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Question about LG RD-JT91 Multimedia Projector

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All lamps are flashing

When the power cord is connected, all lamps flashing, and nothing happens. Try to wait for a hour but with no difference. Is there any way to reset the projector? It's a year old, and about 170 hours used.

Posted by Lars Jacob... on

  • pmmms Nov 13, 2007

    all lamps flashing, and nothing happens

  • Anonymous Mar 22, 2014

    I have an Optoma HD80 projector which is three years old and has developed this fault. When plugged in it goes through all blue LED's flashing self-test then only Power LED is on as normal. When Power switch is pressed, the usual noises start, fan, color wheel etc, the lamp comes on at start up intensity and shielded then everything stops, all noises stop, lamp goes out and all the blue LED's flash and it stays in this condition. It will not power off by the power switch and after pulling the mains plug leaving 15 mins and try again it is exactly the same. There are no red LED's only flashing blues, the lamp is about 150 hours old and an original Optoma expensive replacement
    Any ideas please

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9 Answers

Anonymous

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In PSU, on the secondary side of switch supply there are electrolytic capacitors: for 13 V is 470uF/25V and for 5 (and subsequent 3V) is 1000 uF/16V. Those capacitors in some devices from this series use to break (why? I don't know: maybe cheep quality). Check voltage on rectifiers outputs with oscilloscope: if there are not constant voltage on one of them you should replace it with the new one (of course good quality). I've got the same failure subsequently on 5V supply (this reparation was done by LG service, but when I asked them they answered they replaced mother board - bull shit!) When the same "flashing" problem after guaranty occurred again, I had found soldering traces on the cap on 5V!And guess what - it was cap with a different brand than others.



This solution is maybe only for el-geckos, but no service wanted to repair my quite new, still worth something projector (not in Sweden any way). If you can’t do a job your self you still can ask some handy friend which know how to solder parts. Be careful! There is high, dangerous voltage on primary, so you must know what you are doing!



I'm sometime very irritated: that capacitor cost less in bulk than 2 cents each! But the ordinary people must buy a new projector because of lack of service!

There is PSU diagram:All lamps are flashing - 1af7f4a.jpg

Posted on Dec 11, 2007

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GREAT! Thank you so much, BruceRob and Beeblebrox! I was able to revive my RD-JT92 with your help.
To help others, here is a picture of the capacitor that I changed to get it running again: www.cliff.de/galerie/RD-JT92-inside.jpg

Cheers, 

Cliff

Posted on Aug 06, 2008

  • mely cas
    mely cas Oct 29, 2014

    Hi All,I come back on this old post. Does anyone still has this picture that shows which capacitor had to be changed. The link is dead and I would really appreciate to get the image. Thanks. Syl

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Anonymous

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I experienced the same flashing lights problem. Followed BruceRob's advice to fix the PSU board. To open the case, you unscrew all the screws marked with arrows on the case, plus a little hidden screw inside the lip of the connector flap cover! It is akward to unscrew this one. You have to remove the main PCB by undoing its 6 screws and carefully unclipping each of the cable connectors; the flexi-cable just pulls out. Now you have access to the PSU PCB. Undo 2 screws and the 2 hex pillars. Remove the PCB carefully - it might still have lurking high voltages on it! It disconnects from the the high voltage unit by unplugging the one cable.

Now you can check the caps that BruceRob referred to. In my case, the version seems a little different, i.e. the 5V section used a 220uF cap (the culprit in my case) and a 470uF cap instead of the two 1000uF ones. I replaced all four of the large electrolytic caps on the 13V and 5V sections for just in case.

Incidentally, if you measure the PSU outputs under no load conditions, it seems to work fine, but if you attach a load, it starts to oscillate. I used a 12V 120ohm bulb as test load on the 13V and 5V sections. After my fixes, the 13V section only delivered about 11.5V, but the 5V and 3.3V were fine. The 13V is intended mainly for the fans I think and they worked fine afterwards.

Before closing up, I blew out all the collected dust which gathered over the 2500 odd lamp hours of my unit. Buying replacement caps for all electrolytics on the PSU board cost me about R5 (ZAR).

Posted on Apr 17, 2008

mely cas

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Hi All,
I come back on this old post. Does anyone still has this picture that shows which capacitor had to be changed. The link is dead and I would really appreciate to get the image.
Thanks. S.

All lamps are flashing - e9e6354c-6d38-4c21-82da-7f9aed2043e6.jpg

Posted on Oct 29, 2014

  • mely cas
    mely cas Nov 02, 2014

    I get the orginial image. Here it is. Very helpful because I had exactlythe same problem nd was able to fix it.

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Joerg Peschke

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Thanks for posting this great fix & the detailed descriptions!
I just managed to get my old RD-JT91 by replacing all 4 caps. Just a few cents investment - and a fully functional projector.

Thank you so much!!!

If anyone finds this helpful, here is the service manual - it contains some diagrams and part lists.
http://diagramas.diagramasde.com/otros/LG%20RD_JT91%20DLP%20PROJECTOR.pdf

Posted on Jul 29, 2014

  • Simon Sundstrm
    Simon Sundstrm Mar 18, 2019

    Hi i know its been a few years but do you still have that pdf by any chane?

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Anonymous

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Thanks guys!
Amazing, one of my friends (with more skills into electronics and stuff) managed to make my projector come to life again with help of your great explanations, drawings and pictures. It was quite tricky but after a few hours we put all parts together - and it worked!

Again, thanks a lot for your help.

Posted on Oct 14, 2008

Anonymous

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This site is fantastic.
Many thanks for the the detailled explanation of the problem.
By changing the capacitors my projector works properly again. The counter of lamp life time displays: 4089 h.

GRACIAS! Bravo!

Posted on Jul 23, 2008

Anonymous

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Where do you buy a power supply for this kind of projector?

Posted on Feb 25, 2007

Roar Sol?st

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Yes I had the same problem for a while ago. It was a defect power supply

Posted on Feb 23, 2007

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Toshiba TDP-P9 Lamp time reset

Hi,
I had sleepless nights with my customers TDP-P9 projector where I changed the lamp.
The lamp timer resetting gave me headache but now I finally solved the right combo:
1: Unplug the power cord
2: Hold down 'On/standby' 'Input' and 'up arrow'
3: While keeping the buttons pressed, insert the power cord and wait for the projectors led's to flash briefly and then power button to keep illuminated and then starting to blink.
4: Release the buttons and power on, it should now have 0 hours in the timer.
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My panasonic TH42PX60U won't power up. No red light flashing. Completely dead. I tried unpluging and using different power outlets. Still nothing. Any help?

1. Check all cable and input connections are secure & all are tightly connected.
2.Check power cords and also power outlet , if possible try to unplug and reconnect . A replacement of power cable or use another power outlet is another good option.
3. If you are sure that power is reaching your TV(check it out with a test lamp that both neutral & ground or earthing is functioning, i.e. the test lamp glows) then probably the power board needs replacement.
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Wont turn on, nothing.... Power supply is good

Replace the power-cord.

Wait until midnight, and turn out all the lights in the room, so that's dark in your computer room.

Turn on the monitor, and see if you get any light and/or any lamps (green? yellow? red?)

Try a different monitor attached to your computer.

Try your monitor on a different computer.
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TV WENT OFF AFTER WATCHING AND NOW IT WON'T GO ON AT ALL

Try to do the following, it didn't work for me but it may work for you...


The STANDBY light will flash if an issue is detected within the television. This can sometimes be resolved by simply following the steps below to reset the television.
  1. Turn off the television. IMPORTANT: For a projection television that uses an internal lamp, wait 5 minutes after turning off the television to allow the lamp to cool before continuing with the following steps.
  2. Unplug the television power cord from the electrical outlet.
  3. Let the television remain without power for 60 seconds.
  4. Plug the power cord back into the electrical outlet. NOTE: If the television is plugged into a power strip or surge protector, remove it from the power strip or surge protector and plug it directly into the wall outlet. If the issue is resolved, the problem is with the power strip or surge protector and not the television.
  5. Turn on the television.
If the issue is still unresolved after following all of the troubleshooting steps, service may be required. Please note the number of times the STANDBY light flashes and relay that information to the service center.
0helpful
1answer

Green light flashing

Was this happening before the lamp problem? What usually causes this is 4 capacitors on the DM module inside the TV. But usually this will happen over a period of time.
1helpful
1answer

Lights flashing

Try the steps mentioned bellow

Unplug the power cord from the All-In-One as well as the power outlet when there is still power in the All-In-One. and wait for atleast 1Min
Plug the power cord directly to a wall outlet without surg protector. (if possible connect it to a different power outlet)
Before connecting the power cord to the All-In-One press and hold the # and no 6 button and then insert the power cord, do not release the keys
until you see a message a reset (if the screen goes blank then release the keys and turn the power on)

Then check and see

Good Luck
1helpful
1answer

Panasonic large screen Model # PT-61LCX65

Here is the proceedure to replace the lamp and reset the lamp hours.
Lamp Replacement Procedure:
1. Press the POWER button to turn off the power.
2. Wait for about 1 minute until the cooling fan stops.
Note:
The lamp cooling fan will continue to operate for about 1
minute after the power is turned off. Do not unplug the AC
Cord from the outlet until the fan has stopped. Avoid
interrupting the power by using circuit breakers or switchable
power strips.
3. After the cooling fan has stopped, unplug the AC Cord from
the outlet.
Note:
Please wait more than one hour before replacing the lamp.
[ Forced cooling function ]
If you need to replace the lamp more urgently:
- The Projection display has a forced cooling feature.
After the POWER button is turned OFF, and during the
first minute of the normal cooling fan operation, press
the VOLUME UP button on the unit and CH UP key on
the remote at the same time for more than 5 seconds.
The cooling fan operates for about 10 minutes. (LAMP
LED will flash 5 times every 5 second and POWER LED
will flash red for 10 minutes.)
4. Remove the Front Cover Unit from the latches.
5. Turn the Knob to the left.
6. Pull the Lamp Cover out.
7. Loosen the Screw on the Lamp. Then, pull the Lamp.
Note:
Because the Lamp may still be hot, use caution when
handling.
8. Install the new Lamp, and tighten the Screw.
9. Install the Lamp Cover, and turn the Knob to the right.
10. Install the Front Cover Unit.
Lamp Time Reset Procedure:
Be sure to reset the Lamp time to "0" after replacing the new
Lamp.
1. Plug in the AC Cord, and turn on the power by pressing the
POWER button.
2. Press and hold the VOLUME DOWN button on the unit and
the SPLIT key on the remote together for over 5 seconds
in power on condition.
When the reset is finished, the display will indicate that the lamp hrs have been reset to 0 and the LAMP LED goes out.
0helpful
1answer

FAST BLINKING GREEN & WON'T POWER ON

I had exactly this problem. After plugging and unplugging it multiple times over several weeks (even plugging it in quickly after it was unplugged but with the green light still flashing as suggested here) all to no avail, it just started working on its own one day. It worked for a few weeks and then the problem re-appeared.

InFocus tech support recommended:
1. Check whether the lamp door is securely closed.
2. Check the color of the LED and the number of time it blinks. (For me, a very fast almost flickering flash)
3. Does the fan operate? (My fan would go on when plugged in)
4. Remove the lamp module, shake it gently and reseat the lamp module.

For me, these steps did not work. InFocus then recommended that I send it to ProjectorDoctor http://online.projectordoctor.com/, and it was diagnosed with a bad power supply. $395, but it is fully functional again. Good luck.........
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No power

I agree with you, because if the lamp is bad then the set will still try turning on and the red light will come on in front. There is no circuit breaker but there is a small glass fuse. Follow the AC power cord and where it connects into the power supply board there should be a glass fuse. You can try replacing that fuse but if that does not fix it then have the set serviced by a different shop.
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