NiCAD Battery Charger

Thread Starter

beatsal

Joined Jan 21, 2018
289
I have a 18VDC Charger which is showing 5VDC, hence not charging the battery. It is a Sears Craftsman. Any help appreciated.
 

Dodgydave

Joined Jun 22, 2012
10,326
That's a switchmode type psu, it could be a regulator Tl431 or caps gone faulty..
Have you got a dvm to check out the supplies, are you familiar with switchmode types?

Take pics of the trackside and a better picture of the inside.
 

Dodgydave

Joined Jun 22, 2012
10,326
Looks like an Hltek Microcontroller on the trackside...also a Brown solder mark near the Hltek chip probably a resistor.
 
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Thread Starter

beatsal

Joined Jan 21, 2018
289
So what could have failed? Not familiar with SMPS, but wonder if the open circuit voltage (without battery connected), I measured i.e. 5VDC is indicative of a failure?
 

Thread Starter

beatsal

Joined Jan 21, 2018
289
That's a switchmode type psu, it could be a regulator Tl431 or caps gone faulty..
Have you got a dvm to check out the supplies, are you familiar with switchmode types?

Take pics of the trackside and a better picture of the inside.
Checked the main cap which is visible in the pic, it is 400V, 100 MicroF. it shows infinite R, so no short there.
 

Thread Starter

beatsal

Joined Jan 21, 2018
289
It has 2 power transistors, one shows a short; problem is the markings on them have been erased, so don't know what they are. Any clues?
 
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