SHARP GF767Z PROBLEM.

[CONION C100F]

Hi, just wondering if anyone out there has come across this problem with the SHARP GF767Z .

The left channel outer speaker was blown so I tried another speaker and it works BUT I noticed that when I connect the other speaker,the cone moves out and makes noise ,then sounds normally, and then the magnet on the rear gets warmer than the other speakers , and also noticed that the transformer and especially the other square thing (don't know what you call it) that's marked with: GIL-04
8215
+ AC -
and on the circuit board is marked with: D901.
Well that gets really hot to the touch.
(Attached some photos of it.)

And when I disconnect the left outer speaker, the temperature of both the transformer and the other thing cools down again to normal.

I hope that I'm explaining this well enough to understand what's going on and someone out there has any ideas, solutions or has come across this problem before?

Thanks in advance.

 

[goodman]

From the description I assume that the problem is in the power amplifier of this left channel.
The next photo shows this chip attached with 2 screws to the large radiator.
There are 2 such chips Hitachi HA1392 on the board - one for each channel.
You need to trace the cables from the left speaker and find the problematic chip.
You need to replace it with a new one.

And this black thing DIL-04 converts voltage from the transformer from AC to DC 12 volts.

Before taking action, wait for the opinions of other people on this forum.

 

[CONION C100F]

From the description I assume that the problem is in the power amplifier of this left channel.
The next photo shows this chip attached with 2 screws to the large radiator.
There are 2 such chips Hitachi HA1392 on the board - one for each channel.
You need to trace the cables from the left speaker and find the problematic chip.
You need to replace it with a new one.

And this black thing DIL-04 converts voltage from the transformer from AC to DC 12 volts.

Before taking action, wait for the opinions of other people on this forum.

Hi and thanks for your reply.
I will wait and see if anyone else replies to this and in the meantime I will look more into it and try to find if there's any of those chips anywhere and take your advice and inspect the wiring etc.

 

[floyd]

Hi and thanks for your reply.
I will wait and see if anyone else replies to this and in the meantime I will look more into it and try to find if there's any of those chips anywhere and take your advice and inspect the wiring etc.

It almost sounds like the one speaker is connected out of phase meaning the positive and negative wires are reversed. This will cause the speaker cone to move outward instead of inward. It will also make the sound very flat because the speakers are working against each other.

 

[CONION C100F]

No, I've connected it right, white wire to +, black wire to - .
I've tried several speakers and they all do the same so I'm thinking there's a problem somewhere.

 

[goodman]

I assume that the chip Hitachi HA1392 is damaged and shorted, which is why the speaker and the DIL-04 rectifier block are heating up.
Which of the two left speakers is defective - the one in the middle with the chrome cap or the one at the end? Is the other left speaker working or not?
If you continues with the attempts, may burn out other elements and the repair will become very difficult and expensive.
If everything else works well - this is a positive sign, for less damage...
It is also necessary to check what voltage is on the end of the power supply board on 2 pins on CNP 901?

 

[Eddy]

I assume that the chip Hitachi HA1392 is damaged and shorted, which is why the speaker and the DIL-04 rectifier block are heating up.

The speaker coil heats up because the HA1392 is blown. Replace the power amp and measure the impedance of the speaker to check if the coil is not burned

 

[Tinman]

Something else to check are the caps before the woofers.
An woofer on an SCR-8 burned up on me before I realized it (I smelled something heating up but couldn't find it in time).
The1500uf cap before the burned woofer was shot.
They're C164 and C264 below.

 

[Superduper]

The speaker moving like that suggests that there is DC current in the output to the speaker, which is absolutely NOT supposed to happen. If you connect the speaker outputs to a multimeter set to (DC Volts) setting, I bet you will find that it measures DC. You can measure directly across the speakers. Speakers should only see AC, never DC beyond just a few millivolts. It will burn up the speakers if you keep it powered on. The rectifier and transformer getting hot means they are getting overloaded beyond their specifications and I suspect they will be damaged either already, or soon will be.

Something is shorted and if there is DC going to the speakers, the output amp chip is almost certainly toast. If you change the amplifier chip, always verify that there is no DC going to the speakers first after the swap before reconnecting the speakers. If there is still DC anywhere, you will have to sort that out before operating the set or further damage will result.

 

[CONION C100F]

I assume that the chip Hitachi HA1392 is damaged and shorted, which is why the speaker and the DIL-04 rectifier block are heating up.
Which of the two left speakers is defective - the one in the middle with the chrome cap or the one at the end? Is the other left speaker working or not?
If you continues with the attempts, may burn out other elements and the repair will become very difficult and expensive.
If everything else works well - this is a positive sign, for less damage...
It is also necessary to check what voltage is on the end of the power supply board on 2 pins on CNP 901?

It's the left outer speaker, all the rest works fine.