MTX 81000D (2)

[Exbass17]

MTX 81000D (2)
This is another amp im working on (No Sound) Led 238 flickers on and off

I noticed D228 (A56) 3 out of 4 have been burned and resistors there parallel with at R430 and R431 I was wondering if there could be more that could have went out as well with these components any help?

I went ahead and removed (Q430,Q431,Q432,Q433) and I noticed led 238 is flashing faster now and extra component noise

 

[Exbass17]

Replaced all listed components above now I have a fully lit led238 but now I am just getting static through the speakers with and without rcas connected

 

[Exbass17]

I cannot see anything else that could be burned board looks like its in good shape and inductors don't appear to be saturated like my other 81000d

 

[Perry Babin]

Do you have a scope or any other way to follow the audio through the circuit?

 

[Exbass17]

Just the DMM I am hoping in a few weeks ill have a scope

 

[Perry Babin]

It may be best to wait until you have the scope. What make model are you going to buy?

 

[Exbass17]

Fixxing to get one just like yours or close in case I get lost with it

 

[Perry Babin]

Tektronix 465B?

It's a nice scope but you have to spend a lot of money ($400+) to get one that's been refurbished. They are about 30 years old and have some issues with failing capacitors. Otherwise, it's a great scope.

I'd suggest something from the Tek 2200 series. Send me auction numbers (via email) for any scope you intend to buy if you're buying from eBay.

 

[jurand87sca]

Hello. I need a Q239 symbol from mtx thunder 81000d. or replacement component. it's named c1nya..
sorry for my poor english

 

[Bertje]

Probably a JFET J111 but when you measure drain - source you have about 28 ohms. Then it's ok.