If you are sole sourcing ANYTHING, then you are setting yourself up for disaster, ESPECIALLY IF YOU WORK IN CONTROLS!!! Use a different design approach. Component Obsolescence should NEVER BE A PROBLEM. It sounds like you do A LOT of analog and NOT A LOT of PLCs or PLD's or other firmware...
How about this: what part of the product is damaged? the power supply to ICs? the Power supply to a logic section?
Identify that and you'll know what zener you need. It looks like a 1Watt zener, so it's probably used for a cheap regulator (is there a series resister connected to it?)
Wait a sec!
You covered all your basis for microcontroller requirements, but why would you use an external scsi port when your computer has USB, parallel, and serial ports? These are much more documented and MUCH EASIER to work with than SCSI.
If you are reading an analog signal and want a microcontroller to do ANYTHING with it, you need an ADC circuit, or a microcontroller with one built in, like Microchip's PIC 16C67x series. The output is in 8bit BCD. Micro controllers will properly not react to an analog signal.
2600Hz LOL!
Thanks captain crunch whistle. The 2600Hz tone has long been disabled by the phone company, so forget about phreaking.
Anyway, why not grab a simple TL074 Op-amp and making 2 x 12db/octave notch filters. Look up Delyanis filtering, or 4th order active bandpass filters.
Does...