Entries in this series:
- 1) TS1000 upgrade
- 2) More Power! « you are here
- 3) On The Big Screen!
- 4) Oh the memories we’ll make with 16k!
2023, 02 , 05
As I’d mentioned in my previous post in this series, I’ve been poking around my TS1000 a bit and doing some online digging. I found this series about refurbishing and upgrading a Sinclair ZX81.
And since I wrapped up my last post testing the that unit is still alive and kicking (I think. Video is still a thing to verify with the MK One eyeballs, though it looks good in the multimeter), it’s best to jump on to the next stage. Upgrading the power converter.
That’s really big heat sink
So here we have the humble Timex Sinclair 1000 motherboard. Four integrated circuits (Ferranti ULA, Z80 CPU, 16k ROM, 2k RAM), some resistors, a few capacitors, a handful of diodes, connectors and a couple of coils.
And one power regulator with attached heat sink. Here’s a close up. Regulator in the red box, the aluminum heat sink in the green box.
All that will be replaced by this little modern Traco DC to DC power converter, which steps the incoming power down to 5 volts from the incoming 12 volts provided by the wall plug power supply. It works by switching the power on and off really really fast. Power coming in ramps up to 5 volts, bam, it turns it off, then back on. Cool.
Unlike the original power regulator which dissipates the extra voltage by turning it into heat and piping it out to the heat sink to prevent melting the computer. I love modern components 🙂
Doin’ the work
Swapping out the regulator for the power converter is pretty simple:
- Unscrew the heat sink. A set of pliers to hold the nut on the backside while unscrewing the screw was all it took.
- Gently lift the regulator slightly away from the mother board. This will give you better access to the three pins.
- Decision time. Do you cut the pins and then desolder the remaining fragments in the mother board, or desolder the whole thing at once? That’s a personal call based on your skill and comfort level. And who knows, maybe you want to salvage the parts for another project. Either way, remove the regulator and clean up any remaining solder exposing nice, clean, holes.
- Solder in the new power converter. It’s important to make sure you put it in the right way. There are three leads. The component datasheet has the following detail:
Note that Pin 1 has a DOT beside it. This is your clue for orientation.
- Pin 1 is your incoming voltage. You’ll be soldering it to the line that comes in from the power supply connector.
- Pin 2 is the ground, which will be soldered to the line that is the board’s ground.
- Pin 3 is the output voltage which will be soldered to the board’s 5v power line.
A nice thing about this Traco unit, it’s a pin-compatible component. It just fits right in where the old one came out without much fuss.
In my case, there was a resistor that encroached a tiny bit into the area. Some gentle prodding and prying allowed me to get the converter properly seated against the motherboard and soldered in.
- Fairly simple replacement / upgrade. The Traco converter is a pin-compatible component.
- Easier to snip the leads of the power converter then desolder the fragments from the motherboard and clean it up. Also less risk of overheating the traces and possibly having them lift off the board. These old things can be fragile
- Mind the tight resister placement. Gently coax it over just a bit to ensure the power converter sits flush with the mother board.
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