# Power Adapter ISSUES



## Hughesie (Apr 24, 2006)

hi guys i really need your help on this one 

i have a phonic mm1002a (my first mixing desk)

and dug it out a few days to discover that the power adapter is faulty and doesn't work at all. i would use a universal adapter except it has a unique powe input (circular pin design) not the standard kettle plug design 

please help me it has become an item that i tresure 


and don't suggest phonic i have already tried them


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## Chris15 (Apr 24, 2006)

Are you sure that the power supply is in fact faulty? Try checking it with a meter. If it is dead, perhaps try sending it to a service dept. If it is not dead, perhaps it is the power connector. More details might help us with with more ideas. Voltage, connector images, etc. A service type establishment may be able to get a service manual which would enable them to troubleshoot more effectively.


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## Hughesie (Apr 24, 2006)

pictures are coming here is what it says

input 240v-50hz
output 16.8v x2 ac 0.5a

i think it might be a loose wire not being an electrics expert i can fix it


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## Chris15 (Apr 24, 2006)

Hughesie89 said:


> pictures are coming here is what it says
> 
> input 240v-50hz
> output 16.8v x2 ac 0.5a
> ...



A couple of questions:
Do you have a multimeter?
I am guessing that this is a heavy, transformer based supply?
If so, you should find that between pins you should be able to find the transformer windings. I would be guessing a number in the tens of ohms.
How many pins are there in the connector and any indications of how they are wired?

The thought of a loose wire would seem logical.


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## Hughesie (Apr 24, 2006)

ok i have taken some pictures and will upload them now 

i have treated the adapter very well 

i took the cover to have a look and i don't even know what am looking at


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## Hughesie (Apr 24, 2006)

ok here is the web address th acess the pics

http://www.villagephotos.com/pubbrowse.asp?folder_id=1660428


also i don't have a multimeter


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## Chris15 (Apr 24, 2006)

Pity about the multimeter. One of those 3 pins will be a common and the other two will each be 16.8 volts AC. At least that would be my guess. Can you take the cover off?


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## Hughesie (Apr 24, 2006)

yeah i'll do that now


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## Hughesie (Apr 24, 2006)

The pictures are up 



http://img.villagephotos.com/p/2005-12/1118034/DSC01377.JPG
http://img.villagephotos.com/p/2005-12/1118034/DSC01379.JPG
http://img.villagephotos.com/p/2005-12/1118034/DSC01378.JPG


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## Chris15 (Apr 24, 2006)

The left hand side in the first picture is the mains input. It is at this point that I MUST warn you not to plug this in and turn it on without the cover properly attached.

Picture 3, can you pull the heat shrunk connections off? I am thinking that they are removable terminals.

Also could you open the connector up? There might be a disconnection there.


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## Hughesie (Apr 24, 2006)

if mean the orange stuff then no

thanks anyway 

no really much i can do


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## Chris15 (Apr 24, 2006)

Black bits on the end of the wires coming in.


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## Chris15 (Apr 24, 2006)

It may be worth your while trying to get your self a multimeter after the ANZAC Day holiday. A basic one will only set you back about $10. If you can get one, then it should be an easy matter to diagnose the fault. I am sure that you will find other uses for it also, things like checking if a cable is broken spring to mind. Let me know if / when you get one and we'll see about diagnosing the fault.


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## Mayhem (Apr 24, 2006)

Ok guys – first off it is good to see the thought process here and so far so good. One thing to keep in mind is that the first thing to look for in any electronic problem is a mechanical fault. Such things as broken wires (as you noted), dry solder joints, blown fuses and worn connections are often the most common faults.

I agree with Chris that a multimeter would be very helpful here, as currently you are looking only at the power pack as the fault. Could also be the desk (fuse, switch, wire etc inside). 

Looking at the pictures, I wonder if the connector is making good contact? There connectors can loosen up, so that the pins no longer actually touch the sockets. One thing to try is closing the sockets up a little using a small screwdriver. Or, open up the pins a little.

However, you do need to first off isolate the power supply as the fault. If you can get your hands on a multimeter, test the power at the 3 pin socket. Before you do this, put the power pack together to make sure you don’t get a zap. Given that this power pack has no diode rectification, your will need to have your meter set to AC volts. 

You could probably take it into your school and ask one of the manual arts teachers to check it for you. If the power pack works, then you will need to look at the desk.


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## Chris15 (Apr 24, 2006)

I am guessing that Victoria is currently on school holidays as NSW are. The fact that the plugpack has a marked output of 16.8V AC, it is going to have an AC output. From the looks of it, the three output wires are connected to the two ends and the centre tap of the transformer. Therefore, inside the mixer there will be rectification diodes and other power supply circuitry as well as (hopefully) a fuse. With a multimeter, it should be a one minute process to check the transformer is working. In reality, you only need an AC voltmeter, so when you get back to school, your science dept. might be able to help you out there. In all likelihood, it is probably only a simple fault like a blown fuse or a dry joint or a disconnected wire, but a multimeter is really going to make diagnosing that fault much easier.


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## Mayhem (Apr 24, 2006)

Ok – was just shutting down my PC and noticed that I still had your pictures open. I had another look at the pic of the back of your desk and noticed two things that I missed earlier (was watching the Simpsons at the time!).

1. When compared to the other pins, the lower left pin has been squashed – note the gap on the others. This could be a problem. There is also some discolouration adjacent to this pin but that could also be camera flash.

2. I noticed also that the power switch shows signs of arcing (or heat damage), with an obvious burn mark on the bottom.

I have a sneaking suspicion that there is some damage to the power input stage of this desk and that your best bet would be to have someone service it for you. 

It is possible that the power connector has been wiggled a bit too much when connecting/disconnecting the power supply and this has squashed the pin and resulted in a high resistance connection. This could then result in heat damage that could be seen in the switch. Although, I wouldn’t like to state exactly what has happened to the switch. It is difficult to see if that is an arc or overheating. Then again, it could be a switch fault or something else in the vicinity of the switch and the squashed pin could be pure coincidence and not affecting the power at all. However, if it were mine I would certainly spread that pin to ensure that it makes good contact.

You could do that first and then see if the board works. I would do so with the switch off and just see if anything trips the RCD that you are sure to be testing it on. If nothing untoward happens, I would switch the power off at the wall and then switch the desk on before switching the unit on at the wall.

In saying this however, I still recommend that you get someone qualified to take a look at it for you, as that switch will certainly need replacing.


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## Chris15 (Apr 24, 2006)

It is starting to look less like this is a problem with the power pack and more like a problem with the power supply inside the mixer. Taking Mayhem's advice and getting it looked at by a professional would seem to be an appropriate thing to do. We will continue to provide advice if you would like it, but I think there will be a point where we draw a line and recommend that you have it professionally serviced, not necessarily because we are questioning your ability, but because if you were to follow our instructions and something were to go wrong, then you could hold us liable and I for one do not need that.


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## Hughesie (Apr 26, 2006)

ok i have sent it to a friend who is an electronics expert 

hopefully he will fix the problem

just in case i have sent an email t the place i purchaced the item from also some good news is i was looking at new phonic desks and they all seem to have that adapter input style (screw 3 pin design


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## Chris15 (Apr 26, 2006)

Hughesie89 said:


> just in case i have sent an email t the place i purchaced the item from also some good news is i was looking at new phonic desks and they all seem to have that adapter input style (screw 3 pin design



You would want to check VERY Carefully that the voltages and pinouts are the same before you even thought about substituting the power supplies. Failure to do so could mean that you destroy another power supply. Consider what we have said in that it might not actually be the external power supply but rather something internal in the mixer.


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## Hughesie (Apr 26, 2006)

i have just recived a message from a person i emailed about the adapter

Electronic stores like Dick Smith carry a variety of power adaptors. As
long as the voltage and currents (amps) is the same as , or very close
to what you require it should work. Also, the pin connection needs to be
the same. (obviously)

Also, CMC are the Australian distributors of Phonic. See
www.cmcmusic.com.au

Regards,


Greg Goris
Store Manager


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## Chris15 (Apr 26, 2006)

Dare I say that if you don't have a multimeter, then you might have trouble getting the pinout right. I somewhat doubt Dick Smith will carry a centre tapped power supply. Ask whoever you sent it to to check if the power supply is outputting the proper 16.8 volts. I am guessing that between one of the pins and each of the other two, you will get 16.8 volts and between the other two pins you will get either 33.6 volts or 0 volts depending on how it is wired. The more I hear, the more I think that it is something internal.


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## Mayhem (Apr 26, 2006)

DSE along with Jaycar and Altronics all stock multi tap transformers but the question remains as to what the fault is. I wouldn’t even worry about trying to find a new transformer when you don’t yet know whether the fault is in the power supply or in the desk. Post again once your friend has isolated the problem.


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## Chris15 (Apr 26, 2006)

They will sell the transformers but not plugpacks. Just got out the Jaycar catalogue and the closest that they have is a 15-0-15 transformer. Altronics are much the same. DSE has a smaller range the either of the other two. Wait until you hear what your friend has to say abut it. Then we can consider ways to replace the transformer IF that is the problem.


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## Hughesie (May 6, 2006)

ok i have the results of the intesive psu search 

apparently the power pack was faulty and is out of production so im going to have to throw the desk away and buy a new one (sob)


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## Chris15 (May 6, 2006)

How is the supply faulty? Is the transformer blown or what? And have you managed to get a multimeter?


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## cutlunch (May 6, 2006)

Hughesie89 said:


> ok i have the results of the intesive psu search
> 
> apparently the power pack was faulty and is out of production so im going to have to throw the desk away and buy a new one (sob)



Before you throw away the board I would get a transformer specialist to look at it. They will be able to test it to see if the coils are damaged. If they are they should be able to rewind it. Get a quote to see if the cost of a rewound transformer vs a new board makes it worthwhile.


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## Mayhem (May 7, 2006)

Hughesie89 said:


> ok i have the results of the intesive psu search
> 
> apparently the power pack was faulty and is out of production so im going to have to throw the desk away and buy a new one (sob)



I don’t want to sound rude, but I would have expected an “electronics expert” to have given you a bit more advice than to simply throw it away. 

You should be able to find a transformer that will suit this supply. The idea of having it custom would is also a viable option for you. Another thing is to look at the power supply kits that DSE, Jaycar and Altronics have for their own amplifiers. If I remember correctly, some of these are within the power range you are looking for.

ADVISE: I would try to find a local audio service technician to look at it for you. They might have a second hand transformer or can tell you who best to source one from. 

In most cases, the power needed is variable to a certain degree and you might find that a 15V supply or a 12V supply might work. However, you would need to have someone qualified to look at the desk and advise you on this.

Otherwise, if you are going to toss it, you can toss it in my direction!


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## AVGuyAndy (May 7, 2006)

I wouldn't spend much time or energy on this, I would just get a new board at this level of equipment we are taking here.


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## Chris15 (May 8, 2006)

AVGuyAndy said:


> I wouldn't spend much time or energy on this, I would just get a new board at this level of equipment we are taking here.



From the original post

Hughesie89 said:


> please help me it has become an item that i tresure



The item has significance to the owner and so he wants some help to make it work again, so we are providing the help. I'm sure that if the original poster had not wanted to make it work again, he would not have asked.


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## Hughesie (May 9, 2006)

emailed some people and found out the following infomation to part i require is 
Phonic part number:353-22009-000-0. (if that helps anyone) it will cost me $80 plus shipping of course i could just walk into my local sound store and buy a small two channel phonic desk for only $50 

WORK THAT OUT!


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## AVGuyAndy (May 9, 2006)

Ahem, I am entitled to my opinion. And it looks like the OP is buying a new board anyway!


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## Hughesie (May 13, 2006)

looks like it will be cheaper


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