Tuesday, July 14, 2015

Sinotech CRT television with rainbow screen now repaired

One of my customers from Zimbabwe  Mr.Beau Friend send in an email to me a few days ago....let’s hear what he was up to.....

Greetings Humphrey,
A friend brought in a Sinotech CRT TV for repair - my TV repair experience is fairly limited hence I purchased your recent book to assist me in getting up to speed in this field of repair.
I've sent a picture of the fault - I have a very pretty rainbow effect but not exactly sure where to look for the fault.
I replaced a 1k resistor that had dropped to 270 ohms in the HOT circuitry but still the same - I've thoroughly checked the PCB for cold joints. Any suggestions?
Many thanks and kind regards,
Beau Friend

Hi friend, first note that resistor can never change value to low... So I suggest you replace the 1k resistor back. Unless if the value went up.
No 2...the problem presented on the screen point to degaussing circuit.
Change the posistor directly and see if there will be change and come back to me.
Finally thanks for buying my book.
Regards Humphrey

Humphrey, you are a star - it was the positor. I've sent pictures of the resistor I removed and the reading I measured on my meter - the resistor color code appears more like 1k rather than 270ohms - what's your thoughts?
Kind regards,
Beau Friend

Congratulations! I suggest you use the original resistor. . That resistor is okay.
Kindly send me the screen shot of the new screen after replacing posistor so that I can write a small article on the same.
Regards Humphrey

Here's the repair results - many, many thanks.

This is awesome

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