I have a client with a perfectly good working system except the 3 zones wired out of a PX-603 expansion amp are buzzing from a bad Capacitor. I could pull the PX-603 and have it repaired or I can replace it with a new one I found. Im leaning towards replacing it.
Question is, Am I correct in assuming that all of the programming happens in the PX-600 and as long as all the dipswitch settings are correct on the PX-603 it should be a direct swap with no additional programming or pairing needed?
Google wasn't much help and Id rather hear from a CI anyway.

Fred, I know you guys were distributors. Maybe you have the answer.

I'm not sure what "new" means. I found a marketing cut sheet that was copyrighted 2003. In general I'm leery of units that have been sitting in a box for almost 20 years. You can have capacitor problems with these units too.

It's a judgement call. I'd open the existing unit and inspect it. If there are obviously heated areas, components in these areas could be primed for fail. In this case I might lean toward the "new" unit. Unless there are dozens and dozens of capacitors, I'd think about replacing the capacitors in the "new" unit. If you replace any power supply capacitors be sure to use a similar type of capacitor. In this area simply using the same value (at the best price, of course) may not yield good long term success.

Inspect the soldering, especially in the heated areas. Look for discolored glue areas. Some units used a light tan, almost white goop to mechanically stabilize things. Fast forward 10+ years and that goop becomes a medium to dark brown and it's conductive. I know some units that will spit and fuss until I scrape the goop from the PC board's input wiring. Listening to the unit, you'd imagine all sorts of really hard to track down issues, but one quick scrape with a knife fixes everything. Look for this goop near power supply capacitors. The conductive goop could inject noise to a nearby signal wire that is in the same pile of goop.

Plan is to pull this one and repair it if possible for a backup.
In the meantime I found one thats been sitting new in box Im going to grab.
I just need to know if its a direct swap being that theres one there now.

I found a 1995 manual. A Q&A comment indicated to me that software development had already stopped and you'd be trapped in the Windows 3.1, NT, or W95 environment.

Various manuals here. Didn't read them.

Wow. A blast from the past. Bad news is that I tossed my Audio Access manuals last summer. My recollection is dip switches on the 603, but don't recall what they mean.

It's a great sounding system, easy for end users if it's programmed well. Utterly useless if you want meta data on keypads.

And who are you calling old?

Thanks Fred. That’s my thought. Since the 600 has a 603 programmed into it already then matching the dip switches should make it a direct swap with no further programming needed. Was hoping to confirm that.

Thanks Buzz, I went through the manual I found and all it really says is that if a 603 is added then the 600 has to be above a certain software version and then the 603 can be added to the 600 software. What I don’t see is that specific programming and if it’s for any 603 set the way you put it in programming or if it’s specific to that piece of equipment due to MAC address or other. My thought is that the 603 is dumb and the 600 does all the work therefore as long as the dip switches line up then it should be a direct swap and the 600 won’t know the difference. Hopefully somebody can tell me if that assumption is correct.

How would have thought that Fred was getting there....

There are significant advantages of being “old”. For example: The Beatles will be issuing new releases every day.

still have not found an answer to this