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post #751 of 1686
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 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

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.
post #752 of 1686
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
post #753 of 1686
Thanks! The bottom of the board looks fine so it looks like I am in business.

Quote:
Originally Posted by runeight View Post
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.
post #754 of 1686
Quote:
Originally Posted by shellylh View Post
Thanks! The bottom of the board looks fine so it looks like I am in business.
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!
post #755 of 1686
Quick question. I assume that I don't need to use the little plastic washers when mounting the BD139 transistors to the head sinks since they don't seem to fit.
post #756 of 1686
Thread Starter 
No. In fact, you don't even need insulating pads, just thermal grease, because the packages are plastic.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #757 of 1686
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
post #758 of 1686
It looks like they're Fairchild because the have a little stylized F. I bought a kit and I don't have access to the kit BOM right now. They're entirely plastic.
post #759 of 1686
Thread Starter 
Quote:
Originally Posted by 00940 View Post
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.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #760 of 1686
Quote:
Originally Posted by sachu View Post
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

I had to look at drawings and the datasheet before I answered
post #761 of 1686
could i use a bc547b as a sub for the bc 550 in the e12? they ahve been missed off a farnell order.

Cheers
post #762 of 1686
Thread Starter 
Quote:
Originally Posted by adamus View Post
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.
Dr. Cavalli gained notoriety with his first DIY amplifier projects. His success has blossomed into Cavalli Audio, a world leader in amplifier design.
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post #763 of 1686
thanks runeight
post #764 of 1686
Quote:
Originally Posted by shellylh View Post
Thanks! The bottom of the board looks fine so it looks like I am in business.
Hmmmm - you are using a socket, and not soldering the opamp in directly, yes?
post #765 of 1686
Is it important to get a good solder joint when soldering the heat sinks to the board? My 15 watt iron is not really up to it.
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