Miller Repair

Use a 220 uF at 16vdc. Observe polarity. That cross hatch is the negative ( - ) side.

The cap still standing on the bad board (2nd picture down) is labeled on the board as to what it is. Looks like 16 volt - 10uF, could there be markings on the board for the bad one, maybe under the silicone or hot melt glue or whatever is on the adjacent wires? Looks like some of the components are labeled. The larger one in the bottom picture, next to the switch, looks like a 16 volt - 220uF from here.

Maybe one of the electronics folks will be along to let you know how critical it is to get the exact same cap. There might be some leeway here, but I am not experienced enough to say on that one.

Edit: That was fast, they have already been here!

It's not terribly critical, but 10 X does matter. Use the 220uF, it's probably a filter cap for the supply voltage to the circuit and 220 uF is a good value for that. 16 VDC rating.

Dang!

You guys are GOOD! The visible marking do indeed state 10uF, 16v, which is what is marked on the smaller cap. So I carefully chipped away some of the hot melt that reinforces the power leads. Underneath that, practically buried by the transformer, is a 220uf marking! Time to check my left over parts from previous projects box! I may just have one.

Thanks, guys!

Chris

LVHR

Dumb question, but how did you blow the cap?  My real question is, what makes you think that's the only failure on the board?

GRJ,

Not a dumb question, rather a dumb person answering it! I had cut the battery pack off in preparation to hardwire it to one of Miller Engineering's AC adapters. In a senior moment, I forgot the adapter puts out DC. I applied AC instead, and BANG! I did not see any magic smoke leak out any where else, so I'm crossing my fingers that is all that went bad. I know, it is an assumption, and you know what happens when you assume.

I went looking for a cap in my spare parts tonight. Lots of caps, but nothing even remotely close. Time to visit a RS before they go completely belly up.

Chris

LVHR

Chances are slim the chip survived. It depends on the timing, if the cap was a good short and was first.

If you have any cap that is a higher voltage say, and any capacitance of 100 uF or more, you could tack it, on there observing the polarity, just to see and not waste any money on it.

Also is this for a sign that can be plugged into the desktop base. I think they are limited to a six lead terminal sign and only cost around $25. That could be an option and the base looks pretty good on the layout.

I'd probably consider investing in the regulator that's behind the cap, chances are it's not that healthy now.

Since the board is powered by 3 x 1.5V batteries (or 4.5VDC adapter) so I don't think it has a regulator per se.  The IC labeled U1 does the voltage management and the white lettering on lower right U1 ...F629 (circled) makes me think it says 12F629(?).  That's a programmed IC so not user-replaceable - a sticker like CHASPRDF probably indicates a custom (programmed) device - short for CHASe Pattern or something like that since this is an animated multi-output controller.

BUT. It appears there's a small diode on the upper left (circled).  That might block AC or reverse-DC from getting to U1...letting the blown cap take the hit if the user hooks up the DC adapter backwards (or applies AC).  

Looks like Radio Shack has the 220uF (35V) capacitor "on-sale" for $1.19 on eBay right now w/free shipping. 

http://www.ebay.com/itm/like/400777795911?lpid=82

Or $1.49 bricks-and-mortar:

http://www.radioshack.com/220u...29.html#.VIst9Mm5zSg

As cjack suggests, if it's just the cap that went south, if you have anything close just try it.

Good luck!

You can connect it directly to a 4.5 volt DC source without the cap if you believe it's just the cap that's bad.  It should work fine.  OTOH, that tiny diode wouldn't seem to be much protection if you exploded the cap.  I'm not sure I'd want to connect this to a working sign.

Well, I was able to get the cap from RS. I installed it today. Unfortunately, no joy. The damage is beyond a simple cap. At this point, considering what you guys have been saying, I doubt that it is worth spending any more time trying to fix it. I'll order a replacement from Miller Engineering.

Thanks for all the effort with my problem.

Chris

LVHR

Oh well.  Sure seems that you're not the only one who has converted from battery-pack to adapter or other external power.  As such you'd think there would be some kind of reverse/AC protection on the board which may have added 10 cents to the cost.  But as they seem to be $10 or so, I suppose it's time to move on...

I think the new power supply is the right answer, no sense risking the sign as well with a botched repair on this one.