kiev
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Re: Gen1 DCDC Converter Troubleshooting and Repair

Sun Nov 01, 2020 5:54 pm

That's what we want, a Low on pin 13. Now to get a Low on Pin 12...

Pin 12 is fed from the inverted output of an AND gate, so both inputs must be Hi. One side is from an [Comparator]op amp reading the temperature sensor, and with TP217 reading as you measured, then that half is good. i just haven't had time to sort thru all the traces for the other half of the AND gate.

So i've spent several hours this evening scraping off the coating and tracing back and forth with all the tiny vias and traces, and i'm still not close to finding any real signal yet, it's never ending gates. The one half- AND gate has split into 4 more AND gates, so it's going to take quite a bit of time to ring this out. i've got to give my eyes a rest.
Last edited by kiev on Mon Nov 09, 2020 7:24 am, edited 1 time in total.
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eldenh
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Location: Port Angeles, WA

Re: Gen1 DCDC Converter Troubleshooting and Repair

Mon Nov 02, 2020 7:23 pm

It looks like much of that signal processing is on the bottom side of the board, but it seems that the inputs are from the top side. Is it possible to probe the status of the inputs from the top?
2012 ES

kiev
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Re: Gen1 DCDC Converter Troubleshooting and Repair

Tue Nov 03, 2020 9:33 am

It might be possible once we figure out the circuits. It took a long time to figure out the OBC and even still the control board is not fully traced out and i have no idea about the microcontroller code. The control board is similar to the LV section of the DCDC with the tiny vias.

All those little 2-via pads with the tiny 0.01" holes seem to be carrying signals, versus the larger diameter vias carry voltage or ground. There is no reference designation on the vias and they move the signal from the top layer to the bottom layer, sometimes they are hidden underneath a chip, and it is difficult to keep track when flipping the board over back and forth, and then trying to sketch the circuit at the same time.

Plus the clearcoat removal is tedious and time consuming--it causes many false readings if not removed.

The top layer seems to have 5 main traces from the PWM chip back to the LV section, and the bottom layer has 4 or 5 that do the same. These are likely the most important for control and that is where i am focused to determine their function. Of those lines i think we know what 3 of them do based upon your measurements.

TR104 provides a TR103-current sense signal to the PWM on pin 9 labelled as Current Limit (ILim).
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kiev
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Re: Gen1 DCDC Converter Troubleshooting and Repair

Wed Nov 04, 2020 10:09 am

When you were doing these tests and measurements, did you have a 12V battery connected to the Output of the 125A fuse?

Here is a sketch of a circuit which provides the command signal to pin 1 of the PWM chip IC201. It seems to combine a sense of the input and output 12V of the aux, the 15V of TP201, and the output current for charging the aux battery. Probably not an issue here for you unless you had no aux connected.

Image
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eldenh
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Location: Port Angeles, WA

Re: Gen1 DCDC Converter Troubleshooting and Repair

Wed Nov 04, 2020 12:09 pm

I had 12v hooked to the output when I first set it up for testing, but not on subsequent days. I just tested it again with 12v on the output and pin 8 of IC201 is still being held low. Pin 12 of IC206 is high.
2012 ES

kiev
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Re: Gen1 DCDC Converter Troubleshooting and Repair

Wed Nov 04, 2020 12:41 pm

Okay thanks for checking with the 12V connected.

i will sketch up what i have traced for the pin 12 gate later today; part of it is related to the temperature sensor that ends up driving pin 5 of IC207, and something else is driving pin 4 but i can't find what else is being "sensed".

Here's a draft schematic that might give you an idea of how the circuit seems to ramble on. And this is just for the feed to pin 12 of the OR gate, and it still needs work.

[edit] updated drawing
Image
Last edited by kiev on Thu Nov 05, 2020 10:09 am, edited 1 time in total.
kiev = kenny's innovative electric vehicle

coulomb
Posts: 237
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Location: Brisbane, Australia

Re: Gen1 DCDC Converter Troubleshooting and Repair

Thu Nov 05, 2020 5:42 am

kiev wrote:Here's a draft schematic that might give you an idea of how the circuit seems to ramble on.

Heroic work, Kenny. It sure does ramble.

Thanks for all you do.

kiev
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Re: Gen1 DCDC Converter Troubleshooting and Repair

Thu Nov 05, 2020 8:27 am

Thanks Mike, it always helps to get your review and analysis, hopefully it will make sense before too long.

@ elden, when you have made your tests, was the board fully mounted into the OBC housing with all 7 of the hold-down screws? The reason i ask is that there are some Grounds traces on the board that will be floating unless the screw makes the connection thru the housing; actually it is only screws 1-3 and 5 that are used like this and would need to be mounted, screws 4,6,7 have no connection. And then the housing would need to be connected to the negative terminal of the 12V aux battery. A floating ground could be causing the PWM not to start.
kiev = kenny's innovative electric vehicle

eldenh
Posts: 65
Joined: Sat Oct 03, 2015 7:18 pm
Location: Port Angeles, WA

Re: Gen1 DCDC Converter Troubleshooting and Repair

Thu Nov 05, 2020 9:05 am

Thanks for the hard work! I'll try to see what I can find in that shortly. I mounted the board with the 4 screws that have metal pads assuming them to be important, but have omitted #s 4, 6, 7 expecting to have to remove the board to replace whatever had failed.

Trying to troubleshoot from your pencil sketches has been rather difficult because my eyes have trouble distinguishing the pencil lines from a grayish background. I choose to build a spreadsheet to help me find where I can try to probe with the board mounted. In doing so I found that Q219 is listed as "KN" and "G16". I can't make out the label in the underside photo, so don't know which is right.
2012 ES

eldenh
Posts: 65
Joined: Sat Oct 03, 2015 7:18 pm
Location: Port Angeles, WA

Re: Gen1 DCDC Converter Troubleshooting and Repair

Thu Nov 05, 2020 10:01 am

Thanks for the hard work! I'll try to see what I can find in that shortly. I mounted the board with the 4 screws that have metal pads assuming them to be important, but have omitted #s 4, 6, 7 expecting to have to remove the board to replace whatever had failed.

Trying to troubleshoot from your pencil sketches has been rather difficult because my eyes have trouble distinguishing the pencil lines from a grayish background. I choose to build a spreadsheet to help me find where I can try to probe with the board mounted. In doing so I found that Q219 is listed as "KN" and "G16". I can't make out the label in the underside photo, so don't know which is right.
2012 ES

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