20 Most Recent LG RD-JT91 Multimedia Projector Questions & Answers

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:1af7f4a.jpg

LG RD-JT91... • Answered on Mar 18, 2019

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.

LG RD-JT91... • Answered on Jul 16, 2015

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.

LG RD-JT91... • Answered on Jul 03, 2015

the mother board is broken, any questions, feel free to ask me have a nice day! Jerry Lampdeng Limited

LG RD-JT91... • Answered on Mar 04, 2014

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!

on Aug 28, 2012 • LG RD-JT91 Multimedia Projector


Hi fabiano did you ever find a solution the vertical line in your RD-JT91 Multimedia OH projector. I now have the same problem. Gary

LG RD-JT91... • Answered on Nov 26, 2011

Hi Mike

Press the following buttons quickly - Up , Down , Left , Right , Menu & then Enter - this should reset the timer.

LG RD-JT91... • Answered on Aug 19, 2011

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.

LG RD-JT91... • Answered on Dec 08, 2009

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

LG RD-JT91... • Answered on Dec 03, 2009

If you look at the projector with the lens pointing towards you, the cable colors is, starting from the right, orange-red-brown-black-blue.

LG RD-JT91... • Answered on Sep 29, 2009

Sent the unit to the agents here to replace the lamp did not relish having to do it myself Thanks anyway

LG RD-JT91... • Answered on Mar 31, 2009

Not finding what you are looking for?
LG RD-JT91 Multimedia Projector Logo

Popular Tags

32 questions posted

Ask a Question

Usually answered in minutes!

Top LG Office Equipment & Supplies Experts

Lawrence Oravetz

Level 3 Expert

10548 Answers

ADMIN Canada
ADMIN Canada

Level 3 Expert

37987 Answers


Level 2 Expert

170 Answers

Are you a LG Office Equipment and Supply Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

View Most Popular

LG Office Equipment & Supplies

  • LG Office Equipment & Supplies

Most Popular Question

lg rd jt91 psu problem

  • Office Equipment & Supplies