AMP-70 Weird problems encountered in testing！

[dianying123]

Hi Guys
I was recently testing a 100w power amp (AMP-70 https://www.diyaudio.com/community/threads/winfields-100w-dc-10mhz-1000v-us-amplifier.287023/) and according to JD's patch documentation, I built a flywire on the B side of the board
As described in the picture
Now as soon as the power is turned on, Q27, Q27, Q28, Q33, Q34 will be shorted
I don't know if I need to disconnect or jumper the wires there in advance?
Also, is this J7 jumpered correctly?
Can anyone help me or give me some tips, thank you very much!

 

[dianying123]

Sorry, I didn't describe the problem clearly.
Update

 

[dianying123]

I've worked on that board and now you can see the waveform is much better than before. I set a 50 ohm load (See attachment)
I wonder if the DC-DC is interfering?
The problem is that the voltage can't go any higher or it will burn out the TO220 (Q20,Q24). It can only run at low voltage.
About that flying wire. I connected it according to the documentation and it caused a short in TO220.
If you can give me some advice, I will be able to finish this project faster. Thanks

 

[Rory Christ]

If you reread those instructions, it is necessary to cut the trace after the via so C01 is no longer connected to the output, but is instead connected to Q25’s emitter by the jumper wire.

 

[dianying123]

Hi Rory Christ
Thank you very much for your reply
Although I didn't understand your explanation, I'm just a beginner

 

[dianying123]

Hi @Rory Christ Thank you very much 🙂
I've figured it out.