Skip to main content

Has anyone attempted to repair a Miller Engineering board on the component level? I'll admit, I did something really stupid and blew a cap on the board. (Senior moment!)

I first contacted Miller, hoping they would have some sage advice. Unfortunately, they are strictly an importer.  

 

So back to the board. I was able to remove the remnants of the blown cap. I am hoping that is all that was damaged. Problem is, I don't know what size cap it was. I have several ME signs, and all the boards are different. I have some pics below.

 

The first is the damaged board (left) with the closest configured board I have (right).

 

The second is a close up of what is left. The cap goes at the base of the red stripe, inside the circle. Based on the markings in the circle, I think the cap is polarized.

 

The third shot is the undamaged board. I think the equivalent cap on this board is the one marked 20microF.

 

I'm thinking about using a 20mF polarized cap as a replacement.

 

What you think?

 

Chris

LVHR

 

 

1 Both Miller Boards

2 Blown Miller Board

3 Good Miller Board

Attachments

Images (3)
  • 1 Both  Miller Boards
  • 2 Blown Miller Board
  • 3 Good Miller Board
Original Post

Replies sorted oldest to newest

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!

Last edited by rtr12

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

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

Originally Posted by lehighline:

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.

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.

 

1%20Both%20%20Miller%20Boards

 

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!

 

Attachments

Images (1)
  • 1%20Both%20%20Miller%20Boards

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

Add Reply

Post

OGR Publishing, Inc., 1310 Eastside Centre Ct, Ste 6, Mountain Home, AR 72653
800-980-OGRR (6477)
www.ogaugerr.com

×
×
×
×
Link copied to your clipboard.
×
×