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Fixing ES China Kit in CRT TV
The following conversation with Mr. Albert van Bemmelen when commenting on my previous article, http://jestineyong.com/grundig-tv-repair-tips-china-kit-and-rejuvenation/ is the reason for writing this special article on Fixing ES China Kit.
Albert van Bemmelen August 20, 2016 at 4:13 am : As soon I read the title of your repair I knew it could only be from one person. Indeed very nice detailed TV CRT picture! Again well done although I not really know what Board or Tools you exactly used to do that. Like the China made Kit ES Board you mentioned? So this repair still is something I myself therefore would not undertake. Too many unclear proceedings remain.
Parasuraman August 22, 2016 at 10:10 am : I shall address replacement of PCB in another separate article with pictures and DOs & DON’Ts. Kindly wait.
Albert van Bemmelen August 23, 2016 at 4:47 am : Thank you dear Parasuraman Subramanian. I will, and look forward to that !
Since CRT TVs have gone out of the market for quite some years now, and the manufacturers of these TVs have either closed down or switched over to latest LCD/LED TVs, getting replacement of defective components is extremely difficult. In other cases, the board would have become so bad due to several repairs done that reviving it would not be economically viable. If major costly components like the SMPS, FBT (LOT) etc. are to be replaced, the cost will come to almost near to the cost of a new kit!
If the µController is defective, which can happen in lightning cases, getting a replacement is almost impossible. The ES Boards are introduced by China a few years back to give new life to the good old CRT TVs, the tubes of which are still in excellent condition. Some of these TVs have been working for even 20 years! The ES boards are available in two types, one for using in 14” to 24” TVs and another for use in 26” to 29”. Let us now see the board of the first type. The following are the pictures of the main board and CRT board and the mounting base of the main board:
Following are the pictures of what comes with the kit (1) Remote Control without battery (2) Mains Cord (3) Front Panel Control (4) AV in for rear fitting (5) Two pair wires with two pin connectors for speaker connections (6) Yoke Connector with wires, with separate horizontal connector.
The positions where the connectors go into the board are (1) Front Panel has two connectors, one 4 pin and another 2 pin and these goes to XS702 and XS701 at the front side of the PCB (2) The Power cord goes to XS501 and the Degaussing coil has to be connected to XS502. No connector comes for that. We need to connect the existing connector of the CRT on to this. Sometimes it might be necessary to split the connector into two for insertion on this or even solder it. (3) The AV in for fitting on the rear cover has to go to XS800 just behind the AV RC sockets already fit on the board. (4) We need to buy an extension RF connector for the tuner as shown below, which should be fit on the rear cover and inserted to the Tuner while fixing the back cover.
In the earlier times, the kits were coming with Degaussing Coil connector with wires, CRT Earth wire with spring and also the above RF Extension cord. But nowadays, these are missing in the kit. Either the smart dealers are removing it for sale separately to make more money or the suppliers have eliminated it on getting market feedback, to make the kit competitively priced. It is also a practice by manufacturers to reduce accessories, dimensions, weight etc. instead of increasing the prices. This could be one such! Anyhow, let us continue on our subject….
The yoke connection has two separate connectors, one for vertical and another single one for horizontal. The horizontal connection is made separate in order to select the appropriate pins on the board to increase the horizontal width depending on the size of the CRT. Just see the connectors on the board and its connections under the board:
From the bottom view of the PCB, you will notice that the horizontal connection is linked to 3rd pin of XS404 near the FBT (LOT). According to the size of the CRT, we may have to change the positions of this to 1st, 2nd, 4th or 5th. For a 21” TV, the 3rd pin is ok. But sometimes, due to the design of the yoke or wearing out, it might be necessary to change the position.The width is adjusted by additional windings provided inside the FBT to adjust the frequency of oscillation. We must appreciate the Chinese brain for their innovative ideas and technological advancement and improvisations, at the same time, making it affordable!
The CRT base comes with CRT socket suitable for thick neck. But if the TV in which the replacement of the board is being done has thin neck, we need to buy a suitable socket, remove the thick one and replace it in the place provided on the board. Just see the connections:
Since the inside connections are different between thick and thin neck Tubes, the track is laid in appropriate positions. For example, the first pin (as you view it in clockwise direction) has no connection in thick, but that is blue for thin neck, so is linked to pin 6 etc. This is another brilliant design arrangement!
Lastly, the kit has one schematic with it, and may or may not match with the board!
Advantages of new board (to list a few):
(1) Very compact and universal, and might suit most of the old TVs.
(2) Comes with remote and advanced features.
(3) Parts are easily available and very economically priced.
(4) Connections are made as simple and easy as possible.
(5) It is easier and takes less time than it requires to trouble shoot an old board, fetch replacements and take risks associated with it.
(6) The TV gets new life and can last for more time.
(7) Comes with a 6 months’ warranty. (Some dealers do not pass it on!)
Disadvantages (to list a few):
- The quality of picture may not be the same like the original board; that is for sure!
- Fitting the new board requires cutting, drilling, shaving and a lot of manipulations on the cabinet of the old TV.
- The front panel has to be fixed out projecting and may not match with the cabinet.
- Earlier the board was coming with stereo audio IC, but now it comes with mono with two connections from the same output! (another compromise)
- The new board has to be retouched all over, as the soldering is so thin and might develop dry solders within weeks.
- Some of the components like the Rectifier diodes and Filter Tank Capacitor in the primary might have to be changed, because of poor quality.
- The board uses a two legged PTC which looks like a Ceramic Capacitor instead of the three legged coil cum thermal cut off resistor. As a result the board can withstand only upto around 240V. Any fluctuation beyond that will blow this out, along with some other components as well!
- All the features available in the original board may not be available in this. For example, sound quality selections and graphic equalizer etc. may not match. So are the special video features.
- If the on/off switch is on the board in the old TV, we may not be able to fix the new cord with its switch. So, we may have to leave it as dummy on the front panel and customer may have to use the mains on/off near the plug outlet! Then we may have to either cut the switch off from the cord and directly solder or keep the switch pressed and connect.
- The board comes only with one AV in. The AV out cannot be used as it is on the board unless we provide a separate connection for it ourselves.
Fixing the board:
Sequence to be followed (1) Fix Control Panel, which has Remote Sensor in front of the TV (2) Check whether the on/off switch that comes in the cord can be fixed somewhere in the front panel of cabinet. If not, that has to be made a dummy. (3) Look for any audio/video in or out sockets fixed at the sides or rear of the cabinet. If so these can be wired in. (4) Fix RC sockets of Audio/Video in at the rear cabinet or wire these if already available. (5) Fixing board inside the cabinet (6) Connect the board to CRT.
(1) Fixing the Control Panel: The key control panel, which has the remote sensor in it, may have to be located at the front side of the cabinet, under the door if there is one or in such other place without spoiling the look of the TV. There has to be a hole for running the connector cable of the control panel, preferably covered by the panel itself. Then, we may have to peel off the sticker from both sides of the control panel to expose the screw hole and provide screws of desired length and fix it. It will be a good idea to keep the control panel in position, mark the holes using a sketch pen, and then drill the cabinet using a down sized drill bit, so that we can use a self-threading wood screw to fix the panel. After fixing this and routing the connecting wires inside, gently rub the sticker back to its position, which will cover the screw holes. But before that, please ensure that your fingers are clean; otherwise you are likely to leave an indelible mark of dirt on it! (There is a protective transparent sheet stuck on it, to avoid scratches. If there is dirt mark that can be easily removed.)
(2) Fixing on/off switch: If this can be fixed on to the front panel, it can be placed to synchronise with its button. Otherwise, the on/off switch has to be removed and connector directly soldered to the cord. This is always depending on the set and switch positions and we have to use our common sense and expertise.
(3) Fixing AV In: Look for any audio/video in or out already there on the cabinet sides or rear. Then either wire these in or fix the supplied AV in socket in the place provided.
(4) Fixing AV in/RF Socket at Rear Cabinet: Locate the RF socket next to the AV in giving sufficient space for connecting the input cables with fingers.
(5) Fixing the board: The board has to be housed firmly on the inside bottom of the cabinet, and we should be able to fix the back cover with its interlocking properly. The board should not be too close to the back of the CRT, which is ground, and B+++ Red thick wire from the FBT that goes to the anode of the CRT should be away from it and should not be too close to any other wire. For this purpose, we may sometimes have to remove the base of the Board that comes in the kit, and Fix the PCB on the cabinet with screws. It might also become necessary to remove some of the projections on the front side of the cabinet. The bottom of the PCB should have some space for ventilation. It might, therefore, become necessary sometimes to provide a socket (a plastic separator) underneath on the screw to hold it high. Then fix the back cover and check whether any portion of the PCB is projecting out because of which, the rear cover will not lock in properly. If the PCB can be fixed a little further into the front cabinet, following the guidelines given above, it can be done or we may have to cut and remove the projections from the rear cover. From my experience, some of these moulded projections/slots or protuberance can be removed by bending with a player. The materials used in CRT TVs are generally a bit flexible and might not crack, unless it has become solid hard due to ageing.
(6) Connecting Board to CRT: This is now very easy, as we have fixed all boards and accessories. Replace CRT socket if necessary from thick to thin. First discharge the Tube from the Anode to ground using a thick wire. I suggest wearing gloves if it is a humid area. Keep the main board inserted into the specified area, Solder speaker wires on the speakers or if these have separate two pin connectors, you can use that. Then insert the connector in its sockets. Insert the control panel connectors. Insert the Degaussing Coil and mains cord connectors in its sockets. Then insert the anode wire and cap firmly in and press with fingers around it to release trapped air and to enable vacuum hold. The anode wire should be free and away from the back of the CRT as well as other wires to avoid arcing. If the old board had a round plastic anode wire separator, you can use that. If not, use a small plastic lid, make a hole in the centre for housing this wire, cut in to the centre and insert this wire, place it on the back of the CRT. This is to make the wire stand away from arcing areas. Insert the CRT socket at the rear of the Tube firmly, but gently, without causing any twist of the arm or applying too much of pressure. This portion of CRT is very brittle. So, it should be done very carefully. Solder the earth wire or insert the single connector that comes from the earth wire wrapped behind the CRT in the appropriate place in the CRT PCB. Insert the AV in extension if it is on the side.
Recheck all connections and specially ensure that the CRT earth wire is in its place and the anode cap is locked in properly. Decrease the Screen and Focus controls on the FBT to minimum. Put batteries inside the Remote and keep it ready. Keep the front of the TV in view and stand on side, a hand length away to reach the screen control. Switch on the TV. Wait for filament glow at the neck of CRT. If the filament is not glowing, use the power on from the remote. Once you notice filament glowing, press menu on the remote and slowly adjust the screen voltage using a small screw driver, until image is seen. Select AV mode. Select settings and decrease the brightness and contrast to minimum. The raster on the TV should be dark and no image should be visible. If it is visible or if you see the tube is glowing, decrease the screen voltage until it is completely dark. Then slowly increase brightness and contrast to see a fairly good picture of the Menu. Adjust the focus control on FBT for a fine and sharp image. Connect any audio/video input and repeat the focus adjustment. (Kindly view my earlier articles on CRT repair to know more about board replacement, one link given at the top of this article and another: http://jestineyong.com/transplanting-keys-in-crt-tv-repair-model-supra-st21k33f/ )
Entering service mode: Adjustment of vertical height or any other deformities, including basic sound setting is possible in this mode. Press into the small hole in the remote control at the bottom with a tip of pen or pencil. (Unfortunately I forgot to take a close shot of this)
You will find a lot of settings coming on the screen (Adjust these only if you know fairly well about horizontal/vertical alignment. It is always a good idea to take a snap of each setting so that you can return to the original values, if you get lost). By doing experiments, you can learn what changes it does to learn it practically. (I am yet to learn all those appearing there). To change to next menu, either press the button again or press ‘mute’ button on the remote. Following are the menus and its original values that I have saved once. It may vary from kit to kit. (I am not fully aware of the explanation and/or function of the nomenclatures used)
Please visit the following site for a different kit: http://electronicshelponline.blogspot.in/2012/05/how-to-enter-service-mode-to-chinese-tv_23.html
Inter actions with the customer: Before changing the board, educate the customer about the advantages and disadvantages. Check whether they have a Power Transformer near their house or in the premises, if they are living in a flat. If that is the case, unless it is auto adjusting transformer, it will increase the voltage to as high as 270V, where there is no load. If that is the case, advise the customer to buy a Bucking Voltage Stabilizer of good quality.
After all adjustments are over, re-do the screen voltage and focus adjustment as described above. I hope I have covered all important points.
While writing it down, there are many steps, but when you do it practically, these are very simple to do. So, never look aghast by reading all these! The job is very simple and any person with basic knowledge of CRT repair can easily do it!
All the best! (I am approaching the ES Company to part me a portion of their profit on increase of purchase due to this article – LOL)
This article was prepared for you by Parasuraman Subramanian from India. He is 68 years old and has more than 30 years’ experience in handling antique equipment like Valve Radio, Amps, Reel Tape Recorders and currently studying latest tech-classes conducted by Kerala State Electronics Technicians’ Association. He has done graduation in BBA degree, private diploma in Radio Engineering and retired as MD of a USA company. Presently working as Consultant to Hospital and other institutions.
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