Overview:
Ive got a Ryobi 6 port charger and it suddenly stopped working. No signs of life at all... After dismantling it i found there was a blown IC on the A/C side of the board. (board pics attached)

The blown IC is a "TOP267EG" (AC/DC Converters Integrated Off-Line Switcher) According to the datasheet (datasheet attached) it has a output voltage of 19v.

(The TOP267EG incorporates a 725 V power MOSFET, high-voltage switched current source, multi-mode PWM control, oscillator, thermal shutdown circuit, fault protection and other control circuitry onto a monolithic device)

Main Question:
Since this IC just outputs 19v which then gets fed to the DC side of the PCB, couldn't I just use my own power supply that has a 19v output and connect it to the output pad of that IC?

I don't see why this wouldn't work unless the PCB has a way of monitoring that IC and can tell if it is not functioning properly...

Regardless though it shouldn't hurt if I connect a 19v supply to the output pad and see what happens correct?

 

Hi,
sure you can

 

The switch-mode psu gives out 5V and 20V according to the pcb markings, the output side is on the left, not where you marked it.

 

Hi,
sure you can

Ok great! I also posted this question over on the eevblog forum, And somebody responded And basically called me an idiot and said that I could not just inject 19v because this IC puts out a variable voltage and not a steady voltage.

Which I told him I do not believe that is correct.

The switch-mode psu gives out 5V and 20V according to the pcb markings, the output side is on the left, not where you marked it.

Yeah there is a LM7805 & LM317 on the DC side the board.

I am pretty sure the pad/pin I have circled on the attached photo of the PCB is the output pin... that's the "drain" pin. Thats where I can inject 19 volts correct?

 

to
bigjoncoop

I guess, there's a misunderstanding concerning 19V. The specification where 19V is mentioned is taken from a foreign PSU description.
In fact , those TOP267EG can be used to produce any output voltage. Output voltage depends on the ferrite transformer data.
Output on yours PCB is on the left from the circle you marked, as it was noted before.
It seems, theres's more than one converter on the PCB.

I do not understand, why not to replace the TOP267EG ?

 

to
bigjoncoop

I guess, there's a misunderstanding concerning 19V. The specification where 19V is mentioned is taken from a foreign PSU description.
In fact , those TOP267EG can be used to produce any output voltage. Output voltage depends on the ferrite transformer data.
Output on yours PCB is on the left from the circle you marked, as it was noted before.
It seems, theres's more than one converter on the PCB.

I do not understand, why not to replace the TOP267EG ?

Well when i originally posted this question, I was hoping to fix the issue right away... As luck would have it, the component that failed is obviously something I don't have in my stock...


But I went ahead and ordered a new TOP267EG the other day.

So as for the output pin on this IC...
Your saying that where the source pen is connected would be where voltage would be injected? Just curious.

 

to @bigjoncoop

TOP267EG is related to the mains 230/120VAC. So, it is in the so called primary side of the PSU. In most PSU's the primary side is marked by a brigth line and marked "High voltage" or similar.
The so called secondary side is after the transformer.
There is no point to inject any foreign voltage into the primary side , into any pin of the TOP267EG.
I do not understand, where from the "19V" come from. From a specification of an unknown PSU?

 

Make sure you check the electrolytic capacitors. Often they loose capacitance and cause problems in switch mode supplies. As they go low, they no longer can absorb the switching spikes and so pop the switching FET. Low ESR caps may be required too, not just standard ones. Measure the capacitance if you can.