May be just the caps themselves failing, having developed a high E.S.R. They look highly stressed ripple current wise, try replacing with suitable new ones. The plug/socket to the diode bridge isn't open circuit is it. These limit the max voltage across the caps.
Probably just the caps themselves 🙂
Probably just the caps themselves 🙂
Thanks your advice. Actually I replaced new capacitors with same specification but there is no improvement. I don't know what happen.
Ragnwald said:
No it's correct do do it like that. 4700uF NP caps are not a very common item to find.
t2060079 said:
One thing I can think of is:
check the max Voltage rating of those caps.
The other thing is CHECK the polarity.
see to that they are not put the wrong way!
Because if, this is certainly a big problem ...
Correct is:
- cap + .... resistor .... + cap -
if we are to believe in your schematic
Third, as capacitors normally do not get very hot:
Have a look if actually it is caps that produce heat.
Maybe it is some resistor? Close to those caps.
a shorted diode in the bridge rectifier would have been my first choice until i looked closer at the schematic. the bridge rectifiers are actually connected as voltage limiters here. very strange, but the caps are probably hot because a diode in the bridge is open. these are very low voltage caps, and the bridge rectifiers limit the voltage across the caps to about 2v (+/- a sizeable fudge factor of about .8V)
Thanks for your all advices. I measured the voltage across R106 and it was about 0.8V. Is the BR3 health?
On the other hand, the C101 and C102 are not hot. They are okay.
On the other hand, the C101 and C102 are not hot. They are okay.
Dare we even ask what it is 🙂 I'll be honest, I can't just at first glance figure it out at all. Has it worked all right in the past and suddenly this problem developed ?
The C110 was broken down. Then I replaced C110. During the test, I found the C107 and C108 very hot last week.
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