[Magic77]

I just finished building a MINT. Here's the problem:

LED lights.
No sound at all coming from headphones.
Re-checked all solder joints and jumpers, C1, R8. Looks OK.
Nothing is getting Hot.

Only difference is that I am using an OPA2134 chip opposed to the OPA2132 with the BUF634's.

I beleive the 2134 is OK and should work in this circuit?

The only other thing I can think of is; my soldering of the SO-8 chips may be the culprit. Could I have shorted one of them out while soldering them?

Thanks for any advice.

 

[eyevancsu]

Maybe you just burnt one of the chips. when i started soldering smt chips, i burnt way too much money away.

 

[Magic77]

Quote:

Originally posted by eyevancsu Maybe you just burnt one of the chips. when i started soldering smt chips, i burnt way too much money away.

Yes. I would say that is the problem with my MINT. I have some extra chips I can try; but like you said; you can burn away lots of Money if you don't know the proper way(or have the proper tools) to solder SMD chips.

 

[tangent]

If you spent more than about 5 seconds on a pin, it may well be burnt. That applies if your iron is within a reasonable temperature range for the chip. Check the datasheet's "absolute maximum" section. If your tip temp is higher than specified, it will die in less time.

Also, are you sure you got the orientation right? The pin 1 marking on some SMT chips isn't obvious.

 

[Magic77]

Quote:

Originally posted by tangent If you spent more than about 5 seconds on a pin, it may well be burnt. That applies if your iron is within a reasonable temperature range for the chip. Check the datasheet's "absolute maximum" section. If your tip temp is higher than specified, it will die in less time. Also, are you sure you got the orientation right? The pin 1 marking on some SMT chips isn't obvious.

Thanks. Yes, I would definitely say I spent more than 5 seconds on most pins. I'll check the datasheets, and I'll have to try some new chips.

 

[sygyzy]

Quote:

Originally posted by tangent If you spent more than about 5 seconds on a pin, it may well be burnt. That applies if your iron is within a reasonable temperature range for the chip. Check the datasheet's "absolute maximum" section. If your tip temp is higher than specified, it will die in less time. Also, are you sure you got the orientation right? The pin 1 marking on some SMT chips isn't obvious.

I think the tough part is the small pictures on the tutorial. Not to knock it at all since it was my building bible. When I have time I am going to try to take detailed pictures of everything to show orientation. For those who don't understand little electronic symbols etc, it's tough. For the big Panasonic capacitors, the only way I knew the orientation was looking at pictures and turning them to orient the same way. II had to squint and guess at the surface mount components.

 

[blipblop]

Although I am really a novice to this stuff, ONE thing I learned in my highschool Electronics class (10+ years ago) was that ICs need to be dealt with carefully. In fact, many parts are burnt, yet still work to some extent so we never realize.

Magic, I would buy a IC socket. Don't bother with the gold-socket stuff for a CMOY. Head over to radioshack and buy an 8-pin socket. That will allow you to spend the necessary time soldering without killing the chip. Then slide the chip in after you are done. This ALSO allows you to engage in another expensive hobby - "Rolling" Opamps, that is, trying out different kinds to hear the different nuances of each.

EDIT: Although the above is good advice, I wouldn't be so quick to jump to the conclusion that its the chip. You might end up spending unecessary money, plopping in another chip, only to find that the damn thing still doesn't work.
I would take a magnifying glass to the solder joints first to make sure they are all clean and NOT shorting. Then I'd look at each and every piece to make sure that the resistors are the right value, the capacitors are the right value, and that the ones that are directional are soldered in the right configuration. Then, I'd look to the panel-mounts, that is, the jacks, and the pot. The fact that the led works means you have soldered the battery in the right configuration, unless both battery and LED were configured backwards...