Hi there, please I need your help. My PPI 2150m muted suddenly. It has 13,9 volts on speaker outputs, both channels, with no input signal. If it has no load, it keeps cold. If it has speakers load, it warms very soon. It is connected to a preamp PPI Par224 and I noticed that red led output clip lights on. I opened the amp and tested: power mosfets seem to be good, output transistors seem to be good as well, no burned components at sight. It seems to be a failure in preamp section with anomalous tension. My suspect is on opamps. What do you think about? Thank you for your precious opinions. Greetings from Italy.
Referencing CT or non-bridging speaker terminals;
Rail voltage?
Regulated voltage?
Any DC on opAmp output pins?
Rail voltage?
Regulated voltage?
Any DC on opAmp output pins?
Perry Babin, It goes constantly to over 2 millions ohms, on positive and negative speaker output. I mean amp disconnected at all.
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Dr Zeus, what do You mean CT? I can't do measurement without clamping rear cover on, over heating risk.
If you're going to work on these amps, you need to make clamps. The ones shown below are very easy to make and work well.
He likely meant , the secondary center-tap. The secondary center-tap and the non-bridging speaker terminals are the secondary ground and often the best for measuring secondary voltages.
He likely meant , the secondary center-tap. The secondary center-tap and the non-bridging speaker terminals are the secondary ground and often the best for measuring secondary voltages.
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I can't find it on the secondary, and I don't know what to measure, I'm not so expert as You are. What do You tell about the Infinity resistance between +B and speaker outputs?
Here is another basic fact:
some weeks ago, amp started farting while the system was turned off, no ignition key in the dashboard! It stopped farting after 1 minute. On Turning on, everything ran well for many weeks until yesterday.
some weeks ago, amp started farting while the system was turned off, no ignition key in the dashboard! It stopped farting after 1 minute. On Turning on, everything ran well for many weeks until yesterday.
What's the DC voltage measured across the primary ground and the B+ terminal?
Do you read infinite resistance between the B+ terminal and the non-bridging speaker terminals?
Do you read infinite resistance between the B+ terminal and the non-bridging speaker terminals?
Sorry, I don't understand your first question: I think the same voltage from the battery. For second question: turned off and disconnect amp or connected and turned on amp? Thank You.
Hi there. OK, found it and fixed. The problem was a desoldered leg on the 7915 transistor (15V phantom power supplier on DIN connector). I hope this will help for the future.
Thank you everyone. Bye.
Thank you everyone. Bye.