Originally Posted by Luke Purcell
So you bought the x9 :-)
Sorry I haven't replied sooner as I haven't revisited this thread in a while.
I am in Brisbane and I now have an RS40 and an a black X3 I am playing with. I have the RS40 up and running and installed. I've put about 15 hours on it since repairing it.
I also now have 3 ballasts to play with. One I've had to replace all the ICs on the heat sink as the MOSFET failed short and blew the fuse on the main power supply as well as having a hole blown in the Bridge (The 20 pin IC on the ballast heat sink).
BTW I bought a 220W Mitsubishi ballast off ebay cheap ($20) that is plug compatible, but JVC must have messed with the ROM on their ballast as when you try this one it fires the lamp 3 times then the projector stops with the same error.
I'm slowly learning what looks good on these ballasts and what doesn't. I've probably spent more on repairing the existing ballasts than just replacing them. The bridge IC itself is about $20 AUD.
I've done the cap fix on the IR board on both projectors and my plan is to get the X3 working and sell it to pay for my costs in buying and repairing both projectors.
There is something odd going on with the RS40 though. When I first turn everything on the colours are off and I have to power off and on the Onkyo receiver to get it displaying properly. I have set a delay in powering on the projector in the Logitech remote but have yet to try it.
Also I am trying feeding it SBS and Top/Bottom 3D from a Popcorn Hour VTEN and it doesn't seem to detect the 3d signal.
Playing a 3D bluray from a PS3 works fine though.
Background: I am an Electronics Engineer trained in design and repair of analog and digital electronics. I believe these ballasts to be very dangerous. From what I can gather, they need to ignite the lamps with a high voltage arc of several kV. After that, the arc is almost a dead short, drawing tens of amps until the pressure in the lamp builds up.
Human skin has quite high resistance, but having played with high voltage before, I can say the arc will easily break the insulating dry skin, and cause a conduction path to your bloodstream. Blood is quite conductive, being mostly water, with dissolved electrolytes (and for me, the major food groups - chocolate, beer, fried chicken and potato chips). Coupled with the tens of amps from a mains power supply, I think it can easily kill you. Please be careful.
I stand far away (arms held this far apart). And use the remote to power it up.
I have got both the X9s working. I got two of them based on the balance of probability that they won't have the same fault. Anyhow, both ballasts were bad.
I did crudely draw out the schematic, and it's quite simple. There were two faults, both on the low voltage side. One had a bad reverse buck converter IC, which took out the current limit resistor. Fortunately, the micro controller on the daughterboard was fine. The other had a bad SMPS converter IC.
1) DC 380V -> LV Electronics (17V and 5V) -> MCU and SMPS controller on daughterboard
2) SMPS controller -> Isolation transformer -> MOSFET -> DC2 Rail (I didn't measure, but I imagine around 60-100V)
3) DC2 Rail -> Sanken H Bridge chip (the 20 pin on the heatsink)
4) MCU -> Controls Sanken H Bridge
5) MCU measures DC2 rail as well and input 380V DC
I did sniff the protocol with a logic analyser. I thought it would be very complicated from what I read on the net, but as it turns out, the communications are very rudimentary. In fact, there's hardly any! No serial protocol, no chit chat, no query of lamp hours, or power or anything!
Looking at the waveforms, the JVC sends a 'high' to power on the ballast. The ballast should respond with a high for about 5.5s then low.
From then on, there is mostly no more communication. The tricky part is during projection, the JVC sends a continuous signal, IIRC it was around 200 Hz. It's continuous.
When you power down, then there are several breaks in the 200 Hz signal, something like 5-6 breaks. That signals the ballast to turn the lamp off. The ballast acknowledges by bringing the signal 'high', and turns the lamp off. After that, you have 60 seconds of cool down, and all power is removed.
On the X9, the 380 VDC is also removed in standby.
Seeing that I have both working now, the motivation of trying another ballast isn't really there. I am worried that in the long term, this ballast will be unrepairable. The Sanken chip is no longer manufactured. Other ballasts use discrete MOSFETs so that's always repairable. If you have a ballast that you want to shoot my way for research, I think it's easy enough to build a bridge board.
Basically you need a translator, JVC <-> translator <-> 3rd party ballast.
Something like a $3 arduino board and some software should do it. It would help if you knew how the 3rd party ballast works though.