hmmm, I just noticed something else when I removed the power wires to get ready to clean the transformer. I checked voltage from pos to neg on the supply terminals and I got 10+v and it eventually died down to mid 5v's. I switched and test the other posts, same reading... now heres where it gets strange... with one probe on the remote and the other on power I get mid 5v's as if I connected it to the ground post with other lead on pos. If I leave it on the remote and move other prob to ground I get 0.002v. Like its shorted to ground somewhere? or is this normal?
Last edited:
All cleaned up the best I could. Heres another pic. Its still a little hard to tell but it looks like a winding behind/between the front two in the square is shorting toward them.
Also might be worth mentioning that the owner had this amp attached to his enclosure. I was just talking to him.
Also might be worth mentioning that the owner had this amp attached to his enclosure. I was just talking to him.
Attachments
Maybe I should pull the board and see if these are broken solder all the way or just not filled properly. Not sure how I missed the transformer stuff till today. I wonder if there is broken legs I just can't see.... one of the ones in this pic is the 15v supply transformer. They don't appear to "wiggle" in location
Attachments
Last edited:
Owner said he was backing out of the driveway, stereo was on, radio low, and he heard it "click into protect". Went back there and nothing seemed out of place or smelled so he shut it off and back on with no change and its been in protect ever since. Even though the top lights up fine and there are no clip or protection lights lit on the amp.
I will try to get my hands on another battery tomorrow (incase current supply is the issue) or maybe try to figure out why my pyramid ps-50 is only producing between .5 and 1.5vdc.
I will try to get my hands on another battery tomorrow (incase current supply is the issue) or maybe try to figure out why my pyramid ps-50 is only producing between .5 and 1.5vdc.
It appears to be a diode for the relay... guess I should replace it. Perry this wouldn't cause DC to go to the output terminal right? Possibly part of the cause of the excessive current though? I've pulled a few of the outputs but they are all ok. Think I'm going to pull them all and check every one.
Attachments
Last edited:
After lifting it, you were right it was fine.
SO! After going to remove the output transistors, I found that broken legs are a LOT HARDER to notice than I thought. It turns out I had broken legs on 4 of the outputs. The desoldering pump sucked them right into it, lol.
Also L7815 has a broken leg, plus that broken master/slave rca...
Looks like I have some work to do.... I'm going to remove all the rest of the transistors and check them all. None of the outputs where shorted or leaky.
SO! After going to remove the output transistors, I found that broken legs are a LOT HARDER to notice than I thought. It turns out I had broken legs on 4 of the outputs. The desoldering pump sucked them right into it, lol.
Also L7815 has a broken leg, plus that broken master/slave rca...
Looks like I have some work to do.... I'm going to remove all the rest of the transistors and check them all. None of the outputs where shorted or leaky.
Last edited:
I cleaned it up well. 
Just wanted to update and say that after replacing the whole one side (2 banks) of output transistors (cause 5 of the 8 had broken legs), replaced the 7815, and rebuilt the broken legs on the master/slave rca. This amps good as new.
Only 0.003vdc on outputs now (was over 60), and is only pulling 3.7a of current @ idle with no limiter.
Thanks again Perry!
The one transformer (that feeds the 15v supply) is still ringing... is there something I can do to quiet it up? It changes pitch when I twist it. Or should I just leave well enough alone?
Just wanted to update and say that after replacing the whole one side (2 banks) of output transistors (cause 5 of the 8 had broken legs), replaced the 7815, and rebuilt the broken legs on the master/slave rca. This amps good as new.
Only 0.003vdc on outputs now (was over 60), and is only pulling 3.7a of current @ idle with no limiter.
Thanks again Perry!
The one transformer (that feeds the 15v supply) is still ringing... is there something I can do to quiet it up? It changes pitch when I twist it. Or should I just leave well enough alone?
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.