The Zurich / Watson 25/30Amp 13.8V Power Supplies

Following my Previous posts I have had more mail re these PSU’s, GW4TOD has a problem with the Voltage leaping up intermittently which sounds very similar to my original problem. Hopefully we can help solve that one.

UPDATE

OK I have heard back from GW4TOD, his problem was indeed the Set Voltage Pot at fault. Now I know of another example I will warn that this is a common fault and a serious one at that. The over voltage could possibly do damage to equipment. I recommend either my 12Volt float battery system or Thyristor Crow Bar circuit across the output.

END

Really good news he has found the circuit diagrams for several versions of the supply, these will be very helpful. Thanks for passing them on.

They are available to download from me here:-

W25SM Circuit

W30AM Circuit

Watson W-30AM Power Supply-Chassis parts

Watson W-30AM Power Supply-Control board

Watson W-30AM Power Supply-Fan controller mods

The Sammy on 12 Volts DC

Following the comments from ‘balmaha’ on my previous post, (he won’t last long now, another Sammy sold) I have today gone the full mile and purchased the Maplin Car Laptop Power Unit I mentioned.
A very good buy at the current offer price, rated at 150 Watts it slumbers along on the Sammy. It has been on for 3 hours and still feels cool.

Measuring current when the connection is a Cigar Lighter Socket is not easy so I am using my DC PSU meter as the not highly accurate instrument. When charging the Netbook Battery the current is slightly less than 2 Amps by the look of it and just over 1 amp once the cells are charged.
I have not gone for critical power saving settings, back lighting is at mains power level, performance full, USB GPS powered on, Wireless Internet on and connected and Bluetooth on too.

This gives me a portable radio set up using the FT-897 with a total current consumption of around 5 Amps on TX. Mind you on WSPR for an output of 1 Watt, 69 Watts consumption is still pretty disgusting.

Incidentally internal Battery powered I viewed a few videos on Youtube, tried out the GPS on a stroll up the road, slung the Sammy on chair still switched on while I ate lunch picked it up an hour later and the battery indicator said 6 1/2 hours use left. One day I will have time to run it flat.

Personally it gets my back up when people avidly support junk just because they made the mistake of purchasing it, for instance the Icom IC706.
So do not take my word for it take a look at the views of 799 other purchasers here PURCHASER REVIEWS.