Talyvel 3 Repowering

I think it will run off the charger without the batteries. I got one that had pretty dead batteries, but left it on the charger for a couple days, and the batteries started to work. It worked fine for a year or so, but when I put it away for a while, the old packs croaked. So, I finally made up new packs with new cells from Digi-Key.

I wouldn't screw around with such an expensive instrument. I think the readout box goes for $1200. Probably more, now. And, I don't think you'll get a circuit diagram from Taylor Hobson.

Jon

Jon

Another reason I was considering a power supply is that I don't have the charger. I may take your advice and rebuild the battery packs. If you would be so kind as to give me the ratings from your battery charger (voltage and amperage or watts), I would appreciate it very much. I am sure that I can put together a charger.

Hmm, somebody has been into it and it is all held together with tape. I used solder-tabbed C cells for the batteries.

The charger is a wall-wart looking thing, but it has a power cord instead of the prongs sticking right out of the "wart". The cable to the readout box has a 3-pin Lemo plug, but there are only two wires connected to it. The wall wart has an aluminum label that says "Rank Taylor Hobson / Talyvel 3 charging unit". No rating, it doesn't even say 120 V AC on it for the input.

I'm kind of guessing the battery packs are in series and center tapped, so maybe the charger puts out about 18 V. First thing might be to trace out the wires from the charger connector and see if they are direct connections to the battery terminals.

Jon

Jon,

Could you plug in the charger and measure the voltage across the two output sockets that have wires going to them? I looked at the old battery packs and each says to charge at 120mA for 14 hours. If you can give me the actual voltage across the output terminals of the charger, I will have everything I need to size a charger. I would prefer not to pay the ridiculous price that Taylor-Hobson will charge for a new charger.

Did your Talyvel have two battery packs with individual snap connections for each pack?

Again, any help will be greatly appreciated.

Yes, they are built like stacked cordwood, 7 cells, I think. I just made the new packs shaped as close to the original as possible. There isn't much extra space in the battery compartment. I used the old wire and connectors from the old packs.

Jon