I’ve got an old Mirtone 70605 single zone panel & have no idea what they used for end-of-line resistors. Anyone know?
I have a thumb drive with a bunch of manuals but nothing for Mirtone. In fact, I’m pretty sure I’ve come across a Mirtone panel at some point but can’t remember where. So rare around these parts. I did find this thread that shows the inside of a Mirtone 7200 with a couple of EOL resistors installed - I tried zooming in but can’t seem to make out the first color band on the resistor. ??? - PURPLE - RED - GOLD which might be 4.7K?
Common Trouble on Mirtone 7200 panel]Common Trouble on Mirtone 7200 panel]
The device loop uses a 4.7K as E.O.L. resistor. Thank goodness something conforms to current standards. But the NAC uses something else. I’ve tried 3.9K, 4.7K, and a couple others I found in my spare parts collection. Still no luck. I heard an old-timer say NAC 's used to use 10K for EOL so I’m trying to find one in my collection. If anyone has any knowledge or experience with these older systems, does this sound right?
If you look back at the link I posted, I’m going to assume that the NAC on that board is on the lower left (can’t see the markings but process of elimination tells me that). Looks like the resistor they have installed is red-red-orange which would be 22K. Worth a shot. If you need a 10K (or 22K) I’m sure I’ve got a couple I could spare - let me know.
I don’t know about the Mirtone’s, but we use 24k fairly regularly for NAC EOL’s so they can get up there.