Time to look at a Gridcase 1520 portable computer.
Not the one that had the power supply failure; this is the cheaper model with the LCD screen instead of the gas plasma display.
When it turns on it complains that the real-time clock has stopped and the CMOS configuration is invalid.
Time to open it up and replace the CMOS battery!
Some time ago I purchased a VCR player to use while digitising some family video tapes.
It was the rather fancy Sony SLV-373UB with on-screen menu and massive jog-wheel remote control.
Shortly after I had transferred the last video from tape, the VCR player quietly died—the front panel display turned off and it stopped responding to any input.
Inserting a cassette didn't prompt it to pull it in and load it.
I put the machine to one side and forgot about it for a long time.
Now I have unearthed more tapes to digitise and dispose of, I've been trying to get the player working again.
(The new tapes aren't anything exciting — old WordPerfect training videos).
Since the VCR is quite old (I think from 1990?) with no obvious mechanical problems before the failure, I suspected the power supply.
Electrolytic capacitors from the 1990s tend to have dried out or leaked after thirty years so they're a first suspect for failures that don't involve loud bangs.
A few years ago the power supply for my Gridcase 1520 portable computer died.
It emitted a cloud of bad-smelling smoke and wouldn't turn on again.
I placed it to one side and forgot about it for a few years.
Now it's time to get it working again!
The Grid 15xx-series of portable computers use a removable power supply.
It's shaped a bit like like a brick with one edge rounded off.
Once the power supply is removed it can be replaced with a battery pack and the power supply used as an external charger.
I have a couple of battery packs but they are long since dead and will not hold a charge.
Maybe I'll open one up one day and see if they're fixable…
As I was testing the new switch on my second AX-990 (with the cover removed) I happened to touch the heatsink and was surprised to find it was very hot.
It's a piece of hardware literally designed to absorb and re-radiate heat, so perhaps I shouldn't have been too shocked at this.
But it was very hot — almost untouchably so.
That got me thinking: is it possible to replace the linear regulators with a modern equivalent that emits less heat?
After all less heat is better, right?
And electricity turned into heat is basically wasted energy.
One problem that's been apparent on both my AX-990s was the incredibly poor video quality.
Colours would be distorted and sometimes the TV would lose the video signal entirely.
The culprit is the toggle switch on the rear that changes between MSX and Sega modes.
Often just touching it lightly was enough to make the video signal dance and flicker.
With only a small amount of work this can be fixed and perfect composite video is the result!