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Post Info TOPIC: waeco 40lt thermister not working again
dorian


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waeco 40lt thermister not working again
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You can test the board yourself. It'll only cost you 10 cents in parts.

Go to Jaycar and buy two 10Kohm 1/4 Watt resistors.

Take your old scrap thermistor and cut off the beaded end. Strip back the two wires and connect them to a single 10K resistor (as shown in either of the first two drawings). Plug this 10K dummy thermistor into your control board. Does the display show 25C?

Now add a second 10K resistor in parallel with the first, as in the third diagram. The combined resistance will be 5K. Now plug this 5K dummy thermistor into your control board. Does the display show 25C?

       ___
      [o o]
       | |
       | |
       | |
       / |
       \ |
   10K / |
       \ |
       |_|

           ___
          [o o]
           | |
           | |
        ___| |___
        |  ___  |
        |-|___|-| 

           10K

           ___
          [o o]
           | |
           | |
        ___| |___
        |  ___  |
        |-|___|-|
        |  ___  |
        |-|___|-|  

         2x 10K = 5K


-- Edited by dorian on Thursday 17th of April 2014 07:10:13 PM

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dorian


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Here is the first part of a circuit diagram for the CF-40 Ver A.

More sections are in progress.

                         Waeco CoolFreeze CF-40 Ver A Main PCB

                            U1 = S3F9454BZZ (8-bit microcontroller)
                            U2 = 24C02 (2Kbit serial EEPROM)
                            Compressor = Danfoss BD35F


                                                                             VCC
                                                                              +
                   Comp-T (thermostat + RPM select)                           |
                    ___                                                       |
                     |                                                       .-.
                     |                                                       | |R14
                     |              Override                                 | |
           |---------+---------|     Switch                                  '-'
           |         |         |      _/                                      |      Thermistor
           |         |         o----o/  o---|                                 |         |
          .-.       .-.    CP4 o------------|                           ___   | CP5    _V_
          | |R6     | |R7      |                              |----+---|___|--+--o----|___|--|
          | |       | |        |                   VCC        |  C8|    R16   +--o-----------|
          '-'       '-'        |                    +         |   ---         |
           |         |         |                    |         |   ---         |
           |         |        .-.     |-------------+ 5V      |    |          |
            \|        \|      | |R1   |             |         |   ===        ===
          Q1 |--|   Q2 |--|   | |    ---       .----+----.    |   GND        GND
            <|  |     <|  |   '-'    ---       |   20    |    |
           |    |    |    |    |      |   N/C -|2      19|----|
          ===   |   ===   |   ===    ===  N/C -|3        |
        Comp-C  |  Comp-C |  Comp-C  GND  N/C -|4      18|---o CP6-1
       (common) |         |   ___              |       17|---o CP6-2                  VCC
                |         |--|___|-------------|5      16|---o CP6-3                   +
                |             R9               |       15|---o CP6-4                   |
                |                    CP6-6 o---|6        |              P/B       +----+--+---+
                |                    CP6-7 o---|7  U1    |     ___    switches    |       |   |
                |                              |       14|----|___|---o CP6-5     |      .-. .-.
                |   ___ R8                     |         |     R15                |   R13| | | |R12
                |--|___|-----------------------|8      13|- N/C             U2    |      | | | |
                    ___                        |         |                  __    |      '-' '-'
   Comp-D o--------|___|-----------------------|9      12|-----|     |----o|1 |o--+       |   |
 (error LED out)    R2                 ___     |         |     |     |----o|  |o--GND     |   |
                                   |--|___|----|10     11|--|  |     |----o|  |o----------|   |
                                   |   R11     |    1    |  |  |     |----o|__|o----------)---|
                             BUZ1  |           '----+----'  |  |     |                    |   |
                           |\ __   |                |       |  |    ===   24C02B          |   |
                           | |  |--+                |       |  |    GND                   |   |
                           | |__|--+               ===      |  |                          |   |
                           |/      |               GND      |  |--------------------------|   |
                                   |                        |                                 |
                                  ===                       |---------------------------------|
                                  GND

(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)


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dorian


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Part 2 of main PCB

                Waeco CoolFreeze CF-40 Ver A Main PCB



                                                                       Comp-P (Battery Limit)
                          ____                                           |
                         |    |                                      |---+---|
                   |-----|7810|-----+----o                           |   |   |
                   |     |____|     |+                      zero    .-. .-. .-.
                   |       |       === C1                   ohm  R3 | | | | | |R4
                   |       |       /-\                      link    | | | | | |         Remote
                   |      ===       |                               '-' '-' '-'         Battery
                   |      GND       |                                | R5|   |          Limit
      D1           |               ===                               |   |   |          Selector
V+ o-->|--+---+----+               GND                               |   |   |
          |   |+   |                                                 |   |   +---------o CP3-4
          z  ===   |                                                 |   +---)---------o CP3-2
          A  /-\   |                                                 +---)---)---------o CP3-1
          |   |    |                                                 |   |   |
          |   |    |                                             Low |  M|   | High
         === ===   |      ____                                       o   o  /o
         GND GND   |     |    |                                            / Battery Limit
                   |-----|7805|------+-----+----o Vcc(+5V)                /  Selector Switch
                         |____|      |+    |                             o    (slider)
                           |     C2 ===   --- C3                         |
                           |        /-\   ---                            +-------------o CP3-3
                          ===        |     |                             |
                          GND        |     |                             o
                                    ===   ===                          Comp-C (common)
                                    GND   GND


(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)


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DeBe


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Very interesting, did you do this?



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dorian


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Yes, I used your photos. Some parts are not visible, so I had to make educated guesses.

Edit:  Just in case I misunderstood the question, the software was written by Andreas Weber, not me.



-- Edited by dorian on Saturday 19th of April 2014 03:15:47 PM

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"No friend ever served me, and no enemy ever wronged me, whom I have not repaid in full."

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DeBe


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Thank you for this will eventualy try & check & fillin values.



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dorian


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Here is the Control Panel circuit:

                Waeco CoolFreeze CF-40 Ver A Control Panel PCB


                   VCC
                   ___
                    |
          +---------+---------+
          |         |         |
          |         |Q7       |Q8                  digit
          |         |         |                    selects
           >|        >|        >|     ___  R20
            |---|     |--|      |----|___|-------o CP6-1      Vcc
           /|   |    /|  |     /|     ___  R21                ___
          |     |   |    |----)------|___|-------o CP6-2       |
          |     |   |         |       ___  R22                 +-----------+
          |     |---)---------)------|___|-------o CP6-3       |          _|_
          |         |         |                                |          ---
          |         |         |                          .-----|------.   _|_
    .-----|---------|---------|------.                   |    14      |    =
    |                                |         ___ R24   |            |
    |              DP1               |--------|___|------|3        1,2|----o CP6-6  segment data
    |  _______   _______   _______   |         ___ R25   |            |
    | .       . .       . .       .  |--------|___|------|4          8|----o CP6-7  segment clock
    | |       | |       | |       |  |         ___ R26   |            |
    | |       | |       | |       |  |--------|___|------|5          9|---- Vcc (/CLR)
    | |       | |       | |       |  |         ___ R27   |            |
    | |       | |       | |       |  |--------|___|------|6           |
    | '_______' '_______' '_______'  |         ___       |  SN74HC164 |
    | .       . .       . .       .  |--------|___|------|10          |
    | |       | |       | |       |  |         ___       |            |
    | |       | |       | |       |  |-+------|___|------|11          |
    | |       | |       | |       |  | |       ___       |            |
    | |       | |       | |       |  |-)-+----|___|------|12          |
    | '_______'o'_______'o'_______'o | | |     ___       |            |
    |                                |-)-)-+--|___|------|13          |
    |                                | | | |             |            |
    |                                | | | |             |            |
    '--------------------------------' | | |             |     7      |
                                       | | |             '-----|------'
                                       | | |                  _|_
                                       | | |                   =
                                       | | |
                         VCC           | | |
                          +            | | |
                          |            | | |
                          |            | | |
     LED select           |            | | |
                  ___   |<             | | |
        CP6-4 o--|___|--|  Q5          | | |
                  R23   |\             | | |
                          |            | | |
                          |            | | |
                   +------+------+     | | |
                   |      |      |     | | |
                   |LED3  |LED1  |LED2 | | |      LED1 = Power
                   |      |      |     | | |      LED2 = Turbo
                <- V   <- V   <- V     | | |      LED3 = Error
                   -      -      -     | | |
                   |      |      |     | | |
                   |      |      |     | | |
                   |      |      |-----| | |
                   |      |              | |
                   |      |--------------| |
                   |                       |
                   |-----------------------|




                                 VCC (CP6-9)
                                 ___
                                  |
                                 .-.
                             R19 | |
                                 | |
                                 '-'
     Pushbutton                   |
     Switch       CP6-5 o---------+
     Detect                       |
                                  o
                               J1 |
                                  |
                                  o
                                  |
                   +---------+----+----+---------+
                   |         |         |         |
                   |         |         |         |
                   |         |         |         |
                  .-.       .-.       .-.       .-.
               R18| |    R17| |    R16| |    R15| |
                  | |       | |       | |       | |
                  '-'       '-'       '-'       '-'
                   |         |         |         |
                   |         |         |         |
                 | o       | o       | o       | o
               |=|       |=|       |=|       |=|
                 | o       | o       | o       | o
            SW4    |   SW3   |   SW2   |   SW1   |
          On/Off   |  Turbo  |  Temp+  |  Temp-  |
                   |         |         |         |
                   +---------+----+----+---------+
                                  |
                                 ===
                                 GND  (CP6-8)


(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)


-- Edited by dorian on Sunday 20th of April 2014 01:13:58 PM

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dorian


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Datasheets, etc:

www.danfoss.com/businessareas/refrigerationandairconditioning/danfosscompressors/instructions_bd-series.htm
www.ra.danfoss.com/TechnicalInfo/Literature/Manuals/06/BD35-50F_101N0210-20-40_0300-20_08-2011_dehcei100b602.pdf (Danfoss BD35F with 101N0220 control)
www.ra.danfoss.com/TechnicalInfo/Literature/Manuals/06/bd_code_numbers_09-2009_ea100a902.pdf

www.ti.com/lit/ds/symlink/sn74hc164.pdf
www.samsung.com/global/business/semiconductor/file/2011/product/2010/2/23/342731um_s3x9454_ref10.pdf (S3F9454BZZ)


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DeBe


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Heres a rough copy of the circuit with the values filled in.WAECO CF-40 VER.A MAIN BOARD.JPGWAECO CF-40 VER.A CONT PANEL.JPG



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dorian


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Thanks very much. I think there is now enough information for a full service manual.

BTW, resistors R6, R7, and R1 now tell us what speed the compressor is running at.

According to the compressor datasheet ...

0 ohm -> 2000 RPM
277 ohm -> 2500 RPM
1523 ohm -> 3500 RPM

From your circuit diagram ...

Q1 and R6 (270 ohm) select 2500 RPM.

Q2 and R7 (1.5K) select 3500 RPM ("Turbo" mode?).

The override switch and R1 select 2000 RPM.

The battery limit resistors select the following cut-out/cut-in voltages:

Resistance   12V cut-out   12V cut-in    12V max
------------------------------------------------
R3 = 0        9.6          10.9          17.0
R5 = 24K      9.9          11.1          17.0
R4 = 82K     11.3          12.5          17.0


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03_troopy


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I'm impressed... well done guys..

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dorian


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AISI, we could determine whether the main PCB is switching on the compressor by monitoring the voltage between the compressor's T and C terminals. This same voltage is also present at the terminals of the override switch or at CP4 on the main PCB.

My reading of the datasheet suggests that the following relationship applies:

T-C Voltage   RPM
------------------
0V            2000
1V            2500
2V            3000
3V            3500
5V (?)        off


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AlanMcR


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dorian wrote:

You can test the board yourself. It'll only cost you 10 cents in parts.

Go to Jaycar and buy two 10Kohm 1/4 Watt resistors.

Take your old scrap thermistor and cut off the beaded end. Strip back the two wires and connect them to a single 10K resistor (as shown in either of the first two drawings). Plug this 10K dummy thermistor into your control board. Does the display show 25C?

Now add a second 10K resistor in parallel with the first, as in the third diagram. The combined resistance will be 5K. Now plug this 5K dummy thermistor into your control board. Does the display show 25C?

<drawing removed for brevity>


-- Edited by dorian on Thursday 17th of April 2014 07:10:13 PM

dorian,

Your posting seems to imply that the NTC thermistor is the 5K variety.  Everything I've seen indicates that the NTC sensor is 10K.  My CF-40 is exactly 10K@25C and the fridge works. 

...Alan



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DeBe


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Yes they are 10K @ 25 deg C. The ones Jayco sell work.

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67HR


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Ok, Mine is a CF35 (same unit)

My Thermistor packed it in a few weeks ago, I read up everything on here and decided to go to Jaycar and buy the thermistor. Well someone had beaten me too it and bought all the 10k stock. So I bought two OEM units, one so I could have a spare like the CF80's

When I opened the the end to get to the panel to drill the hole for the new thermistor I found it had already been done this way. I remember my Waeco failed during warranty, now I realize it was a thermistor fault then.

See pic of drill hole with thermistor wire coming out of case.

This made it easy for me to dig out the silicone they used to fill the hole. I cleaned it out and re fitted two thermistors side by side (I now have a spare like the CF80) and in my enthusiasm I failed to take a pic of the two units glued in :oops: 

I bought the two thermistors and thermistor heatsink compound to put on the unit heads from Allvolts Power Solutions in Broome; They were very helpful and quick with their supply. They also included the "factory" repair guide for replacing the thermistor in CF-35 -40 models.

Second pic is unit working at set temp of 04 deg :D 

IMAG4459.jpg20180222_170901.jpg

I'd just like to say thanks to everyone who posted here as it made the repair easy.

Thanks 



-- Edited by 67HR on Thursday 22nd of February 2018 11:29:23 PM



-- Edited by 67HR on Thursday 22nd of February 2018 11:30:16 PM

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DeBe


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Good to see you fixed it.

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Russell Jay


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Hi, question for debe, I have a waeco cdf 40, maybe 2012 model. Was thrown out 3 months ago ,I picked it up, plastic top slightly warped, but hey, it works. After a lot of rain recently and it got wet, the display tells me the fridge is running at 65 c. Inside is 10c or less. Runs on ac and dc voltage. It freezes with emergency over ride. I can think of a few of reasons why. The glue for the thermistor has broken down. A resistor has died. The thermistor is stuffed, there is a short elsewhere. Any help would be appreciated before I look at paying for repairs, and I live in Katherine, so big dollars.

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Russell Jay


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Edit... sorry cfx 40, white main pcb sp 291 A'S A

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DeBe


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If the display has played up since getting wet, sugest removing the display & carefully dry it with a hair dryer ( dont over heat it).

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