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# Doble M4000 Temp Sensor Help

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1. ## Doble M4000 Temp Sensor Help

Looking to repair our M4000 temp/humidity sensor cable, can anyone help with the pinouts? Connector pins are labeled 1-4, need to know which color goes to which pin.

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## Internal components are very cheap to replace

Originally Posted by SecondGen
Looking to repair our M4000 temp/humidity sensor cable, can anyone help with the pinouts? Connector pins are labeled 1-4, need to know which color goes to which pin.

Hi, I don't remember the pinouts, but if ever the unit goes bad, it's usually either the thermistor or the humidity sensor. Doble (if I remember well) sells replacements for around $1,600 and the thermistor is$1.00 and the humidity sensor is around $10. There's a part number on the humidity sensor and that's the one that usually goes bad. The thermistor does not have a part number, but I figured it out my measuring it's resistance at two temperatures and found some with matching specs. The sensor communicates with the main unit serially, so you won't damage anything by just trying several of possible combinations. Good luck. 3. ## Probe pin out Originally Posted by gchoquette Hi, I don't remember the pinouts, but if ever the unit goes bad, it's usually either the thermistor or the humidity sensor. Doble (if I remember well) sells replacements for around$1,600 and the thermistor is $1.00 and the humidity sensor is around$10. There's a part number on the humidity sensor and that's the one that usually goes bad. The thermistor does not have a part number, but I figured it out my measuring it's resistance at two temperatures and found some with matching specs.

The sensor communicates with the main unit serially, so you won't damage anything by just trying several of possible combinations.

Good luck.
If I recall I believe it looks like this!

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Originally Posted by SecondGen
Looking to repair our M4000 temp/humidity sensor cable, can anyone help with the pinouts? Connector pins are labeled 1-4, need to know which color goes to which pin.

Just checked my test set for you.

Red > 1
Silver > 2
Black > 3
Green > 4

5. Originally Posted by rofo42
Just checked my test set for you.

Red > 1
Silver > 2
Black > 3
Green > 4
was 5 a shield ?

6. Thanks for all of the responses, hopefully its just the cable and I can find some time by end of the week to get this thing fixed. Looks like the terminals on the connector are really small, its going to be a trick to solder.

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Originally Posted by SecondGen
Thanks for all of the responses, hopefully its just the cable and I can find some time by end of the week to get this thing fixed. Looks like the terminals on the connector are really small, its going to be a trick to solder.
Those devices go bad quite often from what I have seen. I hate to say it, but the cable is probably not the issue. Just saw a bad weather sensor last week, actually.

8. Originally Posted by SecondGen
Thanks for all of the responses, hopefully its just the cable and I can find some time by end of the week to get this thing fixed. Looks like the terminals on the connector are really small, its going to be a trick to solder.
In the meantime,
If you didn't already figure it out, you can bypass the temperature sensor in the DTA settings. We had a tech leave it on a transformer thru a week of thunderstorms and had to have it replaced (sitting full of water destroyed it), but we found out he left it when we went to use it and it was missing.
Luckily, I always carry a cWheap temperature/humidity gauge I bought at Home Depot to use to input manually into DTA.

9. Originally Posted by gchoquette
Hi, I don't remember the pinouts, but if ever the unit goes bad, it's usually either the thermistor or the humidity sensor. Doble (if I remember well) sells replacements for around $1,600 and the thermistor is$1.00 and the humidity sensor is around \$10. There's a part number on the humidity sensor and that's the one that usually goes bad. The thermistor does not have a part number, but I figured it out my measuring it's resistance at two temperatures and found some with matching specs.

The sensor communicates with the main unit serially, so you won't damage anything by just trying several of possible combinations.

Good luck.
So, we tried the pinouts suggested in the thread and now the sensor gives us crazy high temperature (200C) and no humidity. Either we got the pinouts wrong or the sensor is bad. I need to get my hands on another cable to be sure but next step would be replacing the sensors.

10. Originally Posted by Kalbi_Rob
In the meantime,
If you didn't already figure it out, you can bypass the temperature sensor in the DTA settings. We had a tech leave it on a transformer thru a week of thunderstorms and had to have it replaced (sitting full of water destroyed it), but we found out he left it when we went to use it and it was missing.
Luckily, I always carry a cWheap temperature/humidity gauge I bought at Home Depot to use to input manually into DTA.
Thanks Rob. We've been bypassing the sensor in DTA for quite sometime now and also use external meters but I thought it would be nice to get this thing working after an easy fix - so far no luck.

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