Deluxe Memory Man positive ground?

[lopsided]

Hey guys.

My friend gave me a Deluxe Memory Man with a broken switch and possible someting else.
The DC adaptor is also missing. It should be 24V 100mA but I am not so sure about the negative/ positive orientation.
I found mixed recommendation on the web claiming it should be center negative or positive.

I opened it up  and the electrolytic caps connect to the ground on their positive side. So i believe it must be positive ground, am I right?
If yes it seems to be wired for a center positive adaptor.

It is 2002 reissue with four MN3008.

Hope somebody can confirm I am right at this, I don't wanna damage it more then it possibly  already is.

thanks
Jakub

[Govmnt_Lacky]

Well....

Looking at the LARGE photo here that I found online:

http://www.ehx.com/products/deluxe-memory-man/product-photo

It appears that the Deluxe Memory Man is a CENTER POSITIVE connection.

[lopsided]

thanks for the reply Govmnt_Lacky,

I probably should have been more specific, I am talking about the older bigger reissue model like this http://i197.photobucket.com/albums/aa79/LPValdez/IMG_0006.jpg
it has no sign on the case, and because I found kind of mixed information on the internet I thought I would rather ask.
From what I've seen inside it seems to me it needs center positive too.

Now what I would love if anyone could answer, if I am right with the positive ground assumption of the circuit. I kind of suck at reading double-sided PCBs, but that's the impression I got.

J.

[Govmnt_Lacky]

IMHO... 

You really do not need to be concerned with whether or not it is "positive ground" or not...

What you need to know is if the power adapter is CENTER Negative or CENTER POSITIVE.

You can do this many ways. I am not familiar with the circuit however, I am ASSUMING that there is some form of voltage regulation in the circuit (I doubt that ALL of the components run on 24V)

Just find the regulator, look up the datasheet, and ring it out to the power adapter. That will tell you whether it is center positive or center negative 

Even if I am off-base, this gives you an idea of techniques that you can use.

[lopsided]

thanks,

I will take a look at it, when I come home.
The reason I was interested in the positive ground is that when I first check out the dc wiring, I've seen that the center of the jack is wired to ground on the PCB, and because up to now I have come across only negative ground circuits i assumed the dc jack must be center negative.
But then I have noticed that the electrolytic go with positive to ground so it probably must be positive ground - hence center positive jack.

Anyway, thanks a lot, I'll check it one more time and then see if I can make it work.

J.

[Galego]

I've recently repaired a 2xMN3005 DMM and it was positive ground.

[lopsided]

thanks Galego, i checked it once more to be sure and mine is positive ground, center positive too.
so turned it on and besides the broken chorus/vibrato switch it seems to be working just fine.
gonna test it more tomorrow as it's night already here, but it seems definitely worth investing in new adaptor, despite being told it might be broken.

J.

[Galego]

thanks Galego, i checked it once more to be sure and mine is positive ground, center positive too.
so turned it on and besides the broken chorus/vibrato switch it seems to be working just fine.
gonna test it more tomorrow as it's night already here, but it seems definitely worth investing in new adaptor, despite being told it might be broken.

J.

The one i fixed, also had a busted chorus/vibrato switch, seems like someone kicked it in, but i was able to put it back together. The problem with this one was also that it only delayed with the delay knob way down (very short delays). Once you increased the delay time it would squeak and stop delaying. The problem was the 4558 located under the delay knob, once replaced it was OK.