Re: Reset-Switch for a 8580-111?

Hi Louis !

Well hell, can you coble together a momentary switch off the PSU 5v sense voltage? IIRC, that's what the toggle switch does as well.

Peter?


Hmmmpf ?

Sorry. I was asleep.

The Mod. 80 does not use a sense voltage. The power switch is a real "Power Switch" for mains-AC.
Tie down sense voltage on "later" PSUs is ... well ... useless, since it *is* tied to GND when the system is running. You need to pull it off GND (with a breaker switch), but that turns down the main PSU within the PSU .... and that is what a reset switch usually bypasses. Its purpose is to reset the machine *without* turning the PSU off and back on again.

However: a healthy PSU will surely not complain on it - given you leave it some time to really come down before you power it back on.

But a Reset switch will also prevent the HDs from coming down ...

Christian Holzapfel wrote:
I have an old book about PS/2's hardware too, it (generally) suggests to connect a switch from GND to the "Power Good" line of the PSU, which is also wired down to the PSU connector on the planar. I tried and used this with my model 8530-486 (slc2 upgrade :-)) a few years ago. I tied one end of the wire 'round a screw (=GND), the other end was stuffed into the PSU connector before connecting it to the planar; so everything could be removed easily, all done without soldering. If it works with a 80's power supply, you might find out...

Can only speak for a Mod. 60, where I did exactly that: wiring Power Good to GND.
In brief: it did not work as supposed.
The board largely resetted, the HDs kept on running, but after the reboot mouse and keyboard failed to respond.

Haven't tried that on a Mod. 80 (or any other) so far.
On the power plug it is the pin #12 - marked with "X" when looked into the connector from the pin-side. Pin #11 is one of the GND wires.


9
3 D O O X O 15
2 O O O O D 14
1 D O O O O 13
7

When using the power good signal one should take in account that pulling down the signal *may* also cause a power supply restart - where it takes down the DC outputs and you are basically back on the off-on-cycle and even worse, since the recover time is fairly short. Don't know if the HDs would like that.

I would opt to break the power good line with a toggle switch.
NC is tied to the line *from* the PSU, NO is connected to GND, COM goes
to the board.

NC NO
PSU >----o\ o----+
\ |
COM o -+- 0V / GND
|
Board <----+

What happens ?
The PG signal gets taken off the board, the signal itself is not forced to anything, so the PSU-internal logic doesn't care. The board pin is tied to GND and signals a missing PG to the reset logic, which then -consequently- resets, while all supply voltages are still present.


Discussable idea ? Any volunteers ?

--

Peter from Germany
http://www.mcamafia.de
.

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