Date : Fri, 10 Apr 2009 14:43:20 +0100
From : bbcmailinglist@... (Ian Wolstenholme)
Subject: Master Compact Power Connections
I've just noticed another thing about this PSU inside the Master Compact.
It has a solder point for the Earth, but nothing attached. I think when I
removed it from the FileStore I must have desoldered the earth wire to
get it out.
There are two Earth wires on the Compact, both with spade connectors
at the end so I presume I need to cut the spade off one and solder the wire
onto the Earth point on the PSU.
But the question is - which Earth wire is the right one to connect to
the PSU? There is one coming from the power input socket where you
plug in the kettle lead, and one coming from the power output socket
which powers the monitor.
I'm presuming the other one goes to the Earth point on the casing.
Probably a good job I didn't switch it on before noticing the Earth
wasn't connected to anything.
Best wishes,
Ian
----- Original Message -----
From: Ian Wolstenholme [mailto:bbcmailinglist@...]
To: bbc-micro@...
Sent: Sun, 29 Mar 2009 23:04:17 +0100
Subject: Re: [BBC-Micro] Master Compact Power Connections
Thank you, the multimeter confirms that the two pairs are top and
bottom like Rob said.
The curious thing is that the two leads from the internal PSU don't seem
to fit. They are a bit smaller than the mains ones, so I'm wondering now
if it's the power supply from the FileStore, and I swapped it with the Compact
because the FileStore one wasn't working.
A quick check of my website confirms this! I must have cannibalised
the Compact drive box for more than the floppy drive, taking the PSU as
well, and for good measure, the lid!
Restoring the Master Compact is going to be a bit more involved than
I thought, and I've run out of weekend again! Anyone got a Master
Compact PSU going spare??!!
Best wishes,
Ian
----- Original Message -----
From: Phil Blundell [mailto:philb@...]
To: bbcmailinglist@...
Cc: bbc-micro@...
Sent: Sun, 29 Mar 2009 22:14:24 +0100
Subject: Re: [BBC-Micro] Master Compact Power Connections
On Sun, 2009-03-29 at 21:48 +0100, Ian Wolstenholme wrote:
> There are two sets of blue and brown leads and you can see one set of them
in the first picture.
>
> What goes where, and what might happen if I do it wrong?
You can't really tell for sure by looking at the switch (unless it has
markings on that aren't shown in the photos). You really need to do
some tests with a multimeter to figure out which pins are which, Even
looking at another Compact is not necessarily a 100% guarantee since
your switch might be different for some reason (production change or
field repair for example).
Most likely, you want to connect the two brown leads to the top two
blades of the switch, and the two blue leads to the lower two blades on
the switch (or vice versa). However, it's best not to guess since doing
it wrong will mean that when you turn it on the switch will present a
dead short across the mains; this isn't likely to do you or your table
any real damage, but you might trip a circuit breaker in your fusebox
and the switch will very likely be destroyed by the experience.
Assuming you do have a multimeter on hand, proceed as follows:
1. Turn the switch off and verify that there is no continuity between
any two pins.
2. Now turn the switch on. You should find that the four pins now form
two pairs, with continuity between the two pins in each pair.
3. Connect the two blue wires to the pins from one pair, and the two
brown wires to the pins from another pair. In other words, when the
switch is on, you want the wires of the same colour to be connected
together. It doesn't matter which way round the wires go.
p.
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