SOHA II Builders Thread
Mar 31, 2009 at 12:19 AM Post #751 of 1,694
You may want to wait for another to respond and confirm this, but I think you will be fine. Pin 2 is used, but 1 and 8 are not. Your pad for pin 2 doesn't look too bad. You should solder your socket back in, then check for continuity between pin 2 and the resistor and cap pads that it connects to.

In regards to not being able to get it back in. How are you removing the solder? I'm assuming your using solder braid. Are you using flux? If not, you need to. If you are, use more
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You may also want to add a bunch of solder into the holes (again with flux) and then re-remove it with the braid. I usually put my liquid flux on the braid. It can be tedious to get the holes opened back up without a solder sucker, but I don't own one and I do fine
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If you think it was heat that damaged the PCB, turn down the iron. You only need it hot enough to melt the solder. It's OK if it takes a second for the solder to melt. Especially when you're doing rework and you have the heat applied for a longer period of time.

Good luck! I would try to salvage that board. I don't think you've damaged it beyond use. You got lucky on which pads have the most damage.
 
Mar 31, 2009 at 12:34 AM Post #753 of 1,694
Thanks! The bottom of the board looks fine so it looks like I am in business.
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Quote:

Originally Posted by runeight /img/forum/go_quote.gif
Edit: Ahh. My original text referred to the wrong amp. On this amp none of the pads are grounded so if the traces are solidly connected to the pads on the bottom of the board you are ok.


 
Mar 31, 2009 at 4:32 AM Post #754 of 1,694
Quote:

Originally Posted by shellylh /img/forum/go_quote.gif
Thanks! The bottom of the board looks fine so it looks like I am in business.
smily_headphones1.gif



I have lifted quite a few traced prototyping & tweaking various amps - even if the pad comes completely off you can scrape a little of the board away to expose the trace or jumper to the next component..

That didn't look bad at all!
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Mar 31, 2009 at 1:09 PM Post #757 of 1,694
I don't know which brand you have at hand but for newbies here: be careful as some BD139 (philips among others) have metal pads connected to collector.

You don't need to isolate the screw from the plastic body but you need an insulation pad
 
Mar 31, 2009 at 4:11 PM Post #759 of 1,694
Quote:

Originally Posted by 00940 /img/forum/go_quote.gif
I don't know which brand you have at hand but for newbies here: be careful as some BD139 (philips among others) have metal pads connected to collector.

You don't need to isolate the screw from the plastic body but you need an insulation pad



Thanks. I did not know this and have never seen one with metal pads in a TO126 package. But good to know for anyone who might have one of these.
 
Mar 31, 2009 at 5:17 PM Post #760 of 1,694
Quote:

Originally Posted by sachu /img/forum/go_quote.gif
ummm..I think if runeright says it should be fine..it should be fine..that is if what he asking you to check is fine.

He is the designer of the amp



He posted while I was posting
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I had to look at drawings and the datasheet before I answered
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Mar 31, 2009 at 5:18 PM Post #761 of 1,694
could i use a bc547b as a sub for the bc 550 in the e12? they ahve been missed off a farnell order.

Cheers
 
Mar 31, 2009 at 5:48 PM Post #762 of 1,694
Quote:

Originally Posted by adamus /img/forum/go_quote.gif
could i use a bc547b as a sub for the bc 550 in the e12? they ahve been missed off a farnell order.

Cheers



Yes.
 
Mar 31, 2009 at 6:54 PM Post #764 of 1,694
Quote:

Originally Posted by shellylh /img/forum/go_quote.gif
Thanks! The bottom of the board looks fine so it looks like I am in business.
smily_headphones1.gif



Hmmmm - you are using a socket, and not soldering the opamp in directly, yes?
 

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