply...  Probably two unrelated 
> issues.
> 
> Fun stuff!

Ain't it though???  8o) 

Now try putting back the rest ( minus the AppleTalk PhoneNet ) one at a time 
until something kills it. Sounds like you could have a short in the Primary 
serial port ( printer port ) if that is from where you were PhoneNetting. 

I agree with the Caps theory. 

Bill