Computer power supply fails to start

Hi all,


I've adjusted my desktop case of an old computer so I could slide my empeg player easily in it. Internal in the case I've also mounted an external amplifier. Some old car loud speakers also fit in the case.
I've got 2 problems :
1. I don't know whether the empeg player sends a signal to the remote amplifier if he's not connected in the car.
If not, how can this be solved ?
2. My computer power supply, which I want to use for my empeg and the amplifier, won't start.
What is needed to start the power supply ?

When this configurations works I can use my empeg player also on vacation !

Thanks in advance for all replies.

Cheers,

Guy Van De Wiel

I am assuming you are using an ATX power supply? (You said old, but just how old a PSU?)
You can look here for info on how to use a psu with no systemboard/motherboard.

As for the amplifier power on, are you using a docking sled to "slide" in the empeg? If you do, obviously, like your car, you need to connect the blue wire, the amp remote line. If you are not using the docking sled, you could create a toggle switch, for when the empeg is slid in, to turn on the +12v dc from the psu to the amp, along the remote line.
Anyone want to double check this? The remote line on an amp is +12vdc, right?

And now for something completly different.....

Smoker_Man
#080000449 MkII - 36Gb Blue

Smoker man

Thanks for your reply !
I've got it running at the moment.
The power supply is about 4 years old I believe, it's from my Pentium 133.
I've used an old sled of my previous car radio.
After some modifications it's does the job.

I've put a 0.75 Ohm resistor with a heatsink (!) between the 5V (red wire) and the ground (black wire). Apparently you have to load the 5V power to get the remaining voltages stable...

For the remote signal to my amplifier I've used a +12V wire (yellow cable) of the computer power supply.

It seems to work but I've got noise. I've used the amplifier (Magnat Classic 170) before in my car and I had the same problem... that's why I put it aside.
I thought it would work better in this 'desktop case' configuration.
I'll guess I have to check the board again for a possible solution although I tried a lot of the suggestions.

Has anyone used a Magnat Classic 170 before succesfully?

Cheers,


Guy.

Well, I am going to put my arse on the line and say" If your amp has given you problems before, and it's still giving you problems, well, then, connect the dots....."

Using my (inferior) powers of deduction, perhaps the power supply isnt producing a nice clean power signal (yes it produces dc power but I wouldnt hold a stick against it if it is passing ac line noise into the dc stream).
I would pickup some line filters and install them before the amp, on the +12vdc and the ground connector leading to the amp. Plus if the amp is not properly shielded (most are not, primarily the expensive ones are), then perhaps the psu is inducting ac noise directly into the amp, if the line filters do not fix the noise issue, then a nice lead plate between the psu and the amp would be worthwhile (not really portable then is it!) Or maybe those little ferrite donuts that sit around mouse/keyboard cords might help if they straddled your +12vdc and ground connectors?

Or just get another "known good" cheapo amp?

I suspect that these few suggestions might help you, I have been tinkering with the idea of doing this, but I think I would use an old Compaq 4/66 chassis (nice and slim, about vcr width) to mount a docking sled into, use the psu, but mount rca connectors onto the back, rather than an amp.

Let me know if these work.
Rounding up those ferrite donuts might be tricky, the only keyboards I have seen them on are the new MS keyboards with the built in usb connectors. But if you cn fine an old(er) kb with the donuts on them, and you are handy with a knife, I am sure you can coax those donuts out into the sunlight!

Have fun, and let us know if it works!

Smoker_Man
#080000449 MkII - 36Gb Blue

Smokerman,


I became father for the second time at 16 januari and since that time I didn't have the time to boot my computer.
Meanwhile I visited a professional car audio shop to eliminate my noise problem in the car. Even with a filter (Dietz 660 LF transformer) I have a lot of noise. Then when you put a wire between the input of the filter (on the RCA connector) and my sled all the noise is gone... I apparently have a voltage difference between my sled and my RCA connectors.
The audio specialist says this isn't a normal behaviour and assumes there is something wrong with either my player or my sled.
I'm going to inform with the support team of Empeg whether to send my player back for a checkup or not ...
If everything cools down here at home I will continue the 'desktop approach' and inform the board.
My apologies for the late response.

Cheers,

Guy Van De Wiel

Hey, no problems, you do have your hands ful!!

I am not too sure about the voltage differences, but perhaps the amp in the car is unable to handle the 3 volt output of the empeg.

Smoker_Man
#080000449 MkII - 36Gb Blue

Then when you put a wire between the input of the filter (on the RCA connector) and my sled all the noise is gone... I apparently have a voltage difference between my sled and my RCA connectors.

Not exactly... that's not a voltage difference, that's a ground loop.

You didn't say whether your Empeg is a Mark1 or a Mark2. If it's a Mark1, what you describe is normal and the player should have included grounding leads to handle that very situation.

If it's a Mark2, you've got a ground loop because of a differential in ground potential between one or more of your system components. You haven't detailed your system architecture, so it's hard to say where the problem might lie. Check out the following documents on how to resolve noise issues in car audio installations:

http://www.installdr.com/TechDocs/999501.pdf
http://www.installdr.com/TechDocs/999502.pdf
http://www.audiocontrol.com/techpapers/tech1002.pdf



___________
Tony Fabris

Hi,


Silly me. My system architecture is as follows :

Mark II with serial number 060000049 --> RCA cables --> input Dietz filter --> output Dietz filter --> input amplifier Phoenix Gold QX 4040 + a wire between input RCA connector of the filter and the sled.

I will checked your links.

Cheers,

Wheel.

Unplug the RCAs and check the resistance between the shield of the front RCAs (and the rear ones too) and the empeg's case. This should be 0 ohms. If it isn't, that's a sign that at some point, the ground connection to the empeg wasn't connected and the empeg tried to ground through the audio grounds (and burnt them out).

We've thickened up the tracks on later issue empegs, but this is a sign of an install problem - it will never happen on a correct install. If your unit has blown tracks, we can fix it very easily if it comes back here.

Hugo

Hugo,


I owe you a beer !
I've measured the resistance like you told in your reply :
Between case and front RCA connectors : infinite
Between case and rear RCA connectors : 1.2k Ohm

So your story of burned tracks will be my case.
Thank you for your advice and support !
What I don't understand is, I've never smelled something burning or saw any smoke. I assume you would, when those tracks melt away.
I've had this problem from the very beginning... and always
disconnected my battery before I started wiring.

Ooh this will hurt to send him back...

Cheers,

Wheel.

Hmm, not good. The tracks are very fine (as they are only audio grounds, after all!) and I bet you probably wouldn't have noticed them go. Are you sure you never had a bad ground connection, eg during installation when the sled wasn't fully fitted?

Also, check the ground wire to the sled is secure.

I should be able to get it fixed very quickly. If you don't want to return it yet, you can always just short these RCA shields to the empeg ground and it will behave as if it were fixed.

Hugo

If this turns out to really be the problem, would one of you kind gentlemen please let me know? I'd like to add it to the FAQ, including details of how to diagnose it and what possible things might cause it.

___________
Tony Fabris

Hi,


I'm pretty sure because I've soldered every wire onto the delivered connector and disconnected my battery.
What I forgot to mention is that I need the filter to make it work.
If the problem is only related to a ground loop than a wire between the RCA connector and the sled would do the job without the filter. But this isn't the case.
So I think there is something else we overlook.


Cheers,

Wheel

What I forgot to mention is that I need the filter to make it work.

When you mentioned that filter, it raised suspicion to me. What exactly is that filter? I wasn't able to find any information on it.

Does the system work OK with the filter removed from the equation?

___________
Tony Fabris

Tony,


My empeg only works when I connect it at my stereo at home, in the car (Audi A6 maybe this is the problem) it has never worked.
That's why I went to the car audio specialist because I knew several filters existed but I didn't have them at home to do testing.
The guy at the shop experimented with this Dietz 660 filter and finally he could make my empeg work together with the extra wire as mentioned before.
But before buying these filters (I need two of them) I informed Empeg support because the guy at the shop assumed a problem with the Empeg player.
About the filter I've written down what I could find on it's case and that's the only thing I know about it :
Dietz 660
LF-transformer
f= 20Hz-38kHz.
I could make a phone call tomorrow to find out more details.

Because I heard that American amplifiers work on another principle than European amplifiers I bought a second amplifier the Phoenix Gold QX 4040. Before, I used a Magnat Classic 170 (German). But the noise stayed the same.

Cheers,

Wheel

This sounds odd to me. When you say "doesn't work", what do you mean? It doesn't boot, it doesn't make sound, it makes sound but there's noise, what?

I find it odd that you'd need any sort of a filter, regardless of the amplifier. And as far as I know, American and European amplifiers do not work on different standards.

I'm very confused by all of this. Hugo said you need to send the unit back for repair, so definitely do that. My concern is: why did the failure happen in the first place, and what's so different about your system that made the failure happen?

___________
Tony Fabris

Tony,


What I meaned with 'doesn't work' is : he plays sound but there is a lot of noise.

As I was told about the difference between the amplifiers : American amplifiers would disconnect the ground from the RCA cables when in use.

I'm already 3 months confused and searching the actual cause... ;)
I'm already arranging the shipment of the unit with David Moss of the customer services. As a matter of fact the fax is coming in right this moment.
Guys, your support is amazing !
Tomorrow (Thursday) TNT is going to collect the unit.

Believe me, I would like to know the answer to your latest question also Tony !


Cheers,

Wheel.

Hi all,


After been cut off the Internet for 2 months I'm back !!!
I had a discussion with my provider Telenet (which sucks !) about preformance problems and half March they cut my line without notification...
But that's all behind me now.
I want to inform you about the cause of my noise problems with my empeg player. I'm very sorry it took so long to reply.
It was actually an electrical problem I had with my car. Apparently the isolation of the 'horn-wire' was damaged which caused the noise on my Empeg player.

I want to thank all of you who helped me with my problem.

Cheers,

Wheel