Mtx ta92001 distorted output.

[kfx5050]

Yep. I have voltage on a two of them flow in both directio. The rest of the diodes show open in both directions.

The op amps was getting hot. With everything put back together

 

[Perry Babin]

Something very strange happened to this amp. With the exception of the diodes in series with the grounds in the older MTX amps, you have more defective ES2D diodes in one amp than I've had in all of the MTX amps I've had to repair, ever.

 

[kfx5050]

Yea I'm starting to realize that. I have the new diodes in. Still have 27.08 volts DC at speaker terminal. Not shore on what to do. At this post. The two brass color long resistor. Are the post to read the same + and -. Voltage? One shows -114.8 the other one shows 103. No load on speaker terminal

 

[Perry Babin]

I would expect the voltage to be equal on the shunt resistors.

Does the voltage on the speaker terminals cause high current draw or not when a load is connected?

 

[kfx5050]

A 4 ohmes load it doesn't. . Amp pull 1.8 amps. The speaker are quite right now. That's with the op amp removed. Resistor 4111 removed and the ne5534 remove. The axial resistor by the shunt resistor still hot but not burning this time

 

[Perry Babin]

As of now, are all of the parts in the amp?

Is LED400 lit?

 

[kfx5050]

No. The rail caps are removed because once I connected a load to the amp I was getting a very violent spark. And all the stuff in post 145

 

[Perry Babin]

A violent spark where/when?

I think you added to 145 after I posted.

 

[kfx5050]

When all the components were installed resistor 4111 op amps ne5534 and the rail caps what the amplifier powered up no load connected I was getting a 108 DC voltage at the speaker terminals once I connected a subwoofer it drew amperage above 28 amps in the subwoofer was pulsing as if it was playing 20hz tone. Very load. Spark came from two mosfet that fell one the high side one the low side and it's also the spark came from the speaker terminal once I was connected the speaker it sparked. It hasn't sparked today so far today and everything's been okay.

 

[Perry Babin]

Install everything but R4111.

Does the load on the speaker terminals still cause increased current draw.

If you want/need help, you need to wait for suggestions. Doing things (removing and installing components) without mentioning them makes helping even harder.

 

[kfx5050]

Everything is is install but r4111. With 4 ohm speaker load amp pulls 1.8 amps fans are off. With no load. Fans are on amp pulls 2.8 led400 is half way on.

 

[Perry Babin]

The fans come on because there is voltage on the terminals.

Is the LED always half lit or only when there is DC on the speaker terminals?

Are the supply still present (and correct) on the op-amps as well as all of the opto-couplers?

Is the rail voltage still uneven (with or without the speaker load)?

 

[kfx5050]

Led is not always half-lit.

Op amps and couplers yes

With load and no load the same -109.7 / 108.1

 

[Perry Babin]

Without R4111, does the op-amp nearest it get hot?

What does the output of that op-amp look like when you drive a test tone (50-100Hz) into the amp?

 

[kfx5050]

Op-amp near LED 400 do not get hot. the two smd transistors are getting very hot. The op amp are only showing DC volt. When I play a test tone there is no wave on my scope. hz are blank.

 

[Perry Babin]

Which two transistors are getting hot? The PZTA06/56?

Do you see audio on your scope if you place the probes across pins 1 and 7 of the op-amp near the ribbon cable for the preamp board?

 

[kfx5050]

yes the PZTA06/56 both are getting hot

the op amp by the ribbon cable for the preamp board shows across pin 1 and 7 23.26MHz at 1.3 volts my voltage at the op-amp is 27.14

 

[Perry Babin]

Drive a 1v 50-100Hz signal into the amp. Set the scope to manual, 2ms and 2v/div. What do you see across pins 1 and 7?

 

[kfx5050]

scope shows nothing cross pin

 

[Perry Babin]

Do the same at the op-amp near the RCA jacks. What do you get?