Master Electronics Repair !

Welcome to Master Electronics Repair! website.Here you will find:Service Modes, Circuit Diagrams,Service manuals, Firmware Update procedure, Disassemble procedure, Universal remote control setup codes, Troubleshooting, Diagnosing, Measuring, and more.... of many of LCD/LED TV/Displays,others various electronic apparates,trough many technical notes and tips/tricks to help repairing/fixing Troubles/ faults,for electrical technicians.This site helps you to save the Earth from electronic waste!

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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Note that if you don't find what you searched for, try it after a period of time; the site is a never ending job !

..............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 30 March 2019

FLUKE 192B _196B-C _199B-C SCOPE-METER SCHEMATIC

FLUKE 192B _196B-C _199B-C Scope-Meter SCHEMATIC

ATTENTION: Never attempt to open this instrument, unless you’re familiar with repairing measuring instruments. This is a very delicate and accurate measuring instrument and somewhat costly too.

BATTERY

Battery operating time is does not meet the specification (4 hours)
1. Turn the ScopeMeter on (battery power only)
2. Check the voltage across R4101 (near the battery connector) for about 140 mV. This corresponds to a current of about 0.95 A. If the current is much higher the cause of the problem is not the battery. Battery is discharged when ScopeMeter is not used for some time (2 or 3 weeks).

1. Turn the ScopeMeter on (battery power only)
2. Check the voltage across R4101 (near the battery connector) for about 0.15 mV. This corresponds to a current of about 1 mA. Turn the ScopeMeter off and on, and check the voltage again for 0.15 mV. Do this about 10 times. If one or more times a current of about 1.2 mV is measured (8 mA), the cause is a defective IC D3550. This IC takes care of a correct power state of D3500. As the 8 mA discharge current can have damaged the battery, you must check the battery capacity as described below.
3. If the current is much higher then 8 mA the cause of the problem is not or is not only D3550

To check if the battery has a correct capacity
1. Do a battery refresh

2. Disconnect the BC190 Battery Charger/Power Adapter
3. Start a TrendPlot: RECORDER
4. When the battery is discharged the ScopeMeter will shut down. Now connect the BC190, turn the power on and check the length of the TrendPlot trace. For a new battery pack this should be about 4 hours. Depending on the number of applied charge cycles the battery capacity will decrease. If the TrendPlot trace has a length of 3 hours or less you may consider to replace the battery pack.

Loading Software
To load a new software version in the test tool contact an authorized Fluke Service center.

ELPLODED VIEW

FLY-BACK CONVERTER

1. Check the fly back converter output voltages +5V2, +3V3GAR (+3.3 V), +3V45, +2V6, -1V8, -5V2 and +30V. Check FLTPOWIN1and FLTPOWIN2 (6.5Vrms, ≈ 70 kHz) on for example T1102 pin 3 and pin 5.

a.If one or more voltages are correct, then check the rectifier diodes, coils, and capacitors of the incorrect voltage (s)
b. If none of the voltages is correct, then the fly back converter does not run correctly, continue at step 2.
2. Check VBATT for >7 V.
3. Check N4000:49 (FLYGATE) for a square wave voltage of at least some volts (for a correct Fly Back Converter 50...100 kHz, ≅8 Vpp). If no square wave is present on N4000:49 go to step 4. If a square wave is present on pin 49 (maybe not the correct value), then check N4000:55 (FLYSENSP) for a saw tooth voltage of 50...100 kHz, 300 mVpp.

a. If no sawtooth voltage is present on N4000:55, no current or a DC current flows in FET V4001. The primary coil of T4001 or V4001 may be defective. Check also R4101 (current sense resistor); it can be fused due to a short in FET V4001.
b. An incorrect sawtooth on N4000:55 can be caused by:
* overloaded outputs (Frequency too low, <<50 kHz)
* underloaded outputs (Frequency too high, >>100 kHz)
* bad FET V4001 (Sawtooth voltage is not linear).
4. Check N4000:62 (PWRONOFF) for >+3V. If wrong, see Section 7.5.13 Power ON/OFF.
5. Check N4000:43 (COSC) for a triangle wave form, 50...100 kHz, +1.6 V to +3.2 V. If wrong check C4123 and connections; check IREF, see step 6.
If all correct, then replace N4000.
6. Check N4000:74 (IREF) for 1.6 V. If wrong:
a. Check N4000:73 (REFPWM2) for +3V3. REFPWM2 is supplied by N4000, and derived from REFP. Check N4000:72 (REFP) for 1.22 V. If wrong, check V4114 and connected parts.
b. Check R4021, replace N4000.
7. Check N4000:51 (VOUTHI) for <2.5 V (nominal value 1.8 V). If wrong check R4014 and connections to N4000.
8. Check N4000:57 (IMAXFLY) for 570 mV. If wrong check R4020 and connections to N4000.