AC Adapter model AA-091AD not working

[mikey5791]

Hi,

I recently dug out this non working OEM AC adapter (input 230V), it was meant to supply output
9V DC for a modem (already sold without the adapter). Tested on the output side with a Digital multimeter but zero power. Then I pry open to check for fault inside the case.

Nothing seem burn inside the case or any burnt smell. I checked for resistance on input AC wire (red colour) using the 200 ohm scale and got reading of 1.7 ohm. Is this normal?
I checked for resistance on output DC plug but all I got is "1"- this is overlimit reading on my DMM. FYI, I have basic solder skills with a 30-70 watt solder gun.

Anyone kind enough to guide me how to diagnose/repair this adapter to working.
Thank you in advance.

 

[Martaine2005]

it was meant to supply output
9V DC

Did you check the output voltage with meter set to AC?
It is an AC adapter.

Martin

 

[Martaine2005]

 

[duke37]

The adaptor gives AC out. If you want DC then get another adaptor with sufficient current capacity to suit the load. It may need to have a stabilised output.

Stuffing AC into a DC load may have caused damage, perhaps that is why the AC adaptor has an open circuit secondary. Another reason for lack of output is damage to the cable.

If you get a DC supply, make sure it is connected the right way round.

 

[cjdelphi]

It supplies 9v ac not DC. ..

Set your multimeter to AC mode, then you will read between 9 - 12vac

I doubt it's dead, can't say the same for the thing you tried powering though lol

 

[mikey5791]

Haha my silly mistake is thinking this unit is a DC adapter. After I set my DMM to AC mode and got reading about 11vac, then I realised my noob mistake of not reading the unit label (AC adaptor).

Thank you for pointing me to the right direction.

 

[duke37]

Haha my silly mistake is thinking this unit is a DC adapter. After I set my DMM to AC mode and got reading about 11vac, then I realised my noob mistake of not reading the unit label (AC adaptor).

Thank you for pointing me to the right direction.

How then did you measure the output open circuit in #1?
I would think that the PSU is nothing more than a transformer and if you have output, there should be a measurable resistance at the output with no input.

 

[Martaine2005]

How then did you measure the output open circuit in #1?

My guess is that he left his meter on 200Ω and got 1.7 from the secondary and OV or 1 from the primary.

Martin