MTX Thunder Elite 1501d

[jordan_ciaramit]

It appears someone has worked on this amp before and it may have some incorrect parts installed.

Can someone please confirm the part numbers for location Fet 191, 192, and 401?

Currently the amp has IRF940 in both FET401 & FET192 positions and a IRF640N in Position FET191. When powered it blows the MMBT5401 and the 2 - MMBTA42 by the irf640N


Thanks

 

[Perry Babin]

Contact MTX for the correct part numbers.

Do NOT power up the amp with any of the clamps off of the transistors.

Disconnect the preamp board after replacing the blown regulator components to see if that stops the transistors from blowing.

 

[jordan_ciaramit]

There is a SOT23 transistor feeding the a3120 that is labelled c1v9b...I could not find the part number in the SMD code book, however, I think this component is defective. I need the datasheet to confirm.

Does anyone know what the c1v9b is?

I am getting 76volts on the outputs.

 

[Perry Babin]

It's not defective. It's a jfet.

Post the DC voltage on all pins of both op-amps near the 3120s.

 

[jordan_ciaramit]

Okay, I had replaced both NE5532 and while taking measurements I shorted pin 8 and pin 7 and it blew a hole in the ic... Pin 8 has 80.6 volts on both NE5532.

I do not have anymore 5532 at the moment. i will trace back the 80volts on pin 8 as I feel this is part of my issue.

I did get some measurements on 1 NE5532

NE5532
1: -12.39
2: -13.2
3: -12.59
4: -14.6
5: -12.19
6: -12.05
7: -0.5
8: 80.6

 

[Perry Babin]

You blew the 15v regulator. If the preamp board was plugged in it likely burned several resistors and possibly some of the ICs.

 

[jordan_ciaramit]

Okay, I had replaced both NE5532 and while taking measurements I shorted pin 8 and pin 7 and it blew a hole in the ic... Pin 8 has 80.6 volts on both NE5532.

I do not have anymore 5532 at the moment. i will trace back the 80volts on pin 8 as I feel this is part of my issue.

I did get some measurements on 1 NE5532

NE5532
1: -12.39
2: -13.2
3: -12.59
4: -14.6
5: -12.19
6: -12.05
7: -0.5
8: 80.6

These measurements were taken before I shorted pins 7&8 together. Luckily I did not have the preamp board plugged in.

 

[Perry Babin]

The 15v regulator has failed. If it failed when the preamp board was plugged in, the preamp board likely suffered damage. Check all resistors marked 10R0 on the preamp board as well as R318 and R319 near the op-amp closest to the RCA jacks.