madness
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Oct 24, 2006, 9:45 PM
Post #1 of 1
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Dead RCA HD52w57 - ATC321
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OK here goes nothing...... I am working on a RCA HD52W57 for a friend. This is a pretty sweet set and not too overly complicated. Now for my problems or should i say the sets problems. When he brought it to me, it would not power up at all. Upon inspection the Deflection board had resistor R14705 burnt up. I checked the HV splitter and could not find any visible problems (read somewhere that this may cause the resistor to blow). I replaced the resistor and tried the set again. The power button will now come on, flash ten times and go solid. The relay will kick in and you hear a high pitched squealing noise but none of the guns appear to have any power. (Set is protecting itself?) SO then next i go to the AC-IN board and remove the power (BP204) to the deflection board. Now the squealing noise stops. This makes me suspect the AC-IN.
Remove the AC-IN board completely and power it up. Check voltage on BP204, manual says it should be 124.8v DC-on and 149.8v DC-off. It reads 174v. I then check voltages at the plugs on the board.
BP601 checks good.
BP602 checks as follows Pin1 (22.8v) reads 9.37v, Pin2 (0v) reads 9.37v, Pin3 (-22.3v) reads 9.37v, Pin4 (0.95v) reads 1.02v, Pin 5,7&9 are ground, Pin6 (0.69v) reads .003v, Pin8 (12.53v) reads 12.53v.
BP603 checks as follows Pin1,3,5,7&10 are ground. Pin2 (12.54v) reads 12.53, Pin4 (-5.1) reads -11.61, Pin 6 (5.01v) reads 5.00v, Pin8 (33.3v) reads 45.8v, Pin9 (5.72v reads 6.82v, Pin 11 (12.54v) reads 12.53v, Pin12 (5.72v) reads 6.81v, Pin11 (0v) reads 0v, and Pin14 (4.59v) reads 5.00v.
It looks as if there are two main transformers on this board (LP201 and LP601) LP601 supplies most of the voltages to plug BP603. My question is should i attempt to repair this board myself or just send it off for repairs? I can replace anything on this board but i am just not sure where to start. Also should I be checking anything else on the Deflection board for damage? I can't tell what is making the squealing noise, probably something getting too much voltage fron the PS board, but nothing looks to be damaged other than the fried R14705.
Basically, any help or advice would be greatly appreciated.
Thanks
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