[Info-vax] VAXStation 3100

[John E. Malmberg]

On 1/16/2019 4:29 PM, Bill Gunshannon wrote:
> On 1/16/19 4:48 PM, Arne Vajhøj wrote:
>> On 1/16/2019 3:41 PM, Bill Gunshannon wrote:
>>> But here's the new problem.  I plugged an Expansion box in
>>> the same outlet strip and connected them together. Kicks
>>> the GFCI breaker!!  Disconnect the SCSI between the two
>>> boxes.  As soon as I turn the second one on it kicks the
>>> GFCI.  Either one is OK by itself, but the two together
>>> kicks the GFCI.  Other than a wiring problem in the power
>>> supply (I assume it would take one of them having the white
>>> and black wires reversed in side the box) what else could
>>> cause them to kick a GFCI as opposed to a circuit breaker?
>>
>> I am not a hardware guy.
>>
>> But I had a printer that would always trip
>> GFCI.
>>
>> And I have read about other having same problem with
>> a printer or some times with a computer.
>>
>> Some say that a better quality GFCI will solve
>> the problem.
>>
>> I suspect that the easiest/cheapest solution will be
>> to use an UPS.
>>
> 
> Actually, I just read something that said UPSes can trip
> GFCI breakers.  I fiddled with outlets here and have made
> the determination that the GFCI is either cheap, rated to
> small or just plain worn out.  It would not surprise me
> to find out that boxes this old have leakage to ground.
> And an excess of that would definitely trip a GFCI.

A GFCI can false trip from some inductive loads such as compressors in 
freezers.

GFCIs can fail with age.  If it is bad, you may want to replace it with 
an GFCI+ARC Fault.  In some cities that is required on a replacement.

Not sure that a switching power supply could cause a false positive.

Try another circuit with a different GFCI?

Regards,
-John