Wanted: Scrap QFP and leadless chips, bad PC board prototypes

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I'm trying to test a homebrewed IR-reflow solder controller. Basically,
this is an add-on that gets hacked into a consumer toaster oven. It
uses a temperature sensor aimed at the bread^H^H^H^H^Hboard tray to
determine the approximate surface temp, and a microcontroller to handle
the heater PWMing and profile timing. You enter the soldering profile
on a keypad, hit "start" and walk away - in theory.

However, I've run out of unwanted boards and chips. I'd be interested
in acquiring any unwanted, non-functional *cheap* devices and scrap
PCBs that have appropriate land patterns on them. I'm mainly interested
in TSOP, TSSOP, TQFP/PQFP/MQUAD (44 through 208 pins), but I'm also
curious about MELF and similar packages.

I'd prefer unstuffed PCBs but can deal with desoldering and cleaning if
I have to. FR4 is the only material I'm attempting to qualify.

Although I don't intend to use this on BGA packages, I'd also be
moderately curious to test the controller on BGAs if there are
devices/PCBs available. (I have access to X-ray facilities to check the
results).

If you have suitable scrap materials for sale, please email me!


Re: Wanted: Scrap QFP and leadless chips, bad PC board prototypes
I'm trying to test a homebrewed IR-reflow solder controller. Basically,
this is an add-on that gets hacked into a consumer toaster oven. It
uses a temperature sensor aimed at the bread^H^H^H^H^Hboard tray to
determine the approximate surface temp, and a microcontroller to handle
the heater PWMing and profile timing. You enter the soldering profile
on a keypad, hit "start" and walk away - in theory.

However, I've run out of unwanted boards and chips. I'd be interested
in acquiring any unwanted, non-functional *cheap* devices and scrap
PCBs that have appropriate land patterns on them. I'm mainly interested
in TSOP, TSSOP, TQFP/PQFP/MQUAD (44 through 208 pins), but I'm also
curious about MELF and similar packages.

I'd prefer unstuffed PCBs but can deal with desoldering and cleaning if
I have to. FR4 is the only material I'm attempting to qualify.

Although I don't intend to use this on BGA packages, I'd also be
moderately curious to test the controller on BGAs if there are
devices/PCBs available. (I have access to X-ray facilities to check the
results).

If you have suitable scrap materials for sale, please email me!


Re: Wanted: Scrap QFP and leadless chips, bad PC board prototypes
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Hi,

If this is just for a hobby project you don't really need a controller.
I'm pretty happy with the results that I got using an $18 toaster oven
and a melting temperature indicator:

http://www.beloev.net/gbvio.html

True, you may get more consistent results with a temperature controller
but I think other factors like, for example, the solder paste
application process, also influence the quality of the final result.

If you are willing to spend some money, this company sells test PCBs and
dummy ICs (i.e., packages with no silicon inside):

http://www.topline.tv /

Regards,
-- Georgi


Regards,
-- Georgi

Re: Wanted: Scrap QFP and leadless chips, bad PC board prototypes

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Basically,
controller.

This is for two purposes: 1) assembling protos for customers with less
work than hand-assembly and less expense than contract assembly, and 2)
because it's a fun project :)

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oven

Yes, I've read your page. This method doesn't allow one to reach even
approximately the right profile, though. In particular the cooling
phase must be controlled. For example with this method I have cracked
ceramic packages and often created dull joints by cooling too fast.
Conversely, cooling too slow affects longevity.

I'm basically looking for someone who has scrap parts and/or boards for
sale, so that I can do some more inexpensive testing. Each board can be
used 2-3 times for tests (though only the first test is really
definitive).


Re: Wanted: Scrap QFP and leadless chips, bad PC board prototypes
Nice project:

Sorry I have no boards or components to contribute but what are the
details of the project?

uC, IR sensor, etc.


snipped-for-privacy@larwe.com wrote:
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for
be


Re: Wanted: Scrap QFP and leadless chips, bad PC board prototypes
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I can't say if they meet your definition of cheap, but these guys offer
dummy components - good for practice work and testing land patterns:
http://www.practicalcomponents.com /

ISTR they're about $1/chip, with a minimum purchase of ~$60.  They offer
practice boards, but you'll probably find that running your own batch is
cheaper.

Richard

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