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TCCH Elcon charger troubleshooting and repair

103402 Views 368 Replies 34 Participants Last post by  pdove
Several of us dudes have been looking into some failed chargers to determine if repairs are possible. In the bad units we have seen that the input start relay and by-pass resistors have been overheated and failed. The main board has been traced and sketched up in another thread: http://www.diyelectriccar.com/forums/showthread.php/tcch-elcon-1-5kw-charger-schematics-89470.html

We have made some good progress on tracing up the control board, and in the process found a defective FET driver that was pulling down the 12vdc supply. This may be the mechanism for causing the relay and bypass resistors to get so hot.

The fet driver was drawing excess current from the 12vdc supply (the viper circuit) such that the viper went into re-start mode. But doing that would cause the start relay to lose hold-current and go open--now the full 120vac would be carried thru the 2 paralleled 150 ohm bypass resistors (~190 watts in 1 watt devices).

We hooked up an oscilloscope and applied power to the viper and found it was in an infinite start-up loop and never able to kick in to regulation mode due to the Fet driver load. When we isolated the driver out of the load path, the viper came up and went into normal regulation. It appears to be a good device but should be swapped out anyway since it may have been overstressed.

The control board has two separate 12vdc supplies generated by the viper--one for the analog section and one for the digital portion of the control board. The analog end shares power with the start relay and the digital end shares power with the output relay.

If anything should cause the analog-end 12vdc supply on the control board to get pulled down low, it will take out the start relay and cause catastrophic failure of the charger due to the by-pass resistor configuration.
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Discussion Starter · #322 · (Edited)
The little 10 Ohm resistors R107 on pin 5, and R108 on pin 9, were intact, as were all the other resistors in the U2 current sense circuitry.

The sparkling cap was arcing between it's case and the lead of Resistor R15 on the main board AC input schematic (that you found and added). i think that pin 9 trace runs under the cap, so it may have been subject to arcing also.

And if there was trace metal debris still in the vicinity, then the cap case might be shorting to the remaining trace. The case is connected to neither + or - but can read a charged voltage.

Gonna need to pull the board and remove the caps, then put some eyeballs or camera on what is underneath them.

[edit: note to check continuity between cap case and pin 9 since measurement between pin 9 and R13 was open, and pin 9 was reading 160VDC.]
 

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On further investigation.... daughter board pin 9 is supposed to go to right side of the current sense wire so it reads across pins 5 and 9. I get an open on pin 9 so the trace is gone. In addition resistors R8 and R9 are shorted the ones that go to the gates of Q7 and Q8.R6 and R7 still read 10 ohms.

I am not sure the effect this would have on the FETs but is must br raising the Gate current.

Now it makes sense why it won't ramp the current.
 

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Discussion Starter · #324 ·
i thought you looked at the bare control board and it was pin 9 that went to R108..?

On the main board there is a large ground area underneath the big caps with two little traces running to pins 8 and 9 of the control board, these are both "upstream" of the return current sense wire, but only pin 9 runs to the + input of the current op amp inside the PFC chip.
 

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i thought you looked at the bare control board and it was pin 9 that went to R108..?

On the main board there is a large ground area underneath the big caps with two little traces running to pins 8 and 9 of the control board, these are both "upstream" of the return current sense wire, but only pin 9 runs to the + input of the current op amp inside the PFC chip.
You are right I typed the wrong number. I corrected it in my post.

In addition, the insulation on the big red jumper wires is cracked and missing in places.
 

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I have TCCH-240-5 1.5kW charger.

When I connect the battery it starts pulling the battery down. I removed the output relay and C14 and it still pulls the battery down. I am struggling with what else could cause this. I would suspect C21 and C13 but the charger is out of the case so the chassis connection is not present. They go to a bolt hole that's not connected. R10 and R2 seem to read fine with a meter. D2 seems to work as well. I also noted that with the charger plugged in and no battery connected I read 2 volts on the output even with the relay and C14 removed. It is just not making sense looking at this schematic.
 

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I also noted that with the charger plugged in and no battery connected I read 2 volts on the output even with the relay and C14 removed. It is just not making sense looking at this schematic.
I would not worry about that; it could just be leakage through the MOSFETs. It's also possible it comes from CMPREF on the processor via several resistors and D12.

I'd consider replacing D12 even though it seems to work OK. It's supposed to stop the battery draining.

Is it possible that there is conductive muck on the PCB, perhaps under the output connector? Higher voltage may find a path that a 3 V multimeter does not.
 

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I would not worry about that; it could just be leakage through the MOSFETs. It's also possible it comes from CMPREF on the processor via several resistors and D12.

I'd consider replacing D12 even though it seems to work OK. It's supposed to stop the battery draining.

Is it possible that there is conductive muck on the PCB, perhaps under the output connector? Higher voltage may find a path that a 3 V multimeter does not.
Turned out to be low or dead cell in the battery. Haven't steps tested the cell yet.
 

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Turned out to be low or dead cell in the battery. Haven't steps tested the cell yet.
aha, you mean the pack voltage was not within parameter, charger doesn't 'see' a valid pack voltage, and doesn't start charge?

Thats a trick with these suckers... the final test has to be the charger hooked up to a live pack providing at least minimum voltage set in parameters before they even start up....
 

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I have:



Elcon EV Charger - TCCH-120-15
Alg 521av, 144V2K5W 52CELL

Control board: TCCH1K5W A Ver 1.8


I have a blown control board with a hard (1.2 ohm) short between VCC and DGND. This was caused by a bad simulated battery hookup which fed line voltage back through R39. Removed U3, VCC to DGND still shorted. Powered charger, 12VDC at CON32S pins 22 & 23 is good. Unfortunately I'm not having any luck isolating this short. Do any of the experts here have any ideas? Thanks, -Reed
 

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Discussion Starter · #334 ·
Fuse R39

On the control board, R39 is actually a Fuse marked "JB" on my board, that connects pin 2 of the 7-pin header (GND) to pin 22 of the control board, DGND.

During this incident did you have any sort of enable circuit connected to the round 7-pin connector on the side of the box?

Did you have any circuit board damage on the Output side of the Main board?
 

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I don't remember (it was some time ago). If I did, it would have been just a jumper between pin 1 & 3. I don't see any damage in the output section.



About that fuse, It didn't appear to blow. It still measures 1.6 ohms.
 

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I have:



Elcon EV Charger - TCCH-120-15
Alg 521av, 144V2K5W 52CELL

Control board: TCCH1K5W A Ver 1.8


I have a blown control board with a hard (1.2 ohm) short between VCC and DGND. This was caused by a bad simulated battery hookup which fed line voltage back through R39. Removed U3, VCC to DGND still shorted. Powered charger, 12VDC at CON32S pins 22 & 23 is good. Unfortunately I'm not having any luck isolating this short. Do any of the experts here have any ideas? Thanks, -Reed





My first guess is that the processor if fried. There may be other parts causing the short. The most common parts to fail are the Opto couplers On pins 6 and 7 of the 7-pin flat connector but they shouldn't cause a short. I have seen D8 D9 D13 and D14 bad before but not usually shorted.I have also seen U6 the LM258 chip bad before.
 

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I was afraid of that. I'll try lifting the VCC pin on the processor pin first. It seems that if it's the processor I'm in bad shape. I'd need to get a new processor, a programmer and firmware (I don't have a copy of the firmware). The PCB seems pretty fragile (I had trouble with the voltage regulator pads coming loose). Is there any source of new or used control boards?



Thanks -Reed
 

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Discussion Starter · #338 ·
check the LM20 temperature sensor chip, U11.

It's not clear exactly what happened--you said that line voltage (120vac?) got connected to the charger output? which side of the output, the + or - wire?
 

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I was connected to the serial interface through the 7 pin connector to a desktop computer (through the key board USB hub and a USB2Serial cable). I was powering the charger through a small isolation transformer. I was looking at received packets and wanted to see the battery voltage change so I connected a bridge rectifier and cap directly to the line, charged the cap to ~160VDC, disconnected the line then connected that to the battery output on the charger. I did this a couple of times with out a problem, but then forgot to disconnect the cap charger once. DGND is connect to battery ground internally. Blew out the control board, the keyboard and the USB2Serial cable. Didn't destroy the iMac.
 

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U5, Phillips P89LPC938FDH was shorted. I got it off without damaging the board. My board has a thick clear coat which makes it hard to work on. I also lifted U11 and U4. U11 I think I can salvage. U4 and U3 I will have to replace. U4 is not on the 2018 May 24 version of the control board schematic. Does anyone have any info on this part? Also any ideas on how to proceed at this point (finding firmware)? Thanks for the help to this point.
-Reed
 
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