Global Specialties PB-503 Transformer change (110V to 240V)

[grayduster]

Hi there,

Having decided to start learning electronics, I picked up a cheap second hand PB-503 from Ebay (coming all the way from the USA) to accompany the Art of Electronics course (only a tad daunting!).

As expected, when it arrived, it was configured for 110V (see pictures below).  I could just plug it into a step down transformer (my UK supply is 230-240V), but I assume it's better to rewire!

I took some pictures below, and had a look for the schematic (best I could find was https://ctemedia.s3.amazonaws.com/gs/discontinued/files/PB/pb-503_v1_interplex/PB-503_V1_1990_manual.pdf), I assume I can just desolder orange and red wires from the primary side of the board, solder them together with heat sink (to connect the two primary windings in series) and Bob's my mother's brother?

(There does appear to be jumpers on the side of the board that's horrible to get to, but not having easy access in there, the above seemed more obvious - is there anyone far more experienced than me at this that wants to jump in to point out anything horrible about doing this, or perhaps any improvements on the above? (perhaps the fuse current rating would need altering, and might be worth re-capping?)

Image album: https://imgur.com/a/RMixk

Many thanks!

Grayduster

[eblc1388]

I assume I can just desolder orange and red wires from the primary side of the board, solder them together with heat sink (to connect the two primary windings in series) and Bob's my mother's brother?

That's part of it.

Take care to study the "Before/After" connection schematic and remove also the connections between Yellow/Red and Orange/Brown wires, shown in the image below.

The orange & red wire, after soldered together, still need to go to the neon lamp terminal of the switch or else you have no power ON indication.