Power supply question VM140

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1

Hello,

I found an old AC/DC adaptor which meets the requirements for powering the VM140 board. It’s got a switch to select different output voltages from 3 to 12V and has a max of 300mA output. I think it is referred to as one of those old ‘Tandy’ adaptors.

But when I measure the actual output it almost reaches 17V ??? . Could this be normal due to the fact that it is an unregulated power supply? Or could it be broken and unwise to further use it to power up the VM140 board?

Unware of this when I wanted to install the board drivers i connected it. LED12 started to blink and all input leds also lit up which would be normal as mentioned in the manual. Then i remembered i should have first checked the adaptor, disconnected it and came to the result mentioned above. It was connected for about 10 seconds or so.

Any chance i might have damaged anything?

Greetz

Bender

2

Ok, after some searching I discovered that it is normal to have this high output under no load operation of an non regulated power supply.

So I guess it would be safe to use it for my VM140 board but i’m still going for someone to confirm this.

Grtz

Bender

3

That’s true, 12 x 1.41 = 17V. You measure the top voltage when the adapter is unloaded.
You can used as 12V DC adapter (for your VM140,…).

4

Ok thnx for confirming.

Now i can start experimenting :smiley:

Bender