Earthquake 200DHC

S Merlington · 2012-12-24 6:18 pm

Scope set to 5 ms 10 volts/div

200 hz sine wave

First pic is on the positive terminal

2nd pic is the negative terminal

Perry Babin · 2012-12-24 6:57 pm

Do you have a triangle waveform on pin 6 of the 4080?

S Merlington · 2012-12-24 7:05 pm

Perry Babin · 2012-12-24 10:35 pm

Do you have audio on pin 7?

Does this amp have pull-down resistors on the output transistors?

S Merlington · 2012-12-25 2:36 am

It has audio on Pin 7 but its clipped the bottom of the sine wave is flat..

Yes the outputs have pulldown resistors..

Perry Babin · 2012-12-25 1:18 pm

If you're absolutely sure that it has pull-down resistors on the outputs, remove the 4080 and see if it has a clean signal on pin 7.

S Merlington · 2012-12-25 10:39 pm

Pulled the HIP4080 and tested for audio on Pin 7 I get a square wave on Pin 7 so the audio is clipped

Perry Babin · 2012-12-25 10:45 pm

Do you get clean audio if you short pins 8 and 9 of IC2?

S Merlington · 2012-12-25 11:04 pm

Perry Babin · 2012-12-25 11:14 pm

That would seem to indicate that the components feeding the 4080 are OK. Remove the jumper.

Do you get clean rail-rail oscillation on the output transistors?

S Merlington · 2012-12-26 2:39 am

Sorry im tired tonight long day..

I meant the audio is not clean on Pin 7 when i short pins 8 and 9 together on IC2

Perry Babin · 2012-12-26 6:00 pm

Do you have clean audio on pin 14 of the 3404?

S Merlington · 2013-01-06 7:49 pm

Do you happen to know what the part number for IC2 is?

Perry Babin · 2013-01-06 9:47 pm

NJM3403

Earthquake 200DHC

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