Saturday, September 25, 2010

Smile monitor shut down with a vertical line on the screen - chassis CA6415-CA6515

Smile monitor shut down with a vertical line on the screen - chassis CA6415-CA6515


Most of my customers come to me through referrals by others who I have maybe repaired their equipment and are happy with our service.

So I got this phone call from a customer who wanted me to look at his monitor which according to him was dead.


It was just near my residence and I decided to take a walk there.


When I arrived at the site I connected the monitor back to the CPU and applied power: Relay is heard clicking as the monitor try to come up and... The monitor came up and shut down after a few seconds, but before it shut down I was able to see on the screen a thin vertical line.


Facts at hand.
1. Monitor came up and shut down
2. Vertical line on the screen.


Probable cause: maybe the monitor is being shut down by the safety circuit because the fault is a serious one.


Vertical line on the screen- Usually vertical line is caused by failure in the horizontal circuit especially the deflection circuit.


For those who are new to electronics repair let me emphasis here that whenever you see a horizontal line on the screen, the fault is on the Vertical circuit, while vertical line on the screen point to fault on horizontal circuits.


Vertical line is caused by failure in the horizontal circuit especially the deflection circuit. Therefore check components for deflection circuit gone open (i.e. the horizontal pulses are not going back to the ground. The culprit could be an open capacitor(ceramic like the s-correction capacitor, linearity coil open, dry joint on the horizontal deflection yoke connection, also the yoke could be open etc.


So I opened the monitor and went straight to the deflection circuit to test my hypothesis. I found capacitor (c125) 0.39uF which is the same as no 394 was totally open.




I replaced it with capacitor no 474(0.47uF) which was readily available in the market and the monitor started smiling again.


Tip1: when measuring the components around the fly back in-circuit there is a tendency to get low resistance especially on capacitors (Ceramic) even if they are open because of having other low resistance components or path and hence never trust your reading when doing measurement in circuit. You must remove one leg in order to get correct reading. This applies also when using ESR meter. Sometimes if you notice a funny reading from your ESR meter it’s better to disconnect one leg from the circuit.


Tip 2: Observe carefully to see if there is any capacitor which has its body surface bulging out. Even slight swell on the capacitor body is enough evidence to suspect a faulty capacitor. (Observe carefully the body of all ceramic capacitors: if bad they become swollen and look like the back of a camel-or underfeed cat. i.e. backbone plus a big stomach) by the way sometimes you don't get the exact replacement for the s-cap. In this case you can always use a cap which is near that in capacitance but same working voltage.




Thank you guys




Let meet in our next Class


11 comments:

  1. HELLO HUMPHREY
    I MAY SAY THANK YOU FOR YOUR VERY BEAUTIFUL ENGLISH WORDS THAT YOU HAVE TO DIS CRIB THE PROBLEMS IN THE SETS.
    I WILL REMAIN YOUR FOLLOWER
    REGRADES
    beh

    ReplyDelete
  2. Hi Beh, thank you for your comment, i believe there is power in simplicity.

    Regards Humphrey

    ReplyDelete
  3. yes this trure you discribe problems like a soft breez in summer and that is why everythings is going smothly
    rgrds
    beh

    ReplyDelete
  4. DEAR HUMPHERY

    i have this request from you .most of your articles are really useful i want to have a copy
    of these would you please make a also a printable
    version of your articles.
    thanks
    beh

    ReplyDelete
  5. Hi Beh, i suppose you can also print directly from the site,for jpg you can save them on your computer and print them also. otherwise i wish you all that best.

    stay safe Humphrey

    ReplyDelete
  6. HELLO HUMPHERY

    thanx for reply. my problem is how can i make a jpg copy from your article to send to fotoshop?. my knowledge in computer is not strong plz let me know?
    thanx & best rgrds
    beh

    ReplyDelete
  7. hi Beh, click on that jpg image on the website, it will open in an enlarged version, click again on that jpg and you will see some icon on the upper left hand, Click the first icon and it will ask you where to save on your computer.
    hope this help otherwise you can send me a email if you need more info. regards Humphrey

    ReplyDelete
  8. HELLO HUMPHERY

    thanks for your info i will try and i will tell you also my e mail address is
    behzadrasteen735@g mail .com


    beh

    ReplyDelete
  9. oh, thanks for sharing this. i do a lot of programming and a little electronics. your tip brought my good old smile monitor back to life.

    michael

    ReplyDelete
  10. Thank you for passing by Michael, i am happy to hear that your monitor is smiling again.

    regards Humphrey

    ReplyDelete