Gridcase 1520 Battery Eject Button

My more beat-up Gridcase 1520 was missing its battery eject button. To get the battery or power supply out I needed to poke a flat-bladed screwdriver into the hole where the button should be. Very inconvenient!

Since I had my other 1520 disassembled I removed the battery eject button to have a look at it. It's shaped like a long, thin 'T' with a step in the middle to keep the button held in place against the rear of the battery compartment. The 'base' of the T is sloped so that when the button is pressed it slides over and depresses the spring-loaded clip that holds the battery in place.

I measured it up and managed to bash together a workable model using OpenSCAD. A friend with a 3D printer very kindly printed a couple for me. It fits almost perfectly!

The OpenSCAD source and STL model are available for download.

Gridcase 1520 CMOS Battery Replacement

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!

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Power Supply Repair: Sony SLV-373UB VCR

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.

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Repairing a Gridcase 1520 Power Supply

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…

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AX-990 Regulator Replacement

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.

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