Q. I have this-and-that TV model / board with such-and-such failure symptom.
Will the repair kit / EEPROM / component you sell fix my problem?
A. All of our repair kits / components (including EEPROMs) have - or must have! - a disclaimer in them stating about this:
"Coppell TV Repair LLC does NOT guarantee this kit will fix the problem with your TV.
We offer repair kits based on first hand experience repairing TV modules at component level and the best promise we can give is that the parts in our repair kits are assembled based on actual experience that have actually resolved particular problem, usually more than once."
Whenever a failure occurs there is always an element of randomness in it.
For example when a component shorts out for whatever reason that leads to great increase in current in the circuit; that increase may or may not lead to failure of other components dependng on how worn they are as well as how exactly the first failure happened; if it has taken 1/10th of a second longer it may have lead to protection circuits kicking in and saving the rest of the circuit; however if the burn happened faster - which is again function of many factors - then other components may have failed.
That is also one of the reasons we do not like to release repair kits based on a single experience and that is also why listings also contan languange that contents of a repair kit may change over time as we may get additional information about components that tend to fail, even if less often.
I regards to failed EEPROMs it is even worse than with power components like transistors, diodes and fuses.
First, an EEPROM does rarely ever fail in a way that can be determined with a multimeter - there are no shortages, no open circuits, nothing that really can be easily verified to confirm that the EEPROM is bad.
It's the 0s and 1s inside that are messed up and what's worse they can be messed up in a way that may result in many different failure symptoms, This is especially true for NAND flash EEPROMs, but is generally true for all kinds of memory devices.
A bad EEPROM could have the block containing EEID information needed for HDMI communication thus rendering HDMIs unusable.
The odds of that happening are fairly low (based on the ratio of the EEID block of 512 bytes to the 1GB or 2GB size of the EEPROM), but it has happened and we've seen it.
Or if the bootloader or the startup program fail then it could render the whole EEPROM unsuable resulting in a dead TV.
Or if the high level application memory block was corrupted then the TV may be stuck in initialization and keep on looping.
All those potential failures look differently on the outside - from totally dead TV to TV that is stuck in initialization , but never starts to TV that seems to be operating properly,but lacks HDMI inputs or sound or video is corrupted.
And unfortunately pretty much all of those symptoms can also be caused by other failures, not just the EEPROM.
So, particularily in regards to EEPROM failures there is absolutely no guarantee that replacing an EEPROM will fix any particular problem!
The best and most practical way to know if an EEPROM is good or not is to take it out of a board and put it into a known good board to see if it works there.
That is what we do and unless you do the same you will alaways be taking a chance, nothing more.
If anyone tells you differently they either do not know any better or are trying to take advantage of you.