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-   -   help troubleshooting samson db500A powered 15 main (http://www.diyaudio.com/forums/pa-systems/204297-help-troubleshooting-samson-db500a-powered-15-main.html)

Basscrime 11th January 2012 06:58 PM

help troubleshooting samson db500A powered 15 main
 
Hi, i bought a pair of samson db-500A powered 15 inch 500 watt speakers used of craigslist a while ago, used em for a fiew shows and love em.
there biamped, the tweeter and 15 each have there own amplifier.

PROBLEM:

I was mixing at home the other day and noticed that one of the 15's in one speaker wasnt playing anything, i was only getting sound out of the tweeter, so i turned the speaker off, then back on again and the 15 kicked back in. the same thing happened again a day later but this time it didnt kick back in as soon as i restarted it, so left it off for a while, turned it back on and the 15 was playing music again.
turned it on this morning, and the 15 played music for one song, i played another song 10 mins later and my 15 isnt playing anything again!!
I have never heard of or seen a problem like this before, could it be a loose connection to the amp for the 15?
i have shows coming up this month so i need my FOH mains badly.

any and all help is much appreciated.

Basscrime.

Basscrime 11th January 2012 07:49 PM

i was just listening to a track while i had the 15 working, and then it cut out but it didnt cut out, it faded out like someone slowly pulled a fader down on a mixer, this is verry strange...

diy didi 27th February 2012 06:06 PM

i'm convinced there is a design flaw. I have the same problem with one that a client brought for a repair. I'll be able to tell you later, once i've figured this one out.

diy didi 28th February 2012 07:57 PM

Found the problem!!! Send me a pm if you haven't solved it yet.

Enzo 28th February 2012 10:44 PM

Well, come on, why not share the solution with all of us?

When I see that symptom in anything, my first reaction is dirty cutout contacts on a jack. But it certainly coul dbe many different things.

diy didi 9th March 2012 12:46 PM

ENZO. correct Dirty jack contacts. Weird but true.

jacksnakes 10th February 2013 12:52 PM

Hi guys.
Having a couple of issues with a pair of DB500a's.
In one speaker, it sounds like the 15 has gone - in the other, it sounds like the tweeter has gone..
So, after having read this forum, I decided to take them to bits to have a look.
First, I took the front off to look at the cones to check the connections.
They were okay.
Then I took the backs off both, and swapped them to see what would happen. Lo and behold, the problems got swapped too...
Although the 15 inch fired up intermittently with a fiddle with the volume control...so, I now have a couple of circuit board-type things out of the speakers - I have heard both tweeters working, and both 15 inch cones working, so I am happy that those parts at least are not damaged.
However, how do I go about fixing what appears to be the actual issue - the circuit boards are either dirty or something is wrong.
How do I check, how do I repair?

Any and all help much appreciated.

Enzo 11th February 2013 09:58 PM

So you have dete4rmined that the board in one amp will not drive the woofer, and the board from the other amp will not drive the tweeter, is that correct? And by testing, you have foud that both tweeters and both wooferes are in fact functional, yes?

Each board has an individual problem. It COULD be as simple as a dirty connections, but I'd wager it is more likely each board has an electronics circuit problem. Do you have and know how to use a soldering iron and a multimeter? And can you change components on a circuit board?

jacksnakes 12th February 2013 11:50 AM

Quote:

Originally Posted by Enzo (Post 3366024)
So you have determined that the board in one amp will not drive the woofer,

Yes - bearing in mind that the knobs and switches are still attached to the board, and that turning the 'line in' volume control up and down will produce intermittent sound from the woofer.
Quote:

Originally Posted by Enzo (Post 3366024)
and the board from the other amp will not drive the tweeter, is that correct?

Yes.

Quote:

Originally Posted by Enzo (Post 3366024)
And by testing, you have found that both tweeters and both woofers are in fact functional, yes?

Yes - there are no clicks, fuzzy sounds - nothing out of the ordinary from either woofers or tweeters on both cabs (depending on which board is used!)

Quote:

Originally Posted by Enzo (Post 3366024)
Each board has an individual problem. It COULD be as simple as a dirty connections, but I'd wager it is more likely each board has an electronics circuit problem.

I think my best case scenario is looking like one dirty contact (woofer, since it comes on if you play with the knob), and one possible electrical contact

Quote:

Originally Posted by Enzo (Post 3366024)
Do you have and know how to use a soldering iron

Yes
Quote:

Originally Posted by Enzo (Post 3366024)
and a multimeter?

Not quite so much...
Quote:

Originally Posted by Enzo (Post 3366024)
And can you change components on a circuit board?

not something I have done before, but will give it a go if I know which components are u/s

turk 182 12th February 2013 02:14 PM

cracked solder joints can also be an issue pull out a magnifying glass and and inspect where pins from a connector are joined to the board, also try tapping the assembly while running at low volume and see if it cuts in and out a sure sign of a crappy /broken contacts.
in basscrimes' case i'd be looking for bad cap's, interstage and decoupling, to me the hint there is the volume fade over time.


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