[Boatanchors] SB-303 Calibrator Part Needed

[J. Forster]

NTE is an end-of-life parts company. They produce replacements for no
longer made parts from other manufacturers. Blame Motorola or TI or
whomever. There were few industry standard pinouts in the early days of
ICs. It was also not clear which families would be winners and which
also-rans.

-John

===========



> Of course NTE had to be different than TI (or vice-versa) and the other
> DTL
> chip makers :) I'll never understand why NTE put Vcc on pin 11 and GND on
> pin 4...
>
> The NTE9924 is a quad 2 input NOR gate.  A 74LS02 or 7402 is the same in
> function but NOT in pinout.
>
> You can still find the NTE9924 on the web for $11-$15 each. Or you could
> make NTE9924 out of a 7402 by moving the pinouts around using an IC
> socket.
> It wouldn't be pretty, but it *may* work. I do don't know about the
> loading
> of a 7402 as compared to the NTE9924.
>
> Got an oscilloscope?  Check the signals going into and out of the NOR
> gates
> on the 25KHz side & also check the voltages on Q602. Q602 is the 25KHz
> amplifier (I have a schematic if you need one).
>
> I'm guessing the 100KHz section works just fine?
>
> Good Luck,
>
> Walt - WB2VSJ
>
>
> -----Original Message-----
> From: boatanchors-bounces at mailman.qth.net
> [mailto:boatanchors-bounces at mailman.qth.net] On Behalf Of Mark Johnson
> Sent: Monday, February 15, 2010 7:46 PM
> To: Boatanchor List
> Subject: [Boatanchors] SB-303 Calibrator Part Needed
>
> Team;
>
> I'm in need of IC-601 for the SB-303 Calibrator. This is Heath PN 443-8,
> or
> a Motorola MC724P or NTE9924.
>
> The 25khz output is not working and I believe that my IC is shorted.
> Anyone
> have one of these? I'll buy an entire BFO/Power Supply board from a scrap
> SB-303 if required.
>
> Thanks!
>
>
> Mark V Johnson VE3DJU/VE3DDI
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