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!

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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 KV EF29M - CRT TV TROUBLESHOOTING

SONY KV EF29M - CRT TV TROUBLESHOOTING

Fault:  Dead set.
     Check ON/OFF switch, for contact break if any.  If it is OK, check fuse (F1690).  The fuse can be located at [H7] board, just near to the ON/OFF switch.  If found open, never put an other fuse in place, till the reason for the blowing of fuse is detected.
 
     Desolder out the degaussing thermistor (THP 2600).  If this posistor has short inside, fuse will blow up. Check the bridge rectifier and associated components, disc ceramic capacitors [D2600, C2607, C2606] for any short.  Check them with an analogue multimeter set to Kohms range.  If any  reverse leak found, replace that component.  If bridge rectifiers have shorted diodes inside, may cause fuse to blow. Even a single diode inside it has the short, it will cause a blown up fuse, as soon as you switch ON the set.

     If bridge rectifier, and all other related components are found OK, measure the resistance across (C2617 – 560MFD__450VDC).  Set an analogue multimeter to Ohms range and check.  Under no conditions, the meter should read below 500Oms.  If it reads below this range, make sure that the power regulator control IC (IC601_STR S6709N) is faulty.  Resolder this IC out from circuit.  Now check the resistance across C2617.  If found high, STR_S6709 is defective.
 
Before replacing this regulator IC, the other components connected with this IC should be checked. Check these components one by one.  [ R618_0.1Ohms, D603, C603, R604, D601_8.2V ZENER DIODE, and Q600 [2SD1640Q].  It is advised to replace these components, before replacing a shorted STR. Replace the capacitor [C605_100Pf-3KV].  Replace the optocoupler, [IC603_ON3171R] as a precautionary measure.
 
After replacing all these components, disconnect [R886_1.2Ohms 2W], current limiting resistor to LOT, connect a 100W filament bulb in series with the V+ve supply line, and switch ON the set, keep it at this condition for about 10 minutes or so, make sure that the B+ve voltage is steady all the time.
Connect reconnect R886 back, and check the set.

If STR regulator has found defective, never replace it without checking other connected components to it.  Especially, the Zener Diode [D601].  It will get damaged along with the STR, when it gets shorted.  Even though, it may measure good, it is best to replace it along with STR. Any fault to this diode will cause an other STR failure.
All component numbers showed here can be seen printed on either side of the printed circuit board.
Posted By: FRANK at 02:35
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