A few days ago I got a knock at my gate very early in the
morning and I wondered what could have necessitated the visit and I almost came
out armed.
Upon opening the gate I found one of my neighbor standing
there holding a woofer and after excusing himself he told me that he wanted it checked
urgently and he suspect it burnt after the power surge though I can’t remember
experiencing any in my house.
I took the machine and kept it in my workshop which is
within my house and went to work. In the evening I came back and went straight
to the woofer and before opening I could smell something burnt inside and after
opening this is what I saw.
Yes! The four bridge
diodes were burnt beyond recognition.
Before continuing I
decided to check if the transformer was gone or not and after dis-connecting it
from the board I applied the power and I was able to test all the outputs and
were okay and with this I concluded the transformer was okay.
To me this was a big
relief since getting the spare for this kind of transformer is not easy in my
place.
I decided to replace
the four diodes and therefore I removed them carefully and replaced them, since
the two fuses were okay I did not suspect any more components shorted.
I then decided to
apply the power with the motherboard connected but since I was not sure if
there were any other component shorted I decided to use my series lamp current
limiter.
After applying the
power I noted the bulb remained bright and this means there was still something
shorted in the system.
To get the culprit I
decided to use the touch method whereby after applying the power via the series
bulb for a few minutes dis-connected the power and started touching main suspect
component which are prone to shorting like transistors, I.Cs and I after
touching one of the amplifier I.C TDA2030A I noted it was very hot for my
finger and concluded this must be one of the culprit.
Also keen observation
I noted one of its leg was dark meaning it was getting very hot to the point of
changing the color as you can see the picture above.
I pulled it out of
the circuit and again applied the power and this time the series bulb lite and
then went off.
This is a good sign
that no more shorted component in there and therefore got a replacement ic
TDA2030A which was readily available in my store.
I replaced it and
after applying the power I got aloud humming sound from the woofer and I
concluded I may have finally got the system working again.
Here is the inside of
the woofer
Thank you guys
See you in the next
class
great i like the information.
ReplyDeleteThanks for your feedback Khan.
DeleteRegards Humphrey
Good job Sir,
ReplyDeleteThanks Yogesh
DeleteRegards Humphrey
Dear Sir,
ReplyDeleteThanks for your useful classes, will you please explain me, How to add the USB port option in old CD player.
add MP3 Decoder Board..
DeleteRegards Humphrey
My sayona lost the should. What could be the problem.
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ReplyDeleteHello, I have a sayona pps SHT-11488T.the is a problem with the bass I have tried repairing by replacing transistor but iam not successful. It was brought to my workshop from another workshop.
ReplyDeleteKindly if you have an idea on how the transistors are placed, assist
Hello, I have a sayona pps SHT-11488T.the is a problem with the bass I have tried repairing by replacing transistor but iam not successful. It was brought to my workshop from another workshop.
ReplyDeleteKindly if you have an idea on how the transistors are placed, assist
Were you successful since got the same issue
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My sayona SHT-1079BT dead help
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Audia menu not working
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