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 !

Saturday 2 February 2019

SONY STR-K740P - K840P HOW TO RESET, CIRCUIT DIAGRAM - FM STEREO FM-AM RECEIVER

Sony STR-K740P - K840P How to reset, circuit diagram - FM STEREO FM-AM RECEIVER

STR-K740P/K840P is the tuner and the amplifier section in HT-DDW740/DDW840.
ICs used: M61511FP, NJM56500, UPC2581, STK350-230, LC89056W, TORX141(Infrared sensor), TC7WU04F, NJM4565N, AK4527, CXD9617R, 1561LV6416-15T, BR24C16, MB90470(System control)

US Model
Canadian Model
AEP Model
UK Model
E Model
POWER OUTPUT AND TOTAL HARMONIC DISTORTION:
With 8 ohm loads, both channels driven, from 40 – 20,000 Hz; rated 100 watts (STR-K840P only)/80 watts (STR-K740P only) per channel minimum RMS power, with no more than 0.09 % total harmonic distortion from 250 mill watts to rated output (Models of area code U only).
Amplifier section
POWER OUTPUT
Models of area code U, CA
Rated Power Output at Stereo Mode
(8 ohms 40 Hz – 20 kHz, THD 0.09 %)
STR-K840P: 100 W + 100 W
STR-K740P: 80 W + 80 W
Reference Power Output
(8 ohms 1 kHz, THD 0.7 %)
STR-K840P: FRONT1):100 W/ch
CENTER1): 100 W
SURR1): 100 W/ch
STR-K740P: FRONT1): 80 W/ch
CENTER1): 80 W
SURR1): 80 W/ch
Models of area code CEL,CEK
Rated Power Output at Stereo Mode
(8 ohms 1 kHz, THD 0.7 %)
STR-K840P: 100 W + 100 W2)
STR-K740P: 80 W + 80 W2)
Reference Power Output2)
(8 ohms 1 kHz, THD 0.7 %)
STR-K840P: FRONT1): 100 W/ch
CENTER1): 100 W
SURR1): 100 W/ch
STR-K740P: FRONT1): 80 W/ch
CENTER1): 80 W
SURR1): 80 W/ch.
Models of area code AR, SP
Rated Power Output at Stereo Mode
(8 ohms 1 kHz, THD 0.7 %)
STR-K840P: 90 + 90W
CENTER1): 120 W
SURR1): 120 W/ch
Models of other area code
Rated Power Output at Stereo Mode
(8 ohms 1 kHz, THD 0.7 %)
STR-K840P: 100 W + 100 W2)
STR-K740P: 80 W + 80 W2)
Reference Power Output2)
(8 ohms 1 kHz, THD 10 %)
STR-K840P: FRONT1): 120 W/ch
CENTER1): 120 W
SURR1): 120 W/ch
STR-K740P: FRONT1): 100 W/ch
CENTER1): 100 W
SURR1): 100 W/ch
Main board circuit diagram [Click on the circuit diagrams to magnify]
Digital board circuit diagram
Power & Standby circuit
Tuner reset
You can change the AM tuning scale to 9 KHz or 10 KHz.  After tuning in any AM station turn off the receiver.  Hold down the Preset tuning + and – ve together.
All preset stations will be erased when you change the tuning scale. To reset the scale to 10 kHz (or 9 kHz), repeat the procedure.
Factory preset mode
All preset contents are reset to the default setting:
While depressing the Video-1 and the 2CH buttons simultaneously, press the Power button to turn ON the main power.
The message FACTORY appears and switch OFF the set.
While depressing the Video-1 and the 2CH buttons simultaneously, press the Power button once more.
The message FACTORY appears and the present contents are reset to the default values.
AUTO BETICAL MODE
* This mode is installed in the Europe models only. When this mode is used, the receiver scans the broadcasts that can be received by
the tuner, and sets up the broadcasts. Be sure to start scanning after connecting the antenna.
Check that the antenna is connected.
Press the Power button to turn ON power, while pressing the Memory button.
The message AUTO-BETICAL SELECT appears and the receiver starts scanning.