Sanyo projectors - yellowing

[lordjimbob]

Is anyone else having problems with sanyo projectors?

 

The vast majority of mine are starting to develop a yellowing in one corner/side (which side/corner depending on whether it is upright or upside-down!) - it has been sent to promethean who said it was dirty and needed cleaning, as well as a new bulb, as it had been used for a whole 50% of its capacity (point being?!). Anyway I know for a fact it isnt dirty inside (wink wink, nudge nudge) and has been cleaned in excess of their guidelines. He suggested my school was particularly dusty.... I said if I cleaned it well within their guidelines of monthly, how is it my responsibility... brick wall! Again, my school must just be dirty...

 

They want £175 to clean it, and I am not allowed to take the cover off myself as this will void the warranty.

 

He explained that when a yellowing occurs in a particular area, it is a result of an internal filter burning up - but it just so happens, for me, that wasnt the case (an expression from the royales comes to mind!). So he kind of admitted they run too hot anyway....

 

So what do I do? All the projectors are now showing signs of this. I have spoken to a guy at another school who has literally just been sending them back and fourth for the past year! Not the solution I want.

 

Grrr!

[SpuffMonkey]

I've had this on Mitsubishi's - its expensive and annoying - haven't found a real solution though.

[CyberNerd]

This happens because the filters aren't being cleaned.

When the filters become clogged, air gets sucked around the filters. This allows dust to get onto the lenses (there are lots of lenses). Eventually the dust gets burned on, causing yellowing.

First you need to get a maintenence schedute together to get the filters cleaned once a month or more regularly if needed. I keep trying to tell management about TCO....

 

Then yuo'll need to clean all the projectors, £175 sounds about right, we've done a couple ourselves - it took us about 2-3 hrs using a bottle of isopropanol and some lint free cloths. Like promethean said, you'll need to change the bulbs as well so it might be best to sell em and buy new ones.

[webman]

I heard it's the prism inside that needs cleaning or re-conditioning when this occurs due to the heat or light from the lamp. Our oldest projector sufferes badly from this and projects a large yellow area in the middle of the screen. I also heard you can go on a training course to get certified to clean them properly, or send them away for £60-£100 a time to get them done professionally.

[CyberNerd]

I heard it's the prism inside that needs cleaning or re-conditioning when this occurs due to the heat or light from the lamp.

 

It's the combination of heat and dust

[western]

Dont buy Sanyo again!

[webman]

Thanks for that CyberNerd

[eastlondon]

I also had this with our Phillips lc 4433

 

We got about 4 years out of them b4 it started, we have changed all of them this summer as in their 5th year some became unusable, we are now only going to use the Epson EMP 82 misco give us a good price.

[lordjimbob]

This happens because the filters aren't being cleaned.....

 

But they are though, thats my problem - what more can I do? Nothing, as I am "not allowed" to do it as it will "void the warranty".

[CyberNerd]

Well I guess if they are being maintained as per manufacturers instructions then you have cause to return them, they are within warranty.

[Geoff]

I had this with a NEC. They just swapped it out.

[drjturner]

This happens because the filters aren't being cleaned.....

 

But they are though, thats my problem - what more can I do? Nothing, as I am "not allowed" to do it as it will "void the warranty".

 

You are cleaning all 4 filters on your projector?

 

How blocked are they when they are cleaned, If they are really badly caked in dust I would suggest doubling your cleaning reigeme. If they are caked this will cause extra heat in the projector and the dust in the atmosphere will be pulled in from other non filtered areas of the projector.

[lordjimbob]

This happens because the filters aren't being cleaned.....

 

But they are though, thats my problem - what more can I do? Nothing, as I am "not allowed" to do it as it will "void the warranty".

 

You are cleaning all 4 filters on your projector?

 

Yup, all 4 at least every 2 weeks. They arent even dirty enough to merit doing every 2 weeks a lot of the time, but it is still done to maintain their condition - fat lot of good its doing!!!

 

So again, cannot do anything more really. It's clearly a fault with the projector(s) and being fobbed off "it's dirty" isnt really good enough!

[Sylv3r]

This problem has been spotted on several of the projectors here also which are all Sanyo. We have sent them to Promeathean for a full optical clean which I think was around the £175 mark, but they didnt come back any clearer then when they went to be honest.

[SpuffMonkey]

First you need to get a maintenence schedute together to get the filters cleaned once a month or more regularly if needed. I keep trying to tell management about TCO....

 

Then yuo'll need to clean all the projectors, £175 sounds about right, we've done a couple ourselves - it took us about 2-3 hrs using a bottle of isopropanol and some lint free cloths. Like promethean said, you'll need to change the bulbs as well so it might be best to sell em and buy new ones.

 

We've got them in every classroom - we'd need extra staff for a cleaning regime like that!

[CyberNerd]

@SpuffMonkey

 

We're in the same position. We don't have the staff to clean them as regularly as they need, thus they die quickly. Can't get it through to manglement the concept of TCO - if they keep deploying new equipment they must also budget for its upkeep and disposal. brick wall.

[Outpost]

Sorry I didn't reply earlier.

 

All sanyo's at my schools have started to fade and yellow. I can't remember which model though but they're all the same. Someone got on to the suppliers who then informed them that these projectors were unsuitable for classroom use. WHAT??. Cleaning the filters didn't stop the slow decline either. One school got lucky and managed to have seven of their projectors cleaned for free. The story I was told was they got CLEO involved as it was them that recommended the projectors. Unfortunately some of the projectors came back with a full screen but still dimmed.

[CyberNerd]

Someone got on to the suppliers who then informed them that these projectors were unsuitable for classroom use. WHAT??

 

I heared the same thing, one of our guys got onto sanyo and were told they aren't designed to run 8hrs per day in a classroom - we'd need a decent projector for that (£2k).

 

Doesn't stop the cowboy ICT firms deploying them though

[mrtechsystems]

We have used Epson all the way but I have just been informed we have a new ACTIVSTUDIO + 2 with a sanyo projector thanks for the info on them please could anyone tell the model numbers will post back on what we got also need to check out the warranty info aswell

 

Thanks ppl

 

Mr Tech

[PeterH]

Folks,

 

We've had this problem on lots of Sanyo projectors and have managed to successfully fix it. Repairing these projectors is possible, but its not an easy job. If anything goes wrong during this process or if you loose or damage any of the parts, it will likely be very difficult if not impossible to get the projector working properly again, so this is perhaps the last thing you should try before replacing it.

 

The problem is caused - as someone else has suggested - by overheating. Buried deep within the projectors optical path are two lenses that have some kind of colour-correction filters glued onto them. The problem is that the glue that is used to stick these to the lenses, which should be transparent, turns dark after a period of time, probably caused by the heat from the lamp and perhaps also insufficient cooling. This darkening causes loss or reduction of one of the primary colours, resulting in a yellow patch on the image.

 

The solution is to dismantle the projector and remove the lenses so that the colour correction filters can be removed. The projectors work fine without them - the whites tend to be very slightly off-white, but its very hard to notice.

 

Be warned that these lenses are buried deep within the projector and dismantling is not a five minute job. If you've not done it before, it'll take several hours, plenty of clear space, a steady hand, a selection of screwdrivers and a sharp craft knife.

 

After removing the top of the projector, the are two circuit boards layered on top of each other that need to be removed. There are lots of cables that interconnect these boards which will need to be removed, so you'll need to keep a careful note of which cables go where. A digital camera might be useful here.

 

After unscrewing the top board and unplugging all the cables, it will need to be gently pulled to un-mate the PCB-mount connectors on its underside which push into sockets on the board underneath.

 

Once this board has been removed, the board underneath can be dis-connected, unscrewed and removed. In approximately the middle of the board, you will find three flexi-print cables that connect to the 3 LCDs on the prism module. Be *very* *very* careful with both the felxiprint cables *and* their sockets. They are very fragile and damage to the cables or sockets will almost certainly render the unit in-operable and unrepairable.

 

Afte removing the bottom board, you can then very carefully un-screw and lift out the prism module. Whilst you're there its a good opportinity to have a general clean-up, probably with a can of aero-duster or similar to remove all traces of dust.

 

Once the prism module has been removed, you should be able to identify the two lenses, to the left and the bottom of the prism module, looking from the back of the projector. These are held in place by small metal clips that need to be un-screwed.

 

After doing this, you will need to loosen all of the screws in the black plastic channeling that surrounds the optical path through the projector. You can then carefully prise the top of the channeling away sufficiently to remove both of the lenses. This isn't very easy, as you need to remove quite a lot of screws and move cabling out of the way, but it is possible if you're careful.

 

If you've got this far, then you should have the two lenses in your hands. On one of them, you will clearly be able to see the darkening of the colour correction filter.

 

To remove the filters and the glue that fixes them to the lenses, you will need to soak the lenses in methylated spirit for a few hours and then you can beging to *very carefully* lift the plastic filter away from the surface of the lens using a sharp craft knife. The best technique is to try to lift the filter at the edges or the corners using the knife, taking great care not to scratch the lens. You should find that the plastic filter itself comes away easily, but the glue that remains will be a lot more difficult to get off and will require extra soaking in the meths and more work with the knife.

 

By the way, don't worry if the metal bracket glued to the top of the lens comes off. This is used to help hold the lens in place, but isn't really needed - the lenses won't fall out once the projector is re-assembled.

 

I must emphasise how easy it is to scratch the lenses. You need to be very very gentle with the knife indeed, as even small scratches will quite likely be clearly visible on the image once the projector is re-assembled.

 

Having cleaned up the lenses, all you have to do it to put the whole thing back together again. As long as you have made a careful note of where all the connectors and screws go, this should be fairly easy. Again, take great care with the flexi-print cables and connectors on the prism assembly.

 

When you come to re-insert the topmost of the two circuit boards, you need to make sure that it is aligned in extactly the right position, so that the PCB plugs re-mate with the sockets on the board underneath. Also, be very careful that you don't get any of the cabling trapped between the plugs and sockets as you push the two boards back together.

 

Having re-connected and re-wired you should hopefully now have a fully working projector. Good luck!

[webman]

PeterH, thanks for the guide, I'm sure that will be very useful for any of us who want to tackle this problem.

 

A tip that some may find useful when dismantling something with a lot of different-sized screws (eg. laptops!) is to draw a basic diagram of the part you are removing on paper, and place the screws on small blobs of blu tac where they came from. It saves putting smaller screws back in large holes and vice versa and.

[mullet_man]

We have around 10-15 Sanyo's and all are showing yellowing some worse than others.

 

E_G_R tried to clean one once, after we had taken apart one which was a broken in a failed break in (before attempting a working one). Everything went back in correctly but when we turned it back on it, the fans came on for a second and then it just shut down.

[meastaugh1]

Are there any projectors beside the Sanyos that will provide a similar long throw? I've used Epson wherever possible, but they are comparitively short throw.

[Norphy]

The NECs that we have are quite long throw.

[pooley]

Benq have long throw too.

 

What is it with certain makes of projector - all our Toshiba have red blobs.

 

think il try dismantling one and repairing it.