Pa Monitors need fixing... Newbie here needing help.
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Posted on Feb 26, 2011 07:07 pm
RockWood610
John
Member Since: May 06, 2007
Hey guys. I've been in bands the past 3 years. I know how to hook up the majority of all gear, and with a possible new band starting, I got out my old PA gear for vocals.
I have 2 Grund Audio Design monitors. Here is a link of the exact ones I have:
www.sabaturproaudio.com/G...ker_p_2216.html
There is issues with these. In one monitor, the sub woofer doesn't work. And in the other, the horn doesn't work. Not knowing a lot about the wiring of monitors, I decided to take them apart and explore. I discovered in the one that had the working horn but the dead woofer, that there is an easy soldering fix for it.
Here are 2 pics I took of the connections. Both monitors have 2 1/4 input jacks and a crossover dial.
Here is a pic of the input jack set that has a couple simple soldering fixes:
Here is the one that shows a lot of poieces not soldered at all:
Now, I have a 700watt power amp, and all I really know is how to connect the mixer to it, and then the monitors to the amp. When it comes to the monitors themselves and how to wire them, I have no idea what to do.
I really wanna get these fixed, but all the places around here are charging way to much on labor and it could be easier for me to buy new ones compared to their prices. Something I don;t have money for right now. So I would like to know if there are any how to videos or easy ways to re-wire these. I guess my main question is, is there a simple replacement input jack I can buy that you just connect the speaker wires to? Or is this something where you have to buy transistors, plates, ect and soldering them all yourself? I think I can handle an easy soldering job, but I don;t even know what half the parts are in those pics for them...
Thanks in advance!
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Feb 27, 2011 01:25 pm So, the glue let go on the crossover. Not the worst thing that could happen. And most of the pieces are probably still good, and just need to be reattached to the board again.
Should any of the pieces not be in working order any more, no biggie. You can order the replacements from Mouser. They are cheap, and Mouser is fast to ship them out.
www.mouser.com/
If you are not sure of the values that you need for each of the crossovers, you can request the schematic from the manufacture. It seems that they are willing to share looking over the website. Here is the link to contact them.
www.mouser.com/
I can help you with rebuilding them with any info that you may need. Or, in a worse case scenario, you can ship them to me, and I'll fix'em up and ship them back.
Feb 27, 2011 01:49 pm Thanks Rob. I had no cue where to go to even find parts. So thanks for the link.
I am not sure what all the parts are, but an old bandmate of mine is coming out tonight to take a look at them. He has built his own cabs for his DJ rig.
As far as the on pic, if the white piece that isn't glued is the cross over, then it is more then unglued I think. It looks like on the first one that still has it intact has soldering on it in 3 different places. The other one where the glue came off, shows the same soldering coming off of the cross over, but it isn't attached to the board.
There is also little lamps on these models. I'm not sure what they where for, all I know is if there was a hot signal that hit the monitors, they would light up. I am pretty sure there are 2 of them in each monitor, but Idk if any if them work anymore.
What exactly are these lamps for, as well as the cross overs? And is it important for them to be replaced??
And is there any kind of glue I should use to put these back together? Like a glue gun type or something?
Thanks again Rob!
Feb 27, 2011 02:09 pm The lamps serve two functions. One, it's a fuse. So, if the element is broken, it stops the signal form getting through. Second, it what is called a choke. If you should start to send too much power to the monitors, the lamp starts to light up. When it lights up, it becomes a resistor, pulling power away from the horn.
The White rectangle pieces are Power Resistors. Wire wound ceramic resistors to be exact. You should see a value of something around 10K, or 56K on them. And sometimes they use a "J" as well. You can just take your ohm meter, and just measure them to make sure they are still good.
Now the glue should be a high temp glue. Being they are power resistors, they do get hot. So, hot glue will loosen up when you run them. You can use RTV to put them back on, Since RTV is an automotive adhesive, and will resist the higher temps.
Feb 27, 2011 02:11 pm OH! I forgot. The lamps are automotive overhead dome lamps. So, you can go to Pep boys, or NAPA, or any other part stores to buy them.
Mar 01, 2011 02:07 pm Thanks Rob. I guess my first real question is, what type or size of soldering pen would I need to repair these? I having one would come in handy.
Is there any how to websites or videos on this stuff? Is like to learn it so I can do this repair work myself.
Mar 01, 2011 09:59 pm It a shame that your not closer to me. It would be easier to show. But, your on the other side of the state.
So, if your looking for a cheap soldering station, I would recommend the Hakko soldering station. It has good temp control, and you can get different size tips for each of their stations.
For just starting out, I would go with this model.
www.hakkousa.com/detail.a...4800&Page=1
Since your not working in a shop doing full time repairs, I won't suggest stations that do SMD/SMT soldering. (Surface Mount Devices/Surface Mounted Technology) That are the tweezers and hot air stations. For what your going to be doing, just a pen is good enough.
There are tons of videos on YouTube that show how to solder. And I can link a few here for you. The biggest thing to learn, is not to over heat the board that your working on. All you want to do is just heat up the area you want to solder, and tack the component down. It sounds easy enough, because it is.
Most of the time, you will find that you will be running at around 650/700 degrees. And this is for desoldering, and resoldering. It heats up the solder quickly, and as long as you don't hold it there for over five minutes, doesn't damage the board.
Each of the videos that show the solderwick are a little sloppy. If you put just a touch of solder flux www.mouser.com/ProductDet...252bcatmdEfQ%3d onto the wick, and it will draw all of the solder right up the wick. I do this a lot for suborn solder that just refuses to leave the hole in the board.
I think that it's great that you want to learn how to so this on your own. Any assistance I can offer, I will. Just let me know what you get stuck on, and I'll see what I can do.
Mar 04, 2011 12:45 pm Thanks for all the help Rob. An old band mate of mine came over and fixed them. And I just bought some new lamps for them. Hope they are ok to use.12.8 volts at 12.4 ways is what I got.
Mar 04, 2011 08:57 pm Your fine with the voltages. .4 of a volt is not going to hurt anything.
