21 Inch Hotpoint CRT television (model 21JI8US) wide horizontal lines repaired

By on January 3, 2018
crt tv repair one horizontal line











I got a phone call from a client who wanted me to check a television which the owner wanted to dispose as a junk. Since the client knew I am technician, wanted me to check it out and see if it is repairable so that she can make a decision to buy or not.

I passed by her place and was taken to the store where it was kept and the first thing I did was to connect it to the power outlet to find if it has any life in it and this is what I saw.

crt tv repair

With this, ‘on the screen’ I was able to conclude that the power supply (s.m.p.s) is up and running, horizontal drive is up to the task, horizontal output is doing fine, fly-back is very happy and therefore after opening I need not go to any of those circuits for any troubleshooting purposes since it will be waste of time which is a limited resource (we all have 24 hours in a day) and technician are not excepted.

Using the same symptoms to analyse the problem I was not happy with the way the vertical circuit was doing its work because I expected the screen to be full vertically but this is not the case as seen from the screenshot above.

After that initial conclusion it is now time to open the set for the practical part of it and to test my hypothesis.

After opening the set this is what I got, one inch deep of dust layer covering the main board, I took care of that using a soft brush

horizontal line in crt tv

After cleaning the board things are now taking shape and it is time to start troubleshooting.

repairing crt tv

With the dust taken care of, I started my troubleshooting, first I scanned around the vertical circuit and I was able to pick two capacitors with the top slightly swollen.

repairing crt tv one line

The capacitors were labelled C562 and C563 and both were rated 1000uF/25V.

bad caps in tv

I soldered the two capacitors out of the circuit and tested them out of the circuit and this is what I got.

yiwanjia esr meter

A capacitor rated 1000uF is now reading 36.17uF and ESR reading of 0.15K ohms equal to 150 ohms (0.15 X1000=150 ohms)

I have intentionally taken the same data for a good capacitor with the same value as you can see here below.

yiwanjia capacitor tester

So a good capacitor of the same value is now reading C=985 uF and an ESR reading of 0.21 ohms.

Some technicians ask me what is the best ESR values for capacitors and my answer is to compare with the same values capacitors but any capacitor with the ESR over 5 ohms, one should compare other factor like voltage rating/values. After replacing the two capacitors, now it is time to power up and this is what I got on the screen.

how to repair crt tv

Nb: I was not able to get the circuit diagram of this Television and therefore I can only assume that the two capacitors were used to filter the vertical circuit supply.

Thank you friends

Humphrey Kimathi


humphrey kimathi

Humphrey Kimathi is from Nairobi Kenya and the author of CRT Troubleshooting guideDVD Player repair guideCRT Television repair course and Basic Electronics course. He is also a blogger at Electronicsrepairmadeasy.com

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Note: You may check out his previous repair article below:





  1. Albert van Bemmelen

    January 3, 2018 at 6:08 pm

    Nice job Humphrey. I however wondered why you took the time to brush off the one inch deep layer of dust covering the main board by using a soft brush?
    I just would have used an 8 bar air compressor. I clean most of my laptops the same way. (only not the tiny Fans of those brittle Eee pc's!).

    • Humphrey Mndaka

      January 3, 2018 at 10:28 pm

      Thanks for feedback Albert, Regarding the use of soft brush, let me it was only the option on the table since i was doing my repair on site.
      Regards Humphrey

      • Amir Mukhtar Ashrafi

        January 8, 2018 at 2:20 pm

        Good Job Humphrey Kimathi
        Keep Sharing Expertise .
        Thanks you
        Amir Mukhtar Ashrafi
        Karachi . PK

        • Humphrey Mndaka

          January 11, 2018 at 7:17 pm

          Thank you Amir for the encouraging words. i am humbled...

          Regards Humphrey

  2. Mark

    January 3, 2018 at 7:25 pm

    Hey Humphrey,

    Good repair! Looks like you might have needed a chisel to remove all the dust!
    If you are looking for a good ESR chart, here is one that I have been using for some time. I hope it helps.

    • Humphrey Mndaka

      January 3, 2018 at 10:35 pm

      Thanks Mark, Regarding the issue of dust? hahahee, you are spot on...Yes! and the ESR chart you referred looks good.

      Regards Humphrey

  3. Kigoma charles

    January 3, 2018 at 7:59 pm

    This is really very good and i like the work you are doing for the world and mostly some of us who are still learning to repair electronic ampliances.
    However,i would like to get copy of all the E-Book Repairs but i have failed to get.Please, iam need of these coppies,just give me all the details.
    My sincier thanks goes to Mr Justine Yong and the tire staffs and every one who are working tiresomely day and night to see that you educate the whole world and even making us to earn some living and creating jobs for most of us.

    • Humphrey Mndaka

      January 3, 2018 at 10:40 pm

      Hi Charles, Thanks for your feedback, i am glad you are learning something new everyday. Regarding buying my eBooks you can order them from Jestine Young easily via western union or money gram if you don't have paypal account.

      Regards Humphrey

      • moniem

        January 4, 2018 at 7:28 pm

        very good informatiom

  4. Yogesh Panchal

    January 4, 2018 at 6:10 pm

    Good job!sir.

    • Humphrey Mndaka

      January 4, 2018 at 9:27 pm

      Most welcome my friend Yogesh.

      Regards Humphrey

  5. Robert Calk

    January 4, 2018 at 6:49 pm

    Good job, Humphrey. According to the ESR chart I have, that capacitor should not have ESR above 0.10. Too bad you didn't have a vacuum cleaner with a brush attachment for the dust.

    • Humphrey Mndaka

      January 4, 2018 at 9:34 pm

      Thanks for you feedback Robert, about the new capacitor ESR... not bad,was within the range.
      Regard Humphrey

  6. Tyrone.

    January 4, 2018 at 6:52 pm

    Thanks Humphrey for the good work that you are doing Happy New Year God bless

    • Humphrey Mndaka

      January 4, 2018 at 9:37 pm

      Thanks Tyrone, and thanks for the blessings. received with both hands.

      Regards Humphrey

  7. Suranga Electronics

    January 5, 2018 at 1:57 am

    Good Job Friend !

    • Humphrey Mndaka

      January 8, 2018 at 2:32 pm

      Thank you Suranga
      Regards Humphey

  8. Ojtech

    January 5, 2018 at 3:38 pm

    Thank you Sir. I have one JVC AV28R25EKS that will on for few seconds and go back to standby with steady red light. Everything looks fine after several testing. What would you think is the caused of the problem?

    • Humphrey Mndaka

      January 8, 2018 at 2:41 pm

      Hi Ojtech, In my case i had something on the screen and therefore was able to figure out the faulty circuit even before opening the set...in your case since nothing is on the screen it is hard for me to give any opinion without opening it which is not possible from where i sit on the other side of the world.
      Regards Humphrey

    • Robert Calk

      January 10, 2018 at 10:44 pm

      I don't have as much experience as our friend Humphrey does, but if it were me I would check for bulgy or high ESR e-caps. If they seem good I next would check the diodes in the power supply secondary, then go from there.
      If you do not have an Isolation Transformer and know what you are doing, you should take the TV to an experienced repairman before you think about checking anything with the TV powered up.
      Buying Humphreys' e-book on repairing CRT TV's would be a good idea if you have the equipment and knowledge to work on them.

  9. benson

    January 5, 2018 at 6:51 pm

    where exactly do you under
    take your repairs ihave a32inch sony tv which is keeping on rebooting

    • Humphrey Mndaka

      January 8, 2018 at 2:45 pm

      Hi Benson, this can be sorted by actual troubleshooting since the symptom does not point to any circuit...but could be something sorted/overload.

      Regards Humphrey

  10. Parasuraman S

    January 5, 2018 at 9:34 pm

    Excellent work! Thanks for sharing!

    • Humphrey Mndaka

      January 8, 2018 at 2:55 pm

      Thank you my friend Parasuraman

      Regards Humphrey

  11. Amir Mukhtar Ashrafi

    January 8, 2018 at 2:22 pm

    Thanks you Sir Jestine for Technical Web Portal to Learn Experts solutions.

    Also, Credit Goes to Mr. Humphrey Kimathi for share knowledge and work done.

    thansk you
    Amir Mukhtar Ashrafi

    • Humphrey Kimathi

      January 9, 2018 at 10:30 pm

      Thanks for the credits my friend Amir.
      All the best

      Regards Humphrey

  12. Joshua oloo

    January 9, 2018 at 8:36 pm

    Thanks Mr.Humphrey for the article.keep it up.

    • Humphrey Mndaka

      January 11, 2018 at 7:15 pm

      Thanks and welcome Mr. Oloo.

      Regards Humphrey

  13. Dennis

    January 11, 2018 at 9:53 am

    Hi, my name is Dennis I am just starting in this electronics repair so my skills are not that sharp plz forgive. I have a 21" Samsung CRT TV which has no display, sound is ok. I have checked almost everything, from B+ = 180v, heater filament is glowing, supply to vertical IC (LA78040) is +/- 14.5v but the h-out from a TDA935.. series microprocessor is 0.7v. The challenge I don't have an oscilloscope to check the signals. Help me I am stuck

    • Humphrey Mndaka

      January 11, 2018 at 7:14 pm

      Hi Dennis, in your case i strongly recommend you invest on CRT television troubleshooting guide/CRT tv repair course sold on this website so that you can improve on your troubleshooting skills.
      Regards Humphrey


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