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Kevin,

I would use a razor blade or xacto knife and cut the pins flush with the body of the chip to remove this part. Then you can easily unsolder the leads. Why not just put a diode in series with the battery for reverse protection?

Steve G.

The output of the 555 goes low for about .1 seconds when power is applied. After that it stays high until the power is removed and the circuit resets. So yes it is a single shot. The TLC555 is the cmos version of the NE555. You can use the NE555 in this circuit as well. You can also try just connect...

Correct! May need to amplify depending on signal strength, or try 1N60 germanium diodes. The silicon diodes are actually more sensitive then you would think. I'd use a low impedance line transformer with a 2 or 3X stepup winding for the amplification if possible. The 7555 may require 2 chips to work...

Thanks MrAl,

I edited the schematic in the origional post. Was using "Paint" and forgot to flip that diode after importing.

Steve G.

Miguel, Doesn't use a 7555 but maybe this will help. Here's is a similar circuit I built some time ago using a LM393. I changed some of the values to meet your specs. Requires a switched 5 volts from your line detect relay or circuit to power. After the output goes high which will release the relay ...

Adi, I have used the 1760 and the 2560 in the "stand alone" operation, so have some experience with these chips. All you need to do is pulse the play line low when power is applied. This TLC555 one shot timer should do the trick. Power the 555 with the ISD1760 supply. http://www.postimage....

Robert,

That's a nice looking wide band front end. Happy to see it working the way you hoped.

Cheers,
Steve G.

Craig didn't say which model he bought but it's probably this one:
http://www.testequipmentdepot.com/welle ... wesd51.htm
So the numbers are correct.
Cheers,
Steve G.

Actually there are some brands with a fairly low melting point:
http://www.ceitron.com/solder/rosin.html
Standard 60/40 rosin core solder melts between about 360 and 600 degrees F. from what I've read.

Cheers,
Steve G.

Craig,

The temp generally depended on the job required. My bench iron was normally set at 800 degrees but it was used for a lot of desoldering also.
If it gets the job done then OK ,but 380 seems quite low to me. I don't think I would lower the temperature.

Steve G.

Craig, The discharge time on the caps is why the LEDs stay on so long. You could install a "bleeder" resistor across the caps to speed up the discharge, say maybe a 1K ohm 2 watt but that still leaves about 10 seconds and waste power. Better idea is to use a DPDT switch and disconnect the ...

Well it wasn't just luck I tried this on three different size boards and they were all within 1/2% of the image size. The actual dimensions of the board are .875" wide by 4.625" in height. Next I tried it your way using the margins in the Page Setup by setting the left/right at 3.813"...

Thanks MrAl that was very informative and gave me the insight I needed to correct the problem. Now I didn't correct it by using the margins as you explained but by using the attributes to confine the so called margins on the Paint canvas so to speak. I drew a full size PC image which has the same di...

On the subject of PC board fabrication I have drawn out some PC board layouts using MS Paint but can't seem to be able to print the layout to the exact dimensions as on the screen. I have tried saving in different formats and pasting in Wordpad but still cannot get it exact. So can it be done using ...

You can use a LM350 and adjust the output voltage as needed. It's rated at 3 amps.

http://www.electronics-microcontroller. ... M350-D.pdf
Steve G