Question about Panasonic PT-40LC12 40" Rear Projection HDTV

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Thermistor troubleshooting I was reading the posts about checking the thermistor on the PT-40LC12. I am wondering what a high resistance across the leads would be as it increases with an increase in temp. Can anyone refresh my physics for me?

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Check this site for more on how thermistors work.

Posted on Jul 10, 2008

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What is Code p2 on a Kenmore electric dryer?


error code indicates that the electronic control board detects an open thermistor (temperature sensor). This is usually caused by a failed thermistor. It can also be caused by a wiring problem or a failed control board.

To troubleshoot this problem, follow these steps:

Unplug the dryer to completely disconnect electrical power. Shut off the gas supply.

Remove the bottom front service panel as shown in the first image below.

Locate the thermistor on the blower housing. The second image below shows the thermistor. It should have a red/white and a black wire attached to it. Pull at least one wire off and measure the resistance across the leads of the thermistor using a volt/ohm meter. You should measure about 10K ohms (10,000 ohms) of resistance at room temperature. If you measure infinite resistance or get much different reading, then the thermistor will need to be replaced. Even if the thermistor reads the correct resistance at room temperature, it could still be defective and giving a bad resistance reading at higher temperatures.

If you suspect that the thermistor is good, check the wiring connection at the main control board (black and red/black wires on the P2 connector). The procedure for accessing the control board is shown in the third image below. With the dryer still unplugged, pull the P2 connector (see diagram of board) and check the resistance through the black and red/white wires. NOTE: The wires down below at the thermistor must be properly attached back onto the thermistor to properly check this circuit. If you get a much higher resistance (or infinite resitance indicating an open circuit) when measuring this circuit from the wires at the control board, then you could have a wiring failure that is causing your problem. If the resistance is the same, I recommend replacing the thermistor and testing the dryer to see if it operates properly.

If you still get the error code after changing the thermistor, then the control board will need to be replaced.

Mar 22, 2015 | Kenmore Dryers

Tip

Whirlpool Dryer Various Test Procedures - Part 2


TEST #4 Heater
This test is performed when either of the following situations occur: Dryer does not heat Heat will not shut off
This test checks the components making up the heating circuit. The following items are part of this system:
Harness/connection, Heater relay, Thermal cut-off, Thermal fuse, High limit thermostat, Gas burner assembly,
Centrifugal switch, Exhaust thermistor, Machine control electronics, Gas supply. Dryer does not heat:
1. Unplug dryer or disconnect power.
2. Remove the back panel to access the thermal components.
3. Perform TEST #4b. If the thermal fuse is OK, go to step 4.
4. Perform TEST #4c. If the thermal cut-off is OK, go to step 5.
5. Locate the high limit thermostat. Measure the continuity through it by connecting the meter probes on the
red wire and blue wire terminals. If there is an open circuit, replace the high limit thermostat and thermal cutoff.
Otherwise, go to step 6.
6. Perform TEST #4d. If this is OK, replace the machine control electronics.
Heat will not shut off:
1. Unplug dryer or disconnect power.
2. Access the machine control electronics, remove the P14 connector, then measure the resistance between P14-3 (red-white wire) and P14-6 (red-white wire) at the connector. If 5–15 k ohms are measured, replace the machine control electronics. If the resistance is greater than 20 k ohms, replace the exhaust thermistor.
TEST #4a Exhaust Thermistor
The machine control electronics monitors the exhaust temperature using the exhaust thermistor, and cycles the heater relay on and off to maintain the desired temperature. Begin with an empty dryer and a clean lint screen.
1. Plug in dryer or reconnect power.
2. Start the Timed Dry cycle.
3. If after 60 seconds, F-22 or F-23 flashes in the display and the dryer shuts off, the thermistor or wire harness is either open or shorted. Unplug dryer or disconnect power. Check wire connections at the machine control electronics and thermistor. If wire connections are OK, check exhaust thermistor resistance per step 5.
4. If F-22 or F-23 does not flash in the display, the connections to the thermistor are good. Therefore, check the exhaust temperature value at any or all of the temperature levels in question, using the Timed Dry cycle, and the following process: Hold a glass bulb thermometer capable of reading from 90° to 180°F (32° to 82°C)
in the center of the exhaust outlet. The correct exhaust temperatures are as follows:
TEMP
SETTING HEAT TURNS
OFF* HEAT TURNS
ON High 155° ± 5°F
(68°± 3°C) 10–15°F
(6–8°C)
below the
heat turn off
temperature Medium 140° ± 5°F
(60°± 3°C) 10–15°F
(6–8°C)
below the
heat turn off
temperature Low 125° ± 5°F
(52°± 3°C) 10–15°F
(6–8°C)
below the
heat turn off
temperature Extra Low 105° ± 5°F
(41°± 3°C) 10–15°F
(6–8°C)
below the
heat turn off
temperature The measured overshoot using the glass
bulb thermometer in the exhaust outlet can
be 30°F (17°C) higher.
5. If the exhaust temperature is not within specified limits, or you have come here from step 3, remove the P14 connector, then measure the resistance between P14-3 (red-white wire) and P14-6 (redwhite wire) at the connector. If the resistance is OK, check P14-3 and P14-6 to machine ground. If resistance is greater than 0 (zero), replace wiring harness. NOTE: All thermistor resistance measurements must be made while dryer is
disconnected from power. The following table gives temperatures and ranges for the associated thermistor resistance values.
Temp
F C
Res
kΩ
Temp
F C
Res
kΩ
50° (10°) 19.0 -22.0 80° (27°) 8.5-10.5 60° (16°) 14.8-16.8 90° (32°) 6.8-8.8 70° (21°) 11.5-13.5 100° (38°) 5.0-7.0 If the thermistor resistance does not agree with table, replace the exhaust thermistor. If the thermistor resistance checks agree with the measurements in the table, replace the machine control electronics.
TEST #4b Thermal Fuse
The thermal fuse is wired in series with the dryer drive motor.
1. Unplug dryer or disconnect power.
2. Access the thermal fuse by first removing the back panel.
3. Using an ohmmeter, check the continuity across the thermal fuse. If the ohmmeter indicates an open circuit,
replace the failed thermal fuse.
TEST #4c Thermal Cut-Off
If the dryer does not produce heat, check the status of the thermal cut-off.
1. Unplug dryer or disconnect power.
2. Access the thermal cut-off by first removing the back panel. .
3. Using an ohmmeter, check the continuity across the thermal cut-off. If the ohmmeter indicates an open circuit,
replace the failed thermal cut-off and high limit thermostat. In addition, check for blocked or improper exhaust
system.

TEST #4d Gas Valve
1. Unplug dryer or disconnect power.
2. Access the gas valve by removing the front panel and drum assembly.
3. Use an ohmmeter to determine if a gas valve coil has failed. Remove harness plugs. Measure resistance across terminals.

on Apr 11, 2009 | Whirlpool LER4634J Electric Dryer

1 Answer

F25 error code


Having an error code on your appliance can be an inconvenience and I know how important it is to have a good working dryer.

The "F25" indicates the INLET THERMISTOR is shorted or the INLET THERMISTOR circuit is shorted. If you replaced the inlet thermistor and control board then it may have bad inlet thermistor circuit. You should disconnect the thermistor circuit connections at the thermistor and control board and test the thermistor circuit for continuity. Check the circuit to see it happens to be open or shorted with an ohm meter.

The inlet thermistor is located on the side of the heating element housing is a thermistor and high limit combination. The part number is 8557403. The inlet thermistor portion of the thermistor/high limit will have two solid red wires connected to it. It could have faulty new thermistor or it could have an open or shorted thermistor circuit or a faulty control board. The thermistor can be checked with and ohm meter. Disconnect the two red wires and place the ohm meter leads across the two terminals. At room temperature it should measure approximately 50k ohms of resistance. If it measures 50 k, then it should be reconnected and then the sensor circuit disconnected from the control board and retested at the harness wires to see if you get the same measurement reading. If it does measure the same, and it continues to display F25, it could have a faulty control board.

What is your model number?

Oct 16, 2012 | Kenmore Dryers

1 Answer

E5 code no top on the E


The code is T5 and that is the thermistor
Check for:
- Clogged lint screen.
- Restricted vent system.
- Check Thermistor resistance. Thermistor resistance 10K ohms at 25 C 77 F (2P-Blue & Red wire)
- Check for diagnostic code 1
Use tech sheet in machine to enter diagnostics mode

Dec 03, 2011 | Maytag Neptune MDG6700A Gas Dryer

1 Answer

The dryer shuts off, keep getting an E1 code, what needs to be done


It sounds like this is a Whirlpool Duet or a Kenmore Elite Dryer due to the error code E1 being available only on this models. The problem here is an open thermistor as what error code E1 means. It's either the thermistor is exhibits an extremely high resistance or the wire harness connecting it to the control board is broken or cut open. Click on the link below for the detailed procedure in accessing the thermistor.

Whirlpool Duet and Kenmore Elite Electric Dryers Not Starting


Measure the resistance of the thermistor and refer the table below. Normal thermistor resistance is around 10000 ohms (10K) at room temperature.

jahn27_560.jpg


Replace the thermistor if the resistance is significantly higher (or lower) than what it is supposed to be based on the resistance table above. Check the wire harness connecting it to the control board, if the resistance turns out good, and make sure the connectors are good and the wires are intact. Replace the wire harness if necessary. Consider replacing the control board if both the thermistor and the wire harness turn out good. The link below might enlighten you further on the troubleshooting of the thermistor.

Thermistor Troubleshooting on Whirlpool Duet and Kenmore Elite Dryers

Aug 21, 2011 | Dryers

1 Answer

What is an E1 problem with the maytag dryer


This must be a Whirlpool-made Maytag dryer and troubleshooting are therefore basically the same. The error code E1 indicates that the thermistor is open or having a very high resistance. Check the wiring connections to the thermistor and make sure it is not shorted or disconnected. You may need to replace the thermistor located on the blower housing behind lower front access panel. Click on the link below for the detailed troubleshooting of the thermistor.

Whirlpool-made Dryers Thermistor Troubleshooting

Jul 20, 2011 | Maytag PYE2300AY Electric Dryer

1 Answer

My dryer stops and shows E1 flashing


I suggest unplugging the dryer and checking the wiring connection of the thermistor to the electronic control board. The thermistor attaches to the control board on the P2 connector (red/white and black wires on pins 5 and 6).

The image below shows the procedure for accessing the control board in this dryer (click image for zoom). If the connection is okay, pull the connector off of the control board and check the resistance through the red/white wire and black wire with a volt/ohm meter (with the dryer still unplugged). You should measure about 10K ohms (10,000 ohms) at room temperature. Make sure that your meter is set to the proper range. If you read infinite resistance (open), then you could have a wire harness connection problem between the control board and the thermistor. Check the resistance across the leads of the thermistor (with at least one wire removed from the thermistor). If you measure normal resistance (10K ohms) at the thermistor, then you will need to repair the wiring connection between the control board and the thermistor.
If you measure the proper resistance through the thermistor circuit at the connection to the control board (red/white wire to black wire on the P2 connector), then the electronic control board is bad and will need to be replaced.

zjlimited_1599.jpg

Hope helps.

Jul 19, 2011 | Kenmore Elite HE4 Electric Dryer

2 Answers

No picture Panasonic PT-40LC12 40


Found that the thermistor/temp measuring device is suspect, no resistance across legs. There is a label there that says F701 see service manual
http://www.goodmans.net/get_item_th-tf117c_thermal-fuse-117-degrees-celsius.htm
I went here for a tech manual for the Panasonic
tv.
http://www.ManualsParadise.com
then ordered
Manufacturer: Panasonic
Part Description: FUSE
Part Number: LSJA0411-1
from
PartStore.com
it was mounted to the case that holds the lamp. had to remove the back panel, etc. Also think I had to splice in the fuse or something. was a while ago.

i purchased a NTE8115 from my electronics supplier, closest I could find.
Radio shack also has them.

remove the back cover and measure for continuity across the thermal fuse
above the lamp housing.
if open jump it wth a 5 amp fuse, be sure to close the safety switch with
the small blue lever then try to power on.
If comes on ok you will need to replace the entire ballast assembly to get
that fuse.
Panasonic does not have a part number for just the fuse on the PT40LC
series.
It is possible to cut off the fuse and replace with another but dont solder

Dec 13, 2007 | Panasonic PT-40LC12 40" Rear Projection...

3 Answers

Panasonic pt-40lc12


Found that the thermistor/temp measuring device is suspect, no resistance across legs. There is a label there that says F701 see service manual
http://www.goodmans.net/get_item_th-tf117c_thermal-fuse-117-degrees-celsius.htm
I went here for a tech manual for the Panasonic
tv.
http://www.ManualsParadise.com
then ordered
Manufacturer: Panasonic
Part Description: FUSE
Part Number: LSJA0411-1
from
PartStore.com
it was mounted to the case that holds the lamp. had to remove the back panel, etc. Also think I had to splice in the fuse or something. was a while ago.

i purchased a NTE8115 from my electronics supplier, closest I could find.
Radio shack also has them.

remove the back cover and measure for continuity across the thermal fuse
above the lamp housing.
if open jump it wth a 5 amp fuse, be sure to close the safety switch with
the small blue lever then try to power on.
If comes on ok you will need to replace the entire ballast assembly to get
that fuse.
Panasonic does not have a part number for just the fuse on the PT40LC
series.
It is possible to cut off the fuse and replace with another but dont solder

Nov 15, 2007 | Panasonic PT-40LC12 40" Rear Projection...

4 Answers

Panasonic PT40LC12 - Blinking green power light - no lamp fire up.


Had similar issue but had high resistance across leads. replaced with thermal fuse from RadioShack in the similar temp and everything works great. Info on the original part is on this link. http://www.willas-array.com/prod/products/directory/pdf/sefuse/FUSE_SMG.PDF Hope that helps. Chris

Apr 15, 2007 | Panasonic PT-40LC12 40" Rear Projection...

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