MAG Innovision Lt765

[KingHuds]

Overnight this monitor died, woke up one morning and it would turn on for a second, display then the power LED would die with a weird click noise then it would restart and keep doing this. I took this apart after reading that it may be the transistor. I stumbled across this forum and figured I might post.

Looking at the power board(?) What I think are the caps, the blue and black ones all look fine, but all are slightly larger from about halfway up, but it looks uniform so I think thats normal? I dont know where the transistor would be or where to look for it so any help is appreciated, and yes I know the picture is terrible quality haha, Ill try to get a better one posted.

[zandrax]

Re: MAG Innovision Lt765

Welcome Kinghuds.
You should post a clearer picture (photo is too out of focus to recognize a bad cap) and wait for Davmax or KC8's advice. Which is the caps brand?

Zandrax

[KingHuds]

Re: MAG Innovision Lt765

Ill try to find a better camera I can use, and the caps were Unicon.

[zandrax]

Re: MAG Innovision Lt765

Use the camera in macro mode and check the focus.
Unicon is a brand owned by the taiwanese caps manifacturer Gemmy: if Google Translate translates correctly the Unicon page on capacitor.web, then there had been leaking caps in past.

Zandrax

[KingHuds]

Re: MAG Innovision Lt765

Still waiting for my friend to get his camera, but after looking pretty closely over the board the only thing that I have found is some brownish goo on two of the smaller black square things on the board, all the caps look the same and I don't see anything leaking, so unless they are all bad, which could be possible.

Picture isnt the monitor board, but I just posted an example of the small parts that I was talking about having the brownish-goo stuff. Hopefully I can pinpoint what the problem is.

[Gianni]

Re: MAG Innovision Lt765

It's important to see the pictures of your problem.

The smaller black square things on the board probably are integrated circuits, diodes or voltage regulators. If they have changed their color than probably they have overheated and this can happen if they have been overloaded or if the voltage went out of spec at high value respect the nominal one.

Till you can post a better picture, you can try to read the marking type on the smaller black square things and look for their datasheet or ask here.
Knowing what they are can help to identify the problem.

Ciao
Gianni

[KingHuds]

Re: MAG Innovision Lt765

Just wondering, does anyone know if there is somewhere to buy new logic/inverter boards? Still working some better pictures.

[pctechguy]

Re: MAG Innovision Lt765

I have this same board- acutally 43 of them - ill be replacing the caps on a few to determine the culpriates- i know the last post on this was 08 but ill have some solution to this soon. There are 21 cap's on this board - Im sure its one in the power section of this board- but this board runs everything except the high-voltage for the lamps. Ps - the "goo" on the transistors is normal - its solder flux. good to have

[pctechguy]

Re: MAG Innovision Lt765

Ps - if anyone knows this board off hand - any indication to what caps are on the supply side vs the operation side (hope im making sence) would be super sweet to get a heads up! replac'n 21 per board would be totally expensive! but since im out of work atm - i suppose i have some time for trial and error cheers - Post'n a great pic next post.

[jetadm123]

Re: MAG Innovision Lt765

I have this same board- acutally 43 of them - ill be replacing the caps on a few to determine the culpriates- i know the last post on this was 08 but ill have some solution to this soon. There are 21 cap's on this board - Im sure its one in the power section of this board- but this board runs everything except the high-voltage for the lamps. Ps - the "goo" on the transistors is normal - its solder flux. good to have

If you're not getting high voltage to the lamps, then you might want to start with the power supply. Verify you're getting the and 12V input. I think those are 3-terminal voltage regulators on the left side of the board (to the right of the "rev S3" silkscreen). Try checking them for proper output voltage. And check for any fuses that may have blown.

[PlainBill]

Re: MAG Innovision Lt765

Something else that helps us help you is a picture showing ALL the boards and connections in the monitor. Some things on this board suggest this monitor has an external power supply. But it's hard to tell which connector is the power input, which goes to the inverter, etc. Unless I'm in the proper frame of mind, I don't play guessing games. If someone won't bother giving adequate information, I won't bother trying to help.

PlainBill

[pctechguy]

Re: MAG Innovision Lt765

Thanks alot for the responses-
- This board does have a external power supply- both i have used are doing the correct voltage.
- Both lamp inverters are operating just fine.
- I have isolated this board to be the problem.

Sorry to bother you Plainbill - but u don't have to guess at anything here I wasn't asking any question to anyone that didn't know this board- Though im sure glad to see your willingness to help people! Thats at least nice.

I looked and looked on the web for a more in-depth "common" issue fix for this board and found only this one that was abandoned a few years ago- I plan to complete it for anyone else who may find it useful! -

My question was only sniffing out if someone around this group of dedicated people that may have already done what I plan to do>!

Problem Outline for this posted issue:

- When powered up this monitor displays perfectly when cold for about 5 seconds and green led is on.
- Once it gets a bit warm the monitor shuts off and goes to the standby orange colour.
- The monitor is not running as there is no picture and the liquid-crystal "melts" back to a neutral state.
- If the monitor is plugged in to a computer when this happens and has a good signal, the monitor will attempt to restart only to fail and go in to a loop of this behaviour.
-Once the monitor is warmed up (usually only takes one power-on attempt) the duration of the displayed graphics on the monitor is reduced from 4-5 seconds to about 1-2 seconds.

If your experiencing this issue with the Mag 765/870 - stay tuned for a solution - Hope i find a easy one.

[retiredcaps]

Re: MAG Innovision Lt765

-Once the monitor is warmed up (usually only takes one power-on attempt) the duration of the displayed graphics on the monitor is reduced from 4-5 seconds to about 1-2 seconds.

This could be 2 seconds to black. Possible causes are

1) bad caps
2) bad inverter transformer
3) bad ccfl or wiring

All the above are discussed in great detail starting with post 13 and 14 at

https://www.badcaps.net/forum/showthread.php?t=10419