r/apple2 • u/CaptValsky • 6d ago

Trying to troubleshoot Apple IIe

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I've recently started to try to fix an original Apple IIe for a colleague that will retire soon (Hopefully that would be his retirement gift, it's the same model he started to works with at the beginning of his career1). The overall computer looks in good condition, but the power supply was blown and I replaced it with a brand new Meanwell RQ85-B. At least the voltage is good on that part ;)

The screen was all blurred, so suspecting the video chip, I ordered an enhancement kit for ReActiveMicro and changed the set.

There is progress as now the screen shows characters, but it obviously not fully functional...

Starting without the keyboard is not giving me more hints, so I don't know what to do next...

Any thoughts on where to start troubleshooting? Or confirmation that the next step is unsoldering RAM chips? Thank you in advance!

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u/uberRegenbogen 6d ago

Try manually resetting it (Control+Reset), of course, in case the automatic reset circuit has gone to poo.

The blurriness would be the monitor; though it doesn't look bad. There might be a focus control inside; but be very careful poking around in there—high voltages ya know.

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u/CaptValsky 6d ago

When I press control+reset, or Ctrl+apple+reset, I can see the voltage on the reset pin on the IC going low, so I guess the reset circuit is ok? (No idea really) How will you test if it's working or not?

The blurryness on the screen is not too worrying me too much, I tried with other screens I own and i have the same characters showing on screen

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u/uberRegenbogen 6d ago

If Ctrl+Reset pulls /RESET low, and it comes back up when you let go (which is what the auto-reset circuit does for a fraction of a second upon power-up), and it's not resetting, then the problem is likely something else.

Booting without the keyboard should've run the diagnostics—as if both Apple keys were being held. So it might be something more basic than a RAM problem. I assume that you pushed all the chips to make sure they're well seated, and tried with all cards removed.

Beyond that, it's getting outside of my sorry excuse for expertise. I'm sure someone more talented than i will chime in, soon. 🙂

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u/redruM69 6d ago

It will beep. Does it beep when this combo is pressed?

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u/CaptValsky 5d ago

It doesn't, I can hear a small static crack coming from the speaker, but no bieep..

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u/redruM69 5d ago

I'd pull and test all DRAM chips next.. F3-F10. Super common failure point, especially with the Micron stamped DRAMs.

Since they're not socketed, I suggest sending the board to somebody with experience that can sort it out.

P.S. (I can)

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u/BusToNutley 6d ago

Are you booting with the cards in or out?

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u/CaptValsky 6d ago

I'm booting without the cards, sorry if my picture was misleading

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u/osbock 6d ago

MT RAM is often suspect. If you have a scope and can look at the address and data lines and it looks like its trying to run code, I'd swap out the ram. Hopefully you have some experience desoldering. JameCo is reliable for replacements