My dear, I am from Brazil and im my church, we have two box like this. Thermal and peak was lighting, both.... It´s incredeable.... The same resistor was open! its unbelieveble...Its exactly the same problem..Thank you so much. You save me! God bless you.
Thank you very much my dear, I have repair my Mackie for nothing, just the resistor 10 ohms and he reworks good, thanks for your video. It's miraculous. BoB from Belgium.
Thanks for sharing this information, very clear!. In my case, my SRM450V1 still sounds amazing but when I turn it on, with no input signal or nothing plugged in, the hi freq driver makes a noise (the same as a circuitry that has a lack of grounding cable). I check the connections, visual inspection and slightly bend the board to find if there was a bad or crackled solder and I coudn't find anything. Comparing with your footage, mine don't have the metal plate attached with the strap in the two red and white cables of the power line....
I replied to this comment on my phone but don’t see my reply. Unfortunately the fault could be anything so sorry I can’t point you in the right direction. I would recommend Not bending your pcb, it may cause a crack or cause a crack in a soldered joint.
Very True, Class a, and ab amps tend to have more reliable torroidal psu's, they tend to sound so much better and have much more power then those small class d amps
Hi John, really interesting video. I think I have the same problem with a Mackie SRM450v3. Today the thermal / limit light started randomly blinking with no input and now it is on permanently even with no input and both channels turned down to zero. What is strange is that if I do provide an audio input and turn it up it still sounds fine with no audio cutout or noise or distortion - everything behaves as it should, except the thermal light is on. Which makes me think it is a random fault rather than a genuine overheating issue. I wonder if it could be the same 10ohm resistor as in your video? The only problem is the V3 board layout is different so its not easy for me to spot the resistors. I have tested a few that I can access, but several are mounted vertically which makes it difficult to test them without completely removing the board from the heatsink plate, which I think will be quite a job and I would rather avoid if possible unless I know this is likely to solve the problem. Have you any experience with the V3 and could you point me to the 15V resistors? I cant find a schematic so I am pretty much testing blind. Thanks for any help you can give, it would be much appreciated. Michael
Hi John, I Some Still have A Mackie SRM 450 I have a issue with 2 of them, when are turned on you get a loud hum for a second or so and the next thing is when a driven loud the power light cut off and also the audio intermittently. when down it starts to work good again
hey john, i have 2 v1's, one with no LF and another with no sound at all unless you turn it up very loud. i have checked all the internal voltages and they are ok. i also compared the level potentiometer resistance and they match so I think that is working ok. Is there anything else I can check? also weird, i have v1 also but i don't have the resistors below the +-15v transistors.
Hi, The one with no sound is possibly a blown input op-amp. No idea about no LF without testing it. Your board is probably a different revision, the resistors will be somewhere else. Thanks
Hi there I bought a mackie srm 450 v 2 with a faulty amp intending to convert to passive can you tell me please what crossovers I need to install and where to purchase in the UK
Hey John, thanks for the video...I've had the v1 for years and have had a problem with overheating and shutting off (which is actually a safeguard mechanism to protect the speaker)...I've seen a few videos on a retro installation of a fan but I don't know if I want to make any permanent cuts in the speaker. Do you have any solutions for overheating?
Hi, There is no easy solution for keeping these speakers cool when being driven too hard for long periods. Keep them vertical and plenty of air circulation at the rear helps. A mains fan pointing at them helps too.
@@JohnB-2021 I bought a cheap clamp-mounted desk fan and my problem child had been behaving nicely. Strange how one is perfect and one has an overheating issue...
hi i got 6 srm450 some made in Italy ,USA , China can you tel me which is V1or V2 or V3 i need to replace some volume pot and it seem they are different !
Hello! I have this speaker. Sometimes it emits small rustles and discharges as if there were cold welds. I checked everything, what can it be? Thank you!
I had a similar problem on one old v1, i think it was dry joints on the small components near the transformer. If not that, it could be any one of the chips or any one of the smd transistors becomming intermittent.
@@JohnB-2021 Thanks a lot for the answer! It has been working perfectly for two hours now. Unfortunately, these intermittent problems are the most complicated
@@Andreadel1994 Hi Andrew, I guessed it was old and you're right, intermittent problems are the most complicated. I have spent too many hours waiting for intermittent faults to appear so stopped repairing v1 450s. In the last 5 years, I had one 450v1 with white noise / hiss, it was a SOT23 transistor working but noisy. It took days to find it. I then had a 450v1 blowing the tweeter twice, found lots of dry joints and changed as many (as I could) SOT23 transistors in the corner of the board in case one transistor was intermittent.
@@JohnB-2021 Thanks so much for your interest! Had it been a transistor or chip the problem would not have been continuous? I forgot !, the problem often occurs when I turn off the amplifier
Hello John b I’m ready change the part but I have the same problem I discovered that if I give it a tap in the metal the light comes on thermal and the vibration of the speaker what could be the problem thanks
It was an overkill design when it first came out. More of a monitor type speaker. In reality class D is what you want nowadays. The new V3 is leap years away from the original design. People are nostalgic about the first versions. Today, it’s considered in the dark ages. Time to move on.
My dear, I am from Brazil and im my church, we have two box like this. Thermal and peak was lighting, both.... It´s incredeable.... The same resistor was open! its unbelieveble...Its exactly the same problem..Thank you so much. You save me! God bless you.
+Helio Junior
Hi Helio,
Excellent news that you found the same problem.
I'm pleased the video helped.
You're very welcome :)
Thank you very much my dear, I have repair my Mackie for nothing, just the resistor 10 ohms and he reworks good, thanks for your video. It's miraculous.
BoB from Belgium.
wow fantastic news, I'm pleased it helped. :)
Thanks for sharing this information, very clear!. In my case, my SRM450V1 still sounds amazing but when I turn it on, with no input signal or nothing plugged in, the hi freq driver makes a noise (the same as a circuitry that has a lack of grounding cable). I check the connections, visual inspection and slightly bend the board to find if there was a bad or crackled solder and I coudn't find anything. Comparing with your footage, mine don't have the metal plate attached with the strap in the two red and white cables of the power line....
I replied to this comment on my phone but don’t see my reply.
Unfortunately the fault could be anything so sorry I can’t point you in the right direction.
I would recommend Not bending your pcb, it may cause a crack or cause a crack in a soldered joint.
Very True, Class a, and ab amps tend to have more reliable torroidal psu's, they tend to sound so much better and have much more power then those small class d amps
Well yes I tend to agree but there are some powerful class D amps with very good power supplies.
Which can be stupidly expensive, which again tend to make the class a and ab better in that respect
Hi John, really interesting video. I think I have the same problem with a Mackie SRM450v3. Today the thermal / limit light started randomly blinking with no input and now it is on permanently even with no input and both channels turned down to zero. What is strange is that if I do provide an audio input and turn it up it still sounds fine with no audio cutout or noise or distortion - everything behaves as it should, except the thermal light is on. Which makes me think it is a random fault rather than a genuine overheating issue.
I wonder if it could be the same 10ohm resistor as in your video? The only problem is the V3 board layout is different so its not easy for me to spot the resistors. I have tested a few that I can access, but several are mounted vertically which makes it difficult to test them without completely removing the board from the heatsink plate, which I think will be quite a job and I would rather avoid if possible unless I know this is likely to solve the problem.
Have you any experience with the V3 and could you point me to the 15V resistors? I cant find a schematic so I am pretty much testing blind.
Thanks for any help you can give, it would be much appreciated.
Michael
The V3 is nothing like the version 1 so your problem is something else.
Hi John, I Some Still have A Mackie SRM 450
I have a issue with 2 of them, when are turned on you get a loud hum for a second or so and the next thing is when a driven loud the power light cut off and also the audio intermittently.
when down it starts to work good again
they the version 1 450
Many make a bang when turing on, never looed for the cause.
Yours sound like they are being driven too hard.
Thanks mate :)
Happy to help
hey john, i have 2 v1's, one with no LF and another with no sound at all unless you turn it up very loud. i have checked all the internal voltages and they are ok. i also compared the level potentiometer resistance and they match so I think that is working ok. Is there anything else I can check? also weird, i have v1 also but i don't have the resistors below the +-15v transistors.
Hi,
The one with no sound is possibly a blown input op-amp.
No idea about no LF without testing it.
Your board is probably a different revision, the resistors will be somewhere else.
Thanks
Hi there I bought a mackie srm 450 v 2 with a faulty amp intending to convert to passive can you tell me please what crossovers I need to install and where to purchase in the UK
You would need a passive cross-over, look on ebay.
I'd keep the speaker as standard, sell it and buy the right speaker for the job in hand.
Thanks
Hey John, thanks for the video...I've had the v1 for years and have had a problem with overheating and shutting off (which is actually a safeguard mechanism to protect the speaker)...I've seen a few videos on a retro installation of a fan but I don't know if I want to make any permanent cuts in the speaker.
Do you have any solutions for overheating?
Hi,
There is no easy solution for keeping these speakers cool when being driven too hard for long periods.
Keep them vertical and plenty of air circulation at the rear helps.
A mains fan pointing at them helps too.
Don't drive the crap out of them. The power it has are for dynamics. Not to play a compressed signal at full tilt the whole time....
@@JohnB-2021 I bought a cheap clamp-mounted desk fan and my problem child had been behaving nicely. Strange how one is perfect and one has an overheating issue...
Thanks
hi i got 6 srm450 some made in Italy ,USA , China can you tel me which is V1or V2 or V3 i need to replace some volume pot and it seem they are different !
The V1 has a mains transformer, the v2 has a switch mode power supply
@@JohnB-2021 sorry but know different they look
Thanks for the video - it is above my skill - I have a mackie s31521z with limit light stuck and stuck in limit mode. Any ideas?
Hi, I can't find that model, is it a mixer?
sorry it should it should be Mackie SR1521z
I think it is an older model - probably first versions
Why my v2 the woofer stop working..only the tweeter are working..what could happen with the woofer
Either the woofer has a loose connection or the amp is blown.
Hi! Are u still fixing amps jhon??
Sorry no.
What kind of probes are you using ??
Sharp probes, a cheap lead kit from the internet
Hello! I have this speaker. Sometimes it emits small rustles and discharges as if there were cold welds. I checked everything, what can it be? Thank you!
I had a similar problem on one old v1, i think it was dry joints on the small components near the transformer.
If not that, it could be any one of the chips or any one of the smd transistors becomming intermittent.
@@JohnB-2021 Thanks a lot for the answer! It has been working perfectly for two hours now. Unfortunately, these intermittent problems are the most complicated
Actually the board is very oxidized, the problem occurred after redoing the welds to the filter capacitors
@@Andreadel1994
Hi Andrew, I guessed it was old and you're right, intermittent problems are the most complicated.
I have spent too many hours waiting for intermittent faults to appear so stopped repairing v1 450s.
In the last 5 years, I had one 450v1 with white noise / hiss, it was a SOT23 transistor working but noisy. It took days to find it.
I then had a 450v1 blowing the tweeter twice, found lots of dry joints and changed as many (as I could) SOT23 transistors in the corner of the board in case one transistor was intermittent.
@@JohnB-2021 Thanks so much for your interest! Had it been a transistor or chip the problem would not have been continuous? I forgot !, the problem often occurs when I turn off the amplifier
Hello,
thanks for your video. Can you please explain how to correctly set the bias on this speaker?
Thanks
Regards
Massimo
If it hasn't been adjusted, don't touch it.
If it has been adjusted, search for a user manual on-line, one manual on Google does show explain.
Thank you so much John! I found it!
where are you based just incase i need my fixed
South Yorkshire
Hello you can help I have mackie hd 1531 when it’s on on pass une minute it quickly turns on thermal light what is you can help thanks
It is a power supply problem
Thanks but it’s necessary change all tablet or change only the part.or you can fix I’m living at Los Ángeles where you at thanks
Find an electronics engineer in LA, I'm in the United Kingdom
Hello John b I’m ready change the part but I have the same problem I discovered that if I give it a tap in the metal the light comes on thermal and the vibration of the speaker what could be the problem thanks
I have never seen a 1531 so don't have a clue.
It was an overkill design when it first came out. More of a monitor type speaker. In reality class D is what you want nowadays. The new V3 is leap years away from the original design. People are nostalgic about the first versions. Today, it’s considered in the dark ages. Time to move on.
HI John
i have a thermal problem with my mackie SA 1232z
i tried many things ..
can i have your e-mail ..
maybe solve this problem togethor
grts Simon