I've never worked on one of these. This looks alot like a CTC203 chassis. I found that the HOT is shorted. I was going to replace it and do the coil which looks the same as on the 203 chassis. Am I correct in assuming that this repair is similar to the 203? Also are the flybacks on these chassis as troublesome as the 203's were or did they resolve that issue with these ATC chassis? Thanks, Lenny Stein, Barlen Electronics
Just a sequel to the above post. I replaced the HOT and redid the coil and now when plugging the set in I hear that little chirp which usually means the SMPS is alive. I then try to power up and it looks like the HV makes three attempts and then quits. I know this is sparse information but does this sound like anything common on this set? Thanks, Lenny
There are some discrete components on this board I can test but there is also a chip I know noting about. Are there any specific tests I can make to rule the chip or for that matter the entire board out? Thanks, Lenny.
Lenny, this chip is LMxxx dual op amp, you can google for the datasheet on IC by 'net by typing in part number on that IC by google LM358 pdf
RCA very often didn't form the legs on that PIN transistor so means transistor isn't sitting flat on the heatsink and it fries. The 68uF NP can be bad as well (usually swelled or burst.)
ATC113 and CTC203 is exact same in horizontal circuits, vertical and power supply. Changed in micro, jungle and video signals which is more complicated than CTC203!! And different AV boards depending on models. So your experience in that areas is good.
HOWEVER: When I see a blown HOT and no glue on the L14401 (I think LL0x in case of ATC113), therefore the flyback transformer is bad as well. As long as the horizontal cap is good. The PIN circuit rarely takes out the HOT unless owner ingored the warning signs like a severe bowed picture too long. :)
Cheers, Wizard
I finally got a look at the PDF using Adobe Illustrator. Didn't know that program would work although it is a bit clumsy to use. I noticed pin 7 off the secondary with the first tap on the winding to ground. No wonder I read a "short" to ground on pin 7. Boy do I feel stupid! Now seeing it on the schematic its like the sun just came out.... So there is no short to ground after pulling the flyback it seems, so the transformer must be shorted. A new one should be here tomorrow. I'll still have to try to figure out why RF03 looks like at some point it had overheated and now reads 220 ohms. Maybe I have a vertical problem too. Dunno I'll try to get the set up and then see. Lenny Stein, Barlen Electronics.
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