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Help identify power components

kellys_eye

Jun 25, 2010
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As we know it generates 12v DC 1a
It generates TWO 12V supplies - one positive 12V (referenced to ground) and one negative 12V (referenced to ground) - the 'ground' is the PGND terminal.

You can get encapsulated power supplies that deliver +/-12V quite readily - fit one upside down and take wires from the inputs/outputs to the correct places on the PCB if you want to fit one.

That said, if the PSU is 'tripping' you should disconnect the output to see if the tripping stops. If it does then the fault is somewhere else on the main board. If it doesn't then the PSU is faulty.
 

73's de Edd

Aug 21, 2015
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All of your efforts so far are being related to . . . . now confirmed . . . . good components that are in the path to that sealed PSU unit.

Did you initially turn the unit on to see if 12VDC was coming out of its output terminals?

Since a WHOLE power supply and associated SMPS circuitry seems to be contained therein.
Otherwise, if you have no 12VDC out and since it did not do a . . .HARD . . .FUSE blow, I suspect some depleted /anemic E-caps within that soft potted supply.
 

ukspawn

Feb 5, 2022
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thank you both for your replies.

I have limited equipment (no multimeter, or know how to use one properly... yet...) and limited knowledge (id never really even looked at a PCB 'properly' until this) so i did not test really anything unfortunatley, it would have saved me some time and money. but so far its been quite cheap and interesting to do, so.. no problem.

You are right I have assumed a lot, but all i have had to go on is some youtube videos on the basics/dangers of SMPS (so i dont die)
and asking on some forums and sending youtubers messages for their opinions and my video of a noise the unit makes.

I just started replacing parts from the power socket down the line as they were cheap enough and i felt it was a good place and motivation to start learning. I have my new unit now and its working so im happy and my music is working again, so this is now my project!

I want to make it so this project is 'better' than the original and will last longer than my replacment unit

i have a fear the new one will simply die again in 12months , because i use it so much. I still dont think its right that it should die that fast, it should last 5-10years of being plugged in and turned on 100% of the time, its not a high power device etc... so there is some problem with quality of parts used or maybe i just got a defective unit. I searched for the units on EBAY and i couldnt find any "for parts" that have been sold so its not like a massive widespread issue that im hearing about on forums etc... but maybe most people just listen to music a bit each day, or 20 hrs a week... iv pretty much got it on 8-18hrs a day. again im just speculating as i have no facts here.

Do you think it would sensible to BUILD my own PSU that is the same design as the original but uses higher rated longer life parts and "high quality" caps etc (nichicon gold!) I wouldnt mind if it were an external box and replace the IEC mains conenctor with a barrel connector or something... "audiophile power supply" - seems like a nice project :) and if i save the unit then i am happy incase my new one goes the same way.

As you rightly say though, i think i NEED a multimeter and some way to test whatever i do next. So i will order one and start learning the basics.

Thank you again for being a lifeline in an endless sea of electronics information.
 

kellys_eye

Jun 25, 2010
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Do you think it would sensible to BUILD my own PSU
A +/-12V power supply is (or, rather, can be) easy to construct although the cost may be a put-off. When you see what mass-production can deliver it makes you wonder why 'we' build stuff too!

Anyway, using a 12-0-12 secondary transformer, rectification, smoothing and 7812/7912 (+12V and -12V regulators respectively) plus a couple of other decoupling capacitors will get you there! Obviously there will be a source of such supplies online (ebay etc) that could be used but you will also have to ensure it operates safely (boxed, earthed etc).

Many amateurs have workbench power supplies capable of delivering these split-rail supply voltages and 'we' would quickly fit a couple of leads to your device and try to power it up by bypassing that module. It would be the go-nogo test to see if the rest of the circuitry is ok because IF the fault is further in the equipment then unless you're very well equipped with test equipment and a wide range of experience then the device would be headed for the dustbin.
 

ukspawn

Feb 5, 2022
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hmm, Im following and in agreement.

so i need to get hold of a cheap 12v 1a "dual" ac/dc SMPS PSU in order to test.

Any reccomendations from anyone?- i dont know the exact terms to search for so im getting so many results - like "dual" is giving me options for 12v and 5v outputs. whats the term for one that produces posotive and negative voltage?

Also, when you say Ground , is that the same as earth?
 
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ukspawn

Feb 5, 2022
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that search term doesn't yield any results for power supplies relevant to this application as far as i can see.

Is there a website, like when you are PC hardware shopping and you Select power supplies, select what input and output requirments and such and then it finds all the power supplies you can buy and then sort them by price etc?

anyone here fancy building me one as a job? PM me if thats allowed here, if not ignore this.
 
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ukspawn

Feb 5, 2022
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thanks but i dont know what that means in terms of how i search for one to buy.

That is what you were discribing above right? how does that convert from AC 230v with L ,N , E? it looks like its already starting with 12v... i dont know if this is what i need at this stage i think thats just confusing me.

I just for the first part of testing need a manufacturers part number, website link or search term so i can buy a cheap PSU to test the rest of this DAC and make sure that building a PSU is actually needed / neccecary .

cheers for taking the time to reply.
 

bushtech

Sep 13, 2016
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If you have a computer power supply lying around that has 12V pos and neg supplies you could use that to test with.
Otherwise search for something like: 12V PSU with pos and neg rails
 

kellys_eye

Jun 25, 2010
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At a push (probably quite easy), get a couple of 8-cell battery holders (AA type) and make two 12V battery packs.

Joint the positive of one to the negative of the other. This becomes the 'ground' (common). The remaining red and black wires will be +12 and -12V respectively. It will work long enough to do the basic checks.
 

Martaine2005

May 12, 2015
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I think the techy term is multiple windings transformer.
Or centre tapped transformer. Search these terms and you’ll find plenty.
Although these are transformers and not SMPS.

Martin
 

ukspawn

Feb 5, 2022
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Thank you all, great information that would have took me ages to find.
At a push (probably quite easy), get a couple of 8-cell battery holders (AA type) and make two 12V battery packs.

Joint the positive of one to the negative of the other. This becomes the 'ground' (common). The remaining red and black wires will be +12 and -12V respectively. It will work long enough to do the basic checks.


Hmm, i like this idea but with 2 x 12v batteries maybe (not car battery :p ), so join the + of Bat A to the - of Bat B - that wire becomes the common ground.

so:

- of batt A = -12v and the + of Batt B = +12v

does that sound right? great idea. Let me see if i can find the 12v cells i had, if not ill do it with AA as you said.
 

ukspawn

Feb 5, 2022
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Not quite. That will be 24V.
You forgot the 0V centre connection.
But I think you understand.

Martin

so if 8 AA (3v) = 24v and we make 2x battery packs (2x12v)

Join them pos to neg, this is CGND wire, remaining are +12v , -12v

isnt that the same as 2x12v battery? join them, as above, then the remaining terminals are ±12v?

im confused lol
 
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