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Thread: E32/34 sword repair info collection

  1. #11
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    Also look for these failed solder joints, resolder them
    https://i.postimg.cc/g0CZ23Ln/sword_1.jpg
    https://i.postimg.cc/nh5s3qk0/sword_2.jpg

  2. #12
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    To add my own experience and a caveat:
    The symptom my car(89 535)exhibited was the fan running any time car was on. Seemed to be speed #3 as turning to 4 increased speed slightly. Autopsy revealed 3 of the 4 MOSFETS were bad.
    I ordered BUZ11a MOSFETs as I read they are more robust.
    10 ST Microelectronics brand ordered from Ebay seller giorgio11185. Good thing he sells by 10 as three(perhaps 5) were bad. I only found this out after performing the repair and having only high speed function.
    After dismantling again the MOSFETs were tested and two of the four installed were bad. Another from the pkg was also bad and two others gave odd results.
    SO, given the tedious nature of this job I advise that these always be tested BEFORE installing.
    After the second repair (all four tested BEFORE soldering in) the FSU is working as intended. Too soon to comment on durability of these MOSFETs but given the rate of defect out of the gate I don't recommend buying them.
    Thank you for all the info and advice previously posted by others.
    info by ross1

  3. #13
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    more info for download for the IHKA control module, next to the sword: Modification of the IHKA control unit (E32/E34) due to possible overheating
    2.39 MB!! (Text copied) The IHKA control unit repeatedly failed after about one hour of driving. In “cold condition” (directly after starting) the unit worked perfectly. The possible root cause was overheating of the entire unit. The housing is completely closed and on the PCB there are several components generating considerable heat. As a solution an active cooling was built in. The cut-outs are located over the components which generated the largest amount of heat. The two fans (30x30x7) were built into the “step” of the housing; there is enough space to the opposing electronic components. At the upper end of the PCB both +12V (KL 15) and ground can be found. There are two massive tracks adjacent to each other. Here a connector was soldered on (after removal of the protection coating, of course. Grind it until you see shiny copper…). There are 5 diodes (1N4001 or eqiv.) between +12V and the fans. The fans are running more silently at 10V (13.8V – 5 x 0.7V). For testing this modification the temperatures at two components (heat sink left – Temp 1, resistor right – Temp 2) were measured. Until about 4400 sec. (1 ¼ h) the control unit was idling – just supplied with 13.8V, no switching, no stepper driving, nothing – but 65°C at the resistor! Then the fans were switched on…
    During messing around with the IHKA control unit to determine the cause of the malfunction I tried to find out more about how the IHKA was built up. Unfortunately the main components (microcontroller, driver IC’s,…) are marked with a special code – sorry, no proven information about these items.Thus: all following information is based on my own fuzzy thoughts about how this unit may work…(Picture and overview at the end of this document)
    The IHKA control unit is diagnosis capable, i.e. (almost) all of the currents / voltages are measured and supervised. This is done by the power resistors together with the LM2901’s which compare analog values (set/actual) and deliver a corresponding digital signal to the main controller. This may evolve to a real PITA as each signal which is not exactly inside the defined limits will trigger an error message. If some values drift over the years there may be error messages where no errors are…
    The stepper motor’s four windings are switched low side (ground) by the ULN2003’s. The bit pattern is stored by the stepper controller into the shift registers (HEF4094) which pass the signals on to the ULN2003’s. There are two driver-IC’s for switching the heating valves etc. (unfortunately these IC’s are coded: L475D). And exactly here is one of the big puzzles of the circuit: adjacent to these drivers there are two 120 Ohm power resistors. But those are not in a ground path due to current measurement or similar, they are just powered – a heating! Why? No clue… I only know one reason for providing such a “senseless” load: even in idle mode the control unit draws a defined amount of current and may be detected by other components of the entire car system. But: exactly those resistors generate a considerable amount of heat! All pictures I found in the web show a nicely tanned area on the PCB around
    these resistors… thus I milled the openings in the housing directly above them. The next heater is the PTC of the fan of the interior temperature sensor. A PTC acts like a fuse. In normal operation it has a low resistance and passes current through. If there is too much current (e.g. a short), it gets hot and changes to a high resistance. The problem: if it gets heated from the “outside” (the overheated housing) it will change to a high resistance and the main controller gets the error message: “short in the fan”. This may be the main problem of the IHKA control unit…Last not least there is the main switch transistor. It is located on the same heat sink as the 5V voltage regulator for the digital circuitry. The transistor switches the KL30 supply (always hot) onto the internal KL15 (hot on ignition). Thus the control unit is powered during the often cited two minutes after engine stop and is switched off after this time. Again a problem: the main transistor itself is switched by secondary switching transistors. Latter ones are the said BC337’s. If they burn out the main transistor is permanently powered and it will never shut down the control unit – the battery will be empty soon enough (…it needs to power the fancy 120 Ohm heating…).
    The main controller is very likely one of the Motorola MC6805 family. Some of the pins can be determined with a high probability (supply, Xtal,...). The reset pin was very interesting – the trace leads to one of the LM2901. In the original condition this part of the PCB was very sensitive, as the circuit remained in reset state if I touched one of the inputs of the LM2901 with the scope probe (!). After having changed the “surrounding” capacitors, this phenomenon has disappeared…
    If the IHKA control unit is already opened and the soldering iron is ready I would change the two BC337 and the capacitors which are populated nearby the heat sink (2 x electrolytic caps, 2 x tantal caps).

    http://www.e32-schrauber.de/bmw/date...difikation.pdf

  4. #14
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    more info for download for the IHKA control module, next to the sword: Modification of the IHKA control unit (E32/E34) due to possible overheating
    2.39 MB!! (Text copied) The IHKA control unit repeatedly failed after about one hour of driving. In “cold condition” (directly after starting) the unit worked perfectly. The possible root cause was overheating of the entire unit. The housing is completely closed and on the PCB there are several components generating considerable heat. As a solution an active cooling was built in. The cut-outs are located over the components which generated the largest amount of heat. The two fans (30x30x7) were built into the “step” of the housing; there is enough space to the opposing electronic components. At the upper end of the PCB both +12V (KL 15) and ground can be found. There are two massive tracks adjacent to each other. Here a connector was soldered on (after removal of the protection coating, of course. Grind it until you see shiny copper…). There are 5 diodes (1N4001 or eqiv.) between +12V and the fans. The fans are running more silently at 10V (13.8V – 5 x 0.7V). For testing this modification the temperatures at two components (heat sink left – Temp 1, resistor right – Temp 2) were measured. Until about 4400 sec. (1 ¼ h) the control unit was idling – just supplied with 13.8V, no switching, no stepper driving, nothing – but 65°C at the resistor! Then the fans were switched on…
    During messing around with the IHKA control unit to determine the cause of the malfunction I tried to find out more about how the IHKA was built up. Unfortunately the main components (microcontroller, driver IC’s,…) are marked with a special code – sorry, no proven information about these items.Thus: all following information is based on my own fuzzy thoughts about how this unit may work…(Picture and overview at the end of this document)
    The IHKA control unit is diagnosis capable, i.e. (almost) all of the currents / voltages are measured and supervised. This is done by the power resistors together with the LM2901’s which compare analog values (set/actual) and deliver a corresponding digital signal to the main controller. This may evolve to a real PITA as each signal which is not exactly inside the defined limits will trigger an error message. If some values drift over the years there may be error messages where no errors are…
    The stepper motor’s four windings are switched low side (ground) by the ULN2003’s. The bit pattern is stored by the stepper controller into the shift registers (HEF4094) which pass the signals on to the ULN2003’s. There are two driver-IC’s for switching the heating valves etc. (unfortunately these IC’s are coded: L475D). And exactly here is one of the big puzzles of the circuit: adjacent to these drivers there are two 120 Ohm power resistors. But those are not in a ground path due to current measurement or similar, they are just powered – a heating! Why? No clue… I only know one reason for providing such a “senseless” load: even in idle mode the control unit draws a defined amount of current and may be detected by other components of the entire car system. But: exactly those resistors generate a considerable amount of heat! All pictures I found in the web show a nicely tanned area on the PCB around
    these resistors… thus I milled the openings in the housing directly above them. The next heater is the PTC of the fan of the interior temperature sensor. A PTC acts like a fuse. In normal operation it has a low resistance and passes current through. If there is too much current (e.g. a short), it gets hot and changes to a high resistance. The problem: if it gets heated from the “outside” (the overheated housing) it will change to a high resistance and the main controller gets the error message: “short in the fan”. This may be the main problem of the IHKA control unit…Last not least there is the main switch transistor. It is located on the same heat sink as the 5V voltage regulator for the digital circuitry. The transistor switches the KL30 supply (always hot) onto the internal KL15 (hot on ignition). Thus the control unit is powered during the often cited two minutes after engine stop and is switched off after this time. Again a problem: the main transistor itself is switched by secondary switching transistors. Latter ones are the said BC337’s. If they burn out the main transistor is permanently powered and it will never shut down the control unit – the battery will be empty soon enough (…it needs to power the fancy 120 Ohm heating…).
    The main controller is very likely one of the Motorola MC6805 family. Some of the pins can be determined with a high probability (supply, Xtal,...). The reset pin was very interesting – the trace leads to one of the LM2901. In the original condition this part of the PCB was very sensitive, as the circuit remained in reset state if I touched one of the inputs of the LM2901 with the scope probe (!). After having changed the “surrounding” capacitors, this phenomenon has disappeared…
    If the IHKA control unit is already opened and the soldering iron is ready I would change the two BC337 and the capacitors which are populated nearby the heat sink (2 x electrolytic caps, 2 x tantal caps).

    http://www.e32-schrauber.de/bmw/date...difikation.pdf

  5. #15
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    Japan
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    Interior Blower Fan Sword Repair
    Our interior (coupe) fan started to only work at full speed (setting 4) and sometimes at 3, 2 or 1. Reading a lot about this over the years I knew it was probably time to do the "sword" repair so I started by removing the glove box and side panels on the right (passenger) side in the car. The glove box is very easy to remove. So is the 4 other panels I needed to remove to gain good access to the sword.

    Once the panels were disassembled I could see a few connectors all the way forward towards the firewall and floor. One yellow, one blue and one brownish. The blue and yellow connect to the IHKA control unit, and the brown 5-pin one connects to the sword. I disconnected the brown connector and used a philips driver to remove the two screws that hold the sword into the blower assembly. Then just pull it straight out to the side.

    Since I know it will take some time for me to order and get time to do the actual soldering and fixing of the sword I decided to figure out how I could at least get the blower fan to run or not when needed while the repair is taking its sweet time in my shop. This was actually very easy and I ended up soldering in 3 wires and connecting a relay instead of the sword. Here is how the wiring and function of the sword connector works:
    Pin Wire color .................................................. .................................. Description....................................... .............................. Functional description
    1 Brown............................................. ............................... Grounding......................................... ............................. Directly and always connected to ground
    2 Black / White .................................................. ............ Output to blower fan motor............................................. When fully grounded fan blows max speed. Allows speed change by adjusting the grounding level
    3 Black / Blue.............................................. ......................... Full speed enable..........................................Wh en speed knob is set to 4, max speed, this wire is connected to +B and enables a by-pass relay in the sword assembly
    4 Yellow / Green............................................. .......................... Ignition power............................................. When ignition is in position 2 this wire is connected to+B
    5 Forgot color............................................. .............................. Blower speed signal..................................... Variable voltage between 0 and +5V supplied from the blower speed knob. About 1.3V at 1, and 2.5V at 3. 5V at 4.

    Please note that the above table is not quite finished yet, the pin-numbering and wire-coloring will be double checked and the table will be updated soon.

    I bypassed the sword function and allow the blower to either not run, or run at full speed by inserting a relay that controls the connection between grounding and the output to the blower motor. This short table explains my temporary setup while repairing the sword:
    Relay pin......................Connected to................................................ ............................................. Description
    30......................... Brown wire.............................................. .................................................. . Grounding
    87........................ Black / White............................................. ................................................. Output to blower motor
    86........................... Black / Blue.............................................. .................................................. . Full speed signal, +B when full speed set
    85............................ Brown wire.............................................. .................................................. .. Grounding

    To avoid destroying the sword connector, I just soldered into the wires just before the connector with the necessary 4 new wires and insulated the joints afterwords. Then I can just remove the relay later and connect the repaired sword. And if it ever breaks again, I can just put that relay back in.

    The sword actually contains one relay to allow for the full speed setting (knob setting 4) that bypasses the electronics in the sword.

    In my case one of the BUZ71S semiconductors probably failed and made the other 3 fail when they then became overloaded. These 4 BUZ71S semiconductors work in parallel and do the actual current controlling like an advanced resistor between grounding and the blower motor ground connector. They will now be replaced by new higher current capable semiconductors which probably will long outlive the life of the car.

    Opening the sword is easy. 4 small philips screws hold two pieces of black plastic casing at the end of the sword. There is a small strip of weatherstrip insulation between the plastic case and the rest of the sword to avoid damp and moisture from entering the electronics. The whole PCB is also covered in a layer of laquer to protect against weather and moisture. You do not have to open the sword case to fix the BUZ71S. They are nailed and glued to the PCB and metal heat sink.

    Before removing the BUZ71S test the NTC as below, and then use a knife and carefully pry under the big lumps of glue over the 3 pins that the BUZ71S are soldered to the PCB with. Just pry off this glue. Its relatively easy and just takes a few minutes of fiddling. Careful not to damage the PCB tracks in the process.

    Then remove the small nut that holds the small NTC thermistor to the heat sink. This is an overheating protection that tells the electronics to cut out if the heat sink gets very hot. It should measure 300-330 ohms when at room temperature. And that resistance should drop when heated up. I used a lighter to slightly warm up the NTC to see if it worked. That might be a good test to perform before replacing the BUZ71S.

    To remove the BUZ71S and replace them, I suggest using a 5mm metal drill and carefully drill out the nails from both the heat sink and PCB side. You do not need to drill far, just enough to remove the top part that sticks to either the PCB or heat sink. Do not worry about drilling into the PCB or tracks when you drill out the nails. There is plenty of PCB left to carry the current under operation later.

    I then used some desoldering wire and desoldered the 3 pins of each BUZ71S. Then just pry the heat sink of the BUZ71S and the PCB. Careful not to bend the PCB too much so its tracks crack.

    Then its just a matter of cleaning of some more glue and soldering in the new BUZ71S, assemble the heat sink and NTC thermistor. Use some spacers and bolts and nuts instead of the original nails to secure the BUZ well to the heat sink so that they can transfer as much heat to the heat sink and not burn out under load.

    When all assembled I would have used to spray glue or clear paint to weather-proof the BUZ71S again.

    Connect to your car and hope it all works well again.
    Troubleshooting for finding whats at fault

    If the blower fan does not work at full speed, then the relay in the black plastic casing is at fault. Also if the blower fan only works at full speed, I would suggest checking that relay first. All other intermittent speeds are controlled by the BUZ71S semiconductors and they will be at fault if 1,2 or 3 settings dont work.

    from here http://www.ow.no/index.php?option=co...=117&Itemid=13

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