If the souce resistors are burned you likely have shorted protection circuit transistors........but they may be ok........but not likely.
Only parallel outputs must match. The IRF540's and IRF9540's dont have to match and by that I mean the IRF540's must match and the IRF9540's must match but the IRF540's dont have to match the IRF9540's.
Hope that makes sense.
So you can use "modern matching IRF9540's" and use the old Harris IRF540's.
If I were you I would replace all the output fets, just to make the amp most reliable. If you dont an old one could short in the near future and you will be starting over.
Only parallel outputs must match. The IRF540's and IRF9540's dont have to match and by that I mean the IRF540's must match and the IRF9540's must match but the IRF540's dont have to match the IRF9540's.
Hope that makes sense.
So you can use "modern matching IRF9540's" and use the old Harris IRF540's.
If I were you I would replace all the output fets, just to make the amp most reliable. If you dont an old one could short in the near future and you will be starting over.
Can you point me out to the protection transistors? In the output stage. Or any other main smd components that fail. I'm ready to order some parts for the output stages. Thx
I just found out the left channel works I put in two irf540's & two irf9540N's and it plays music clear.
But the when I put the test fets in the right channel it just pushed the speaker out no music played just pushing out the speaker. What should I check for in this channel? I switched the source resistors to good ones.
But the when I put the test fets in the right channel it just pushed the speaker out no music played just pushing out the speaker. What should I check for in this channel? I switched the source resistors to good ones.
Drivers should be changed, matched units. And replace all of the ones it has to replace. That way there's no conflict on board. Don't put the power supply fets in just yet. Operate the amp, check all driver resistors for signal, all should be within less than 1% of each other. Then, what I do is put just 2 3205's in per rail, and idle the amp. Should be clear idle usually between 0.85 amps and 1.1 amps. Then power down and finish.
Power supply is working fine now it's just the output stage. I know one channel functions but not 100% sure the right channel is having problems. I installed a set of outputs on the right channel and it pushes the speaker out. That channel had open/bad source resistors. I see a few burn spots on that side too. I'll get pics up to show what I'm talking about.
I'm starting to think about seankane previously mentioned when the source resistors fail. The protection transistors may have failed because I remember looking at the components and traces in that channel I saw a smd transistor with a lil lump in the center of it which is leading me to believe it's no good. And there's a burned surface mount resistor. I don't know the location numbers but will let u know tomorrow i have pics ready to put up.
ha i was thinking that may have been the cause of the DC? I'll recheck everything tomorrow I only have two pairs of each fets so i need to make them last for testing purposes.
People love to bash Rockford. If he's so knowledgeable about them, ask him 'precise' why they're junk.
If the FETs are clamped tightly to the heatsink and you use a current limiter, it's very difficult to damage the FETs. Having all of them installed makes it less likely that one will be damaged.
If the FETs are clamped tightly to the heatsink and you use a current limiter, it's very difficult to damage the FETs. Having all of them installed makes it less likely that one will be damaged.
Back to my project 500 a2, the meter I'm using is a craftsman meter and has a amp meter too? It has a few options; 1. uA, 2. mA 3. A AC/DC. So I set to #3 and it reads "03.97" does this mean the amp is drawing 3.97 amps? I have the probes on the B+ & GND wires. It's powered off my pyramid regulated power supply that is 10 amps constant output. What I'm asking is it necessary for it to draw that much? Or is it because there's still a short somewhere inside that I missed? So far I only got one channel to work the other still needs work. or is it because the power supply is not strong enough? Amp plays audio fine. Someone pls explain.
You wire the meter in series with the power, or ground. remember that the meter is usually fused, a 10a, and one smaller, so if you exceed that, it will pop. I have seen craftsman meters not measure anything until the fuse is replaced. The 3.97a is what your meter pulled from the pyramid power supply. it would have likely blew the fuse if the amp was not drawing much.
So the amp is fine right? Because I let it idle for about 20 mins after I fixed one channel. So I was measuring it wrong ehh I had no idea. But what should the amp usually draw when just on not playing? I also need to fix the right channel still. I'm not sure where to check? I see some smd transistors with a bump on the center of them which leaves me to believe they have burned up. I'll post the transistor location #
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.