Topic: Modifying UA-5

[macacopowa]

HI, finally i did the digimod, apparently all go ok, not are the best solder job but i thought that was fine. But when I switch on the UA-5 with wallmart battery, the the ua-5 didn't work. The light of ON didn't work.
In other post i could read that the digimod don't affect the power on of it. I  suspected that anything go wrong, because at switch on the UA-5 i listened a light piiiiiip, and after a component of the edirol was too hot. Some pics for to clarify
Details from solder job, i can see  little burns, but this is the cause? I'm not sure


And this is the component that after switch on, are very hot, at the corner of right. It's possible to replace this??

[Chuck]

That solder job looks a bit shaky. Is that solder splatter on the board?
I'm afraid your UA-5 may be toast. If so, let me know, I could use it for parts 

[Patrick]

Even if there was solder splatter on the PCB, it doesn't explain why his power wiring was fried.  You said you were using a wallmart battery, did you have the adaptaplugs on the right way?

The solder job does look a *little* shaky, but I have seen worse on functioning UA-5's. 

I'm stupmed.

[Busman Audio]

I have also seen worse soldering jobs on working units.  I have no speculation as to what is exactly wrong but if you have a voltmeter you need to start by testing the points around the power supply like the capacitors around the power supply to see if the juice is getting anywhere it is easy to find the problem if you start from the power suorce and test each component to find the source of the problem.

If you don't feel comfrotable trying to fix it I could take a look. I have parts to fix some problems that could be there.

[macacopowa]

thanks dudes for your hopeful words. I recheck that the wallmart battery have the correct adaptaplugs, and check with a voltimeter .I hope to find the problem

[dklein]

The areas where the digimod solder occurs wouldn't affect aything to do with power supply.  I think your issue is unrelated to the digimod.  And your soldering job doesn't look that bad!

That chip you're talking about is power supply and for some strange reason I think I remember it being a Rohm DC-DC converter.  It must be marked because I don't know why else I would think that, unless I'm thinking of another piece of equipment.  Should be replaceable.  I think it always runs warm though so heat isn't necessarily a problem.
 
Also consider that you might have had a short in some wiring that caused the battery fuse to blow - maybe that's the noise you heard?  Did you get an AC adapter to try?  Got another battery?  At least confirm voltage out of the one you have.  I thought the UA-5 was protected against reverse polarity.  And remember the UA-5 is backward compared to standard - centre pin is ground.

After eliminating that, follow what Busman2 is suggesting - find the point where the power stops.

[Chuck]

Yeah, the UA-5 is protected for reverse voltage. Me and Dutchman found that out at Red Rocks this summer. That may be the problem.

Edit: What about the trace cutting? Was that done? Did you cut the right trace?

[macacopowa]

Hi all, i try to power on with the AC that comes with the UA-5, no luck, now i'm trying to test the components with voltimeter. I pay more attention to the components of UA-5, and i can see that some components have slight signs of use. It's an UA-5 of second hand,I believe that this does not affect the power on of the UA-5, because before making the modification i tried the UA-5 with USB connection and works OK

some pics of signs of use

[bagtagsell]

In my uniformed opinion

1. looks like something burned
2. looks like solder

overall it looks kinda nasty.  Where did you get it at?

[jeromejello]

man, those last 2 pictures... it looks fucked... i hope it can be fixed

[fozzy]

1.  Yea that looks like it is right behind the USB input like someone fed it some voltage or something and toasted it.  Might not impact performance of the rest of the unit.
2. Might want to try to clean that up w/ some copper braid.  It will mostlikely not work w/ that IC's connections bridged.

Check to see if the little wire loop tingy right behing the power jack is getting voltage on the send set of pins, this is just a noise isolation gimick incase you are still getting AC noise when plugging into wall power.

[Chuck]

That solder job looks a bit shaky. Is that solder splatter on the board?
I'm afraid your UA-5 may be toast. If so, let me know, I could use it for parts