overheating projector

[Elliot McAllister]

Just wondering if anyone else has experienced an overheating issue with their viewsonic PJD7820HD projector at a certain lamp hours or something.  Just in the last two days my projector overheats 100% of the time and terminates after about 5-10 minutes.

Here's the specifics:

1. removed UV shield on lamp (I removed this a while ago and had 0 issues)

2. have case open and front removed to have access to optics.

3. have fan in correct orientation - and really it should be fine with the cover open...

4. tried replacing the UV cover (seems to allow it to work a little longer) - but still cuts off with overheat error flash.

5. Removed bulb and placed it outside of enclosure - works until I want to turn it off.

So it's definitely the bulb. I do have a lot of hours on it. Just wondering if there is a certain point by which all bulb just put out too much heat due to age.  Also looking for a good source for replacement!

Thanks all,

Elliot

[mUVe 3D Admin]

Elliot,

When it comes to old bulbs, yes they tend to produce more red or heat producing light toward the end of their life. Do you have the hot mirror removed from the bulb casing? Perhaps that could give you a bit more life out of it. We have a very old PJD7820HD there that still has a very old bulb in it, with the hot mirror removed, with no heat issues at all. So perhaps that bulb is just starting to show serious weakness? If you had another bulb to swap you could test just to be sure.

The bulb model is on the label on the projector casing. An eBay or Amazon search should yield lots of low cost options.

Best of luck and let us know we can be of any further assistance!

mUVe 3D Support

[andy.w...@gmail.com]

Did you ever fix this?  I have the same problem. The bulb has only 77 hours on it. Since I still get the shutdown if the bulb is running outside the unit, I concluded that it's not the bulb at all. Something else in the unit is overheating.  No help from Viewsonic on this.  Googling around they are famous for power supplies burning out, so I'm guess that's the issue. 

Andy

[Matthew Caron]

The only time I had this issue was when something fell into the radial fan inside the projector and jammed it up.

[mUVe 3D Admin]

Andy,

It's possible that is the cause but it would be the first time someone has reported to us that a power supply has died in one of those units. It's probably worthwhile to see, if like Matt suggested, that there isn't any air blockage inside the unit in any way.

The system senses the bulb directly through the filament circuit. So if the system thinks the bulb is doing something wrong it will turn off as well. That means it's possible that your new bulb could be the problem as well. Perhaps it's not a good performing bulb and is generating more heat than the previous, or is simply faulty and the system isn't allowing it to stay turned on.

mUVe 3D Support

[andy.w...@gmail.com]

Thanks for the reply. I have the unit on my desk, all covers removed. Every time I turn it on from cold, it will run for exactly 1 minute and 42 seconds before flagging a thermal error and powering down, whether the bulb is in place or hanging to one side of the system. Its the original bulb with 77 hours on it. If I disconnect the bulb, it of course comes up with a bulb error light. I tried blowing cold air across the Osram board that powers the bulb to cool it. That made no difference.  I did notice that the fan appears to have 3 speeds and quickly clocks up to the highest speed after the lamp goes on. That might suggest that the control board thinks its too hot. 

If I power up the unit immediately after a thermal shutdown,  the red lamp error LED comes on (solid), the (blue) power LED flashes. If I wait for about a minute, the bulb then comes to life, the red LED goes out. You can hear the fan speed increase. After 1 minute 35 seconds, the thermal error kicks in.

Replacement bulbs are over $50 and the original replacement is $200 from Viewsonic. Is there any other diagnostic I can do ahead of spending that money and crossing my fingers.  I really appreciate that you replied at all. You seem to know a lot more than the Viewsonic "customer support" guy does. Given that, what's the funny little plastic tunnel to one side of the lamp ... looks like it would be there to blow air through the lamp, but it has no fan. 

Thanks again. 

Andy 

[Stan Ziberna]

Andy,

That funny little plastic tunnel leads to a cover that contains a blower fan. It is the same fan that cools the heatsink that the DLP chip is attached to.

I find it interesting that you can hear a fan change speed. The one increasing speed may be attempting to compensate overheating of the DLP chip. 

At any rate here is a link to the ViewSonic service manual.  https://elektrotanya.com/viewsonic_pjd7820hd-1w_sm_1a.pdf/download.html 

Hopefully, this will help you find the answers you seek.

Cheers.

[andy.w...@gmail.com]

The "temp" LED is actually indicating something else. The service manual cites that if only the "temp" LED is on, then Fan 1 is 25% or more out of step with the speed it is supposed to be running at.  Fan 1 is the "blower" that sucks air over the heatsink behind the optical unit and blows it down a plastic tunnel towards the lamp. If you use "menu" to select the on-screen-display, then hold down the source and mode keys together you should see a series of numbers on the screen. Use the right arrow key to get to #2, then press the down arrow. A menu should appear, which includes the target speeds and the measured speeds for the fans. Mine said:

Fan1-RPM                           0
Fan2-RPM                           2940
Fan3-RPM                           0
Fan4-RPM                           0
Fan1-Target                        2400
Fan2-Target                        2900
Fan3-Target                        0
Fan4-Target                        0

Note that this projector has only two fans. Fan 1 should be spinning at 2400 RPM and was actually not spinning at all. Being <25% slower than the desired spin speed, it lit the "temp" LED and the unit shut down. A new blower is available as a spare part from Viewsonic. Make sure you get the blower  (it's an axial fan) and not the regular fan that sits in the corner of the unit. 

Some bravery will be required to strip the unit down far enough to be able to remove the fan. If you remove it, you will find the part number on the blower leads you to manufacturer ADDA. The part number has a lot of digits and the exact one used in this projector does not appear to be available from the manufacturer, so I ordered the Viewsonic replacement part. 

My unit shut down reliably after 1 minutes and 40 seconds every time. That seemed to be time it took to try to increase the fan speed, give up, and flag a fault. 

There is a service manual out there as cited by Stan at https://elektrotanya.com/viewsonic_pjd7820hd-1w_sm_1a.pdf/download.html.  If you can navigate around all the ads on that site and actually find the download link, it's useful.  It shows you all the screws you need to remove to disassemble the unit. The connector to the fan has a red (power ... 5v to 12V, increases as the unit tries to increase fan speed) a black (ground) and a yellow (signal) wire. My unit had an increasing voltage appearing across the power wires. When I disconnected the blower I found the wires to be open circuit to the fan, so concluded it was faulty. 

Good luck!

[Diego Lamacchia]

Andy,

I have a viewsonic PJD7820HD and the project turns off after a couple of minutes on, showing a red flag on the lamp due to overheating I believe.

The bulb was 47 hours old, so I ordered a new via Amazon just to find out that it keeps doing the same thing.

I bought this a couple of years ago, and I have used a few times, and the project looks in excellent shape.

Any clues on how to fix this thing?

Any help will be appreciated.

Cheers,

Diego

[mUVe 3D Admin]

Diego,

Are you finding that both fans are moving? Usually there is a bad fan, or fan with something lodged in the blades that is causing the overheating.

mUVe 3D Support

[Antonio Beck]

Hello all

I managed to change the fan (I had the very same problem you guys had). Even though I know the new fan is spinning, the projector still shows 0 for its RPM in the hidden menu. Therefore, it turns off after those few seconds. Any clues? 

Thank you in advance!

[Antonio Beck]

Hello all (thanks Andy for the private answer!)

In the end, the new fan was working fine. It worked outside the projector and inside the projector without the metal lower case (!!!). I mean, when I connected the main board to the power board without the case that stands in between, everything was working.

When I mounted the lower case and the motherboard on top, it stopped working (the fan was spinning but no RPM) !. During some trials, the blue screen with the viewsonic logo was not showing ip (the bulb was working, but no image at all).

Bad contact. It may sound stupid, but you really need to tighten the screws (!). There are two connectors that connect the mainboard to the powerboard, and my guess is that the flat one was the one with some bad contact. I am no specialist (never had opened a projector before), even though I have been assembling computers for more than 20 years, and I have never seen this sort of "delicate" contacts (ok, maybe in those old 486 with VESA connections... :-)

I payed the equivalent of 35 USD for the fan here in Brazil, but you can find the very same one in China for less than 10 dollars. The only bad side is that it usually takes a while to arrive.

Anyway, thank you all for the help. Now it is working fine, and I learned a lot.

Antonio

[mUVe 3D Admin]

Antonio,

Very happy to hear a community member reached out to you and helped you get things sorted. 

One other thing worth bringing up, not necessarily for your sake but possibly for others that may read this thread in the future. These fans have power, control, and signal wires, and you will need to ensure the model fan you order is exactly the same as the one in the projector to ensure proper operation. The fan was probably 4 wire, this would allow speed control as well as feedback of fan speed to system. So any fan purchased would need to use this same interface with the same wiring pinout/order. 

All the best and don't hesitate to reach back out if you need assistance down the road. 

mUVe 3D Support

[Antonio Beck]

Thanks!

I bought the very same fan (that is why it was so expensive). It is also used in other projectors (e.g. Benq). I got the part number from the service manual and from the label on the old fan. This is a 3-wire fan with tachometer, so the speed is controlled by the input voltage.

Thanks again for all your help! Imagine a guy in Brazil with a projector bought in the USA without proper tech support from Viewsonic. :)

[Adrian Giraudo]

Hi Andy,

I am having the exact same problem.

I have a question, how do you know the fan1 is the blower and not the cooler? Because in a photo in the service manual it say it's the cooler. 

But in the text it says that fan1 it's the lamp fan, althought i am not sure wich one is the "lamp" fan

I notice the cooler it's working, i don't know about the blower because it's inside. I dissambly all the proyector and clean the blower and the fan, but it did'nt solve the problem.

I want to be sure wich one it is so i don't buy the wrong replacement.

Regards

[Liam Kavanagh]

Hi, I agree with Adrian's statement. The service manual says fan1 is the lamp fan.

I am getting the Temp led after 1min 40 as well. Though I have replaced the bulb, and both blower fan and lamp fans and still getting the Temp led followed by power off.

The menu with fan target speeds also reads the same as Andy's. Fan1 (lamp fan) has 0 RPM, even though I can see the fan spinning.

Any suggestions on this?

Thanks