Amp powers up and produces rails, 15v reference as well as the op amp voltage supply +/-13v, I also have signal going through pre-amp and xover so no issue there. Seems like the mute circuit may be engaged. Below are the read outs for both 3525 and the 339. The schematic am going off of is a 200.4 which is basically the same layout and circuit except this amp is 2ch vs 4ch 200.4.
IC# LM339
Pin 1: 11v (drops to 7.20 when probed, once 7.20 reaches the orange protect LED lights up)
Pin 2: 8.62v
Pin 3: 14v
Pin 4: 4.29v
Pin 5: 8.69v
Pin 6: 1.85v
Pin 7: 8.62v
Pin 8: 0.098v
Pin 9: 0.77v
Pin 10: 11v (same as pin 1, when probe it drops to 7.20 and orange LED lights up)
Pin 11: 8.62
Pin 12: GND
Pin 13: 0.098v
Pin 14: 13.1v
IC# 3525
Pin 1: 2.42v
Pin 2: 2.439v
Pin 3: 0.009v
Pin 4: 0.320v
Pin 5: 2.066v
Pin 6: 3.75v
Pin 7: 2.02v
Pin 8: 4.83v
Pin 9: 1.01v
Pin 10: 0
Pin 11: 0.606v
Pin 12: 0
Pin 13: 14.24v
Pin 14: 0.606v
Pin 15: 14v
Pin 16: 5.08v
I get clean sine wave signal amplified to 8vrms on both sides of capacitor before the final 5532 op amp used in the bias circuit of each channel.
This pretty much the same circuit used in all GLADE Audio System that are AB amplifiers.
IC# LM339
Pin 1: 11v (drops to 7.20 when probed, once 7.20 reaches the orange protect LED lights up)
Pin 2: 8.62v
Pin 3: 14v
Pin 4: 4.29v
Pin 5: 8.69v
Pin 6: 1.85v
Pin 7: 8.62v
Pin 8: 0.098v
Pin 9: 0.77v
Pin 10: 11v (same as pin 1, when probe it drops to 7.20 and orange LED lights up)
Pin 11: 8.62
Pin 12: GND
Pin 13: 0.098v
Pin 14: 13.1v
IC# 3525
Pin 1: 2.42v
Pin 2: 2.439v
Pin 3: 0.009v
Pin 4: 0.320v
Pin 5: 2.066v
Pin 6: 3.75v
Pin 7: 2.02v
Pin 8: 4.83v
Pin 9: 1.01v
Pin 10: 0
Pin 11: 0.606v
Pin 12: 0
Pin 13: 14.24v
Pin 14: 0.606v
Pin 15: 14v
Pin 16: 5.08v
I get clean sine wave signal amplified to 8vrms on both sides of capacitor before the final 5532 op amp used in the bias circuit of each channel.
This pretty much the same circuit used in all GLADE Audio System that are AB amplifiers.
1.77v across pins 4 and 8. Forgot to mention the amplifier is idle at 700mA should be more like 1.3a, bias trimmers have not been touched (still in factory setting).
Yes, it turns on “red” which I am pretty sure it’s normal (according to manual). Goes to orange if I probe pin 1 and or 10 of 339 (Pulls the 11v down to 7.2)
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Pull Q84 (be careful, this will remove part of the protection).
Does the amp pull excessive current or have excessive DC on the speaker output?
Does the amp pull excessive current or have excessive DC on the speaker output?
Well that did the trick. No excess DC and now have OUTPUT! YAY!! YOU THE MAN PERRY!!
DC offset is less than 10mv on each channel.
DC offset is less than 10mv on each channel.
Yes, it is leaking from collector and emitter (red probe on collector and black on emitter it reads 2.07) with new NPN transistor it reads OL. Will solder new part BC850CMTF here in a few minutes and report back.
Yes, that resolved the issue. Crazy I figured it be the mute circuit and even took measurements for that transistor but didn’t have the courage to remove it. Thanks a bunch Perry!!! Now it function properly!
The mute transistor is needed otherwise there will be a turn on pop and turn off pop as well. Notice when I didnt have the mute transistor and turning amplifier off the signal slowly decrease while being CLIPPED! So definitely needed.
The mute transistor is needed otherwise there will be a turn on pop and turn off pop as well. Notice when I didnt have the mute transistor and turning amplifier off the signal slowly decrease while being CLIPPED! So definitely needed.
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