MOTM

Appealing to the wisdom of those that have gone before me into regions which
I will soon enter...

I've successfully built two MOTM modules: the 101 noise source/s&h and the
420 filter. (I've also finished a 820 lag processor, but haven't tested it
yet.) Both worked as soon as I powered them up, no problems at all.

Next on the assembly list is a pair of 300 VCOs. Having read through the
instructions and looked at the rather dense PC board, I'm feeling faintly
intimidated. Mostly I'm wondering how heat-sensitive some of these arcane
components are. When I was a youngster putting together Radio Shack kits, I
was taught to use a heat sink when soldering any semiconductors. In my old
age I've become more cavalier, and also I now have a decent Weller soldering
iron, so I just solder stuff quickly with a light hand, not bothering with
the heat sink. (Besides, how do you put a heat sink on a 16-pin DIP?) So far
I seem to have gotten away with this. Should I be sensible and use a heat
sink when I'm soldering some of the more unusual parts in the 300s? Or is
this being overcautious? I'd feel even more stupid if I broke a lead on
something by grabbing it too forcefully with a heat sink.

In more general terms, are there any other words of sage advice about
assembling these monsters? I've stuffed a few PC boards in my day, including
some microprocessor-based data-collection equipment (with those nasty square
MCU sockets with concentric sets of pins), but these 300s may be about the
densest boards I've worked on.

I'm considering Larry's tuning modification, but I figure that I should
probably get at least one of them working in stock form first.

Thanks much--
--Adam

P.S. Paul: congrats on the new toy.

The 300 requires patience & attention to detail, but
it's not to tough a build.  Also, I don't think a heat
sink will be necessary if you've got a decent iron &
good soldering technique.  Personally, I thought the
300 was pretty fun to build.


--- Adam Schabtach <adam@...> wrote:
> Appealing to the wisdom of those that have gone
> before me into regions which
> I will soon enter...
> 
> I've successfully built two MOTM modules: the 101
> noise source/s&h and the
> 420 filter. (I've also finished a 820 lag processor,
> but haven't tested it
> yet.) Both worked as soon as I powered them up, no
> problems at all.
> 
> Next on the assembly list is a pair of 300 VCOs.
> Having read through the
> instructions and looked at the rather dense PC
> board, I'm feeling faintly
> intimidated. Mostly I'm wondering how heat-sensitive
> some of these arcane
> components are. When I was a youngster putting
> together Radio Shack kits, I
> was taught to use a heat sink when soldering any
> semiconductors. In my old
> age I've become more cavalier, and also I now have a
> decent Weller soldering
> iron, so I just solder stuff quickly with a light
> hand, not bothering with
> the heat sink. (Besides, how do you put a heat sink
> on a 16-pin DIP?) So far
> I seem to have gotten away with this. Should I be
> sensible and use a heat
> sink when I'm soldering some of the more unusual
> parts in the 300s? Or is
> this being overcautious? I'd feel even more stupid
> if I broke a lead on
> something by grabbing it too forcefully with a heat
> sink.
> 
> In more general terms, are there any other words of
> sage advice about
> assembling these monsters? I've stuffed a few PC
> boards in my day, including
> some microprocessor-based data-collection equipment
> (with those nasty square
> MCU sockets with concentric sets of pins), but these
> 300s may be about the
> densest boards I've worked on.
> 
> I'm considering Larry's tuning modification, but I
> figure that I should
> probably get at least one of them working in stock
> form first.
> 
> Thanks much--
> --Adam
> 
> P.S. Paul: congrats on the new toy.
> 
> 


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In a message dated 4/26/02 9:09:05 PM Pacific Daylight Time, 
winky_dinglehoffer@... writes:


> The 300 requires patience & attention to detail, but
> it's not to tough a build.  Also, I don't think a heat
> sink will be necessary if you've got a decent iron &
> good soldering technique. 

Professor Dinglehoffer is right. The 300 is a lot of work but it's not 
difficult, just follow the directions and take your time. As far as soldering 
larger ICs, I try to use a medium to high heat on my iron (so I'm only on any 
one pin for a second or two). I also will only solder a few pins of any IC at 
one time, letting the IC cool down for a minute before I go back to solder a 
second round of three or four pins.

Good luck!
JB

At 9:37 PM -0600 2002/04/26, Adam Schabtach wrote:
>Should I be sensible and use a heat
>sink when I'm soldering some of the more unusual parts in the 300s? Or is
>this being overcautious?

I don't believe a heat sink is necessary, otherwise Paul S would have 
indicated so. I haven't used a heat sink on any of my MOTM modules 
and have not had any problems with semis being burned. When soldering 
semis I try not to touch the soldering iron directly to the semi's 
pin. I try to heat the pad with the soldering iron, then apply the 
solder to the pad. When the solder melts it nicely wraps around the 
pin on the semi. All of this happens very quickly, in about 1 second, 
so the semi does not get too hot.

Thank you all for helping to assuage my fears. Paul pointed out to me (in
private email) that these days components are fabricated so that they can
withstand being immersed in molten solder by automated assembly machines, so
heat sinks aren't necessary.

Okay, I'm ready. Bring on the 300s.

--Adam