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LG RD-JT91 Multimedia Projector Questions & Answers
All lamps are flashing
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:
LG RD-JT91 PSU problem
Hi there
On the left hand side where all the inputs are located you will see a very small screw , that is most probably what's keeping you from opening it.
Also remember to take off the cover to the front and do this slowly because the translation board's lint is attached to the top cover. Once open you can just unhook it and then you'll be looking for the board with the AC inlet on it.
SNOW LIKE PROJECTION WHITE DOTS
IF it happens right away, it could be serious. If it happens when it is on for a while, you might need to clean out the dust buildup so the bulb can breathe.
Mirror or light tunnel collapsing
A weakness that you might experience with your projector is the collapsing of the light or mirror tunnel. Not sure if this is common to DLP projectors only. The symptom is that you see grey bands or shadows on the edge of the TV image - this is caused by a mirror getting in the way of the bulb light. The glue holding the mirrors together seems to weaken over time (3000 lamp hours in my case) and causes one or more of the mirrors to loose its position. For solution, search for "mirror tunnel" or "light tunnel" under all projectors. The problem seems to be quite widespread. I managed to fix my LG's.
I wonder why the manufacturers don't use a rectangular glass tube that is mirror plated on the long sides ?!?! Suppose they want to sell new projectors after lamp or mirror tunnel expiry!
LG RD-JT 21
Hi Mike
Press the following buttons quickly - Up , Down , Left , Right , Menu & then Enter - this should reset the timer.
WHY DOES A BLUE LIGHT CONTINUE TO FLASH
how many times does it flash? could be lamp, fans or overheating. clean it out with canned air. if the lamp has bulges, black spots, or fogging, replace the lamp.
Projector turns on, bulb comes on and then turns
this is often caused by the projector overheating. You will need to clean out your filters. They can often collect dust and if the projector overheats it will turn off like you suggest. Refer to your manual about cleaning filters as it changes with each model. Get some canned air ideally and give it a spray around the projector and the grils.
Good luck and any more help needed, just ask
Blue LEDs flickering
Hi Altus , yes that is correct.
Which country are you in ? I will try and direct you to a repairer ?
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