Page 2 of 2 FirstFirst 12
Results 11 to 14 of 14

Thread: E32/34 sword repair info collection

  1. #11
    Join Date
    May 2004
    Location
    Japan
    Posts
    9,139

    Default

    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
    Join Date
    May 2004
    Location
    Japan
    Posts
    9,139

    Default

    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
    Join Date
    May 2004
    Location
    Japan
    Posts
    9,139

    Default

    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
    Join Date
    May 2004
    Location
    Japan
    Posts
    9,139

    Default

    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

Page 2 of 2 FirstFirst 12

Similar Threads

  1. sword repair archive
    By shogun in forum 5 Series BMW
    Replies: 4
    Last Post: 01-28-2017, 09:04 AM
  2. Sword repair
    By Rory535i in forum 5 Series BMW
    Replies: 14
    Last Post: 08-21-2013, 07:24 PM
  3. Sword repair resistance values?
    By shogun in forum 5 Series BMW
    Replies: 1
    Last Post: 02-07-2008, 10:42 PM
  4. Sword repair
    By Anthony (M5 in Calgary) in forum 5 Series BMW
    Replies: 3
    Last Post: 05-20-2006, 09:43 PM
  5. Sword repair
    By makaio in forum 5 Series BMW
    Replies: 3
    Last Post: 12-07-2005, 09:12 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •