Harbor Freight Centech charger putting out around 150V

[sparkboater]

Greetings.
This charger stopped working so I started trying to learn what was up including learning a LITTLE electronics.
I cant find a schematic for Centech model Item 60653.
Essentially I put the charger on a weak battery and hooked it up on 2 or 10 amp and am getting (scary) well over 120v at the battery terminals. No hum from transformer
I can take pics in a few days but am hoping someone here may have a schematic and give me some test points I can check. I cleaned up internal connection points. Don't see any burning or bulging capacitors.

Any help appreciated.

 

[Martaine2005]

This might be normal for that particular charger.
I have an old Black & Decker charger which has mains across the battery terminals.
I’ll upload a photo if I remember in a couple of days.(at work).
What does the chargers label have written on it?. Input voltage and output?
What chemistry are the batteries?.

Sorry, should have looked at the photo first!. Mine is an old drill charger.
Martin

 

[dave9]

While not as simple as some, it is a linear transformer based design rather than switching, so it should not be too hard to sketch out a schematic, at least part of it. If you're getting roughly the right voltage off the transformer secondary windings then I'd guess the rectifier diode (probably mounted to that internal heatsink plate) is probably blown, or a fuse or breaker.

These aren't terribly expensive, I wonder if it is the right project at this point in your learning curve, considering it is working with mains voltage, and potentially hooked up to an automotive electrical system (battery in vehicle) where high voltage could cause costly damage.

 

[Bluejets]

Could have an internal short on the transformer ....best take it to a service centre before you electroplate some bystander.

 

[dave9]

^ But on the bright side, once they're electroplated you can use them as Christmas Decorations.