looking for IC: MC790P (Heath p/n 443-9)

[Alan 'A.J.' Franzman]

---- Original Message ----
> Date:    Fri, 24 Jun 2005 00:29:41 -0400
> From:    "Alex [Temple-Heath List]" <temple.heath at MIWWW.COM>
> Subject: looking for IC: MC790P (Heath p/n 443-9)
>
> Hi all,
>
> Today I spend the better part of the day cleaning and restoring a Heathkit
> IG-28 color bar generator. It is now all nice and clean, but I found it has
> one bad dual JK flip-flop chip in the signal divider chain that has a Q
> output pin that does not follow the input signal, so I need to replace it.
> The IC is a Motorola RTL family chip, MC790P or Heath p/n 443-9.
>
> Already did a google search and only came up with lots of obsolete parts
> vendors that either want to charge outrageous prices, or have a huge
> minimum order.
>
> I was hoping that maybe someone would have a spare they would be willing to
> sell me. May even take 2 or 3 as extra spares if the price is right.
>
> Thanks in advance.
>
> 73's
> Alex


I have 11 used pulls of MC890P, which is the uprated version (wider
temperature range, different I/O loading factors).  Unfortunately the only
applicable Motorola book I have is no substitute for actual datasheets and app
notes, so I can't make any claim whether MC890P will work as a drop-in
replacement in your application without more details WRT fanout/in (regarding
both the actual circuitry in your IG-28, and how to apply the numbers attached
to the inputs and outputs of the chips in the book - as well as the chips'
pinouts.)

If you are able to determine that these will work, contact me privately and
I'm sure we can make an arrangement.

Best regards,

A.J.

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