Quote:
Originally Posted by WaveyDipole
Quote:
Originally Posted by usradcoll1
When I first saw the transformer primary connection. I knew that it was connected for 240 volts.
The later Heath offerings were all designed for export using dual primary transformers. I think their reasoning was to ship everything out of the US instead of locations out of the country. Around the same time, they opened retail establishments in the larger US cities. Before that, everything was mail-order.
Dave, USradcoll1, trying to remember!  |
Thanks for that observation. It would make sense to ship outside the USA with the option for both mains supply voltages. I wonder whether this was a project that someone never really made a start on except for making a change in the transformer wiring? I suppose someone might have adapted a Nema5 socket or bank of such for UK mains use, but the Nema5 plug is marked 15A 125V so although that might work, it doesn't sound like it would be suitable for UK mains use? Whatever the case, clearly you are correct and the unit does operate on 240V, just for some reason still had a USA 120V mains cord.
Quote:
Originally Posted by ColinTheAmpMan1
Apart from the schematic that you provided in post #1, do you have any other documentation? I ask because I could probably send you a pdf of the manual/assembly guide for the V-7AU that I have.
Colin.
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Thank you for the kind offer of the assembly guide for the V-7AU. My apologies for omitting to mention it, but I did find the Heathkit Assembly Manual for the IM-28 online prior to starting work on the unit and I am actually following the calibration instructions that I found in that manual. Once I have replaced the remaining capacitor and checked for, and if found, rectified any further problems such as resistors out of tolerance, I will run the calibration steps again allowing a bit more warm-up time. |
The 125 volt rating on the plug means that it is the NEMA 125 volt design, not the maximum voltage that it can safely handle. All our 125 volt devices and flex, known as cord sets here are at least tested for 300 volts.
BTW, the schematic shown and the one available here is the UK version, showing a different transformer primary. The US version uses the series-parallel transformer primary.
Dave, USradcoll1
