[vcf-midatlantic] Schematic work needed
go4retro at go4retro.com
Wed Aug 29 02:56:49 EDT 2018
On 8/29/2018 1:15 AM, Evan Koblentz via vcf-midatlantic wrote:
> I need someone to make two (relatively simple) schematics for me. One
> is the IBM card for the Lego kit, and one is the Lego interface box.
> Here is one side of the IBM card:
> Here is the other side:
> Here's a picture of the top of the interface board:
> Here's the bottom of the interface board:
> Here's a document Dan R. made of the board a year or two ago:
> Now here is the catch..... I absolutely MUST have a complete, perfect,
> finished schematic of the IBM card and the interface board by a week
> before Maker Faire -- so let's say the deadline is Friday, Sept. 14.
Do you have a backup plan? I say that because I professionally feel
that creating a working and tested schematic within your timeline is
going to be nearly impossible.
* The first board is two sided, and those typically need to be
unsoldered to ensure all traces under the ICs have been mapped. One
can try to use a multi-meter, but there are pitfalls
* Even if the schematic is doable, there's no way to truly ensure it's
perfect unless one make a spin of the PCB, populates it, and tests
it. unless one wants to spend $250.00, it takes about 2 weeks to
spin a PCB.
* Though the other board looks to be single sided, all of the items on
the board must be described and validated. The toroids in the
center and right seem particularly problematic, as one needs to
determine the uH, turns, and such of the items in order to be
perfect. As well, those TO-220 transistors (or maybe they are FETs)
sandwiched in between the connectors need to be desoldered or
somehow moved so the markings can be read. The LEDs need to be
scoped to determine their mA rating, etc.
I'm not trying to rain on the parade, but I do want to inject some
realism into the request timeline. Doing such a reverse engineer will
probably take a month or so, assuming someone squeezes it into their
normal workflow and they do this regularly.
Someone already made a schematic of the Apple II card:
Regrettably, it looks like the Apple uses a different schematic
completely (It uses a VIA instead of the IBM PC discrete TTL) and so
this schematic will not help.
RETRO Innovations, Contemporary Gear for Classic Systems
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