Ryobi IntelliPort Battery charger

[WeaselXP]

Broke this one open to find Asia X caps, which are apparently Fuhjyyu budget models. Replaced all (except the one Samxon). This was not done as a needed repair in as much as attempt at trolling certain Czech members of the board.
Have a nice weekend.

[momaka]

Re: Ryobi IntelliPort Battery charger

Well, I don't blame you for recapping it . After all it is a Lithium battery charger - the last thing you want is for the power supply to do something weird, kill the charging IC, and overcharge the battery (thus producing a possible fire hazard). Speaking of a charging IC, I don't see one on your PCB. Is it on the bottom (SMD package)? I certainly hope this isn't a "dumb" charger.

[stj]

Re: Ryobi IntelliPort Battery charger

the 2 large output rectifier diodes will fail at some point and blow the fet.

[WeaselXP]

Re: Ryobi IntelliPort Battery charger

IC's on the bottom of the PCB correct.

[WeaselXP]

Re: Ryobi IntelliPort Battery charger

the 2 large output rectifier diodes will fail at some point and blow the fet.

Any suggestions on corrective action?

[stj]

Re: Ryobi IntelliPort Battery charger

yes.

they are mbr5200 5a diodes.
replace the pair with a single mbr40250 on a custom heatsink.

[momaka]

Re: Ryobi IntelliPort Battery charger

replace the pair with a single mbr40250 on a custom heatsink.

Why go so overkill with the reverse blocking voltage, though? This being flyback topology, I imagine you can get away even with a 45V rectifiers. So something like MBR2045 through MBR2060, MBR3045 through MBR3060, and MBR4045 through MBR4060 should all work too. Plus, those are much more common and probably cheaper too. If you really want to be on the safe side, go for STPS20S100C or similar.

[stj]

Re: Ryobi IntelliPort Battery charger

availability - it's easy to get.
and an 18v charger is something i would not want a shotky in unless it was atleast 10x the running voltage.

[WeaselXP]

Re: Ryobi IntelliPort Battery charger

How you can even tell what rectifier is there is beyond me, guess it will have to fail. If you can't fab a custom heatsink from a beer can, I am out of luck.

[stj]

Re: Ryobi IntelliPort Battery charger

i can tell because i'v fixed about 15 of the lime coloured ones.
2 diodes in parallel is the same mistake as the vestel tv psu's!!