TS1000 upgrade – log entry 2 — More Power!

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:

1. Unscrew the heat sink. A set of pli­ers to hold the nut on the back­side while unscrew­ing the screw was all it took.
2. Gently lift the reg­u­lat­or slightly away from the moth­er board. This will give you bet­ter access to the three pins.
3. 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.
4. 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.

Kind of.

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.

Notes:

• 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.