Konica DR-BC-K4 Battery Charger

[Per Hansson]

Re: Konica DR-BC-K4 Battery Charger

That "mosfet" on the secondary side of things is from what I can work out a PNP transistor type number HT772
From the pdf I grabbed its use's are output for 1Watt audio amp ,Votage regulator, DC DC converter, Relay driver.
package type TO 126
(I really should have known the package type but couldn't recall it at the time I did the reply above...brain getting old and rusty LOL)

Pin out from you pic above is (L2R) Emitter Collector Base
(looking at the numbers on the back)

Interesting, I never even found the PDF, I guess your google skillz are beyond mine Yoda

D2 appears to be a high speed rectifier diode and along with that 16 Volt cap would be the AC secondary to secondary DC (rec, filter part of the circuit)
(half wave by the looks of it) You say you have no DC there
I'll stand to be corrected on this thought.

I said I have almost no DC voltage here, but it slowly climbs up to about 0.7v, after a minute or so...

Next a question you say the DH565 gets really hot, is the transformer or any other components getting really hot? Err make sure you unplug it OK.
If its not doing any work I would expect nothing to be getting overly hot

I measured it plugged in, it is only the DH565 that gets hot, the transformer is at 30°C or so... The rest of the components are cool to the touch...

I dont know how likely it is for the DH565 to fail internally but if static tests of components are not showing up a dud then possibly it is the fault

Again I know its not the answer your looking for but hope it helps

Your help is more than welcome, I've already spent too much of my own and others time on this so why not go to the bottom with it

gonzo0815; ok, well, I was not expecting the caps to be a problem since they have seen so light use, but of course they are still from 2002 or so so it is very probable that they have dried out I guess...

Don't have any that small 400v caps to swap it out with though, I guess it would not be so smart to connect a 600uF cap in it's place

[gonzo0815]

Re: Konica DR-BC-K4 Battery Charger

If you replace the fuse, the rectifier, etc. you can probably use that bugger ;-)
But yes, i think some smaler would be better.

[kc8adu]

Re: Konica DR-BC-K4 Battery Charger

i would first check the output rectifier for a short then replace the dh565.
could still have a shorted winding in the transformer bu that is rare.

[Per Hansson]

Re: Konica DR-BC-K4 Battery Charger

How do I test the rectifier(s)? (they are the D2 and BD1 chips on the underside of the PCB right?)

[gonzo0815]

Re: Konica DR-BC-K4 Battery Charger

Probably D2, ist is probably an shotky type e.g. sbl540 or similar.
You can chek that with an diode or resistance cheker. The diode must led the current flow in only one direction, e.g if you reverse your test tips (and therefore the polarity) it must either let the curren flow or not. If you has no resistance in both directions, the thing is short.
If it is open in both direction it is defective too.
For replacement, you should use any suited shotky diode or some fast switching types.
May be it is necessary to desolder one leg, if you got strange readings.
@kc8adu
why you consider those rectifier to be the faulth? is this a common problem in smps?

[Per Hansson]

Re: Konica DR-BC-K4 Battery Charger

Bought a new charger, got it today in the mail. Hooked it up to 230VAC and put the battery in it; nothing, no "charge" LED blinking...

Me thought this was a bit odd so tried the included power cable, same thing

It also came with a separate 12-24VDC input, for use in cars, so I put it in my car and viola, charging like a sharm

Now where is the irony in this, damn Murphy!

[kc8adu]

Re: Konica DR-BC-K4 Battery Charger

Probably D2, ist is probably an shotky type e.g. sbl540 or similar.
You can chek that with an diode or resistance cheker. The diode must led the current flow in only one direction, e.g if you reverse your test tips (and therefore the polarity) it must either let the curren flow or not. If you has no resistance in both directions, the thing is short.
If it is open in both direction it is defective too.
For replacement, you should use any suited shotky diode or some fast switching types.
May be it is necessary to desolder one leg, if you got strange readings.
@kc8adu
why you consider those rectifier to be the faulth? is this a common problem in smps?

shorted schottky diodes are quite common in smps.they dont survive spikes and near lightning strikes too well.they are usually low voltage and often not much margin for overvoltage.

[Per Hansson]

Re: Konica DR-BC-K4 Battery Charger

Haha, opened the sucker up to see if there was anything obviously wrong with it...

I wont even say a word, the pictures describes it best, though seeing a device that makes the "Deer" brand look über highend sure is a fitting description

[Per Hansson]

Re: Konica DR-BC-K4 Battery Charger

I measure 320VDC up to the transformer on both chargers, and on the other side of both transformers I measure nothing... If I measure across the terminals on the output of the transformer I measure a short, is this normal/the way it should be?

I tried giving the old charger 12v DC on the secondary side of the transformer (behind a diode to not cause a short circuit) but the powersupply shut down (shortcircuit or overcurrent protection I guess)

[gonzo0815]

Re: Konica DR-BC-K4 Battery Charger

Probably there is no short, it is the transformer windign which normaly hasn`t that high resistance. it is the inductance which mathers there. So with normal DVM you read an short.
You should meassure the shotky as kc8adu stated.
I doubth that there is anything else wrong than evt. the shottky and the caps. At least the tiny smps isn`t that dificult to fix, and in my opinion it is very robust.