Murphy V310 LOPT rewind

[G8vsjDave]

Hi Steve, I have a V410 tuner, I don't know what coils are fitted but if the coils in that are any good to you, I'll open it and see what I have.
Dave

[Niechcial,Steve]

That's really kind Dave. Thanks

[G8vsjDave]

Morning Steve, I've opened the V410 tuner and there are only coils for 2 channels fitted. I can't identify the channel numbers but it seems to be one band one and one band three set. Do you want the whole tuner or just the coils. Perhaps we should go to PM?
Dave

[petertheorgan]

am I dreaming or are the coils marked the same as the resistor colour code . IE brown for 1 and white for 9

[dazzlevision]

Originally Posted by petertheorgan

am I dreaming or are the coils marked the same as the resistor colour code . IE brown for 1 and white for 9

Certainly the later Murphy TV VHF tuners (but not the Rank Bush Murphy era) had colour coded channel coils (but some had channel number labels!). I'm thinking the Astra series - V6xx and V7xx.

Note that the V310 series used a Mazda 30L1 RF valves whereas the Astra used a Mazda 30L15, which needed different channel coils. The Astra coils were made of translucent coloured or clear plastic.

I'm not sure about the V4xx and V5xx series, without consulting the service manuals.

[G8vsjDave]

Ok, I've had a closer look and yes, there is signs of paint on the coils - white and brown, so Channels 1 and 9 then. London?
Dave

[dazzlevision]

Here's some information from an issue of the "Murphy Service News" on Murphy TV channel coils, from Band 3 converters up to the V410 series.

From the change of basic part number between the V310 and V410, I think it's safe to assume that, from the V410 series onwards, until the Astra Mark 2, the RF valve was a 30L15 and so required different coils to the V310 series (which used a 30L1 / PCC84).

[Niechcial,Steve]

As Dave (Dazzlevision) says above, the V310 coils are different to the V410. Mechanically the wafers are different, physically the windings look very similar but not quite the same. The coils formers look the same length and diameter for both. Anyway, I took the V410 coils which Dave G8vsj kindly gave me, cut them off the wafers and soldered them onto V310 wafers. The result is lower gain than with the original wafers but they work pretty well .
Thanks to everyone for the help with this. I now have a nicely working V310. I have to say that with rewinding the LOPT, fitting a line osc stage, replacing the CRT , fabricating a new focus coil and new tuner wafers it was all much more time and effort than I would normally go in for on something like this . Apart from the general quality of the picture, two great things about this model are that everything (including picture centering) is adjustable without taking the back off, and the voltage selector is thermally isolated from the droppers so you don't get voltage adjustment wires crumbling with the heat. Couple of pictures attached