Hello, New here.
I was wondering if someone could educate me on what happened today:
I have a 20 year old amplifier that stopped working, I opened it up and found that the power supply was still humming away, and producing a variety of voltages (AC).
On the board of the defunct amplifier were 2 x 200v. 6a bridge rectifiers which I thought I could use to connect to the AC out and get back to DC. I wired these straight to the AC output and verified with a multi meter that they were putting out:
-12V for bluetooth panel
-20V for TPA 3116 (2 x 100W) x 2 - wired in parallel to supply
The blue tooth panel was wired in first and worked fine. I then wired up the amplifier, turned them on (no load) and plugged in. . . . . . . and was treated to a small firework display. Smoke and cracking from all over the place. Both Amplifiers and Bluetooth panel were dead.
What happened here? I checked the voltage all was well. . . .
My only thought is that I overloaded the bridge rectifier causing it to fail? But I have a TPA3116 2.1 board (200W) that draws 50W MAX when playing drum and bass, so I was not expecting a big draw on current.
So I've had the failure. Now I need a teacher. . . .will you be my Yoda?
I was wondering if someone could educate me on what happened today:
I have a 20 year old amplifier that stopped working, I opened it up and found that the power supply was still humming away, and producing a variety of voltages (AC).
On the board of the defunct amplifier were 2 x 200v. 6a bridge rectifiers which I thought I could use to connect to the AC out and get back to DC. I wired these straight to the AC output and verified with a multi meter that they were putting out:
-12V for bluetooth panel
-20V for TPA 3116 (2 x 100W) x 2 - wired in parallel to supply
The blue tooth panel was wired in first and worked fine. I then wired up the amplifier, turned them on (no load) and plugged in. . . . . . . and was treated to a small firework display. Smoke and cracking from all over the place. Both Amplifiers and Bluetooth panel were dead.
What happened here? I checked the voltage all was well. . . .
My only thought is that I overloaded the bridge rectifier causing it to fail? But I have a TPA3116 2.1 board (200W) that draws 50W MAX when playing drum and bass, so I was not expecting a big draw on current.
So I've had the failure. Now I need a teacher. . . .will you be my Yoda?
Pictures, schematics and any info available help tremendously in finding answers also when Yoda is involved.
“Do. Or do not. There is no try.” Yoda, The Empire Strikes Back.
Some words have red LEDs blinking...
What do you mean with "AC output" ? I sure hope you did not feed the amps AC as they are allergic to that.
Tip: always use AC or DC when voltages are mentioned (or use + or - when it is DC voltages). So it is 115V AC mains voltage and for instance +20V on the power rail of an amplifer.
“Do. Or do not. There is no try.” Yoda, The Empire Strikes Back.
Some words have red LEDs blinking...
What do you mean with "AC output" ? I sure hope you did not feed the amps AC as they are allergic to that.
Tip: always use AC or DC when voltages are mentioned (or use + or - when it is DC voltages). So it is 115V AC mains voltage and for instance +20V on the power rail of an amplifer.
Last edited:
From what you write, I cannot spot an obvious mistake. Such fireworks is rare and does hardly relate to the amplifiers being connected in parallel or turned on without load. For such fireworks much energy is needed and most likely the cause was in the power supply.
Can we have more detailed information on the power supply and the way you connected it?
Can we have more detailed information on the power supply and the way you connected it?
Hi thanks very much for your replies:
I was planning to write about my "success" so I have a blog post and a you tube video:
blog
you tube
So to recap I thought each combination of "rails" (?) on the power supply gave a different AC output. But how would you tell which is live and neutral, perhaps that was the problem? The markings on the rectifiers AC input did not differentiate.
I was planning to write about my "success" so I have a blog post and a you tube video:
blog
you tube
So to recap I thought each combination of "rails" (?) on the power supply gave a different AC output. But how would you tell which is live and neutral, perhaps that was the problem? The markings on the rectifiers AC input did not differentiate.
Rectifiers
In addition to that, digging up the service manual / schematics of that amplifier would also help.
That is, assuming you can't be bothered to try to trace out which pins of that ribbon cable go to what piece of the power circuit.
In addition to that, digging up the service manual / schematics of that amplifier would also help.
That is, assuming you can't be bothered to try to trace out which pins of that ribbon cable go to what piece of the power circuit.
Oh oh you better start by understanding/learning the basics and then post stuff on the web. You need a schematic of the old amplifier. Something went very wrong, such experiments can cost you your life !
No friend or person you know with more knowledge that can help you out ?
My guess would be that you had the amplifier board sat in the metal chassis and shorted out the whole thing. Did you record that part too?
Watching your video and reading your blog, being totally honest I'd say:
1. Don't play with mains voltage electronics if you do not know what you are doing (you admit freely that you don't).
2. Take the electronic waste to a proper recycler that doesn't send the waste overseas such as: allgreenrecycling.com/exeter-electronic-waste-recycling/
3. Really, don't play with mains voltage. You might kill yourself, your family, your neighbours.. you get the point. It honestly isn't worth burning your house down or electrocuting someone.
4. If you really want to continue on that path, then get 'overly interested in electronics' and learn enough to know what you are doing, what you need to do and how to keep yourself (and others) safe.
Watching your video and reading your blog, being totally honest I'd say:
1. Don't play with mains voltage electronics if you do not know what you are doing (you admit freely that you don't).
2. Take the electronic waste to a proper recycler that doesn't send the waste overseas such as: allgreenrecycling.com/exeter-electronic-waste-recycling/
3. Really, don't play with mains voltage. You might kill yourself, your family, your neighbours.. you get the point. It honestly isn't worth burning your house down or electrocuting someone.
4. If you really want to continue on that path, then get 'overly interested in electronics' and learn enough to know what you are doing, what you need to do and how to keep yourself (and others) safe.
As a rational engineer, you should first do a damage status. After the fireworks, what seems to be useful to continue with and what is to be thrown away?
Your YouTube video shows a transformer that may still work and some other pieces that could be useful. My impression from what you tell is that the power supply in general belongs to the past. You have to construct a new one, eventually with some old components.
Ready to do that?
You seem to have the gear (Youtube video), I'm convinced you are English (video as well) but one thing confuses me (video), you are in a clearly sunny place. England with sun?!
Your YouTube video shows a transformer that may still work and some other pieces that could be useful. My impression from what you tell is that the power supply in general belongs to the past. You have to construct a new one, eventually with some old components.
Ready to do that?
You seem to have the gear (Youtube video), I'm convinced you are English (video as well) but one thing confuses me (video), you are in a clearly sunny place. England with sun?!
You are in Germany, you occasionally see the sun.
The standard joke with my British friends: A Frenchman travels to England and meets a small boy in the street, dressed in a fabric he does not know. He asks the boy: "What is that fabric?". "It is tweed, Sir. It is good against the rain.". "OK, but is it not too warm in the sun?". "I don't know, Sir. I'm only six years old."
A small deviation, now back to technical business!
The standard joke with my British friends: A Frenchman travels to England and meets a small boy in the street, dressed in a fabric he does not know. He asks the boy: "What is that fabric?". "It is tweed, Sir. It is good against the rain.". "OK, but is it not too warm in the sun?". "I don't know, Sir. I'm only six years old."
A small deviation, now back to technical business!
Last edited:
When you decide to use an “alien” power supply you find in a deserted apparatus, you need to analyze that power supply well. If it has more output voltages, are they referred the same potential?to different potentials? floating with respect to one another? If you do not do this analysis, you risk shorting parts of the power supply through the load circuit, in particular load ground.
You also need to get an idea about current rating, if current limiters are present, etc.
It is not just taking over apparently suited output voltages. This meant as a general comment as I do not know what you did before the “fireworks.”
I fully support your intent of re-use. I do the same but normally such that I salvage all good parts and diligently bring the remains to the recycling center. Then, I test the components I have gained and build my own power supply / amplifier such that I know exactly how it is made. Old amplifiers/receivers contain a lot of quality components that may be re-used and should not just end up on a dump-yard.
5 days of sun in England and gray and chill weather in France: the climate is indeed changing. Enjoy! The silly joke included a veiled question: were you in a place with good supplies of the missing components? You are. Brits are scattered all over the world and you could have been in a more deserted part of the world, with sun.
Let us know if you run into troubles with your own construction.
You also need to get an idea about current rating, if current limiters are present, etc.
It is not just taking over apparently suited output voltages. This meant as a general comment as I do not know what you did before the “fireworks.”
I fully support your intent of re-use. I do the same but normally such that I salvage all good parts and diligently bring the remains to the recycling center. Then, I test the components I have gained and build my own power supply / amplifier such that I know exactly how it is made. Old amplifiers/receivers contain a lot of quality components that may be re-used and should not just end up on a dump-yard.
5 days of sun in England and gray and chill weather in France: the climate is indeed changing. Enjoy! The silly joke included a veiled question: were you in a place with good supplies of the missing components? You are. Brits are scattered all over the world and you could have been in a more deserted part of the world, with sun.
Let us know if you run into troubles with your own construction.
Thanks for you helpful response FauxFrench. I have a tendency to over simplify, as you say I had no clue as to the "durability" of each voltage output, I think I was blinded by confidence.
I see what you mean now, no I am not in chiang mai unfortunately!
Regarding waste disposal, the problem with e-waste in the UK (and suspect many other countries) is although you or I may do the right thing and take our waste to a recycling centre. . . what happens to it then?
At present it is far far far far far easier to get a waste export license (ghana, india) than it is to get a permit to recycle in the UK. A e-waste dealer in the UK can charge to get rid of councils waste and then sell it to a dealer oversees. This happens with all sorts of waste not just e-waste.
I see what you mean now, no I am not in chiang mai unfortunately!
Regarding waste disposal, the problem with e-waste in the UK (and suspect many other countries) is although you or I may do the right thing and take our waste to a recycling centre. . . what happens to it then?
At present it is far far far far far easier to get a waste export license (ghana, india) than it is to get a permit to recycle in the UK. A e-waste dealer in the UK can charge to get rid of councils waste and then sell it to a dealer oversees. This happens with all sorts of waste not just e-waste.
My goodness. Another melt down! I am on the verge of giving up. Have just ruined a 3rd board. . . .any suggestions please?
So this time around I connected:
this board
with
this power supply
speaker outputs were wired to the output board from the original amplifier:
video
What happened:
So I connected up as shown in video, powered up. Checked the voltage at input. Perfect 24V DC. Turned on one amplifier using pot switch attached to board. Smoke + Bad Smell. I only flicked the switch on and off at low volume, there were no speakers attached (although outputs were wired to clamp terminals), no audio source attached.
I disconnected everything bar the power supply, and tried again. More smoke although board may already be damaged at that point I supposed.
I have one board left . . .
The only unknown here is the PCB + speaker terminals from the old amplifier, so may that?
So this time around I connected:
this board
with
this power supply
speaker outputs were wired to the output board from the original amplifier:
video
What happened:
So I connected up as shown in video, powered up. Checked the voltage at input. Perfect 24V DC. Turned on one amplifier using pot switch attached to board. Smoke + Bad Smell. I only flicked the switch on and off at low volume, there were no speakers attached (although outputs were wired to clamp terminals), no audio source attached.
I disconnected everything bar the power supply, and tried again. More smoke although board may already be damaged at that point I supposed.
I have one board left . . .
The only unknown here is the PCB + speaker terminals from the old amplifier, so may that?
Ensure the +and -of the power supply are connected to the correct +/- power terminals of the amp board - if these are reversed it goes up in smoke.
Ensure that none of the speaker terminals in your old case are fastened to the case metalwork - this could cause a short.
For testing purposes, you could connect the speaker wire direct to the amp terminals rather than to the terminals on the case.
Ensure the amplifier board is not shorting on case metalwork or hidden screws.
Be aware your 2 amp power supply will not supply enough current for a 2x100W amplifier at full power.
Finally, post some clear photos of your build the video is not clear.
Ensure that none of the speaker terminals in your old case are fastened to the case metalwork - this could cause a short.
For testing purposes, you could connect the speaker wire direct to the amp terminals rather than to the terminals on the case.
Ensure the amplifier board is not shorting on case metalwork or hidden screws.
Be aware your 2 amp power supply will not supply enough current for a 2x100W amplifier at full power.
Finally, post some clear photos of your build the video is not clear.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.