CurtPalme.com Home Theater Forum

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

Would appreciate help trouble shooting this machine. No error code displayed, powers on for approx. 1 second then off. My first thought is to disconnect the HV circuit and force the error signal inputs, at the CPU card, to a "Good" state so the machine stays on. I believe trouble shooting would be more intuitive if the system were running; mainly because I don't yet have an understanding of signal timing or thoery of operations.

Is there a jumper or switch that will force the system to run regardless of error conditions? Any information will be appreciated!

CunnazZ · Joined: 25 Aug 2007 Posts: 15

Do you have the lens's off.

If so thats your problem Smile

Put them back on and all will work again Smile

It's some stupid safety circuit, it's a bit daft if you ask me Sad

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

That is a good piece of information to have under my hat! Unfortunately, my lenses are mounted securely. I will however explore the possibility that the lens sensing system is not working properly causing the fault. Thanks!

ecrabb · Posted: Mon Mar 31, 2008 3:24 pm Post subject:

Perhaps Graham will be along soon. He's the man when it comes to 1292's.

Have you verified all fans are spinning up? There are a lot of them on the 1292, right? That's exactly the behavior you'd get of the fan wasn't spinning up (admittedly, lots of other issues could cause the same behavior). I had a bad fan and got the same behavior on my almost-newish low-hour G70.

You could also try taking off one of the lens ground wires and firing it to generate that error and see if you can at least verify whether the error display is even working.

SC

**Curt Palme** · Posted: Mon Mar 31, 2008 3:42 pm Post subject:

I've got very little experience repairing 1292s.

However, if you have a problem on one of the video boards such as an input board, processing or driver board, it can shut the set down with no error code. I had that on a 1271 I think. No error codes, powerdown very quickly after turnon.

Turned out one of the CA video output boards was bad, and there simply wasn't an error code check by the CPU for that particular problem.

Atom · Joined: 09 Mar 2006 Posts: 79 Location: Toronto

Hi
You must have the lens on and you have to have the ground wire attached to the ground lug on each lens.There are three wires in total, one for each lens.
Make sure that the fans are all spinning sometimes they can stop if the covers are installed incorrectly and it can prevent one of them from spinning (check all 12 fans !).If you don't know where they all are here are the locations
3 80 mm on the top back circuit boards
2 80 mm on the sides at the back
2 120 mm on the top
3 120 mm on the inside behind the CRTs
2 92 mm on the front ( these fans can be prevented from spinning by the foam that surrounds them if case is installed incorrectly)
Another thing to try is to have a look at each circuit board especially the ones with power transistors and look for cracked solder joints on the power transistors The top two boards (E and DC I think) get twisted when you lift them for access to the CRTs and the power transistors can have cracked solder joints from the stress. If your handy with a soldering iron
re soldering all these power transistors can eliminate drifting.
Andrew

ecrabb · Posted: Tue Apr 01, 2008 3:53 pm Post subject:

I always forget how many fans the 1292 has - because it's just silly. 12 fans - That's like some kind of sick engineering joke or something, isn't it?

SC

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

Does this thing have to be bolted down when all these fans are singing? I bet It’s real quiet too!

Well, the three lens wires are connected and all twelve fans start running. I gave all the PC boards a good visual inspection however did not see anything suspicious. The two digit error display flashes randomly during the power on attempt almost as if it were counting up.

The CPU is now on an extender card for ease of probing. So far the only signal confirmed as good, with 98 percent certainty, is the fan signal labeled “FAN PROT” on the CPU schematic. The signal is hi when the projector is off then goes lo when the start button is depressed then returns hi when it powers down. If one of the fans is unplugged the signal remains it the hi condition.

There is a output signal labeled “POWER CONT” on the CPU. I broke the connection on the extender card and forced the output hi causing the projector to remain on regardless of what error is being detected. I heard the sweet crackling sound of the High Voltage on the tubes. I suspect it will continue to run as long as I force the output hi.

In fear of damaging the tubes, I resist the temptation to allow it to run in this mode until I have a better understanding of the error condition.

Does anyone have or know where I might get additional information regarding the meaning of the signal on the CPU schematic? Or possibly a power on sequence of events? I have purchased the service manual however there are no definitions or diagrams on the power on sequence / error detection.

Atom · Joined: 09 Mar 2006 Posts: 79 Location: Toronto

I seem to remember that all the error signals end up on the circuit board on top of the power supply so if you have the schematics you may be able to find what is pulling that signal down. The noise can be taken care of by fan replacement
Andrew

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

I did not realize that. I will investigate it tonight, thanks!

1031 · Joined: 22 Mar 2006 Posts: 657 Location: Finland

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

I like that technique Jermo it makes good sense! With the heaters off the tubes can’t conduct and destroy themselves in the case where the error condition is related to bias or deflection.

By the way, the error signals are easily accessible on the board mounted atop the power supply, thanks for pointing that out Atom. It turns out there is enough slack it the power supply harness such that you can easily slide out the entire assembly and gain access to these signals during power on.

Can a 1292 owner please tell me how the error display reacts during power on? Does it stay dark? Or flash a rapid sequence of numbers / letters ?

1031 · Joined: 22 Mar 2006 Posts: 657 Location: Finland

I cant take credit for that.. It was someone other that mentionet about that "safety procedure" on some old thread..

macgyver655 · Joined: 22 Aug 2007 Posts: 8508

1031 · Joined: 22 Mar 2006 Posts: 657 Location: Finland

speedyandre · Joined: 18 Dec 2006 Posts: 291 Location: Netherlands

Hi

My 1292 powers up 1 second and then shuts down showing 1E (H/V) and then 20 (power down) on it's error display.
Sometimes 20 stays in the display but most of all the message disappears.
I think it has to do something with the E board or the 115V power it doesn't get, the 2 fans connected to the E board it don't spin up.
On the EA board (beneath the PA power board) I can't measure 115V when starting up, maybe some protection cirquit stops the 115V.
I've seen several topics on this item but I never read how this problem was solved.
One extra problem is that I've got HD10 lenses on it, so I faked the lens protection by grounding the 3 wires.
I hope this is al there is, I couldn't think of more ways to protect starting without lenses Wink

I bought my 1292 'broke' and with most boards removed so I had to assemble it myself.
Maybe some cables are connected wrong or are missing, I hope someone has pics of the cables on the E board and the PS Smile

André

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

I also bought my 1292 in a not working condition, great fun I tell you! Keep an eye on the color and number of contacts to help with the board connections. My projector all apart so if you need any specific information on how the harness is connected to the boards let me know.

John

speedyandre · Joined: 18 Dec 2006 Posts: 291 Location: Netherlands

Hi

Your second picture shows that a cable is missing in my setup!
I've marked it with circles.

Also the seller did find 2 cables at his place and he has sent them to me, I hope to get them tomorrow Razz

Thank you very much for these pictures Thumbs Up

[edit]
One more missing cable Confused

I hope this black cable is the second one Embarassed

André

RogueChili · Joined: 31 Mar 2008 Posts: 162 Location: Westfield, MA

FYI - The black wires are ground wires. They all connected to the chassis via the hing screws.

Atom · Joined: 09 Mar 2006 Posts: 79 Location: Toronto

Hi Andre
I have both of those cables from my spare machine if you need them .
Andrew