av123 onix ufw-10 gone bad

[surfnseattle]

I have a av123 ufw-10 that has gone bad.

whenever I plug it in I get massive humming.

I like the cabinet but I don't know much about repairing it or hooking up a new plate amp.

any suggestions on how to repair or installing an new amp?

[tthurman]

These easiest repair is probably just to drop in a Dayton replacement.

The exact model everyone used to recommend has been discontinued, I nearly certain that this, is its replacement. The older model had a desirable boost feature that appears to no longer be available. Sandbagger and/or dane will likely chime in here with some good advice too, as they are both familiar with this amp, and sub.

Granted this amp isn't rated as high, from a power perspective, but when I compare my original amp UFW-10 up against my RBH TS-10AP, with a 200 watt, I can't really tell a difference. I suspect the original amp wasn't exactly what it claimed to be, but I could be wrong. The later runs of these amps, in numerous versions never where what they claimed to be, you be the judge. You won't find a more affordable solution, or an easier replacement. Take out old amp, remove speaker leads from old amp, attached speaker to new amp, install new plate amp. Doesn't get much simpler than that.

Good luck!

[tthurman]

Additionally, if you know someone that it somewhat good with electronics, get them to pull the plate amp off, and look for bulging caps, there's a good chance that's all your problem is. This would be the most cost effective repair if you can solder good, or know someone that can. Digi-key should have anything you need.

[surfnseattle]

Tthurman,

THANK YOU !!!!!!!!

I've read a lot of negative comments about the onix sub amps.

I'll open it up to see if the caps are bulging.

But, even if they are do you think it would be better to fix it once by replacing the amp ($120 seems VERY reasonable)?

Just wondering if by fixing the caps, I'll start down a path where I'll end up fixing one minor problem after another and end up having to put a new amp in anyway.

what do you think?

[tthurman]

I just think looking at the caps would be a good place to start, it may or may not be the problem, but it couldn't hurt to look. I recently fixed my Samsung computer monitor by replacing bad caps in the power supply for less than $10 shipped. Caps fail, it's not that uncommon, and if that's all it is, it's likely you could have trouble free performance for some time by simply replacing the faulty ones. Hopefully Sandbagger will chime in on this, he would provide a more definitive answer on the possibility of it just being bad caps. One of my ULW-10's whistles, and he indicated that's all it was. Still haven't got around to fixing that though, but I will eventually.

The old amps were good ones, I've still got one too in my original UFW-10, they are only lacking in that they drop like a rock at 30hz. You should see similar performance in that respect with the Dayton, just with less power. If your okay with that, and would rather not bother soldering etc., then the Dayton is a good option.

[surfnseattle]

opened up -10 ....

got it open....are the "caps" the blue cylinders in the pic?

If so, they don't appear to be bulgiing....

Do you happen to know if I buy the Dayton amp, will it have the same screw hole pattern as the onix amp?

Or will need to drill new pilot holes or modify -10 enclosure in some other way?

[tthurman]

Yep, that's at least some of them. Be careful around the contacts they could be holding charge, and shock you if you touch both leads at the same time.

My experience, for what it's worth, is that the larger ones tend to last longer, and the smaller ones are the ones that fail and bulge more often. If that's the only ones you see, and the tops are bulging to create a dome shape, then that's probably not your problem. I would think you would see smaller ones elsewhere on the pcb though.

[surfnseattle]

caps

Actually, I found ones that look more like the pic of the bulging caps.

There are 2 small black cylinders, one is easy to see next to the fuse at the top of the pic. The other is next to the yellow cylinders, behind the wires.

are these them?






Both appear to not be bulging....

[tthurman]

Oh yeah, I "think" I read from older posts that the plate amp screws line up. No way to guarantee that though.

[tthurman]

Yep, from my house, those look good :biglaugh:

Any caps should be listed with their rated microfarad value, XXX uf or XXXX uf, and so on. Their should be numerous caps on the pcb, in all sorts of sizes.

[tthurman]

It looks like several smaller orange and black ones too. Check them all.

[surfnseattle]

Man, there are dozens of these little guys, all different sizes ..... now that I know what I'm looking for.

But, none have the caps bulging.

I think I'm going to go down the "new amp" road.

I checked out the video link for installing the Dayton Audio SPA250 amp and you're right, it looks super easy !

[surfnseattle]

tthurman,

By the way.... HAPPY BIRTHDAY !

Hope you got some BIG celebration plans tonight !!!!!

And, thanks again for the advice - I would have NEVER figured this out on my own.

[tthurman]

Thanks for the birthday wishes!


I hope everything works out well for your repair.

BTW, I found Dane's thread, he was nice enough to save it on his Knology page. You may want to review it for some additional information. I looked at the specs, and size wise, the 250 seems the same as the 240 versions.

Good luck, and let us know how it turned out.

[auge.dog]

I replaced the old amps with the Dayton amp, and it is super easy. If I can do it, just about anyone can.