Hello I need a schematic for this amplifier. I was sure I had it but cannot locate it now. Can anyone help? Thanks again.
This amp is acting strange. I have +142vdc rail on the blue wire and nothing on the red wire. Don't they usually have 68-72vdc on each wire, measuring across the 2 wires would give you your 140vdc? The amp is only drawing 1.5 amps of current at idle like it is not fully powering the output side. It should be drawing around 7-10 amps when working properly. Has anyone had this issue before? Could the regulation circuit be faulty? I still don't have a new scope yet, so troubleshooting the output side should be fun. I believe it to be on the power supply side. It powers up with no audio.
You measure across the red/blue because they're not referenced to ground.
The voltage is split with reference to ground only when you have rail-rail oscillation.
Is the BD enable line going high?
The voltage is split with reference to ground only when you have rail-rail oscillation.
Is the BD enable line going high?
I found some batteries for my old Velleman hand held scope, bare with me lol.
U301 pin 5 has triangle waveform
U302 pin 5 has triangle waveform
U303 pin1 has square wave
pin 3 has saw tooth waveform
pin 7 has triangle waveform
U301 pin 5 has triangle waveform
U302 pin 5 has triangle waveform
U303 pin1 has square wave
pin 3 has saw tooth waveform
pin 7 has triangle waveform
U301 has no waveform on pin 7 and has +5.59vdc on pin 7.
U302 has no waveform on pin 7 and has -4.49vdc on pin 7.
Both of these were replaced with new parts for that reason with same result.
U302 has no waveform on pin 7 and has -4.49vdc on pin 7.
Both of these were replaced with new parts for that reason with same result.
U300
pin 1: 0.006
pin 2: 0.006
pin 3: 0.001
pin 4: -6.15
pin 5: 0.005
pin 6: 0.006
pin 7: 0.004
pin 8: +5.99
pin 1: 0.006
pin 2: 0.006
pin 3: 0.001
pin 4: -6.15
pin 5: 0.005
pin 6: 0.006
pin 7: 0.004
pin 8: +5.99
U301
pin 1: -4.62
pin 2: 1.935
pin 3: 0.002
pin 4: -6.16
pin 5: 0.025
pin 6: -4.59
pin 7: 5.99
pin 8: 5.99
There is 3.350vdc on the speaker terminals.
pin 1: -4.62
pin 2: 1.935
pin 3: 0.002
pin 4: -6.16
pin 5: 0.025
pin 6: -4.59
pin 7: 5.99
pin 8: 5.99
There is 3.350vdc on the speaker terminals.
If you touch a load across the speaker terminals, does the amp draw additional current or does connecting the load simply drain off the voltage?
With a 4 ohm load connected the readings are as follows:
U301
pin 1: -1.440
pin 2: 0.001
pin 3: 0.002
pin 7: 3.850
U302
pin 7: -3.650
U301
pin 1: -1.440
pin 2: 0.001
pin 3: 0.002
pin 7: 3.850
U302
pin 7: -3.650
Solder a relatively low value resistor (1k-10k) between pins 1 and 2 of U301. Soldering across the terminals of R315 will be the same if easier.
U301, P1?
U301, P1?