my mg100dfx problem

[blackcrows]

mg100dfx is 7293 broken.change new ic but burn again.what check it?pls help me 2

[Amp Kat]

You have short in the power supply possibly a diode or another transistor bringing it down. Try ohming out transistors and diodes for shorts and resistors for opens.

[blackcrows]

thanks.new 7293 at I add to , have a voice but , for a moment it dead again.sound ic tak tak and ic burn.

[snsent]

MG100DFX IC TDA7293 Burned

I'm used Marshall MG100DFX and I had a repeated problem. I was changed TDA 7293 IC but still had a same problem after turn ON this amp for testing. Do have somebody help me cause I think that have some others problem cause this is a third time I change TDA 7293 IC in one week.

Thanks

[amptech]

mg100dfx

When you repower up your amp is the fan on?

carry out prolong soak testing to see when the amp act's up...

[Prairie Dawg]

When you repower up your amp is the fan on?

carry out prolong soak testing to see when the amp act's up...

This is all good stuff for me as I have one that's defunct that I'm going to use as a learning tool for solid state.

Question. Will running a MG100HDFX without the speakers connected kill it? Because that's what the owner did.

[snsent]

When you repower up your amp is the fan on?

carry out prolong soak testing to see when the amp act's up...

The fan is running but 7293 is still burned again after 5 minutes I testing. Do you have any suggestion?

Thanks

[JerryP]

Did you change the whole power amp board assembly or just the chip?

You can run it without a speaker.
Jerry

[snsent]

I just changed a TDA 7293 cause I didn't see any broke part. This is a third time I change a same IC in few weeks. Please help me to find out a problem and solve this problem.

Thanks

[Jazz P Bass]

Tda7293

I had one of these on the bench doing the same thing. I ended up changing all the capacitors that are associated with the TDA7293. There are two 0.1ufs & two 47uf/65v electrolytics. I also changed the bootstrap cap, 47uf/65v.
I would double check that the output pin trace, pin 14, is clear of all others.
Check your standby voltage, pin 9. It ramps up to 5 volts.

[snsent]

Thanks for info, I'll try for change all electronic patrs at this power module board and will let you know a result soon.

Thanks
YM Id : snsent@ymail.com

[snsent]

I have change all part on that board but IC is still burn again after 3 minutes...

[Jazz P Bass]

7293 insulator

Please forgive my impertinance but are you using an insulator behind the 7293 ic. Can't have any cracks in it. That rear tab is connected to -V.
Do you have the schematic?
Did you download the 7293 datasheet?
Did you check the mute signal on pin 9?
There really is not that much to this IC.
I believe there may be a few more caps on the main board. I think they are right at the 15 pin connector. Look at the schematic.

[Enzo]

On the main board, find R14, it is 10 ohm 2 watt resistor. Make sure that resistor is not open. Also test R15, a 0.1 ohm 5 watt resistor.

[Jazz P Bass]

R15

Enzo
Humor me if you will. R15 0.1 ohms 5 watt.
W2(speaker ground)goes to inverted input or through R15 to ground.
What in the world is going on in that part of the schematic.
Ignorance is bliss.