25 Oct
2015
25 Oct
'15
5:56 p.m.
On 2015-10-25 8:42 PM, Ian Finder wrote:
No- if it works with the standard display, the supply
is fine.
Now that that's clear, I recall some cube supplies would do this without a load for a
display- I used to test them by triggering the power-on pin, and seem to remember this
behavior occurring if I didn't have a big-ass resistor attached across the pins that
normally supplied power to the CRT.
Try getting a dummy load on there, the circuitry you have may not be putting enough load
on the lines that usually run the CRT to keep the supply in a steady state.
Even though I'm an electronics noob, that seems pretty logical. Can you
spell out what kind of resistor I'd need?
Is it the 20 Ohm 20W between pin 12 (-12V) and GND that is mentioned here:
http://www.nextcomputers.org/forums/viewtopic.php?t=1374&sid=80e5f0626e…
Is 20W the right rating?
Thanks!
--Toby
Cheers,
- Ian
Sent from my iPhone
On Oct 25, 2015, at 16:37, Toby Thain <toby at
telegraphics.com.au> wrote:
On 2015-10-25 7:21 PM, Ian Finder wrote:
I would replace the electrolytic capacitors in the power supply before going further.
Well, the problem disappears with the standard setup. You still think caps could be at
issue with the splitter setup? What's your detailed thinking?
--Toby
Sent from my iPhone
>> On Oct 25, 2015, at 15:38, Toby Thain <toby at telegraphics.com.au> wrote:
>>
>> On 2015-10-25 5:28 PM, Toby Thain wrote:
>> Hi,
>>
>> After a few years I wanted to try my Cube with the soundbox/VGA splitter
>> configuration for the first time. (I have the fading phosphor N4000A so
>> have been keen to have an alternate video solution.)
>>
>> However, all is not well. Using the keyboard power button, the machine
>> powers on for a couple of seconds, just long enough to see a NeXT logo
>> and grey desktop on the VGA (yay!) but then powers itself off again.
>
>
> I did the obvious thing and tested it with a standard monitor and cable and
everything is okay. So the problem must exist with the splitter/soundbox setup. Soft power
signals?
>
> Any suggestions welcome.
>
> --Toby
>
>> Any clues?
>>
>> Thanks in advance
>>
>> --Toby
>> (not having a good classic computing week)