[Spookstah]

I`m setting up my NEC 6PG+ and made a new signal entry and did set all settings to 0 (or in the middle).


I whas working on raster and image centering, but suddenly it starts to fluctuate in horizontal size and after 10-20 changes it is stable but too small.

When i shut down the PJ and wait awhile, the image is normal in size again, but after 30 minutes or so it starts resizing again, but sometimes its immediately too small.


What could be the cause of this behaviour?


side note: I have put 2 extra coolers on def board heatsink and on the C and F drive and also did replace the capacitor on def board.

 

[Tinman]

Sounds like the power supply. Mine did this, and after swapping the Def, sys and wave board, it was the PS.


However, check the H-out and H-width pot. May be dirty. Mark them first!


Marc

 

[deronmoped]

Did this start happening after you made the changes? If so it was probably something you done.


Deron.

 

[Spookstah]



Quote:
Did this start happening after you made the changes? If so it was probably something you done.


Deron.

A few days ago, i did the same setup (using guide from CP) but i had to do some adjustments (shifting image to 1 side) to gether it proper on my screen, so the image whas`nt dead center on the tubes anymore, but it whas my 1st try to setup a NEC and to get to know the PJ and i wanted to correct the position of the PJ and do a whole new setup.

The next day when i did fire it up for my daughter so she could watch a movie on her birthday party, the image whas 10cm smaller on both sides as i had set it up and how it whas when i did do the setup.

(while setting it up the 1st time the PJ did run 4+ hours and there whas no shaking or shifting)



I also noticed the STK of the focus board whas too hot to handle, i could`nt let my hand rest on the heatsink i did add on the bottom of the PJ above the C and F drive.


I will mark the 2 pots and rotate them 2 see if they are the problem.

 

[deronmoped]

Try reducing the amount of focus correction you are using, you could be driving the PJ too hard. Are there any other controls that you are running way high? You may need to work on the physical set of the PJ more.


Focus can be corrected in several ways, physical set up, lens focus, flapping focus, ASTIG and focus pots. The last one you want to use is any electronic focus controls on the remote.


Deron.

 

[Spookstah]



Quote:
Originally Posted by Tinman /forum/post/0


Sounds like the power supply. Mine did this, and after swapping the Def, sys and wave board, it was the PS.


However, check the H-out and H-width pot. May be dirty. Mark them first!


Marc

I`ve twisted the pots 10+ times from min to max and the problem still exists, so those are`nt the problem.


Are there any specific parts in the PS that can cause this failure?

 

[Tinman]



Quote:
Originally Posted by Spookstah /forum/post/0


I`ve twisted the pots 10+ times from min to max and the problem still exists, so those are`nt the problem.


Are there any specific parts in the PS that can cause this failure?

No idea. I just swapped the PS with a spare. The flakey one is still in my shop, but I have not had time or desire to look at it.

Marc

 

[GlenF]

Mine did something kind of similar. You would be watching a movie and suddenly it would go tall. i.e. the entire picture would nearly fill the raster.

It would also shift upwards in position.

It hasn't done it for a while, but I never worked out the problem.

 

[Doug Baisey]

DVD or HD source?


Reason Im asking is if you have the HD set up for multi resolutions depending on what they are broadcast in the HDSTB will change on you. ie: 480I for SD and 1080I or 720P for HD depending on channel you have selected. If your forcing one resolution like 1080I you have to uncheck lets say 480I and 720P so it cant select them. If this does select them you will need a signal entry for each resolution.


Some boxes have a native setting and will go to whatever they broadcast in. Some boxes will only pass what is selected in the set up menu or from the front panel.


With a scaler that looks at the incoming signal properties and assigns it to an output freq this can be tricky depending how its set up as well as the format size. ie: 1.33, 1.78 etc.


This can account for some of the size issues so wanted to mention it. Doug

 

[Spookstah]

Hi Doug,


In my case, it is a HTPC running at [email protected], so no other signals, just this resolution.

Since i dont have spare parts lying around i cant just swap parts to find the failure and thats why i need as much info as possible.


When my image collapses the HV sound you always hear, changes from tone/frequency, so it really looks to my as some sort of failure.

 

[Doug Baisey]

Spookstah,

On yours the deflection alignment / adjustment is pretty important to be exact. H OUT is the protect circuit for the 2SC4288A (HOT) horiz output transistor. The H WIDTH spec voltage is also important, get this to far out and it will overheat causing the HOT to fail as well as the DD50 diode next to it. To many hits to the power supply can be a bad thing. The oscillatior circuits need to also fall into spec for normal lock up as well as the F/V pot (freq to voltage).


In short you just cant go turning these and expect it to be the same afterwards. I know dirty pots can be a problem and sometimes you can get lucky...most of the time you will need the service manual. Remember your changing things from the orig signal entry and default.


Last like Marc said the power supply can also do this. Doug

 

[Spookstah]



Quote:
Originally Posted by Doug Baisey /forum/post/0


Spookstah,

On yours the deflection alignment / adjustment is pretty important to be exact. H OUT is the protect circuit for the 2SC4288A (HOT) horiz output transistor. The H WIDTH spec voltage is also important, get this to far out and it will overheat causing the HOT to fail as well as the DD50 diode next to it. To many hits to the power supply can be a bad thing. The oscillatior circuits need to also fall into spec for normal lock up as well as the F/V pot (freq to voltage).


In short you just cant go turning these and expect it to be the same afterwards. I know dirty pots can be a problem and sometimes you can get lucky...most of the time you will need the service manual. Remember your changing things from the orig signal entry and default.


Last like Marc said the power supply can also do this. Doug

Doug,


I have`nt touch them before this problem occured and i did mark them with a permanent marker before turning them around and doubled checked if they where in original position again.


The only thing i had done whas setting up the PJ according to the manual on CP website and adjusting the astig, the PJ whas stable during the whole setup process and also when it whas done. (atleast 8-10 hours)

The problem occured the next day, when i did enable the PJ again, the image immediatedly did collapse 10cm onscreen on both sides.

 

[Doug Baisey]

You need to test both the power supply and deflection in another chassis or send to have tested. Whos around you over there? Doug

 

[Spookstah]

Nobody i`m afraid, i think i will bring it to a local tv repair center.

They always do our bussines repairs, like tv`s, video camera`s,lcd projectors etc.

 

[Tinman]

I seriously doubt a TV repair place can help you. Most have no clue about these projectors. They were never consumer units to begin with. Secondly, your BEST bet to find this problem is by swapping parts. Unfortunately.


Marc

 

[Spookstah]

Those NEC PJ`s are`nt widely spread in my country, so getting parts would be almost impossible.

One year ago the PSU from my Sony 1252QM whas dead and they did fix it, so i have a little hope and if they can`t fix it, they don`t charge anything.


But i would let te get my hands on a 2nd 6 or 9 PG+

 

[Tinman]



Quote:
Originally Posted by Spookstah /forum/post/0


Those NEC PJ`s are`nt widely spread in my country, so getting parts would be almost impossible.

One year ago the PSU from my Sony 1252QM whas dead and they did fix it, so i have a little hope and if they can`t fix it, they don`t charge anything.


But i would let te get my hands on a 2nd 6 or 9 PG+

Well, I'd give you one if you could have it picked up and shipped. Unfortunately you need to have at least 1000 posts on the forum to qualify for the offer.

However, my first suggestion would be to find a known good PS to swap for testing.

An intermittent PS is very hard to troubleshoot. Especially if you are not sure if it IS the PS.


Marc