🚀 go-pugleaf

josephc@cco.caltech.edu (Joseph Chiu) writes:

>s41758@zeus.usq.EDU.AU (Brian Mesken) writes:


>>I have a server (486) running 3Com's 3+Open connected to two Epson DFX-
>>  .
>>  .
>>  .
>>Has anyone else had these type of problem?
>>Any suggestion on how to solve this problem?

>Hmm, seems to me like there is an e-potential difference causing problems...
>As a test, I'd suggest trying these cases:

>   Disconnect Printer entirely from System, except for the power.
>   Connect Printer to System, power Printer via Power Conditioner.

This one I havn't tried yet.

>   Similarly, connect Printer to System, power Printer by a separate
>     supply-line circuit.

This I have tried both from a seperate supply circuit and from the same
circuit, both have had the same effect.

>   Ensure Common Ground between System and Printer.  In fact, make sure
>     that the two are grounded via the Parallel Printer Cable.

This was the case, the chassis were connected together via the printer cables
I was advised to remove this as it may be causing an earth loop. It is now 
disconnected. I have the system and the printers connected to the same
circuit, to also eliminate the earth loop.

>   (Far shot) Move Printer far away from the System, but using the same
>     supply-line circuit. 

I have them close together because of the length of the printer cable,
but i assume you mean far away electrically, I could try one to another
circuit.

>   
>Another remote possibility is that the Server System's power supply is 
>operating at limit (i.e., marginal) and that the spikes are enough to
>deprive the CPU of needed power.  (Remember, it only takes 1 bad opcode
>taking less than ~100ns to crash.)

Yes, this could be part of my problem, the power supply is up around
255 volts, which is at the upper limit of the 240 volts +/- 6%. I have 
requested the supply be reduced, no action yet.

>Could the other spikes you mention be a result of, say, an air conditioner?
>Out here at the Caltech Campus, all major computing rooms have conditioned
>power going into the machines with individually filtered (passively) outlets.

I expect you are correct, but I havn't been able to prove that it is the 
air conditioners causing spikes. I mean switching the air conditioners
off on off etc. have not showed any measurable spikes.

Thanks for the advice.

--
Brian Mesken                                   mesken@zeus.usq.edu.au
Computer Services Unit,
University College of Southern Queensland,
Toowoomba, Queensland, Australia.