Oops, my obsession with computers from my childhood strikes again!

[rubber_jonnie]

Alternative freeze spray: Dust blower aerosol held upside-down.

If I had a dust blower aerosol...

I use a small compressor and airbrush for blowing dust away and I don't think it's cold enough.

[rubber_jonnie]

And it isn't the 80 column / RAM card. My standard card arrived today and it has exactly the same issues as the RAM2E II.

Need to try and figure this out as I have software that does require the extra RAM, though I'm wondering if it is something 80 column specific.

Also pulled the MMU to hit the socket with some Electrolube EML and it was quite a loose fit. It's those awful single wipe sockets again, they're nothing but trouble.

At least I know now.

[rubber_jonnie]

So, the machine is an Apple IIe P.A.L, board number 870-0073A dated 1982. Its also marked B607-0664. Here's a recap of what's going on.

If I type in PR#3 it goes into 80 column mode, but after about 5 or 10 minutes the machine becomes unstable and I get on screen graphics corruption, or missing columns (Every other one) and from time to time the card just becomes unavailable.

It seems to be thermal as powering off for a short while allows everything to work as normal again, even if only for 10 minutes.

I have 2 cards, a RAM2E II from Garrets Workshop, and a standard remake of the 80 column/64K card. The problem occurs with both cards so I'm confident it's the machine and not the cards.

What I need is a decent schematic for my specific machine, but not having any luck finding one. Mine has the CPU bottom left corner, and the AUX slot in the middle(ish) of the board in front of slot 3 so if anyone can point me a a schematic for this specific machine I'd be grateful.

BTW I do have a number of schematics and PDFs of books containing schematics, but all seem to be different revisions to mine and don't show the aux connector and what's connected to the socket.

EDIT: Schematics found

[Tomswork]

Hi @rubber_jonnie apple the sockets on the ntsc machines can be bad and cause that fault I've never seen a bad capacitor on the boards yet and also the card edge s themselves can wear or crack open at the ends
Some of the large ic are prone to failure but they just stop working. And of course there are discrete parts

Tom

[rubber_jonnie]

Hi @rubber_jonnie apple the sockets on the ntsc machines can be bad and cause that fault I've never seen a bad capacitor on the boards yet and also the card edge s themselves can wear or crack open at the ends
Some of the large ic are prone to failure but they just stop working. And of course there are discrete parts

Tom

Interestingly I decided to pull the sockets for the MMU, IOU and LS125 as all seem likely candidates and found this when I removed the plastic cover of the MMU socket:

PXL_20230406_085829442.jpg (429.58 KiB) Viewed 1057 times

The wipe was barely attached and fell off as soon as I touched it:

PXL_20230406_085850591.jpg (339.88 KiB) Viewed 1057 times

And the one to its left doesn't look particularly good either. I hate these old sockets with a passion, the 600XL I have had a ton of them too.

The RAM cards are both new, so thankfully no splitting to be seen.

EDIT: the broken wipe is the A8 line.

[stephen_usher]

<comedy farmer voice>Ooo-ah! That’ll be your problem right there.</comedy farmer voice>

[rubber_jonnie]

<comedy farmer voice>Ooo-ah! That’ll be your problem right there.</comedy farmer voice>

<comedy farmer voice>Arrr, oi thinks you may be roight</comedy farmer voice>

Running fine so far with new MMU, IOU and LS125 sockets.

[stephen_usher]

[rubber_jonnie]

Sadly, my enthusiasm was too early

10 minutes into testing and the problem is back:

PXL_20230406_111707638.jpg (415.18 KiB) Viewed 1041 times

Disappointed...

[stephen_usher]

Bah!