Scanner adaptor voltage goes to 0 after connecting

Thread Starter

sangpo

Joined Aug 17, 2013
91
Dear expertises,

1, next morning my scanner not powering at all.
2. It is powering when i connevt other adaptor of same brand of scanner.(so scanner is ok)
3. I checked voltage of my adapdaptor with dmm, and it shows 12 volt. (Scanner is rated 12 V )
4.again i connected adaptor to scanner.but no powering. Then i disconnect it from scanner, .without adabptor being switching off the main power socket, I checkhed voltage, but volt is zero.
Then i switch off and switch on again the main power socket to check votage again, then the votage is showing 12 V,

So what is possible cause of this problem?
1. Resistor .?
2.capacitor? Diode?
3. Or what else
Thank you all
 
Last edited:

Alec_t

Joined Sep 17, 2013
11,739
1. Resistor .? 2.capacitor? Diode?
Could be any or all of those, as well as any semiconductor device or a poor connection. I'd vote for the latter, if plugging and unplugging the connector causes a change in the output of the adapter.
Then i switch off the main power socket to check votage again, then the votage is showing 12 V
I don't see how you can get 12V out (other than very briefly as a capacitor discharges) when the mains power is off.
 

sghioto

Joined Dec 31, 2017
1,555
Agree with Alec_t. Suspect an intermittent connection in the cord, most likely at the connector which plugs into the scanner.
SG
 

AlbertHall

Joined Jun 4, 2014
10,554
It could also be an overactive protection circuit in the power supply, which could also be caused by almost anything.
I don't think we are helping much.
 

Thread Starter

sangpo

Joined Aug 17, 2013
91
Could be any or all of those, as well as any semiconductor device or a poor connection. I'd vote for the latter, if plugging and unplugging the connector causes a change in the output of the adapter.

I don't see how you can get 12V out (other than very briefly as a capacitor discharges) when the mains power is off.
-----------------------------
Sorry
It is , that i switch off and then gain switch on the main power socket to check voltage again, then the votage is showing 12 V,
 
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