Hi guys, I'm new hear.
Im in no way an electronics expert, but i do dabble swapping out faulty capacitors in power supplies, and faulty pots in amps etc.
So i have a few QSC RMS 2450 amplifiers. Only one of them has this strange issue.
When i turn it off, after a few seconds, the clip lights light up and distorted audio can be heard. After maybe 6 seconds of this, the clip lights go out and none distorted/ clear audio can be heard. I can even turn the volume pots up and down and it controls this audio as if the amp is still on, although it's not putting out the same sort of volume as when the amp is on.
This will carry on for maybe 30 seconds or so, untill the amp completely goes off and silent.
I'm guessing it's something to do with discharging of capacitors, but can anyone explain why this is happening, why this is the only one of maybe 8 of these amps I've had over the years and how i fix / solve it? Thanks
Im in no way an electronics expert, but i do dabble swapping out faulty capacitors in power supplies, and faulty pots in amps etc.
So i have a few QSC RMS 2450 amplifiers. Only one of them has this strange issue.
When i turn it off, after a few seconds, the clip lights light up and distorted audio can be heard. After maybe 6 seconds of this, the clip lights go out and none distorted/ clear audio can be heard. I can even turn the volume pots up and down and it controls this audio as if the amp is still on, although it's not putting out the same sort of volume as when the amp is on.
This will carry on for maybe 30 seconds or so, untill the amp completely goes off and silent.
I'm guessing it's something to do with discharging of capacitors, but can anyone explain why this is happening, why this is the only one of maybe 8 of these amps I've had over the years and how i fix / solve it? Thanks
Service manual attached. On page 14:
• Amplifier doesn’t stay muted at turn-off: see service bulletin
RMX0003
But I didn't find the bulletin. Maybe you'll have better success.
Good luck!
• Amplifier doesn’t stay muted at turn-off: see service bulletin
RMX0003
But I didn't find the bulletin. Maybe you'll have better success.
Good luck!
Hi guys, OP of this thread here.
So I originally came on here to ask why my RMX2450 amp was still outputting distorted audio for a good 30 seconds after it was turned off.
I was pointed in the direction of service bulletin 3, where an upgrade mod was available to fix this. Unfortunately, this amp is no longer classed as serviceable by QSC, and the modification part is no longer made.
looking at the schematic on the service bulletin, i was able to identify the components needed for this mod, and put it together myself on some copper project board. It's in the amp, and is working (to a point), but it has introduced a second issue. The amp now mutes near enough as soon as i power down, but it makes a massive pop at the start of this process as soon as the power button is switched. This wasn't there before.
Can somebody with some electronics exercise please help me out and look over the bulletin I've attached please and try and answer me a few questions?
I noticed on the schematic on the bulletin, it shows the modified part in red, and lists Q10, Q11 and R22 as the components that are added, and D9 as the componant to be removed. But on the schematict here is also a capacitor, C12, in red, which looks like it as been added (as it isn't on the board already), but its not listed as a new componant in the parts list. Can anyone verify this for me? Also, the Bulletin states that there is a ground wire to connect to the negative pin of capacitor 8. I can see all the new components on the schematic that connect to this negative leg labeled down-arrow P, but the new/ unknown C12 negative leg shows it just goes to a down-arrow, without the P. Can anyone clarify what the score is with C12 and whether the negative leg is supposed to be combined with down-arrow P, or somewhere else??
Thanks
So I originally came on here to ask why my RMX2450 amp was still outputting distorted audio for a good 30 seconds after it was turned off.
I was pointed in the direction of service bulletin 3, where an upgrade mod was available to fix this. Unfortunately, this amp is no longer classed as serviceable by QSC, and the modification part is no longer made.
looking at the schematic on the service bulletin, i was able to identify the components needed for this mod, and put it together myself on some copper project board. It's in the amp, and is working (to a point), but it has introduced a second issue. The amp now mutes near enough as soon as i power down, but it makes a massive pop at the start of this process as soon as the power button is switched. This wasn't there before.
Can somebody with some electronics exercise please help me out and look over the bulletin I've attached please and try and answer me a few questions?
I noticed on the schematic on the bulletin, it shows the modified part in red, and lists Q10, Q11 and R22 as the components that are added, and D9 as the componant to be removed. But on the schematict here is also a capacitor, C12, in red, which looks like it as been added (as it isn't on the board already), but its not listed as a new componant in the parts list. Can anyone verify this for me? Also, the Bulletin states that there is a ground wire to connect to the negative pin of capacitor 8. I can see all the new components on the schematic that connect to this negative leg labeled down-arrow P, but the new/ unknown C12 negative leg shows it just goes to a down-arrow, without the P. Can anyone clarify what the score is with C12 and whether the negative leg is supposed to be combined with down-arrow P, or somewhere else??
Thanks