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LG HT33S
blackillusion:
I have an LG DVD and stereo system LG-Ht33S or HS33S.
It arrived making a terrible loud high pitch noise from the subwoofer, which house the power supply board.
The dvd gets power through a cable from the Sub, it originally had a red standby light. You press the on button to switch it all on the dvd would start up and then the loud high pitch noise would come.
So I entered the subwoofer and found a capacitor? page 44 l606 on the PWM circuit that had bad solder joints, literally dropped off. Check it for a short and it tested like the l605 with continuity. Resoldered it.
Now I get absolutely no power on the dvd no standby light.
No voltages out of the power supply board to the others.
I have the power supply board on its own, and trace 340vdc to the two ICs 901 and 902 and nothing comes out after.
I am really looking for any tips for this. What to test and what to do.
Service manual and schematic is attached.
http://elektrotanya.com/lg_hs33s-a2p_afn70208657.pdf/download.html
jordan:
Check L-932 on secundary PSU (14V)
blackillusion:
Thanks for your reply jordan.
Please excuse my stupidity it was late last nite and I have not tested with negative probe to chassis ground point and positive probe to test point.
I find at CN901
1.GND - 0v
2.P-CNT - 0v
3.P-Sens - 5.9v
4.5.6v - 5.7v
5.12v - 0v
6.5v - 0v
7.GND - 0v
8.GND - 0v
9.14v - 16v
10.14v - 16v
so L-932 is showing 16v also.
IC931
pin 1 = 14.7v
pin 2 = 0v
pin 3 = 0v
pin 4 = 0v
IC932
pin 1 = 5.7v
pin 2 = 0v
pin 3 = 0v
pin 4 = 0v
IC933
pin 1 = 8.5v
pin 2 = 0v
pin 3 = 0v
pin 4 = 0v
Thanks for your help
blackillusion:
Should 12v and 5v be present or do they have to be switched
blackillusion:
Capacitors appear to be fine ESR.
Anyone able to help here, I'm quite novice at this and don't understand why I have no output of those 3 IC's be they permanent? I only see capacitors to GND after each IC so tested ESR and seems ok?
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