Thread: need cow skull circuit help

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The 3 pronged piece that controls the servo on the circuit board broke.I think it's labeled u1 and has a black peice with screw that it is attached to it.The pronges are still attached.when it broke I held it there and the servo worked Can it be soldered or is the board now just trash?This is a board that was already assembled.

Are you talking about the servo connector. If so, go to a store that sell radio control stuff and buy one of these:

Female Servo Leads

Solder it to the board where the servo pin connector is/was. The other thing you might be talking about is the voltage regulator. Does it look like this:

+5V Fixed-Voltage Regulator 7805 - RadioShack.com

If so, you can get a replacement at Radio Shack. There should be a number on it you want to match. The example I gave is a 7805 which is a 5V regulator. Desolder the regulator and replace it. I'd suggest taking a picture first so that you put it in the right way when you replace it.

If it's neither of these, could you post a picture of what is broken?

Here's your part:

https://www.jameco.com/webapp/wcs/st...oductId=107182

It's the 5 volt regulator, the black piece you referred to is the heat sink. If you can actually hold it in place, you may be able to re-solder the legs back together. If you attempt this, do a clean job - you don't want to have solder bridges shorting the board.

Now I realize a cow board is a Scary Terry Audio Servo Driver:

Cowlacious Scary Terry Products

I pulled a spare one and looked at the regulator. If you're REALLY good at soldering, you might be able to reattach the voltage regulator leads. However, the best thing to do would be to contact Carl directly at support@cowlacious.com. He answers promptly and is in the best position to give you advice in repairing it yourself or having him repair it.

I think I may just order another board.I assume the one I need is st200(pre assembeled).What is the st200cb is it the circuit board unfinished.I did email carl and sent this one to my husbands computer guy at work to see if he can fix it.I just want to order the right board.

You want the assembled unit which is $39.95. The -CB is just the circuit board - no parts. If you want to save time and money, get the assembled unit.

I think Carl will fix a board for not much more than the cost of parts. However, you probably wouldn't get it back before Halloween. You could get a new one for this year and get the broken one fixed for next year so that you could have a talking skull duet!

The voltage regulator Otaku suggested will allow the circuit to run of batteries rather than a wallwort. You're going to need to power a circuit with a 7805 in it with at least 7 volts (e.g., a 9V power supply).

While that's a disadvantage, I found myself changing batteries too often during last year's haunt and am driving my skull with an adapter like this SparkFun Electronics - Wall Adapter Power Supply - 9VDC 650mA. The obvious downside to an adapter is that you need 110V outdoors and must take care to do that safely. In my case, I need 110 for the powered speaker system so I already needed to be careful.

Originally Posted by asterix0

The voltage regulator Otaku suggested will allow the circuit to run of batteries rather than a wallwort. You're going to need to power a circuit with a 7805 in it with at least 7 volts (e.g., a 9V power supply).

Actually, that's the p/n that's listed for the circuit on the Cowlacious site. Not sure why a 7805 isn't used, but that's the one that's on the board (U1). Per the manual, the board will run on 5-24VDC.

http://www.cowlacious.com/SupportDoc...t%20Manual.pdf

I think the LM2940 is used because its drop out voltage is only 0.5V versus 2V for the 7805 since the kit contains a battery pack for 4 AA cells. Technically, the 7805 shouldn't work with 6V battery power. However, I've used them in hobby circuits and they've worked just fine. I guess people are probably more likely to use the correct components in commercial circuits.

Thanks that's the one I thought I needed.Hubby said computer shop said it was fixable and I should have it today.But I will order a back up.I miss my singing elvis and can't wait to get it working again.Thanks everyone!!!