kiev
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Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sun Feb 02, 2020 12:33 pm

i think the F701 fuse blew and shut down the 3.3V supply and the IC701 microcontroller. This turned off the base or gate drive for some transistor on the top board that controls the 5V drive for the AC relay coil in the doghouse on the bottom board. This caused the AC path to run only thru the ceramic resistors and caused them to blow. Coil L702 is in the path of this switched 12V that is on that fuse circuit.

If you see any resistor looking components marked FBxxx, be sure to check if they have blown open.

[edit]
So it turns out that i had traced the 5V supply for the AC Relay and posted a description in discussions on page 8 and 9 of this thread, but i had not traced the path for the transistor drive from the microcontroller until now.

The 12V switched power supply coming in on pin7 of the CN101 connector is used to create the AC relay 5V supply, running thru FB729 and then on to IC710, NCP4641 voltage regulator pin5. The +5V on pin1 is sent to the bottom board thru CN1 pins 22-24; the return comes back on pin 25 up to the top board where it is routed to the collector of transistor TR301, the emittter goes to ground, and the base is driven thru a special blue colored resistor, R302 3.3k, from a via that comes up from directly under the microcontroller, IC701. i didn't ring all the pins to find which drives the base but it shouldn't be hard to find if needed.

The CN1 flat ribbon cable has chassis ground on pins 1-4,16,18,20,31,33,40,47-50.
kiev = kenny's innovative electric vehicle

DBMandrake
Posts: 286
Joined: Mon Mar 20, 2017 4:57 am
Location: Scotland

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Thu Feb 20, 2020 7:27 am

DBMandrake wrote:
phb10186 wrote:The obvious two culprits.

I think, especially now that these cars are ageing a bit, I will charge control more closely in the very hot/ very cold weather via the remote... though luckily that is quite rare here in the UK (and the climate is somewhat similar to Japan) (can't remember any charger failures here). If I lived in a hot dry climate, a well placed CPU fan cut into the charger case could also help with heat dispersion, as could (possibly) modification with an improved heatsink in the vulnerable places.

Don't get too comfy, there have been multiple on board charger failures in the UK recently.

Kes who posted this thread is located in Scotland not far from me and has had the charger go on both his cars... :(

He also posted over on speakev.com about his problems, (with more up to date information) and there have been other reports on speakev.com of UK charger failures recently as well.

Makes me a bit nervous about mine which is a 2011 model with over 50k miles now. On the plus side I recently replaced the very weak 12v battery so it has a good healthy 12v battery now. If that is the underlying cause of many of the failures I should be alright for a few years, touch wood.

I also use a Rolec wall charger and always end charging either by letting it finish charging itself (most days) or squeezing the trigger on the J-1772 connector - I never turn the power off at the wall first even if I was using the granny EVSE. So if that's another cause of failures I should be OK there too, especially now I'm aware not to do that.

Unfortunately I was right to be nervous - my on-board charger has now failed as well and probably taken out the 20A fuse and caps based on the symptoms. I have ordered caps and fuse preemptively but haven't had a chance to open anything up yet due to work and constant bad weather in the evenings - hopefully I will be able to look this weekend between rain showers...

I replaced my 12v battery only a year ago and it is still going strong so I would suggest that weak 12v batteries are not an underlying common cause of this common failure.

Also I never switch off the charging at the supply - I always let the car finish charging by itself (the vast majority) or press the trigger and remove the plug from the car. 99% of my AC charging is performed at home, and we do not get power cuts at home either. So I'm also sceptical about the interrupted AC theory.

Mine failed about 2 hours into a charging session at home which started at about 25% SoC and ended prematurely at 70%, so it would have still been charging at a full 13 amps (240v AC input) at the time of failure.
- Simon

EV: 2011 Peugeot Ion
ICE: 1997 Citroen Xantia V6

DBMandrake
Posts: 286
Joined: Mon Mar 20, 2017 4:57 am
Location: Scotland

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Fri Feb 21, 2020 4:27 am

Can anyone who has attempted this repair advise on the following:

I'm not keen on removing the entire on-board charger unit from the car if I can help it, so that I don't have to disconnect coolant lines and refill and bleed it later, but I'm also not keen on doing a close inspection of the main PCB (with the two blue caps) and repair in-situ in the car either, as the weather here is atrocious now and for the near future, with the car situated outdoors.

So I was wondering whether removing the main PCB (with the two blue caps) complete with waffle plate, and bringing that in the house for close inspection and repair and then refitting it was the best approach ?

From what I can see from this thread the PCB with waffle plate can be removed without un-soldering any pins with a little bit of force to make the heat transfer compound let go between the waffle plate and the coolant channel ? Are all the faults diagnosed so far on this one PCB ?

If I don't need to un-solder the waffle plate to effect a repair (fingers crossed - depending on what I find damaged) then can I refit it with the original thermal paste or will I need to clean up and re-apply new thermal paste ? (And if so, any recommendations of what to use ? It's a long time since I last used thermal paste...white beryllium stuff!)

I guess if I did have to remove the waffle plate then I would have to do the re-soldering of the waffle plate to the PCB after it is bolted down to the coolant channel and the PCB was bolted back into the board to ensure a perfect height match and no mechanical stress of the soldered joints...

Those that have un-soldered a waffle plate successfully, do you think a regular vacuum de-soldering station would do the job OK ? I don't have one, but I'm happy to buy one if I need it as it's something I would find useful for other electronics work. (I normally get by with a hand operated solder sucker and solder wick but sometimes wish I had something better for de-soldering...)

My current plan is to leave the charger unit in the car, remove this main PCB with waffle plate together, visually inspect the two 1000pF caps and other parts in the doghouse, replace the two caps regardless, and replace anything else visibly damaged, but also to perform the relay test to check the value of the 2x 4.7 resistors and ensure that the relay shorts them out reliably.

Even if there is no visible damage to them I'm definitely not putting the board back in until the resistors and relay have been functionally checked...

Should I be checking F701 as well ? Is that on the same board ?
- Simon

EV: 2011 Peugeot Ion
ICE: 1997 Citroen Xantia V6

kiev
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Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Fri Feb 21, 2020 6:01 pm

Once you remove the lid screws and carefully pry it up to start breaking the sealant, you will be able to see the smaller top board with flat ribbon cable down to the bottom board. There are the AC input wires into the top board toward the rear and down to the doghouse region below on the left side.

The mounting screws and faston tabs can be removed (slide the white plastic up and it will free the faston clips) and this top board can be laid over to the right. Now the bottom board can be seen and examined for blown components and schrapnel. i have replaced the blue snubber caps without removing the bottom board, and have also removed the board with the waffle plate. And used a vacuum desoldering tool to free the waffle plate, which was a tough job even so and i damaged some of the vias of the solder holes. If i need to remove the top board, i just slide the FRC connector release on the bottom board and leave it connected at the top.

They put too much thermal paste so expect that if you remove the bottom board with waffle plate. There is no worry about solder height--the bottom board floats above the waffle plate and the hold-down bolts/studs hold the plate, not the board.

if you decide to remove the BB and WP, there are numerous faston tabs with the white plastic covers that must be removed. Slide the cover up and it will release the faston lock clip. The wires are all colored and coded to the tabs, but take a picture with phone to remember how the wires are laid and wrapped on re-assembly.

With the faston tabs removed you can use the diode function of your multimeter to check for damage in the waffle plate, hopefully you will have none.
kiev = kenny's innovative electric vehicle

DBMandrake
Posts: 286
Joined: Mon Mar 20, 2017 4:57 am
Location: Scotland

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Fri Feb 21, 2020 10:49 pm

Does anyone know how many litres of coolant it takes to refill the system if I do completely remove the charger and whether regular 50/50 glycol based coolant is suitable ?
- Simon

EV: 2011 Peugeot Ion
ICE: 1997 Citroen Xantia V6

DBMandrake
Posts: 286
Joined: Mon Mar 20, 2017 4:57 am
Location: Scotland

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sat Feb 22, 2020 4:01 am

Ok here's an update on progress.

I've confirmed the 20A MCU fuse has blown, no surprise there, and I can also confirm that one of the two blue caps has split, although not as violently as some other cars as there is no debris anywhere, just a clean double split of the cap:

Image

The resistor I was also a little bit worried about at first as there is a black mark on the corner near the capacitor however on closer inspection I think it is residual potting mix or perhaps just the effects of heat build up over many years heating the potting mix causing it to wick up the side of the resistor:

Image

It doesn't look like an actual burn mark on the resistor and there is no melting of the potting mix at the base of the resistor or the cap itself. So I will measure the resistors from the top and verify relay operation - if they both seem OK I'm not going to replace the resistors because that would require waffle plate desoldering which I am not currently equipped to do.

I presume it's not possible to do meaningful diode checks on the waffle board without desoldering it ? If so I'll just have to take the chance that there is nothing blown on it.

I've decided not to remove the whole OBC box from the car - the outsides are very corroded as are all the mounting bolts, and removal would require work outside the car (not possible with current weather) including draining and refilling the coolant - and I don't have any to hand. (And funny story, my other car, a petrol car broke down terminally last night so I have no working car at the moment making this OBC repair super urgent... :roll: )

So the plan is to remove the bottom board from the box together with attached waffle plate to take inside for repair as it looks a bit too awkward to work on the board in the recess of the box hunched over inside the car to stay out of the rain - especially the potting mix removal.

I've also checked white fuse F701 on the underneath of the top board that was reported as faulty earlier in the thread - it measures ok.
- Simon

EV: 2011 Peugeot Ion
ICE: 1997 Citroen Xantia V6

kiev
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Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sat Feb 22, 2020 6:34 am

Yes you can check all the semiconductors/diodes with the WP still attached to the BB, just have to remove the wiring to the inductors first. But you will have to do that anyway to remove the BB from the box.

Remove the black plastic sleeves on the board standoffs, follow the numbered arrows at the base of the standoffs pointing out the order of removal and installation. There is a schematic with the measured voltage drops, i'll have to look to find the post.
kiev = kenny's innovative electric vehicle

DBMandrake
Posts: 286
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Location: Scotland

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sat Feb 22, 2020 7:17 am

I have the board right out and ready to start working on it now, so if you can give some guidence of which pin pairs to check with a meter in diode test mode to test the waffle plate that would be great.

Did anyone find a replacement source for the four electrolytic caps on the board ? Two of the large ones and the small one have wrinkles in the plastic wrapper suggesting they may have been a bit hot, however they are not bulging at the ends.

The large ones have 4 pins and the small one 3 - a bit of an odd layout! Unlike some of the other units shown in this thread there is no heat discolouration on the inside of the lid at all. I'm desparate enough to get the car working again that I may have to leave the electrolytic caps as is...
- Simon

EV: 2011 Peugeot Ion
ICE: 1997 Citroen Xantia V6

Sandrosan
Posts: 16
Joined: Tue Sep 24, 2019 2:43 am
Location: Milan, Italy

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sat Feb 22, 2020 7:22 am

DBMandrake,
I am sorry for your troubles, you were so ansious and then it happened!
I think a voltage spike has triggered and brocken the blu snubber cap and then blowing the fuse. Is my thinking possible?

I already put 3 SPD 275V AC rated before my EVSE and I am going to put another 3 Varistors at 250V AC or even a bit less as the voltage here is 230V (one P to E, one P to N and another N to E).

I also protected the EVSE line by an A type RCD with overcurrent protection.

I would suggest you to do so too after you fix your OBC. I wish you good luck, I am very confident you will be succesfull.
Cheers

Sandrosan
Posts: 16
Joined: Tue Sep 24, 2019 2:43 am
Location: Milan, Italy

Re: Troubleshooting and repair for On-board Charger (OBC), DC-DC Converter

Sat Feb 22, 2020 7:26 am

Can you reach the electrolitics caps terminls? If you have a DMM with capacitor function you may at least test them.
It is not a sure test for their full integrity but much better than nothing.
I have seen many photos of such board and all of them have these capacitors well suffered the heat, but I think few have been replaced.

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