CurtPalme.com Home Theater Forum

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I won't know until tomorrow and first power-up. But I know what symptoms to look for now.

**Curt Palme** · Posted: Wed Oct 05, 2016 2:07 pm Post subject:

While most of the troubled YA boards did indeed die around the 1500 hour mark, I did have one or two here that failed at about 4000-5000. I've had others of the same production run be fine at 8000 hours, so it's really a crapshoot.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

So what do you think about the program loop theory? Does the description of the loop symptom match up well to known failures of IC421?

You know, the lithographs for making those chips probably still exists somewhere in storage at Sony's fab lab.
I HAVE to wonder how much it would cost to have them dragged out of storage, set up, and have a new run of chips made.

**Curt Palme** · Posted: Wed Oct 05, 2016 2:44 pm Post subject:

No idea. While others chased the possibility of cloning/making the chips, I think it's a dead issue at this point. Good luck trying to get anything out of Sony! I'm really surprised they avoided a class action lawsuit, as they discontinued the sets in 2004, and problems with the YA boards started in about 2006. Heck, Sony California even called ME looking for the chips in about 2007. Smile

When my reply was 'Hey, you're Sony, why can't you get them?' the answer was 'we ran out of boards and chips'.

My understanding is that they offered a few people replacement Sony Ruby projectors-refurbs. Not sure if anyone took them up on that. I do know a couple of g90 owners waited 18 months for a used YA board to come up, when someone sold a set. The boards were selling for $2000 used at one point, now they are around $800 for a replacement. I've got one spare YA board in stock.

HaydnG90 · Joined: 22 May 2006 Posts: 1335

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

HaydnG90 · Joined: 22 May 2006 Posts: 1335

Repairable in that a working IC421 can be installed on an existing YA board. Once the IC421 is toast, thats it, game over.....

draganm · Joined: 08 Mar 2006 Posts: 8990 Location: Colorado

HaydnG90 · Joined: 22 May 2006 Posts: 1335

No you can fix it after it breaks by replacing the faulty IC421 with a good one.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I currently have two G90s that both run and although both need tubes to be sellable, they do work and make rather nice pictures despite some phosphor wear.

One has an interesting fault. Red 88 appears on the back display but only if the unit is in standby. It never occurs when running, only in standby, and it has to spend several minutes in standby for it to happen.

I smelled (once) a hot component smell with the red 88 showing.

Turn the unit off and let it cool down for about 2 minutes and it powers up with no error codes. Until it errors out again when presumably the part heats up again.

By direct board swaps between the two units I have ruled out problems with the YA, GA, GB, or F boards.

Whatever is the issue, it is in a board that receives power when in standby, which is NOT every board. So those boards that do
not receive power in standby can not be at issue. Problem is, I don't quite know which boards those are yet.

Having a thermal camera might help me to track down that hot part more quickly.

As for the IC421 issue, if the programming could ever be read out then it's possible that there's enough available information for an expert FPGA programmer to be able to develop an FPGA solution that would replace IC421.

I actually have asked an engineer friend of mine, who IS an expert FPGA programmer, to at least review this thread and the associated documents. See if he thinks it's worth his time.

Thinking about the idea of brewing up a replacement for IC421, it could be done with another CPLD if enough information is learned about the input commands and the output functions.

That'd start by knowing exactly what those DACS actually do. What functions they address. And what control functions send those commands.

Basically we'd have to break down every function in the projector and define which ones are relevant to this data path and which are not. For example, geometry and convergence functions may be handled by IC421, but that doesn't mean that color temperature settings are. (I don't know.)

At some point when we have a full list of functions handled thru IC421 and their range of possible values, then we have defined the outline of the required programming.

One thing that does work in our favor is that much of the programming can be expected to be repetitious. For example, both contrast and brightness would be substantially the same programming, only at different addresses. A lot of copy-and-paste with minor edits would define much of the programming.

HaydnG90 · Joined: 22 May 2006 Posts: 1335

Not sure its really worth the effort and expense to develop a solution to this problem. A furor developed when many died around the same time and there was VERY limited options to fix the issue. When my IC421 failed I had to wait over a year for a solution and that came when someone local advertised a G90 on Craigslist.
At this point most of the IC421 chips that were destined to fail when programmed have already bitten the dust. There are enough spare working YA boards in circulation now to cover any future losses.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Actually I just lost a YA board to a component failure but NOT an IC421 failure. That board is heading to Craig for repair.

I'm picking up two more G90s this weekend.

Whether or not the effort to reverse engineer IC421's functions is worth pursuing, I can't say. Five years ago it would have been worth doing. Today....maybe not.

FYI, I buy G90s if they're complete units. Price offered varies according to condition and failures.

ElTopo · Joined: 07 Nov 2006 Posts: 1608

You can have the G90's

The Cine9/909 are mine Mr. Green

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Agreed. I'll trade you even. One complete 909 for one complete G90. Just in case either of us finds any.

You get the Barcos, I get the G90s.

HaydnG90 · Joined: 22 May 2006 Posts: 1335

I would take the G90 over the 909 even though the latter could potentially project a better image, if only because replacement parts are easier/cheaper to come by.

ElTopo · Joined: 07 Nov 2006 Posts: 1608

Parts are not a problem if you have enough projectors Cool

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

I will be having a meeting with a well qualified engineer who has agreed to look at the IC421 problem with an eye toward developing a CPLD (Complex Programmable Logic Device) or FPGA replacement solution for it.

He's going to be charging a few hours of his time for this, at a rate of a hundred bucks an hour.

It is understood that data gathering to map out all the input and output functions on IC421 is going to take some time.

Once that data is gathered, all inputs identified and correlated to the control signals going to the DACs, then the real
work begins of drawing the flowchart that leads to the programming.

It is likely that this will also require fabricating a chip adapter as the selected device will probably not be pin compatible with the
original IC421.

I would like any interested parties to speak up and let me know if you would be interested in purchasing an IC421 replacement
solution for any of your own G90s. You can of course post such information here in this topic, but please also send me a private message so I can put it in a prospective customer file.

If you are willing to contribute to developmental costs, then those contributions go as credit toward the final product should there be any.

HaydnG90 · Joined: 22 May 2006 Posts: 1335

I have a spare working YA board (thanks John W) so I'm good.

Even so, glad to see someone taking the initiative, especially after Sony dropped the ball and failed to adequately address this issue when it became clear this was a major problem for their product. I'm sure they were pretty relieved not to have been slapped with a class action suit when the G90 could no longer be supported for the legally required timeframe after production ceased.

cmjohnson · Joined: 03 Apr 2006 Posts: 5180 Location: Buried under G90s

Plans to replace IC421 with a custom FPGA or CPLD are moving forward but it's in the initial stages.