How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Russell H. Your Own Question
Russell H.
Russell H., Service Tech
Category: TV
Satisfied Customers: 9514
Experience:  8+ years of professional experience
13568747
Type Your TV Question Here...
Russell H. is online now
A new question is answered every 9 seconds

I have a Mitsubishi model wd73735 I keep getting the the

Customer Question

I have a Mitsubishi model wd73735 I keep getting the the blocked airflow message and then tv shuts off replaced one fan the dmd one
Submitted: 3 months ago.
Category: TV
Expert:  Russell H. replied 3 months ago.

Hi, thank you for contacting JustAnswer.com. My name is Russell. I will do my best to provide the right answer to your question.

If there is an overheat warning, there may be dust influencing the heat sensors. Dust accumulates on cooling surfaces over time, and can diminish the cooling effect of air circulation.

Also check the airflow, quite simply, of all the fans.

So, I advise cleaning out, quite thoroughly, of all air passages, and especially of all heat-sinks and their surfaces. And also, checking the action of all fans, and the replacement of any fan not spinning at less than an adequate speed.

Let me know what you find out in doing so, and what your thoughts are. And I will advise you further.

Customer: replied 3 months ago.
I didn't see heat sensor how would I check fan with cover off I do hear a fan when powering up
Expert:  Russell H. replied 3 months ago.

Locate the grilles or vents on the TV. Place your hand over those grilles while powering the TV On. Note whether the air-flow is weak or strong.

Customer: replied 3 months ago.
I did that and I feel air in the back but not on the side to the right facing the tv nor underneath I got to add I had it sitting o a carpet floor and figured out it had vents underneath I raised it and the same results
Expert:  Russell H. replied 3 months ago.

The fan may be defective, that leads to he side and underneath-side vents, then. At least by the sound of it, and with a Blocked Airflow message too.

Or you may need to clean with cotton swabs through the rear fan, the heat-sink there, as shown in this video:

https://www.youtube.com/watch?v=F--YakzmPWc

in order to get dust off the heat-sink that is right behind that fan, and that doubtless has a heat/temperature sensor on it, that might be causing the blocked airflow message and shutdown.

Customer: replied 3 months ago.
what would heat sensor look like I have all ready blown off the heat sink when I put dlp chip in I used the old tape between heat sink and dlp chip des that matter?
Expert:  Russell H. replied 3 months ago.

Did the blocked airflow errors start up immediately after you installed the new DLP chip?

Customer: replied 3 months ago.
Expert:  Russell H. replied 3 months ago.

Then the way it was installed might have produced the error.

I would guess that the heat sensor would be very near, or on, or in direct contact with, the heat sink that the back fan has - presumably - right near it or right behind it or right next to it.

If the 'tape between heat sink and DLP chip' is a ribbon connector, check that it was properly re-installed, is not disconnected, nor is it broken or badly creased... if the last, then it would need replacing too.

Let me know what you think, please.

Customer: replied 3 months ago.
ok I didn't see any type of wire or ribbon but I did take it apart and examine it and checked all connections and had tube of that sliver stuff about size of a seed and it did the same thing
Expert:  Russell H. replied 3 months ago.

tube of that sliver stuff about size of a seed

What is that?

Customer: replied 3 months ago.
sliver thermal compound
Expert:  Russell H. replied 3 months ago.

"Size of a seed" ? meaning what?

Maybe a photo posted to me would tell me what's going on. ?

Customer: replied 3 months ago.
maybe more the size of grain of rice attic sliver is the name of it they sent with my dlp chip
Expert:  Russell H. replied 3 months ago.

So in other words, heat-sinking for your DLP chip is installed, with the silver stuff in between the heat-sink and the top surface of the chip?

Customer: replied 3 months ago.
exactly
Expert:  Russell H. replied 3 months ago.

And the thread of silicone 'silver stuff' is about as thick as a grain of rice?

It might need to be slightly thinner, for proper heat-conduction. It is supposed to be a slight buffer, and heat-conductive.

Customer: replied 3 months ago.
it is a little thinner in between a mustard seed and a grain of rice but i will try redoing it in a bit
Expert:  Russell H. replied 3 months ago.

OK. Check all connections, and the cleanliness in fine detail of any metal surface, esp. heat-sinks. Cleaning in detail with dry cotton swabs may be needed, I cannot emphasize this enough.

Let me know how it goes.

Customer: replied 3 months ago.
ok
Customer: replied 3 months ago.
ok I checked all connection they seem fine and heat sink is very very clean it always after 1st time went in was and its still the same
Expert:  Russell H. replied 3 months ago.

Then I have run out of ideas on this case, unfortunately. Is the fan perhaps running slow? you could check its supplied voltage, in case it is a voltage-dependent-speed type of fan. (I think I recall that you replaced the rear fan already.)

Customer: replied 3 months ago.
I did replace it is there a certain direction the fan should run just a tought
Expert:  Russell H. replied 3 months ago.

The fan should run inward if it is near the outer case. There is not much in the way of exceptions to this.

'Inward' meaning, directing or propelling air inward, into the machine.

Customer: replied 3 months ago.
ok done
Expert:  Russell H. replied 3 months ago.

Check on that... is it OK, the direction the fan propels air?

Customer: replied 3 months ago.
I really did it this time I toke almost all apart found thermal sensor and a dirty vent under the covers wish me luck
Expert:  Russell H. replied 3 months ago.

OK. Would you be willing to rate my work and my answers on this question? If so, a five-star rating would be appreciated!

And yes, good luck - I think you're on the right track toward a solution to the problem and the error.