P2250 in protect.

Dearslayer

Super Member
Hi all ... My first post over here on the Yami forum but wondering if I could get some help. Had a P2250 amp given to me today and it's in Protect mode and the A channel clip mode light is also on. I can follow basic instructions for testing if someone can offer up some help. Not sure where I should start.

GT.
 

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I certainly hope I can get some direction to repair it so I can find out how it does sound. amr2 .... Does the left side amp have to be removed to check the output transistors?
 
Well I checked the output transistors on the left channel and they check out ok. Any suggestions on the next step?
 
First verify the power supply voltages going to that amplifier are getting to there designated destinations. If they are. Then start checking the up stream transistors and diodes.
 
Check for cold solder connections around the leads of all the TO-126 and TO-220 transistors.

These transistors tend to normally run very warm. Over the years of thermal cycles. They tend to develop annular cracks in the solder connections.
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Some of the TO-220's may be entirely plastic encased.
TO-220FP case style.

TN320_TO_220_ISOL_A.JPG
 
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Ok thanks so much avionic. I will try to check what I can when I get a moment. My skills are very limited especially at reading schematics etc. With some coaching I can follow directions.

GT.
 
Been away from this since my last post. Pulled the left amp out to check the 8 output transistors again shown in the photos ( those are the outputs correct?). According to the Peak Atlas they all test ok. Checked the back of the board under magnification for cold or cracked solder but it looks fine. Given the fact that I suck at reading a schematic what are the contact points to check the Voltages when I put the amp back in? I hate that I don’t know this stuff as easily as most and need hand holding.

GT.
 

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Thanks Avionic. That amp board looks super clean and no burnt resistors or anything else that would look obvious.

GT.
 
Have you got it back together yet ? We need to verify the power supply voltages are getting to where they are suppose to go.
 
Q219 and Q220 test ok. I will need to pull the right amp out to remove Q319/320. Not sure I will have time tonight. Have to leave for work shortly but will try to get as much as I can done before I leave. So if the Clip light is on in the A channel ( left side ) but the B channel clip light right side isn't on , does that mean that Q319/320 could still cause the A channel to go into protect?
 
So if the Clip light is on in the A channel ( left side ) but the B channel clip light right side isn't on , does that mean that Q319/320 could still cause the A channel to go into protect?
Does the silkscreening on the circuit boards indicate 200 boards or 300 boards ie Q219 or 319 ? Or are they labeled just Q19 or just 19 ?
 
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