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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Thursday 26 March 2020

REPAIR / SERVICING TV TOSHIBA 22DV704R

Technical description and composition of the TOSHIBA 22DV704R TV, type of panel and applicable modules. The composition of the modules.
Toshiba
Model: 22DV704R
Chassis / Version: GRU2 WISTRON
Panel: V216B1-L04 79105088 // V216B1-L02 75016438
Inverter (backlight): integrated into PSU
PWM Inverter: OZ9938GN
MOSFET Inverter: 4511GH (5)
Trans Inverter: TNS94481CT (TMS92903CT)
Power Supply (PSU): DPS-65TP-3 A, REV: 00, GAT 75019625 PC BOARD ASSY, POWER, 65W
PWM Power: 6742MR (8)
MOSFET Power: K4101
MainBoard: GRU2 15 19 22 75019667 PC BOARD ASSY
IC MainBoard: 75019668 DVD-RW DRIVE UNIT, HH SLOT, DAV-RR953WR, RUSS
Tuner: TDTC-G429D
Control: SE-R0337
Technical Specifications 22DV704
TOSHIBA 22DV704R
General recommendations for repairing TV LCD
Any repair of electronic equipment begins with an external inspection of the device and diagnostics of the malfunction. In this case, you should visually carefully examine all the elements of the TOSHIBA 22DV704R TV, both internal and external. Often, for certain external signs, the repairman can draw some conclusions about the reasons for the failure of certain elements of the circuit even before the necessary measurements are made, which will determine the further algorithm for troubleshooting and localizing the defect. Elements with visible damage, for example, capacitors swelled up after boiling the electrolyte, charred resistors in certain nodes of the circuit, as well as ring cracks in solders will help the master to guess the causes and possible consequences of the malfunction.
If the TV does not turn on, no indicators on its front panel are lit or blinking. Also, if the TV does not respond to the remote control and buttons, does not make any sounds or any signs of operability when turned on, there is a certain chance that the power supply module DPS-65TP-3A, REV: 00, GAT 75019625 PC BOARD ASSY, POWER, 65W is faulty and he needs repairs. Sometimes with similar manifestations a problem can only occur in the absence of processor power, but this happens much less often. In this case, first of all, it is necessary to check the fuse at the input of the network. If it is broken, then you should check for breakdown of the PN junctions of the rectifier bridge diodes and the key transistor of the N-FET converter, which can either be on a separate radiator or integrated with a PWM controller in a common chip. K4101 variants are possible.
Power switches in flyback converters fail extremely rarely for no reason and, if they are broken, it is necessary to look for a malfunction in the stabilization circuits by checking electrolytic capacitors, semiconductor devices, and resistors in the primary circuit. The cause may be a malfunction of the 6742MR PWM controller chip (8), which can only be checked by replacing it with a new or obviously working one.
When using the Active Power Factor Correction (CMC) circuitry in the power module, the search for faulty elements is somewhat more complicated.
In cases where the TOSHIBA 22DV704R TV has lost an image, and the sound is there and all other functions are operational, there is a possibility of an inverter (converter for powering the backlight) malfunction. When you turn on the TV, the image may appear briefly and immediately disappear. It must be borne in mind that with such manifestations, the lamps themselves also fail, the malfunction of which can be detected by replacement, by connecting to the connectors for diagnostics that are known to be serviceable and suitable in power.
Diagnostics of the inverter 75019625 PC BOARD ASSY, POWER, 65W, DPS-65TP-3A, REV: 00, GAT can be difficult due to the operation of the protection, which is organized by the designers to prevent negative consequences or fires in emergency cases, for example, during short circuits or breaks in lamp power supply, as well as their possible depressurization. To make the necessary measurements at control points or to take the necessary waveforms, repairmen have to block the protection circuits in order to be able to diagnose.
In such cases, the risk of failure of the power elements of the inverter is most likely, and special care is required during work, and after their completion, it is necessary to restore the protection circuit for further safe operation of the TV by the owner in normal mode.
Repair or diagnostics of the motherboard 75019667 PC BOARD ASSY, MAIN, GRU2 15 19 22 // you need to start by checking the power stabilizers. If necessary, you should update the software (software). Board repair and chip replacement 75019668 DVD-RW DRIVE UNIT, HH SLOT, DAV-RR953WR, RUSS are made with the necessary equipment, and the corresponding hardware base.
Once again, remind users! Attempts to independently repair the TOSHIBA 22DV704R TV without the appropriate qualifications and experience can lead to its complete non-repairability!

SCHEMATIC DIAGRAM  / SERVICE MANUAL   ------------------>    Toshiba 15DV703R, Toshiba 19DV703R, Toshiba 19DV704R, Toshiba 22DV703R, Toshiba 22DV704R, Toshiba 26DV703R, Toshiba 32DV703R
 Service Manuals with Schematic Diagrams 93 pages of 2010 on models 15DV703R, 19DV703R, 19DV704R, 22DV703R, 22DV704R, 26DV703R, 32DV703R.


The appearance of MainBoard GRU2 is shown in the figure below:
GRU2
GRU2 can be used in TVs:
TOSHIBA 15DV703R 15DV704R (Panel M156B1-L02 RevC1 79104859), TOSHIBA 15SLDT3R (Panel M156B1-L02 Rev.C1), TOSHIBA 19DV703R (Panel M185XW01 V2), TOSHIBA 22DV703R (Panel V216B1-L04 Rev C1 (L02 Rev C1)), TOSHIBA 22DV704R (Panel V216B1-L04 79105088), TOSHIBA 32DV703R 32DV704R (Panel T315XW04 V.1 79105169 ).
The appearance of the power supply
Main features of the TOSHIBA 22DV704R device:
Installed matrix (LCD panel) V216B1-L04 79105088 or V216B1-L02 75016438.
To power the backlight, a converter is used, combined with a power supply, controlled by the OZ9938GN PWM controller. The transformer TNS94481CT (TMS92903CT) is installed in the inverter converter. As power elements of the inverter, keys of the type 4511GH (5) are used.
The necessary supply voltages for all nodes of the TOSHIBA 22DV704R TV are generated by the DPS-65TP-3 power supply module or its analogs using 6742MR microcircuits (8) and K4101 type power switches.
MainBoard - the main board (motherboard) is a GRU2 module, using chips 75019668 DVD-RW DRIVE UNIT, HH SLOT, DAV-RR953WR, RUSS and others.
The TDTC-G429D tuner provides TV reception and channel tuning.
Additional technical information about the panel:
Brand: CHIMEI INNOLUX
Model: V216B1-L04
Type: a-Si TFT-LCD, Panel
Diagonal size: 21.6 inch
Resolution: 1366x768, WXGA
Display Mode: TN, Normally White, Transmissive
Active Area: 477.417x268.416 mm
Surface: Antiglare (Haze 25%), Hard coating (3H)
Brightness: 400 cd / m²
Contrast Ratio: 800: 1
Display Colors: 16.7M (6-bit + Hi-FRC), CIE1931 72%
Response Time: 1.3 / 3.7 (Tr / Td)
Frequency: 60Hz
Lamp Type: 4 pcs CCFL Without Driver
Signal Interface: LVDS (1 ch, 8-bit), 30 pins
Voltage: 5.0V


 TOSHIBA 22DV704 LCD TV with V216B1-L04 LCD, 22 "(55 cm) diagonal display in 16: 9 format. 400 cd / m² screen brightness is provided by CCFL (EEFL) fluorescent lamps. Maximum brightness to minimum ratio (contrast) ) is 1000: 1. Dynamic contrast ratio of 5000: 1 is achieved by special control of the backlight. You can view images in high quality HD at a resolution of 1366x768 pixels in the standard for graphic decomposition 720p (HD Ready). The input high-frequency or video signal can be processed in analog systems PAL, SECAM, NTSC. Graphic processing and digital signal generation occurs in the standards 480i, 480p, 576i, 576p, 720p, 1080i, 1080p. Supported media file formats: MP3, MPEG4, VideoCD, SVCD, JPEG.
The power of the acoustic system of sound 6 W (2x3 W) provide two speakers. The audio processing system NICAM STEREO is used.
The external interface (communication with other devices) is supported by standard input and output connectors: antenna input (RF), AV, audio x3, component, SCART x2, RGB, VGA, HDMI x2, USB. An output for connecting headphones is provided. To connect a computer or laptop to this TV model, a VGA (D-Sub 15) connector is used on the TV case, this interface supports resolutions: 640x480, 800x600, 1024x768, 1360x768.
The power consumed by the TV in the operating mode from the network is 55 watts.
Overall dimensions: with stand 552x406x215 mm, without stand 552x375x66 mm.
TV Weight: with stand: 6.5 kg, without stand: 5.5 kg.
Attention! The TOSHIBA 22DV704 LCD TV panel V216B1-L04 is its most expensive component.
Avoid hitting the glass and exerting pressure on the screen to avoid permanent damage to the LCD panel!