Epson Projector Temperature Sensor Repair

Intro: Epson Projector Temperature Sensor Repair

This is an instructable for how to repair an Epson VS210 projector when one of the temperature sensing thermistors stop working.

The projector goes into an overheat protection cycle, where after running for 30 seconds to 2 minutes, the bulb shuts off and all three fans ramp up to maximum speed. The fans stay on for about 2 minutes then the projector shuts down. During this, the red "temp" light flashes.

This is not a plugged air filter! Epson's online help for a case like this places the blame on the user and poor maintenance. Some users have plugged air filters, and when the filter is cleaned, the problem is corrected. This is a manufacturer's defect, tiny cheap sensors. Epson's website does direct you to an "Authorized Service Center" but the website would not load for my region. I don't think service is a real priority for Epson.

The key here is the unit is not overheating, the bulb has been on for only moments, and the unit is cold. This is a failed thermistor sensor, which shuts down, and renders the whole projector useless.

Instead of throwing it out, and buying a new one, we can repair it. The best option would be to replace the failed sensor with an OEM Epson replacement part. However these are very difficult to find, and expensive. Electrical components are cheap, and this is a cheap fix.

This was not the most expensive projector, it was a few hundred dollars on sale. But failed temperature sensors seems to be a somewhat common problem on Epson projectors. People are throwing out much more expensive projectors than this one!

STEP 1: Open Up the Case

From looking online, all Epsons look alike on the inside. There is a lamp, 3 fans, and 2 temperature sensors (some may have 3), mirrors, prisms, three LED screens and a lens.

I figured, the bulb still worked, and all three fans worked as well, so this must be a sensor problem.

Epson used thermistors to measure the temperature because they are very cheap, and they do a good enough job. A thermistor is a type of resistor whose resistance is dependent on temperature. They produce a non-linear reading. When I measured the resistance across the thermistor leads at the connection to the board, I had zero ohms at the intake sensor. I forget what the measure was at the exhaust thermistor, but it was not zero. A return of zero ohms from a thermistor means infinite temperature. So the Epson processor must have interpreted this as superheated air entering the fan, and shut down, throwing a temperature alarm.

STEP 2: Temporary Fix

My original plan was to replace the broken thermistor with a working one from my collection of random electrical components. I was concerned this thermistor might be for a very specific temperature range. I could take a guess at what Epson thought intake air temperature would be. Turns out I couldn't find a thermistor, and at this point I thought this was a long shot anyways, so instead of using a thermistor I took it one step simpler and just used a resistor. I think this one was 200 ohms, another shot in the dark. Looking back, I should have chose one more like 10,000ohms.

Anyways, wouldn't you know it. The projector starts working. I let it run for 5 minutes before I unplug the resistor to see if this is the fix, or its just a coincidence. As soon as I pull it out, the bulb shuts off and all three fans go into high speed mode. Looks like we got it narrowed down!

Without the resistor, the projector would last maybe 5 seconds before shutting down and blasting the fans, so 5 minutes is impressive. I reconnected the resistor, pointed the projector in a less annoying direction, turned it on, and left it on for 2 hours. No problems.

STEP 3: Permanent Fix

There is nothing as permanent as a temporary fix.

I decided against finding a replacement thermistor and just bypass the old thermistor with a resistor. I cut the wire leads leading to the thermistor and soldered in resistor. I plugged it back into the board and tucked the lead under the circuit board.

I plugged the projector in and tested it before I put the case back on. We even watched a movie with it like this. Worked fine.

STEP 4: Final Thoughts

Ultimately this is not the best fix. I justified bypassing the sensor because the intake air temperature is a little redundant compared to the exhaust air. If the projector is really overheating, it will be the exhaust temperature that registers it, and shuts it down.

I wrote this out of frustration with Epson. They have a total lack of support to fix, or even diagnose a problem with their product. Thermistors are incredibly cheap, and an OEM making one to last should not be hard. Also, reading online, other people have the same issue with these sensors, it seems to be a recurring problem.

This projector was not very expensive, I think it was $300, but we really haven't used it very much, maybe 100 hours of watching movies on it, its supposed to last 4-5000 hours. Looking online, people were throwing away Epson projectors that cost $2000 because of this. This fix cost me nothing except for my time. In my case I already had the resisters, but to buy one resistor would have been cheap.

The answer always seems to be "Just buy a new one". Since Epson is the largest supplier of projectors, any replacement would probably from Epson. Demand Better! If manufactures build a sub-quality product, do not just buy another one from them! Fix it and keep using it.

Comments

[uproudtobe]

Thanks a lot. This comment is to highlight that guide is so helpful even since years all over the world 🌎. Epson TW6700 a bit different configuration inside but the fault finding and troubleshooting are same as described here. All the best!!

[Capricornboy]

I also have a Epson TW6700. The strange thing is when I turn off the projector.. it doesn't cool down. It just shuts down after 2 seconds. I think it supposed to cool down for at least a couple of minutes right? Please can you help me to fix this?

[KevinM200]

How do you locate the thermistor leads connection to the board?
Thanks for the great Instructable!
EX7200 with this issue.....

[FilipposS4]

Hey, I am having a similar problem with my EMP TW7000. The only thing is that it has a different type of sensor. It has 4 cables brown, red, pink and yellow. how should I try the resistance trick in order to check if it responds? Thanks.

[PauloCarreiroPortugal]

Hello, i ran into the same problem with my Epson Projector and i manage to find out on my own. You cut the pink and yellow wires and apply the 10k ressistor. in my case my projector has 2 sensors, so if you try at first and it still does not work, try doing the same to the other one. Hope it helps

[baculas]

Hi, did you ever found a solution with the 4 wires thermistor? If yes, how many ohms did you use? Thank you!

[FilipposS4]

Hi, No, no luck at all. It ended up in the bin...

[CylonR]

Epson 475Wi, put 10kohm intake, 8kohm exhaust, tested and fixed no more problem...

[steviemaringo2]

Hi, if you can help me out have a Epson EB-1970w giving exactly same issue as yours but this one has 3 temp sensor all working fine and the fans are working to but it's stills when switching it on after a fews seconds it give temp light blinking. What other components can i check?

[DennisB20]

wonder if you could help me. I have a old epson emp-505 with the over heat flashing light. checked the fans all running fine, but shutting down after a few seconds. just getting ready to throw it out when I came across your article. can you give a rough idea where these Thermistors are located please. yours is the only info i have found and like you say, there is nothing on Epson Site. Thanks for the info.
P.S. Well just found everything i'm interested in on one site:

[ghdasia]

I have an Epson EB-S400 and on switching on the lamp (with low level fan) comes on for 30 seconds, without temp or lamp indicator and then switches off. Fans do
work stronger however when I switch on again immediately after shut down. I have
soldered in a 10k resistor at both thermistor locations as suggested, but it still shuts down. No
lamp indicator comes on but unit shuts down anyway. What could be affecting the logics in this way?

[ghdasia]

I have eb-s400 and lamp comes on for 30 seconds, but no fans. Fans do work however when I switch on Immediately after shut down. I have soldered in a 10k resistor as suggested, but it still shuts down. No lamp indicator come on

[ChicoRuiz]

I have a similar Epson projector, Home Cinema 2030, and last week after waiting for about 4 minutes to appear Epson logo on the screen, after turning it on, none input source was working. All sources present the message: "No Signal". Do you have an idea of what is happening?

[chrisfarrow]

Have you checked the hdmi cable to the projector and dvd if that is what you were using .I got the same message .

[chrisfarrow]

This was absolutely a godsend ..I was ready to bin my Epson projector ...I,d examined mine ,changed the bulb ,took the case off (god knows why ,as I haven't a clue what I was looking for ).you're absolutely right about how Epson try to cut corners ,the ribbon connector from the power button didn't even have a connector on it .They had just folded over the ribbon a Nd wedged it in the female connection...I spent ages thinking I'd knocked it onto the floor and lost the small plastic connector block ,until I realised it never was there .I have ordered a new projector but I shall try exactly what you did with the resistor ,if it works great if not what have I lost ...but thanks for the clear instructions .For someone like me it is unfortunately necessary to state what you may think is blindingly obvious .but it's not to me ..thanks Chris

[kasu1432]

Epson EH-TW6100 projector
Temp error coming 10 minutes display getting off what tha best solution reply me

[dongmole5]

I'm in the process of swapping out the internal model 1040 (1080P) into a EX3240 (800x600). The 1040 does the 30sec shutdown/overheat indicated, which seems to be an indicator of FAN or thermistor problem.
Its not easy to break a Thermistor, especially Epson. So i'm wondering the resistor Bypass is even needed rather than cleaning the Fans properly. But none the less a good idea. Thanks for posting this!!.

https://www.gedat-spareparts.com/ < look for your Epson physical hardware schematic here. Google for the equivalent European model vs. North American.

Request:
No CCT schematic; still looking. If anyone has found the PC board Schematic, please send to me!.

Question:
1. I am assuming 10k ohm is equivalent to a normal heat level. Using a 1kohm would signify overheat condition. Resister load Threshold would be between 6-10k ohms will allow normal usage. I believe this would also create a possible Fire hazard because there will be no Overheating "auto" shutdown. So beware....

2. I need to confirm if the first 2 pics is a the actual thermistor.??? Below there is a question regarding 4 wire and 2 wire TH indicator on the PC Board : Which is it?)
(the Coiled one doesn't seem to be the type: unless its the newer kind; but as per the schematics, i dont' see it . But the Latter does show up on Schematics under 0210 or 200 range)

[GoldMiner1849]

Same problem. But all my thermistors range between 9.5-9.8 kOlms so they seem okay. What next? could there be a fan issue? Why are there four wires going to them?

for those asking, cut the two lines to the bad thermistor and replace with a resistor. At room temp they are near 10,000 ohms and drops with heat. I’m thinking 5-7000 ohms should represent a warmer temp and turn the fans on enough to protect the equipment. Play with it.

[sakurazuka38]

I have the same issue with my Epson 5650. Your guide is very helpful but as a noob i don't understand all the instructions (and i prefer ask before doing a mistake) !

Here is my board : the trick is to put a resitor in the the thermistor socket named AIR-TH (and only it..in another anwer you mentionned also a LV-Th but in my board there is no plug for it) ? The last photo of you guide shows the resistor soldered into the plug so it's not anymore connected to the fan ?

Since i have no reistor i will make an order on electronic shop. Do you recommand another value or type or resistor for a more permanent repair ? Or the 10.000 ohm is fine ?

thank you so much !

[grftjncyfh]

Thank you for your guide, I have an EB-X9, it only has one thermal resistor on the exhaust, strange huh?, anyway tried a 1k resistor on it and runs but after 5 minutes same problem, without anything connected wont even start without the error. Ended up using a 10k resistor and so far so good, only problem is at 10k the fans will only fun at normal speed not high.I may experiment a bit more. Hopefully this has fixed it and is now usable!.