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!

©2010, 2011, 2012, 2013, 2014 Frank Sharp - You do not have permission to copy photos and words from this blog, and any content may be never used it for auctions or commercial purposes, however feel free to post anything you see here with a courtesy link back, btw a link to the original post here , is mandatory.
All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Wednesday, 13 March 2019

RCA ITC PROJECTION TV - TROUBLESHOOTING - DEAD SET - POWER BOARD & SMALL SIGNAL BOARD [SSB] CROSS REFERENCE

TROUBLESHOOTING - NO POWER
The first step in all troubleshooting is to determine what is or is not working. The following information should be used when the set is totally dead or nothing happens when the power button is pushed.

Once the main fuse has been eliminated as a potential problem, measure the +1.8Vs supply at IP551 on the SSB board: The +1.8Vs voltage is the main supply for the main microprocessor, IR001. Without it, nothing will fire up. If missing, troubleshoot the Standby Power Supply.

Once the +1.8Vs supply has been confirmed as operational, check the clock (pin 6) and data (pin 5) lines to the main NVM, IR005.

In the first 100mS after AC power is applied the CLOCK and DATA lines must rise to very near +5V and have at least few cycles of data. This indicates communication between the main microprocessor and NVM (EEPROM). Note only a limited amount of Data is transferred when AC is applied. Communications

will cease until the power ON button is pressed to start the chassis. However, the short amount of data transfer between the microprocessor and NVM is a good indication that communications between the main microprocessor, ROM and RAM were successful and the main microprocessor is alive. From observing clock and data activity, there are two failure indications. First, if there were no signs of data or clock suspect the main microprocessor is defective. However if there is constant communications it indicates the microprocessor is trying to communicate with the NVM and cannot. Suspect a defective NVM (EEPROM). In either case the SSB should be replaced. NOTE: In some cases it may be required to check the communications again. To do so requires the main micro be in a zero voltage state. Be aware the mains doublers can hold a significant voltage for a long period of time. AC must be removed for at least several minutes to give the +1.8Vs supply time to completely bleed off. To save time the +1.8Vs supply may be bled by shorting CP555 on the SSB module. Check the +1.8Vs supply to make certain it is less than +0.2V before attempting to reapply AC power.

RESET CAP: LOCATION

INF_PWR_FAIL

Power Fail (INF_POW_FAIL)

Another useful preliminary check is the INF_POW_FAIL voltage located on the PSD board. The voltage monitors an unregulated rectified output from the +7Vs winding. This can be located on one end of RP231 as shown. During normal operation this voltage will be less than -1V and normally stays around -2V. INF_POW_FAIL can indicate severe loading problems on the standby supplies. Absence of a negative INF_POW_FAIL signal will not allow the chassis to start.

ITC222 Power Board & Small Signal Board Cross-Reference.