I've just been given an Apple IIgs that hasn't been turned on since 1999. What's a reasonable set of checks to go through to make sure I don't toast the thing the first time I plug it in?

The machine has:

  • ROM1
  • Fan-upgraded power supply
  • RAM expansion card with something like 2 MB installed
  • Apple II High-Speed SCSI card
  • AppleColor RGB Monitor
  • single external 3½" drive
  • external SCSI drive (most likely frozen/dead with age)
  • ADB keyboard and mouse (I also have a Mac ADB setup if these don't work)
  • several 5¼" drives (optional for now, but will be needed later)
  • Many system floppies, including originals.

2 Answers 2


Generic answer, applies to any machine of a similar design in that condition:

  • If you can, check the power supplies (not just for the machine preferably, on anything you are attempting to connect to it too!) with a load that you would not mind or manage to destroy (eg a set of power resistors). Do not test them completely unloaded!

  • If you are proficient enough with electricity to do so safely, wire a seriously high wattage lamp (incandescent/halogen and a few 100W. NO LED/CFL/whatever!) in series with the PSU input when first testing it. This will limit the damage that can happen in case something shorts out. Be skeptical of advice to use a variac - the kind of power supplies used in these machines are more likely to end up very stressed than soft started when you give them undervoltage.

  • Check the interior for foreign, conductive objects (do not open the monitor unless you are really comfortable inside CRT monitors. If you have to ask, you aren't.)

  • ...or leaked batteries/capacitors of any kind

  • Connect only a minimum set of peripherals on the first run.

  • If you can, don't use the only copy of some disk in a floppy drive of unknown condition. Also make sure there is no unwanted foreign object or debris in the drive, this could damage floppy disks easily.

  • Avoid involving hardware parts with teardrop-shaped tantalum capacitors in the first test runs as much as you can, they are potential sources of serious trouble.

On the Variac practice: Often recommended with linear power supplies, to reform electrolytic capacitors and limit inrush current that could cook a dis-formed capacitor before it has time to form and damage your rectifier. Actually, it WOULD make sense with switchmode power supplies like the Apple II have IF you would cleanly disconnect everything downstream of the primary rectifier and filter circuit. Since that would mean temporarily modifying a very dangerous area in a power supply... Also, I'd advise against slowly LOWERING the voltage with a variac in any case even on a linear power supply. That would eventually cause the pass transistors to fully open and let a lot of noise onto your supply rails and/or cause uneven undervoltage in the system - risking latchup effects and/or corruption of any writable permanent storage/memory if any is connected.

On "always connect a load": Especially true on earlier Apple II models, some have a power supply of a design (a feedback-less PSMPS ... what could possibly go wrong.) that will give nonsensical voltage readings over even take damage if not loaded.

Oh, and ... if a switchmode power supply seems to be completely dead, DO NOT disassemble it unless you know what you are doing. The worst failure mode (everything downstream of the rectifier/filter is open circuit, no bleeder resistors installed) could give you 400 volts worth of welcome weeks after being disconnected from the mains.

  • You'll need to pull the battery and check its voltage. Most likely it is dead and you'll need to obtain a replacement.
    – Brian H
    Commented Aug 25, 2017 at 21:10
  • 1
    This is all good advice - I would add that in addition to visually inspecting components for dust obstruction that hitting them with compressed air (i.e. electronics dusting can, not a wet air compressor obviously) to confirm that nothing is hidden and that the dust has been pushed out of smaller crevices can be a great preventative step...especially for anything with moving parts (floppy disk, power supply fans, etc).
    – rnxrx
    Commented Aug 26, 2017 at 21:31

This might sound harsch to some people over protective of their little C64, but best practice is just doing - it with apropriate caution ofc.

Always check the inside for obvious dirt, dust, rust and damage. Remove if any. Next plug it in and power it up (keep the lid/cover closed). If the machine has been stored in dry, clean condition, it should be fine anyway.

There isn't anything you can't prevent without spending way too much time. If a cap is dead or some short happened, they will blow anyway. I did reactivate hundrest of machines over the years and basicly all just worked. The faulty ones usually had issues with dirt and rust, easy to detect before. Noe ever 'blow up' or caught fire. PS faults have been rather rare - and easy to detect when the breaker flips :)) Still, watch out for smell and smoke.

I just got two Sourcerers after 30+ years of rather sub standard storage. Quite some rust, but no obvious problems when checking the boards. Both worked right away. The biggest issue was to find a plug converter, as these units had UK plugs.

After almost 20 years, you might want to change the battery. At least if you intend to use the machine more often. It works fine with an empty one, but all setup (time, date, slot assignment) needs to be entered after each power up. The Battery is soldered in, so it needs some (easy) disassembly to change. AFAIR Digikey still got them listed. Use only (if possible) the original types (maybe of larger capacity), as look alikes may show different behaviour and reliability.

  • 1
    After many years of working with old equipment I finally had my first "old age" blowup. A very loud cap explosion in the power supply of my old XT clone after it had been operating for about 5 minutes (prior start was a couple months before this). It kept processing but was generating a stink so I shut it down... I'd seen multiple (newish) CRTs blow up in big ways at school back in the day, but those were just junk... :-) In any case, try not to let things run attended if you can help it! Commented Sep 11, 2017 at 18:54

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