Hey Andy! Whenever I have a blown fuse, I start checking all diodes too, it's quick and they have a hard life in a SMPS. I don't think a problem in the secondary circuit can cause the primary fuse to blow so violently. Kind regards!
Hi, thanks for your thoughts, I'm thinking it's the FET that is a dead short and normally it's not just that. So fitting a new one does not solve the problem. I still think the old style chargers are superior, cheers
I'd agree ref the secondary side of the circuit probably not being the problem, that heating could be those large ceramic resistors. The FET could have been taken out by that cap going short.
That capacitor obviously went short circuit, then open circuit, as could be gathered from the fact that one lead had burned away. The fact then that the replacement fuse blew indicated that there was at least one more short on the board. Entirely possible that it's in the rectifier, but likely that it's also taken out the smps controller, and maybe the mosfet(s) too. Your "properly calibrated fuse" - to steal an expression from another guy's channel - was in this instance for too small, as I'd guess even a fully working circuit would "blow" it, due to the inrush current. I'd guess that the heat discolouration on the output side of the board is probably not a sign of where a problem lies, rather that that part of the board passes a high current for long periods, and it's built to a price. It would take quite a bit of troubleshooting to get the charger to work again, but it's satisfying when one manages it.
Will, good thoughts, so an excessively rated fuse would allow the problem to be truly apparent, and release the blue smoke dragon, shame I never thought of it, still next time, cheers
Hi, not easy as the only usable thing would be the case, needs a transformer, maybe use the original rectifier, and an amp meter. I have a small standard charger on the bench for repair at the moment, cheers
I have the same model and it’s just done exactly the same... I switched the output up from 2A to 8A and after about 10 seconds poof! In addition to the leaking cap and blown fuse (as in your video) I've noticed a blown blue varistor (MOV) which is connected in parallel to a larger black disc shaped component (I'm guessing another MOV) and a resistor (all near the cap you replaced). I’ve not de-soldered it yet to see what exactly its value is, but it has a large visible split running through it which usually means it's gone short circuit... possibly due to age or it's gone faulty. I suspect these are susceptible to overvoltage spikes from the output from the first stage in the PSU so these MOVs are taking the kick... and will eventually fail as each time they take a hit they degrade a little more. Looking at your video @ 21.11 it appears your blue MOV has split. Has anyone successfully fixed one of these as I’m guessing this is an inherent fault that occurs with this model. I'm tempted to remove the MOV (or both) and see if it fires up. No point throwing money on replacement components if it’s not easily fixable. Thanks for making this video. :)
Hi, yes you are right, a cascade effect can cause multiple component failure. Unless you are an electronics expert then an attempted repair could end in expensive frustration, cheers
@@TheInfoworks Hi :) I used to be an electronics engineer so fortunately have the expertise but not the time for too much faffing about. The only reason a varistor would split is if its resistance has gone high, short circuited or hit by something like a bolt of lightning... I tested my popped one and its resistance was very high so basically a short. We'd had a few power cuts etc recently due to wind and storms so the varistor probably took a pounding and mines kept busy trickle charging a people carrier so is left on. There is also a 470K resistor in series with the varistor... not sure why... perhaps to extend the life of the varistor or reduces the changes of it going nuclear? I get the feeling the PSU in these is not brilliant and prone to spiking the second stage. Technically you could just remove the varistor from the circuit and try replacing the fuse to see if it works... hopefully they did their job and the charger will now power up. If it works “great” but you will need to replace the varistor asap as the circuit is not longer protect from surges and you run the risk of completely toasting the charger in the future.
Okay... just a quick update... replace the fuse and varistor and you're back in business. The fuse you need is a 20mm 3.15 Amp quick blow and a 10D391K varistor. I'd also suggest replacing the 105°C 400 Volt 100uF capacitor as they appear to leak so will likely be out of spec. So for just a couple of quid you can fix your battery charger... yay!
...and another update. Out of interest I tested the leaky cap and it only measured 34pF (should be 100uF) so I'd definitely recommend swapping it out as it's smoothing days are over. The battery charger is now working perfectly and currently charging a massive van battery at 8 Amps.
My immediate thoughts are mosfet failure. Wouldn't bother fixing it myself as there is more to go wrong. One can make old style transformer battery chargers even more reliable through removing diode pack since a lead acid battery will rectify ac. I think young men are put off repairing modern items since they're a more complicated to repair than yesterdays items, and they're social media obsessed. Spending their time in a virtual world of gaming and social media desperate to be noticed.
Sounds a bit silly Andy but I would’ve “sniffed” around after the initial pop sound…my small inverter did a similar thing and I sniffed out one of the capacitors. Andrew
Always love your content Andy ✔️ thank you
Cheers Ron.
Hey Andy!
Whenever I have a blown fuse, I start checking all diodes too, it's quick and they have a hard life in a SMPS.
I don't think a problem in the secondary circuit can cause the primary fuse to blow so violently.
Kind regards!
Hi, thanks for your thoughts, I'm thinking it's the FET that is a dead short and normally it's not just that. So fitting a new one does not solve the problem. I still think the old style chargers are superior, cheers
I'd agree ref the secondary side of the circuit probably not being the problem, that heating could be those large ceramic resistors.
The FET could have been taken out by that cap going short.
@@davidbrodie5044 changing these can be a problem as often the driver is faulty also and does not fix the unit, cheers
That capacitor obviously went short circuit, then open circuit, as could be gathered from the fact that one lead had burned away. The fact then that the replacement fuse blew indicated that there was at least one more short on the board. Entirely possible that it's in the rectifier, but likely that it's also taken out the smps controller, and maybe the mosfet(s) too. Your "properly calibrated fuse" - to steal an expression from another guy's channel - was in this instance for too small, as I'd guess even a fully working circuit would "blow" it, due to the inrush current. I'd guess that the heat discolouration on the output side of the board is probably not a sign of where a problem lies, rather that that part of the board passes a high current for long periods, and it's built to a price. It would take quite a bit of troubleshooting to get the charger to work again, but it's satisfying when one manages it.
Will, good thoughts, so an excessively rated fuse would allow the problem to be truly apparent, and release the blue smoke dragon, shame I never thought of it, still next time, cheers
Nice try Andy 👍
Yes, it could have worked, cheers
I think you can remove the circuit boards and convert back to a old style battery charger ?
Hi, not easy as the only usable thing would be the case, needs a transformer, maybe use the original rectifier, and an amp meter. I have a small standard charger on the bench for repair at the moment, cheers
I have the same model and it’s just done exactly the same... I switched the output up from 2A to 8A and after about 10 seconds poof!
In addition to the leaking cap and blown fuse (as in your video) I've noticed a blown blue varistor (MOV) which is connected in parallel to a larger black disc shaped component (I'm guessing another MOV) and a resistor (all near the cap you replaced).
I’ve not de-soldered it yet to see what exactly its value is, but it has a large visible split running through it which usually means it's gone short circuit... possibly due to age or it's gone faulty.
I suspect these are susceptible to overvoltage spikes from the output from the first stage in the PSU so these MOVs are taking the kick... and will eventually fail as each time they take a hit they degrade a little more.
Looking at your video @ 21.11 it appears your blue MOV has split.
Has anyone successfully fixed one of these as I’m guessing this is an inherent fault that occurs with this model.
I'm tempted to remove the MOV (or both) and see if it fires up.
No point throwing money on replacement components if it’s not easily fixable.
Thanks for making this video. :)
Hi, yes you are right, a cascade effect can cause multiple component failure. Unless you are an electronics expert then an attempted repair could end in expensive frustration, cheers
@@TheInfoworks Hi :)
I used to be an electronics engineer so fortunately have the expertise but not the time for too much faffing about.
The only reason a varistor would split is if its resistance has gone high, short circuited or hit by something like a bolt of lightning... I tested my popped one and its resistance was very high so basically a short.
We'd had a few power cuts etc recently due to wind and storms so the varistor probably took a pounding and mines kept busy trickle charging a people carrier so is left on.
There is also a 470K resistor in series with the varistor... not sure why... perhaps to extend the life of the varistor or reduces the changes of it going nuclear?
I get the feeling the PSU in these is not brilliant and prone to spiking the second stage.
Technically you could just remove the varistor from the circuit and try replacing the fuse to see if it works... hopefully they did their job and the charger will now power up.
If it works “great” but you will need to replace the varistor asap as the circuit is not longer protect from surges and you run the risk of completely toasting the charger in the future.
Okay... just a quick update... replace the fuse and varistor and you're back in business.
The fuse you need is a 20mm 3.15 Amp quick blow and a 10D391K varistor.
I'd also suggest replacing the 105°C 400 Volt 100uF capacitor as they appear to leak so will likely be out of spec.
So for just a couple of quid you can fix your battery charger... yay!
...and another update.
Out of interest I tested the leaky cap and it only measured 34pF (should be 100uF) so I'd definitely recommend swapping it out as it's smoothing days are over.
The battery charger is now working perfectly and currently charging a massive van battery at 8 Amps.
Yes, it was a capacitor problem on the recent car charger fix. I'm surprised on a 12v charger that has only occasional use, cheers @@ZilinaSK
My immediate thoughts are mosfet failure. Wouldn't bother fixing it myself as there is more to go wrong. One can make old style transformer battery chargers even more reliable through removing diode pack since a lead acid battery will rectify ac.
I think young men are put off repairing modern items since they're a more complicated to repair than yesterdays items, and they're social media obsessed. Spending their time in a virtual world of gaming and social media desperate to be noticed.
I think if I bought a FET for the input side I would find that the driver would be faulty, cheers
Sounds a bit silly Andy but I would’ve “sniffed” around after the initial pop sound…my small inverter did a similar thing and I sniffed out one of the capacitors. Andrew
Yes, that and looking for burn marks, cheers
I have a ring auto charger. Only used it half a dozen times and it is now broke
Absolute rubbish!
Hi, have you tried cleaning the clip jaws and the battery terminals, Cheers