Sir...i have makie srm450v2 active speaker..when i turning on speaker both led light staying on..(thermal led light and peak led light) how to solve this problem...
It seems you've been lucky in this repair. Usually when mosfets driving a HB smps blow they go together plus also destroying the driver chip. I learnt that transistors always blow before the fuse does. Besides you should have changed both fets as they are not the same.
Raul Romo The first thing to do would be to grab the schematic and check the voltages around the circuit. The schematic is very detailed in that respect, I have found a copy of it here : elektrotanya.com/mackie_hd1521_sm.pdf/download.html Good luck!
Hmm, looks like you were darn lucky with that one! On closer inspection, the one on my bench suffered much further damage - when the FET shorted, it sent mains back up into the PFC circuit, frying the PWM controller chip and various surrounding SMDs, and that's just the dead bits I've found so far. I suspect this one may be bin fodder...
djsherz Yep, that can happen because mosfets have a tendency to fail short circuit. I had a similar issue with a subwoofer repair (video also on my channel) where blown mosfets took out their PWM driver. Replaced both mosfets and the driver and the whole thing was fixed for about a tenner.
How far through does it go? MOSFETs usually fail short so if it were dead I'd expect blown fuses etc. I don't have access to any schematics or this unit any more so I can't remember its circuitry, but it might be worth checking around the switch mode controller chip, if it has one.
You re-assembled, tested it and it blew again because you did not fully fix it? That is what usually happens after replacing that FET and nothing else.
@@fredflintstone2077 Sure, I get that, however if someone is cynical enough to believe that I've not actually repaired this, then they're probably not going to be swayed from their opinion by a video ending showing it working. They'd probably just suggest that I was showing the other unit of the pair.
@@the_equalizor got it. I've got a mackie m1400i. It powers on and the LEDs turn on. none of the fuses are blown (I opened it up). It makes a little popping noise through the speaker when I power it on (like a normal amp does). There's .1 volts at the speaker output. audio input is confirmed to deliver the sound properly. Is this likely a blown capacitor? One of the capacitors has pink on the top and looks a little more bulbous than the rest. Any ideas? thanks for the earlier reply.
@@JustinCrediblename I've not seen pink on caps before, normally when they leak its brown. Bulbous definitely means replace, as they will make the power supply go out of regulation. I wouldn't get hung up on the speaker output, you need to be looking around the secondary side of the power supply, after the main rectifier diodes. Do you have a picture of that area of the main board I could see?
@@the_equalizor P.S. I repaired it. The main caps were bad, the cooling fan was seized, and the ribbon cables which were touching the heatsink was bad. I measured the current that this thing can deliver to my subwoofer, and it barely exceeds 200 watts with a line level input. Maybe I didn't fix it properly. edit: not bad to have 112 dB sustained at listening position in a 6000 sq ft room, I guess. But still a bummer. The silver lining is that I can have flat EQ down to 20 hz without risking the driver. lol.
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Powered speakers... or old school amp rack...? Old school amp rack wins every time.
can you repair 2 I have? one sounds quiet the other shuts off if I pass the dented middle volume
Hi there can you tell what desoldering system you are using looks really good.
Sir...i have makie srm450v2 active speaker..when i turning on speaker both led light staying on..(thermal led light and peak led light) how to solve this problem...
It seems you've been lucky in this repair. Usually when mosfets driving a HB smps blow they go together plus also destroying the driver chip. I learnt that transistors always blow before the fuse does. Besides you should have changed both fets as they are not the same.
Hi I have a rcf 315a mk2 the amp for the low frequency stop working but the highs frequency works you know what is the problem
13:35 famous last words...
i have a mackie HD1521. it turns on, but no sound. is there a way to troubleshoot that?? i have basic 12 volt electrical knowledge
Raul Romo The first thing to do would be to grab the schematic and check the voltages around the circuit. The schematic is very detailed in that respect, I have found a copy of it here : elektrotanya.com/mackie_hd1521_sm.pdf/download.html Good luck!
Interesting - I have one on the bench with the EXACT same fault...
Hmm, looks like you were darn lucky with that one! On closer inspection, the one on my bench suffered much further damage - when the FET shorted, it sent mains back up into the PFC circuit, frying the PWM controller chip and various surrounding SMDs, and that's just the dead bits I've found so far. I suspect this one may be bin fodder...
djsherz Yep, that can happen because mosfets have a tendency to fail short circuit. I had a similar issue with a subwoofer repair (video also on my channel) where blown mosfets took out their PWM driver. Replaced both mosfets and the driver and the whole thing was fixed for about a tenner.
@@the_equalizor Just having a nosey now...
@@djsherz They almost always do. We did not see this one tested and working either.
I have a Mackie SRM450V2 which is dead although there is mains coming in on the primary side of the switch mode PSU Any ideas ? Chris
How far through does it go? MOSFETs usually fail short so if it were dead I'd expect blown fuses etc. I don't have access to any schematics or this unit any more so I can't remember its circuitry, but it might be worth checking around the switch mode controller chip, if it has one.
hello, I have 2 Mackie SRM 450 V2 for repair, I'm in London, who would like to take it for repair? please
You re-assembled, tested it and it blew again because you did not fully fix it? That is what usually happens after replacing that FET and nothing else.
Nope. Still working fine to this day. :)
@@the_equalizor Strange that you do the work sand don't show it actually working afterwards. Maybe include that next time for a better video?
@@fredflintstone2077 Sure, I get that, however if someone is cynical enough to believe that I've not actually repaired this, then they're probably not going to be swayed from their opinion by a video ending showing it working. They'd probably just suggest that I was showing the other unit of the pair.
what were the symptoms of this amp?
Fuse blown, shorted +- rail
@@the_equalizor
got it.
I've got a mackie m1400i. It powers on and the LEDs turn on. none of the fuses are blown (I opened it up). It makes a little popping noise through the speaker when I power it on (like a normal amp does). There's .1 volts at the speaker output. audio input is confirmed to deliver the sound properly.
Is this likely a blown capacitor? One of the capacitors has pink on the top and looks a little more bulbous than the rest. Any ideas?
thanks for the earlier reply.
@@JustinCrediblename I've not seen pink on caps before, normally when they leak its brown. Bulbous definitely means replace, as they will make the power supply go out of regulation. I wouldn't get hung up on the speaker output, you need to be looking around the secondary side of the power supply, after the main rectifier diodes. Do you have a picture of that area of the main board I could see?
what the no part replacment
@@the_equalizor
P.S. I repaired it.
The main caps were bad, the cooling fan was seized, and the ribbon cables which were touching the heatsink was bad.
I measured the current that this thing can deliver to my subwoofer, and it barely exceeds 200 watts with a line level input. Maybe I didn't fix it properly.
edit: not bad to have 112 dB sustained at listening position in a 6000 sq ft room, I guess. But still a bummer.
The silver lining is that I can have flat EQ down to 20 hz without risking the driver. lol.
Serial namber ic pwm for mosffet