A couple of years ago, I posted a repair procedure for Benq W5000/W20000 with half image artifacts. The cause was a design flaw on one of the onboard DC-DC converter, feeding power to RAMBUS framebuffer memory.
Now, I wanted to share with you some repair solutions that you can try for yourself if you have some soldering/desoldering skills/tools or you can go to an electronic repair shop and ask them to change the parts for you.
The fixes will apply to many JVC models (DLA-X3, X7, X9, RS40/50/60 etc), the ones that use Rubycon RPB-0526GA or QAL1305-001 in JVC part numbering.
A bit of background story.
After my first experience with JVC LCOS projector, all I can say is that I've converted from 1 chip DLP to 3 chip LCOS. So, I've traded excellent inherent DLP sharpness with fantastic native contrast and black levels of JVC optical engine.
I've bought mine (DLA-X9) with a faulty ballast, in excellent condition otherwise. At that time, I knew the fault was on the ballast board after trying with a new lamp and measuring signals from mainboard to ballast unit. The mainboard attempted a few times to turn on the lamp then the projector entered in error state with LED condition indicating a failure to start the lamp. Back then, I was lucky to find one used for about $100. I bought it as I was anxious to see the projector working, not having seen one in action before. The joy lasted for about 700h and then again, same symptom. Good lamp would not ignite...another failed ballast. I started to look at my old ballast board to see if I find something wrong with a basic DMM, not having it powered. I found none. I've dismantled again the projector, took the second ballast and looked at the board. Here, there was a fault that I saw without even using the DMM. A resistor close to the power input connector appeared shot. I measured it and it was open. Now, the resistor would not fail on it's own so the culprit was a SMPS controller chip, LNK364 which was feed through this resistor directly from the main 400V. This chip is used as a DC step down from approx 385V to about 17V for other low power circuit stages and finally stepped down to 5v (through a 3 pin LDO) for MCU on logic daughterboard. LNK363DN was shorted so that's why the resistor failed. I replaced LNK chip, LDO chip, resistor. Measured once more the other parts of the circuit for shorts. All appeared good. With hope that the logic daughterboard survived this, I put the projector back together and tested it. BINGO, it worked. I was happy that I was able to cure this just with a couple of $ not having to buy a ballast again. I started to think again at my old ballast...resistor and LNK chip were fine on this one. But as I didn't had time to further investigated I let it away. It didn't take more than a month and again, the projector didn't want to ignite the lamp. I tried to imagine myself dismantling again the projector to get to ballast board. It's not such an easy task. There are a lot of cables, connectors, screws, plates etc. I did it again. This time, resistor fine, LNK chip fine, LDO fine so the logic board received power, like on my old ballast. So I had 2 ballast boards, not working, with apparently the same fault. I did some online research and then I found out that it's a common problem on these models. I even found a guide to replace the resistor and "other component" although it didn't say which. Anyway, I started again to find the recurring fault, this time with the ballast powered, and manually turning it on (the protocol is quite simple), with the lamp connected. I first suspected the HV ignition circuit is bad (I did not have a way to test it live back then) but after some time spent getting to somehow know the circuit, I finally was able to find the fault. Another SMPS/PWM controller chip!!! This time it was the one controlling the power for the lamp. It's present on the logic daughterboard.
So, to summarize. After about 10-15 refurbished units over the years, I can say that ballast board is the number one fault on these models.
The ballast has 2 faults discovered by me.
1. Logic daughter board power supply failure (Resistor/SMPS chip blown, possible other surrounding components). If the logic board was affected by this, further repair might be needed.
Parts needed for repair:
4.7 Ohm resistor, 0.5w or more
Check/replace electrolytic caps near LNK363 and LDO chip
2. SMPS chip for lamp power supply
Parts needed for repair:
All the parts are common and you can find them at many places around the globe. For replacement you need a hot air gun for desoldering SMT components and a soldering iron/station.
Aside from this ballast problem and the capacitor from the IR boards which is mounted the wrong way from factory and will definitely fail sooner rather than later (easy fix, one time) , I still love my JVC projector.
Please note that this fixes only work for the faults described, if your ballast have a different fault, changing above mentioned parts will not cure it. Also, there's a risk of electric shock once you open the projector (even after you removed the power cable) so take the necessary measures to avoid nasty accidents.