[rescue] Sun 3/50 scsi boot string

[Jerry Weiss]

On 12/28/22 1:35 PM, Dave McGuire wrote:
> On 12/28/22 11:42, Kurt Nowak via rescue wrote:
>> I have not yet taken the PS apart yet, so I haven'tB had a visual 
>> inspection yet and whether it has RIFAs. Either way,B I'm not going 
>> to fire it up withoutB my current limitingB dim-bulb tester, Variac 
>> and Isolation Xformer. Unfortunately the lettering on the PS is 
>> starting to disappearB and cleaning the input side will most likely 
>> erase it all. I think I saw a section in the FE manual that has a 
>> rough description of it. The unit is at another location for storage 
>> so I'll have to take sections of it apart to move it by myself 
>> without breaking my back. Too many other projects going on at the 
>> moment.
>
>   That's a switching power supply; it will not play nice with a Variac!
>
>              -Dave
>

My own method for vintage electronics with switching power supplies is 
to turn on the device for less than one minute, then leave it alone for 
a 3-5 multiple of the on-time.  Repeat the process a few times and 
slowing increase the on time.   The concept is to briefly charge the 
electrolytic capacitors, but don't stress them too long. This may give 
them chance to reform their insulating layer and endure longer 
on-times.  If the capacitor has dried out or doesn't survive the initial 
start-cycles then you are SOL.  Use at your own risk.

   Jerry
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