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 17 January 2019

PHILIPS 26HFL4372D LCD TV SMPS SCHEMATIC - 715G3860 PSU

Philips 26HFL4372D LCD TV SMPS schematic - 715G3860 PSU

715G3860 PSU schematic - 26 inch Philips LCD TV 26HFL 4372D

Used ICs: FAN7529MX [SMPS control], STP20NM60FP [FET], L6599DTR
Power Supply Unit
Before checking other parts first check whether fuse on the PSU is not broken. Always replace a defective fuse with one with the correct specifications! This part is available in the regular market.
The output voltages to the chassis are:
* +3V3-STANDBY (Stand-by mode only)
* +12V (on-mode)
* +Vsnd (+24V) (audio power) (on-mode)
* +24V (iBoard power) (on-mode)
* Output to the display; in case of
- IPB: High voltage to the LCD panel
- PSL and PSLS (LED-driver outputs)
- PSDL (high frequent) AC-current.
The diversity in power supply units is mainly determined by the diversity in screen sizes.
The on-board DC/DC converters deliver the following voltages (depending on set execution)
* +3V3-STANDBY, permanent voltage for the Stand-by controller, LED/IR receiver and controls; connector 1M95 pin 1
* +12V, input from the power supply for TV550 common (active mode); connector 1M95 pins 6, 7 and 8
* +24V, input from the power supply for DVB-S2 (in active mode); connector 1M09 pins 1 and 2
* +1V1, core voltage supply for PNX85500; has to be started up first and switched "off" last (diagram B03B)
* +1V2, supply voltage for analogue blocks inside PNX85500
* +1V8, supply voltage for DDR2 
* +2V5, supply voltage for analogue blocks inside PNX85500 (see diagram B03E)
* +3V3, general supply voltage (diagram B03E)
* +5V, supply voltage for USB and CAM 
* +5V-TUN, supply voltage for tuner 
* +V-LNB, input voltage for LNB supply IC (item no. 7T50)
* +5V-DVBS, input intermediate supply voltage for DVB-S2 
* +3V3-DVBS, clean voltage for silicon tuner and DVB-S2 channel decoder
* +2V5-DVBS, clean voltage for DVB-S2 channel decoder
* +1V-DVBS, core voltage for DVB-S2 channel decoder.
A +12 V under-voltage detector (see diagram) enables the 12V to 3.3V and 12V to 5V DC/DC converters via the ENABLE-3V3-5V line, and the 12V to 1.8V DC/DC converter via the ENABLE-1V8 line. DETECT2 is the signal going to the Stand-by microcontroller and ENABLE-3V3n is the signal coming from the Stand-by microcontroller.
SMPS circuit diagram,  PWB component and foil side
Click on the pictures to zoom in
DC/DC Converters
 contains the following linear stabilizers
* +2V5 stabiliser, built around item no. 7UCO
* +5V-TUN stabilizer, built around items no. 7UA6 and 7UA7
* +1V2 stabiliser, built around items no. 7UA3 and 7UA4
 contains the DVB-S2-related DC/DC converters and -stabilizers
* a +24V under-voltage detection circuitry is built around item no. 7T04
* the switching frequency of the 24 to 14...20V switched mode converter is 350 kHz (item no. 7T03 and +V-LNB lines)
* the output signal on the +V-LNB line goes to the LNBH23Q (item no. 7T50)
* the LNBH23Q (item no. 7T50) sends a feedback signal via the V0-CNTRL line
* the switching frequency of the +5V-DVBS to +1-DVBS switched mode converter is 900 kHz (item no. 7T00)
* a delay line for the +2V5-DVBS and +1V-DVBS lines is created with item no. 3T03 (R=10k) and 2T06 (C=100n)
* a 3.3V to 2.5V linear stabiliser is built around item no. 7T01
* a 5V to 3.3V linear stabiliser is built around item no. 7T02
contains the DVB-S2 LNB supply
* the +V-LNB signal comes from item no. 7T03
* the V0-CTRL signal goes to item no. 7T03
* the LNB-RF1 goes to the LNB
Posted By: FRANK at 09:05
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