I changed Q219 and its complementary transistor. Now I can adjust the 7.5Volts on F3. The amp is now fixed, but the A-CAL Fail error for square and triangle is still present.
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The output is correct, sync out as well, amplitude into a 50 Ohm load is ok, on sine, square and triangle & ramp
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When switching to ramp function something curious follows: The display goes off, the ramp function is visible on the scope, but it 'sweeps'.
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Picture 1: relay board, relays are clickking, are these types they reliable? The yellow relays are often mentioned to be cleaned, my could not be opened.
Picture 2: sinus 1kHz, lokks as expected.
Picture 3: ramp moving with about 0.5Hz.
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here is a video: shows the moving of the ramp and then flips to the correct curve? for a second.
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Outputs at the analog switches are as expected, all voltages as well.
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The self test works except the AC fail, FAIL 2, FAIL 3
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The manual says this is 60% of the controller.?
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Any advices waht to test now? ROM/RAM?
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Or has anyone spare? boards for the 3325A to exchange and for testing ?
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Ralf Rosche