Sanyo Projector Losing Signal

[Jacb Robinson]

I am having some difficulties from our Sanyo PLC_XU73. Our church does not use our projector extensively and is normally only used 1 of our 3 services per week, but it is becoming quite a frustrating problem and I cannot seem to find a solution.

The problem:
Without any warning on some mornings when I power on the projector it will not recognize any that there is any signal present and I will just get a blank blue "no signal screen". This problem has happened with 2 different PCs and in both cases the computer always recognized as a having an external monitor connected. Sometimes a simple power cycle of the projector will fix it, other times I have to climb a ladder and simply un-plug and then reconnect the VGA cable in the back of the projector, then other time it takes a hard reset to solve the problem. But now none of those solutions are working. It also should be noted that this same problem occurred before when I had a signal amplifier in line and I removed it and the problem seemed to go away for the better part of a year, but now it's back. It seems to happen randomly too, sometimes once a week and sometimes it may go a month or two and never have a problem.

I know that this projector is not a unit that would normally be put into a church, but we bought it used and don't have the budget for a quality projector.

Another note on my troubleshooting, when we bought this projector it came with an identical twin I have switched them out and got the same problems so I thought it was a cable or PC problem so I took it home and connected it via a 6' cable and my own PC and get similar problems.

It doesn't make sense to me and I am beginning to think they have a mind of their own. Like they each have the same defect.

Do you have any thoughts on these snake oil filled projectors?

Thanks Guys/Gals.

I will post this a couple other places as well, because I need all the help I can get!

[cmchamp]

how is the electric terminated? Is the hot/neutral and ground properly terminated?

[daver2]

It isn't unheard of for two projectors to have similar faults...

We bought four identical projectors for our Church some 5 years ago. One of them in the (Prayer hall) developed an "evil" temperament where it would work with some PC's some of the time etc. We have subsequently diagnosed an internal logic board fault. Both of our worship hall projectors have now got blue casts on a corner of the screen (caused by a failing LCD chip) - and one of those projectors has also developed a similar logic board fault.

We have just taken delivery of two brand new projectors for our worship hall, and I will be swapping the "good" logic board from the projector with the failed LCD chip into our Prayer hall projector (with good optics but a 'possessed' logic board) to give us a completely working setup once again. Interestingly, the projector in the overflow area (which is run in low-power mode - as it is in a much darker environment) is working like a hero still.

So - yes projectors of the same age can develop similar faults under certain circumstances.

Our optical problems could have happened because of poor maintenance. The guy that cleaned the projectors and filters on a regular basis left the Church and responsibility was handed over to the building manager. This meant that the job never got done - with the result that we suspect overcooked the projectors due to poor air flow and the blue LCD chip was in the least cooled position. That's what we think anyhow.

So, my first question is - are your projectors adequately maintained? This is especially true of "budget" or "home/office" use projectors.

My gut feeling would be an intermittently faulty or "dirty" connection somewhere (possibly the VGA connector?) Have a look at all of the signal connectors for bent or damaged pins. Try a little squirt of contact cleaner to be on the safe side.

So, if you swapped the projectors around and took the "faulty" projector home and tried it with another cable and PC and got the same results then I would suspect that it is the projector in some way. As Cory has already asked - did you use the same mains cable?

I assume from your statement above that when you put the "sister" projector in position it also dropped the signal occasionally (thus indicating a cabling/PC fault)?

The usual way of the projector sensing an input signal is for it to look at the (low level) voltage level(s) and timing on the h/v synchronising lines whereas a PC will look for a monitor connection via the monitor ID pins. The synchronising signal is more susceptible to problems than the monitor ID pins (due to the lower voltage level and the timing involved) hence the reason the PC thinks the projector is there whereas the projector doesn't think the PC is there.

You may also like to look at how the projector is terminated. I had a look through the User manual and couldn't find anything at all about termination impedance - hmmmm?

A couple of other things to try off the top of my head:

1. Are you using the automatic sense feature of the projector? if so (and you only use the VGA1 connector) have you tried manually selecting VGA1 and saving that configuration?

2. The projector appears to have two separate VGA input connectors. One of these appears to be switch-able between an input or an output depending on configuration. Have you tried selecting VGA2 as an input (see user manual page 44) instead of VGA1?

3. What resolution are you running at? Have you tried dropping the resolution of the PC to a lower setting (relax the timing) to see if this has any effect.

4. How often are cables swapped on the projector? If often (this applies more for portable devices of course) consider using a sacrificial VGA connector to take the punishment rather than the projector. This device is a small male-female connector joined together. You would leave it permanently connected to the projector so if any damage occurs you can replace the $2 connector rather than damage the projector!

Our prayer hall projector appears to be fine when we use one specific VGA input with the projector configured manually - hence the reason I offer a potential interim solution.

Continue to post the results of any further tests you do - some of them may jog people's memories. I will see if I can find anything more about terminating this beast.

Dave

[Brad Weber]

Originally Posted by daver2

3. What resolution are you running at? Have you tried dropping the resolution of the PC to a lower setting (relax the timing) to see if this has any effect.

Jacob posted elsewhere that they are running at 1366x768 resolution but did not identify the refresh rate. Apparently the projector is only compatible with 1366x768 at 60Hz refresh so that is one thing to check. And I have found many devices to be rather particular about everything being just right with 1366x768 resolutions.

The computer may be seeing a connected display device but is it seeing the projector? Along those lines, I'm curious if they have tried different sequences in terms of turning on the projector and then booting the computer, booting the computer and then turning on the projector, etc.