I have an upgraded SE/30 (MacCon, Daystar Turbo 040 40MHz, 64MB RAM) and I've been taking voltage readings lately. I've found that the five-volt line, when measured at the back of the computer at the floppy connector, varies between 4.75v and 4.90v. You can see how to take voltage readings at the floppy connector from my attached photo.
Obviously, you will need a DMM or volt-meter to do this.
I would be curious to hear the voltage levels taken by other SE/30 owners. If you can kindly take a voltage reading and post here, please also list specifications of your machine (RAM, PDS cards attached, which PSU you have ASTEC or SONY, etc.) When taking the reading, load some programs from the floppy drive and internal hard disk, click and hold the mouse button down on the menu bar, etc. You want to find a LOW reading and a HIGH reading for the five-volt line.
In a nutshell, I am seeking data on other machines in order to acertain whether my 4.75v reading is excessively low or if it is rather common on an upgraded machine. I am led to wonder this because in most of Larry Pina's books (I have them all), he mentions that anything lower than 4.85v is too low, and could be the cause of system instability.
Any SE/30 owners out there?
I've got one, at 32MB, and I have a 40MHz Turbo040 in a IIci that I could add if I had the adapters, and an enet card. I'd be glad to make some measurements for you, if I had the parts to fit the Turbo040 in it... They are a tad expensive though.
SE/30 with 32megs RAM, 40meg HD, Asante ethernet in PDS slot.
Voltage at floppy is 4.812; power supply is a Sony.
I've noticed the comment in Mr Pina's stuff as well but never had a problem...
Hello, and thank you for the voltage reading. Did you measure that shortly after startup, or after the machine had been running for a while? I ask because in my case the voltage drops slightly as the machine warms up. I kept my DMM connector as I worked on my SE/30 for two hours and saw the voltage drop by 0.1v during that time.