32-bit acorn hardware • Re: Acorn A4 Laptop Repair

A few thoughts:
1. Probably needs the brightness/contrast adjusting... see #2 (but note that vintage LCD panels were never as crisp as the modern TFT types - and are a lot more dependent on viewing angle)
2. You might need to get the remnant of the old one out first (depends if it fell out or broke off), but haven't been near those in a few years... sorry
3. Schematics are in the TRM, which is on Chris's Acorns (https://chrisacorns.computinghistory.or ... rs/A4.html) - the drawings are in a separate ZIP due to the size. It has similarities to the A5000, but some bits are missing and other bits are A4-specific.
As well as battery gloop, I think the A4 is one of the ones with the oozy SMT electrolytic caps - if it looks like something's come out of them then it probably has. The good news is that it isn't corrosive (or nothing like the battery juice is), so doesn't need neutralisation but it is conductive (so needs cleaning off) and obviously the cap won't work well either!
4. Consider a DoM rather than a CF as the former are better suited to running in "IDE" mode (some CF's do, others don't, some are hit-and-miss). Also the DoM might not require an adapter.
As to recovering the data, "it depends". If it spins up but you can't hear the heads move then bumping it might be worth a try. If it doesn't spin up at all then it might be more serious (or just not have power). If it spins up and makes head noises, then it might be more ooze in the interface. It might be worth trying the drive on another machine (even an old PC, if only to see if it is detected - although note that most USB-IDE interfaces don't handle errors well: try to find a real PATA interface instead!)

The Conner drives often seen in the A4 have a rubber bump stop in the actuator which goes gummy over time.

They can be "fixed" with a piece of Kapton tape - then imaged. But don't expect the drive to last.

Also, they can't be imaged with USB adapters because they're too old to support LBA mode, and most (all that I've found at least) USB IDE adapters require that.

Thank you both for the information, I appreciate it a lot

It's been some time since I updated this thread, my apologies - my progress is as follows:
#1: the screen seems to be quite usable following some adjustment, I'm probably just not used to older displays.
#2: I've dismantled the screen surround and I think I've managed to work out how to attach the two rotary control caps.
#3: I've managed to get the mouse fully working, so the unit is now usable.
#4: the owner is going to try and recover data from the original HDD themselves, and I'm trying to fit a solid-state equivalent.

At the moment, I've got a 44-pin IDE-CF card adapter and an Integral 4GB industrial CF card fitted, though I appreciate that anything over 512MB is pointless on RISC OS 3.1. I've managed to get !HForm extracted and into a RAM disk (using IanS's self-extracting v2.48) - I've tried initialising the disk using the following configuration:
- 16 for number of heads
- 63 for sectors per track
- 1015 for number of cylinders
- 1014 for parking cylinder
- No defect list
- Initialise, not format
- No soak test
- Bootable disc
- 1024 for large file allocation unit

!HForm gets through "writing defect list" and "creating map", but after a while of "writing map", I get an error: "HFORM failed: disc error 23 at :4/0F990000 at line 3210" - the disk does not initialise properly and cannot be opened on the desktop.

Is this a problem with what I'm doing, or more likely to do with the hardware that I'm using? I think I'm going to try and use a IDE-SD card adapter and a 512MB SD card instead to see if that fixes the issue, but I would be grateful for some advice.

Many thanks,

Adam

Statistics: Posted by TheMightyMadman — Thu Sep 05, 2024 8:38 pm