Mtx ta81001 resistor problem

[kfx5050]

ok im back sorry for the long break. work sent me out of town. ok I fount one of my irf540 shorted so I replace it when I replace it the restitors blow againg when the remote wire is power up with 12 volts

 

[kfx5050]

#21 fet192 and c109 blow

 

[Perry Babin]

Are you sure it's C109?

 

[kfx5050]

im sorry. its q108. it set beside fet192 (wich keep shorting out) and r147 and r148

 

[kfx5050]

problem area

problem area fet192 q108 and r147 r148

 

[kfx5050]

can any body help me out? spent hours reading on repairing amplifier haven't had much luck.

 

[kfx5050]

.....

 

[Perry Babin]

Q109 is supposed to be a high voltage transistor (2L), not a 2G.

When you repair these regulators, you need to replace ALL transistors and diodes and confirm that ALL resistors are within tolerance. If one transistor is leaky (electronically), it will fail.

Q108 is probably failing because the FET has failed.

 

[kfx5050]

Ok thanks I will replace q109 with the right transistor. Is q108 a high voltage transistor (2l)?

 

[kfx5050]

Also is c115 can you alll me what compositor value is I will like to replace the hole area with new parts these are from a ather blow amp

 

[Perry Babin]

I don't have the value of that component. Contact MTX for the values and post them here for others that may need them in the future.

Q109 and Q111 (MMBT5401) need to be fairly closely matched (from the same production batch). When you replace one, you need to replace both.

Yes (MMBTA42). The 2L in location Q108 is wrong according to all of the photos I have. It's marked 1D. Confirm with MTX.

Look up the codes on the following site and then look up the datasheets for the transistors.
The SMD Code Book

 

[kfx5050]

When i contented MTX they tell me that there unable to share that kinda information with me. But I do have two ather 81001 that are in prefect working order never been repair I could check those and see what the value is correct?

 

[Perry Babin]

MTX has generally given values of resistors and such. Did you simply ask for the values/part numbers? Or did you ask for a full schematic diagram?

 

[kfx5050]

Both. I first ask for the diagram thw. For the resistor value.

 

[Perry Babin]

They will not send you schematic diagrams. Contact them again and simply ask for the values of the components.

 

[kfx5050]

Ok will do.

 

[kfx5050]

Ok I am back. Ive replace all of the irf540 ,HUF75339P3_NL, all of the resistors, rebuild the hole area in front of the rca op-amp and still have the same problem. The two resistors r148 and r147 blow as soon power is apply to the remote turn on. Wich part is the voltage regulator? Seem to me im still have a voltage issue, also And replace the irf240 to. All so could part 5532 be damaged do to over voltage? The pre-amp is discounted .

 

[Perry Babin]

What is the DC voltage on the side of the two 100 ohm resistors that are NOT connected to the op-amp?

The op-amps are often damaged when the regulators fail.

 

[kfx5050]

On the left side 82.4 volts dc.

 

[Perry Babin]

It's unlikely that you'll have exactly the same voltage on both resistors.

Left and right depends on the orientation of the amp. Measure on the side of the two 100 ohm resistors that are NOT connected to the op-amp