Taramps md 8000 1ohm

[Bigaz]

Hi guyz, I have a stange problem with taramps md 8000 1ohm, like photo the issue is a blown up transistor. I can't read anything, strange issue amplifier still running but output sound is very low. Thank to everyone can help

 

[Perry Babin]

Does the collector of that transistor connect to the negative terminal of the fans?

Do you have a scope?

 

[jfet]

hello Q20 = smd 6c

 

[Bigaz]

yes scope, multimeter,thermal camera. Other component reach over 100 degrees, stil sound no protection

 

[Perry Babin]

What's the amplitude of the square wave (with scope) on the output transistors (or the input of the output filter inductor)?

Is the audio clean?

What's the maximum amplitude of the audio at the speaker terminals?

How much experience do you have with amp repair?

 

[Bigaz]

75v on output 116khz 14.4v dc in

Audio is clean but still low volume and i cant run for more 10 second because 3 component signed on the bottom turns very hot and smell. Halfbridge no problems, this issue in fullbridge never see

 

[ultra]

You need to be more specific, which 3 components are getting hot ?

 

[Perry Babin]

Did this problem start suddenly after working normally?

Are you sure it's not a dirty switch or pot that's causing the problem? Have you tried operating all of the pots and switches through their entire range to see if any were intermittent?

DCV measured across pins 9 and 11 of the 20957 ICs?

Is EVERY PS FET being driven by a clean drive signal on their gates?

 

[Bigaz]

You need to be more specific, which 3 components are getting hot ?

Resistor was substituted because original was completely burned

 

[Bigaz]

Did this problem start suddenly after working normally?

Are you sure it's not a dirty switch or pot that's causing the problem? Have you tried operating all of the pots and switches through their entire range to see if any were intermittent?

DCV measured across pins 9 and 11 of the 20957 ICs?

Is EVERY PS FET being driven by a clean drive signal on their gates?

Pin 9 and 11 14.8v each driver,
i don't know about previous repair, trimmer are all cleaned with contact spray, fet drive signal very low but present 2vpp, square obviously

 

[Perry Babin]

Are ALL of the PS FETs driven by the same amplitude?

DCV across pins 3 and 6 of IC3 and IC8?

Amplitude of drive on pin 7 of both of those ICs?

 

[Bigaz]

Tomorrow i measure that pin, ill try to sostituite driver output too. Thank perry and all guyz reply ✌️🤝