Hi Everyone,
This is about the CX2168C, #8806 that I asked the value of the burned R840 resistor about two weeks ago.
The resistor is about 1.3KOhm, and I replaced it with 1.5K along with C841 and C844.
Now I am looking for the value of R820?
R820 is the flameproof 1/4W dropping resistor for the standby SMPS, implemented with the Sanken STRD-1005T hybrid regulator/controller chip. R820 is feeding the regulator circuit from a half bridge rectifier from the mains. I have no data on the 1005, but the power transistor part is not shorted. The resistor has opened up and I can only see the first and third dark rings of the color code. I am guessing it to be from 80 to 120 Ohm value. When I scratched roughly around the middle of the resistor, I could measure 66Ohm toward one leg. Anyone know the real value?
R840 was the dropping resistor for a -30V zener stabilized supply, feeding from this standby PS, and supplying an NMOS EAROM. C841 and C844 are the filter capacitors before and after that resistor. The burned resistor measured 1.3K, and calculating with the current consumption of that memory chip, and the zener current, that is a reasonable value.
I also checked the HOT and other shorts as suggested, but obviously the standby PS is not working because of R820.
Thanks for helping, Peter