Color television receiver Samsung CL15K5MNFX/XAP – Schematic, Service mode adjustments

K15D Chassis, CL15K5MNFX/XAP Model – How to enter the factory mode, adjustments, Schematic

Factory Mode
1. Do not attempt these adjustments in the Video Mode.
2. The Factory Mode adjustments are necessary when either the EEPROM (IC902) or the CRT is replaced.
3. Do not tamper with the “Adjustment” screen of the Factory Mode menu. This screen is intended only for factory use.
 When EEPROM (IC902) Is Replaced
1. When IC902 is replaced all adjustment data revert to initial values. It is necessary to re-program this data.
2. After IC902 is replaced, warm up the TV for 10 seconds.

When CRT Is Replaced
1. Make the following adjustments AFTER setting up after setting up purity and convergence
White Balance
Sub-Brightness
Vertical Center
Vertical Size
Horizontal Size
Fail Safe (This adjustment must be the last step).
2. If the EEPROM or CRT is replaced and set SC as 20(factory mode).

Procedure for the “Adjustment” Mode

This mode uses the standard remote control.
The Service Mode is activated by entering the following remote-control sequence 
(1) DISPLAY > FACTORY.
(2) STAND-BY >MUTE >1 >8 >2 >POWER ON.
2. The “SERVICE (FACTORY)” message will be displayed. The Service Mode has four components: ADJUST, OPTION , G2-ADJUST and RESET.
3. Access the Adjustment Mode by pressing the
“VOLUME” keys ( Up or Down). The adjustment parameters are listed in the accompanying table, and selected by pressing the CHANNEL keys Up/Dn.

4. Selection sequences for the all system:
DOWN or UP key:
SCT>SBT>BLR>BLB>RG>GG>BG>VSL>VS>VA>HS>SC>CDL>STT>AKB>FS>NDL>LBS>NSR>SCBT>VOL>CAP>HBS>RP00>RP01>FMWS>AGC1>OMD>SCL>PWL>
MUS>AGC>DSK>DVDB
5. The VOLUME keys increase or decrease the adjustment values (stored in the non-volatile memory) when Adjustment Mode is cancelled.
6. Cancel the Adjustment Mode by re-pressing the “FACTORY” or “Power OFF” keys.

Cathode Voltage Adjustment (Screen Adjustment)
1. Connect CRT socket pin GK to an oscilloscope probe.
2. Input a gray scale pattern. (Use a pattern generator, PM5518)
3. Use the P mode key (on the remote control) for the STANDARD picture.
4. Adjust the Screen VR (on the FBT) so that the voltage on the oscilloscope becomes 125+2.5V

White Balance Adjustment

Warm up the TV for at least 30 minutes in the
Aging Mode (OSD White). This mode is displayed by entering the following sequence:
DISPLAY →FACTORY → FACTORY
2. Input a Toshiba pattern.
(b) Low-Light Adjustment
1. Set SBT to 1.2 fL in the Factory Service
Mode with using CA100.
2. Adjust RG,BG so that the levels are suitable to each local area.
(c) High-Light Adjustment
1. Set SCT to 50FL(13V : 60FL) in the Factory Service Mode with using CA100.

Schematic full

HOME AUDIO SYSTEM Sony MHC-V44D disassembly procedure, SMPS troubleshooting table

Speaker system

3-way, Sound Pressure Horn

Speaker unit

Tweeter L/R: 40 mm, cone type

Midrange L/R: 80 mm, cone type

Woofer: 200 mm, cone type

Rated impedance

Tweeter L/R: 4 ohms

Midrange L/R: 4 ohms

Woofer: 2 ohms

  The laser diode in the optical pick-up block may suffer electrostatic break-down because of the potential difference generated by the charged electrostatic load, etc. on clothing and the human body.
  During repair, pay attention to electrostatic break-down and also use the procedure in the printed matter which is included in the repair parts.
The flexible board is easily damaged and should be handled with care.

The laser beam on this model is concentrated so as to be focused on the disc reflective surface by the objective lens in the optical pickup block. Therefore, when checking the laser diode emission, observe from more than 30 cm away from the objective lens.

If “protectx” (x is a number) appears in the display panel
Immediately unplug the AC power cord (mains lead), and check the following items.
• Is anything blocking the ventilation holes of the unit?
• Is the USB port short-circuited?
After checking the above items and fixing any problems, plug in the AC power cord (mains lead) again and turn on the system.

Releasing the disc tray lock
The disc tray lock function for the anti-theft of an demonstration disc in the store is equipped.

Releasing Procedure:
1. Press Power button to turn the power on.
2. Press the [FUNCTION] button until the message “DVD/CD” is displayed.
3. Press the [ENTER] button and [VOCAL FADER] button simultaneously and hold down for around 3 seconds.
4. The message “UNLOCKED” is displayed and the disc tray is unlocked.
Note: When “LOCKED” is displayed, the slot lock is not released by turning power on/off with the Power button.

Note of replacing the ic2002 and ic2003 on the damp board and the complete damp board
When IC2002 and IC2003 on the DAMP board and the complete DAMP board are replaced, it is necessary to spread the compound between parts and heat sink.

How to open the tray when power switch turn off
Note 1: After the side panel and top panel are removed, this work is done.
Note 2: Prepare the thin wire (clip etc. processed to the length of 8 cm or more).

Disassembly 

Back panel section

Front panel disassembly

Speaker disassembly

Optical device disassembly

SMPS board diagnosis

ROTEL RA 980BX STEREO AMPLIFIER REPAIR ASSISTANCE

Fault: No output from left channel. The right Channel is working fine.

Added some photos and circuit for reference  

While testing the amp noticed that the left channel is giving switch on off thump while powering ON and OFF the amplifier. It happens when there is DC voltage flow through the speakers. It shouldn't be there. And the thump is there only on the left channel. While testing the amplifier section found that all the transistors where idling at mentioned voltage. All Base pins where around +/- 0.5volt. and the output is almost 0.012mvdc.

As the amplifier had an external Pre -IN, Pre -out coupling it was easy to use an external pre amp to test the amplifier section.

 While testing with an external pre amp found that the amplifier section is OK. There were no switch off thump too while working through the external pre amp.

After testing the amplifier stage and confirming it is OK, turn to the next stage. The internal pre amp (tone control) section.

The internal pre amp of Rotel RA 9808X is built with two AD712JN ICs. Where each AD712 is used for the left and right channel separately. Hope Rotel did it to reduce the bleeding between the left and right channel. Its possible to reduce the bleeding between two channels. If we use two op amps separately for each channels than using the half of each.

While testing the pre amplifier it is found that there was a DC voltage of 15V at the pin no 7 (output pin) of one of the AD712 which is used for the left channel. It shouldn’t be there. The output, non inverting and inverting pins of an op amp which is used in the tone stage circuit should be at 0vdc ,if it’s working in dual supply rail (+/- supply).  And there was no voltage found on the pin 7 of other AD712 which is used for the right channel.  While further treating found that the supply voltages to AD712 where ok its there it +/- 17.5V.  

As there was nothing else to check, replace the AD712 with a new one. Then power the amplifier and found that it’s working perfectly. There were no voltages where found on the pin no 7. And also there were no switch of thump too. Also replaced the power filter capacitor and coupling capacitors near the AD712 of each channel as it is found bad.

If AD712 is not available then Instead of AD712 you can use TLO82. It is an equivalent to AD712. Or you can use NE4558 , it will work too but  there will be some difference in frequency response of the amplifier, but not that much noticeable. If your customer is not an audiophile then it’s ok.  

Circuit diagram of ROTEL RA 980BX

TONE 1/2

TONE 2/2

POWER AMP 1/2

POWER AMP 2/2

Power amplifier bias adjust

Prior to adjustment run the amplifier for about 5 minutes with load resistance of 8ohms

SETP	PLUS LEAD	MINUS LEAD	ADJUST	ADJUST FOR
1	TP3	TP1	VR601	DC MILLIVLOT 10mv
2	TP4	TP2	VR602