Weston Master IV Disassembly & Notes (Page 2)

Weston Master IV Disassembly and Notes (Page 2)

Taking the sliding face plate out was tricky. At the bottom (you can kind of make it out in the photo) of each side, the springs stick through the plate. When the baffle door is closed the springs are angled downward and push this sliding plate downward. When the door is open, the springs push it upward. The top of the plate has a tongue that rides in a slot on a lower plate. There's also a little vinyl washer to help it slide nicely.

The way to remove it (IMO) is to pull it up so that the needle won't be bent, then gently rock it up to disengage the springs. Then rotate it 90-degrees (be careful of the needle, it's always in the way) to take the tongue out of the groove. Set aside.

Top Meter Face Removed

Next we had to remove the sliding meter face plate.

On the right hand side, note the wire that runs from the under the meter plate and hooks loosely around a bolt. Gently bend that out of the way. Then left the two washers off and set aside.

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Face Panels Out

Next, we removed the meter. I didn't photograph this bit but it's fairly easy.

At about 4 o'clock and 8 o'clock you should see two hex-heads that will come out. Turn the meter over and remove the three little screws that hold the name plate, and this should let the bolts drop out.

The meter assembly itself should be able to lift up and out. There's a wire that connects from the underside of this to the photocell, and it'll have to be cut somewhere. We cut it in the middle simply for convenience.

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Meter Detail

Two images of the meter unit itself (clamped in a little vise): the magnet, the armature and the needle. The top photo is the front of the meter, as you looked at it during disassembly. The bottom photo is the back of the meter.

We gently held the holding-bar back so the pointer could swing freely. We used a multimeter set on its lowest Ohms setting, placed the negative lead on the magnet (ground) and touched the positive lead on the wire. The needle jumped. That meant the meter itself worked properly. It just wasn't getting power from the photo cell.

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