34A power problems

From: Tony Duell <ard_at_odin.phy.bris.ac.uk>
Date: Tue Nov 11 03:47:20 1997

On Mon, 10 Nov 1997, Daniel A. Seagraves wrote:

> Okay, I narrowed it down some:
> I unplugged everything except J3, the power switch.
> I plugged in that edge connector to the line module, OK.
> Power on: loud click, but the breakers held.
> Next, I plugged in J5.
> Power on: *CRACK!* Both breakers go.
> The breaker on the powerstrip is holding though.
> What is P5 for?

You do have the right sized breaker, I take it. The 11/34 takes quite a
high switch-on surge - I believe the original breaker was a time-delay

I can't remember all the plugs by number, but I can tell you what they are
by description..

Start with _just_ the 3-pin one going to the frontpanel in place. Turning
on the power swtich should cause a sharp click from the contactor in the
mains block (it sounds like you've done this).

Now connect the 4 way one alongside this (transformer primary windings).
Make sure the 8-pin one with all the black wires, the edge connector, etc
are all out at this point. Power up again. If the breaker trips it sounds
like you have a short in the transformer or its wiring.

Now fit the edge connector. If it trips, try it the other way up (I
_think_ the wires exit on the solder side of the PCB, but I'm not sure).
If you can't get it to work, you need to troubleshoot the 15V PCB, which
is quite simple.

Now fit the 8-pin connector with all the black wires (transformer
secondaries to regulator modules). If it trips now, unplug all the 8-pin
connectors from the regulators. Add them back one at a time until you find
the regulator that's causing it to trip, and then debug that module.

Received on Tue Nov 11 1997 - 03:47:20 GMT

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