REPAIRING AND NOT THROWING AWAY

REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

©2010, 2011, 2012, 2013, 2014 Frank Sharp - You do not have permission to copy photos and words from this blog, and any content may be never used it for auctions or commercial purposes, however feel free to post anything you see here with a courtesy link back, btw a link to the original post here , is mandatory.
All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Thursday, 28 February 2019

SONY – KV20M - KV20S - TRINITRON COLOR TVS - STANDBY LIGHT BLINKS TWO TIMES

SONY – KV20M - KV20S - Trinitron Color TVs - Standby light Blinks Two Times

    KV21MB - KV21ME - KV21SB - KV21SE SERIES Sony TRINTRON TVs NO SWITCH-ON.  STANDBY LIGHT BLINKS TWO TIMES
Two blinks of standby light with this model Sony sets indicates B+ over voltage.  That is, 130VDC from the secondary winding of the SMPS transformer supplied to LOT [Line Output Trnsfomer, or Flyback Transformer] has exceeded the predetermined 130 VDC, by some other fault to power regulator section.

    Before doing anything, just check for any loose soldering points on the power supply regulator section.  Check all the soldering of Hi-Watt resistors, which will heat up during working.  Repeated heating and cooling may make its solder terminals to get loose contacted.  Normally, these loose contacts are very difficult to detect without the help a magnifying glass.  Best to do is, to resolder all suspected solder points by applying a little more solder, without making any solder bridge short in between adjacent solder terminals.  There will be very close solder points, which can be make shorted when we resolder them. Take so much care when you do this, as this is the main power regulator section, and if any short when we resolder, will make damage to regulator devices fitted with.

    Resolder all the 8 solder terminals of [T604] first. Resolder all the 5 solder terminals of [IC601; power converter].  Check the solder terminals of this IC.  The main chance for poor power regulation may lie with the loose solder points to this power converter IC.  It will heat up considerably more than any other component, as it dissipates much power by it while it works.

    It is advised to replace the error amplifier IC too [IC602 –UPC1093J-I-T]. This is the IC that controls the regulated output voltage.  It is a three solder terminal IC, usually look like a transistor. Replace electrolytic capacitor [C646 – I0UF 450V].  Replace the Zener diode [D637 – 6.2V]. In most cases these must solve the problem.

    Check the voltage at [TP600] with respect to negative.  In short, check the voltage across [C634].  This is the main 130VDC rail that feeds the LOT of the set.  This voltage is generated between winding terminals 14 & 15 of T603.

    Be very careful while working with this section; especially when you work with power ON condition to take the voltages at different points.  Use of a hand glove is recommended when you work with power section. Never allow children to be near you while you work with this section, especially when working with any electrical equipment.  Be an adult to be by your side as precautionary measure.
Posted By: FRANK at 02:46
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