March Audio P502 stopped turning on

[rodrigaj]

@restorer-john
I totally agree. If it were not for the warranty, I would bypass the piezo switch and hardwire in a power switch.

 

[rodrigaj]

Just to clear things up...Alan has replied...and yes, the travel to Munich show has messed up his schedule.

 

[Kachda]

I agree, the piezo switch is a pain. I put in a trigger switch from Emotiva with a rocker switch hard wired to its power input. I had it laying around from an old system so it didn't cost me anything. Much better...

The entire reason i need to send the amp for service is because the trigger mechanism is broken

 

[rodrigaj]

Yeh, I understood that. I was just saying what I did to avoid dealing with the piezo switch.

BTW, Alan told me that the trigger switch overrides the piezo switch. So when I tried to go to standby with the trigger switch on, the piezo switch would not function. Why the Emotiva trigger switch I use would not shut off is still a mystery.

 

[captainbeefheart]

Yeh, I understood that. I was just saying what I did to avoid dealing with the piezo switch.

BTW, Alan told me that the trigger switch overrides the piezo switch. So when I tried to go to standby with the trigger switch on, the piezo switch would not function. Why the Emotiva trigger switch I use would not shut off is still a mystery.

Try wiggling the trigger plug/jack while triggering it, these solder to a PCB and are the first place where cold solder joints first appear. It might just need a solder reflow with real solder.

 

[Kachda]

To update the thread, I tested the voltage across the TS cable again and to my surprise it was -12V rather than +12V. When the amp wasn't turning on initially, I had checked the trigger cable and I must have somehow made the opposite connection. I switched the cabling, and the trigger mechanism is working again!. So I won't have to send it for service after all.

Alan has been helpful throughout the process, and did offer to ship it to Australia at his expense to check it out. I understand he was a bit tied up with the Munich Hi-Fi show so he took some time to response, but otherwise he has been great throughout. No complaints in that regard.

 

[Kachda]

Why the Emotiva trigger switch I use would not shut off is still a mystery.

If you have a multi-meter, it might be worth checking the voltage across the terminals with the trigger off. Sometimes, it might be sending a weaker voltage rather than turning it off completely (for example 3V-5V signal). This can cause the amp to stay turned on.

 

[restorer-john]

Great outcome for everyone. Amp not faulty. No wasted freight costs to and from Australia and everyone's happy.

 

[Holmz]

… a bit tied up with the Munich Hi-Fi show...

I think is “hi end show”, so just like the trigger wiring… the use the “high end”