A friend has given me a Philips 4462 to repair, a huge three-band table radio from the late Forties. Does anyone have a circuit diagram for this model? Is it the same as the Mullard 98?

I don't have a schematic for the Philips 4462, but I do have the Mullard 98 schematic.

Both sets appear to have the same line-up.

If you unhide your email, I'll send you the model 98.

Thanks. My email address is now on my profile page.

Yes, the Mullard 88 & Philips 4462 do appear to be the same.

Here is a good copy of the Philips manufacturers service manual.

Philips 4462 Service Data

Okay, sent.

Note that unfortunately the original scan is less than ideal, so you'll need to use the zoom button.

Thanks both. I've got the set running now. The main problem was a broken dial cord. There's other things wrong, such as noisy controls and a dead magic eye, but it's up to the owner if he wants these fixed.

The magic eye's now working, though it's very faint. Low emission I suppose. The shortwave on this set is pretty good, and it has mechanical bandspread tuning. It pulled in WWVH in Hawaii on 10MHz using a short piece of wire thrown across the kitchen bench, and that station's not even aimed at us.

Document uploaded to Post 4.

The magic eye's now working, though it's very faint. Low emission I suppose.

The usual cause is low emission from the target (the circular green part). The cathode is most likely ok.

I've heard that there's a way to get some of the brightness back into a magic eye, though I don't see how without pulling the valve apart and applying more phosphor to the surface. They work on a similar principle to a CRT.

A modern alternative is to make or purchase a LED version of this type of valve. The colour is realistic - green LEDs - though because of the physical size of LED packages the resolution is not all that realistic. Maybe there's a market for Cree or another maker of premium LEDs could make replica magic eyes for the radio fraternity with SMD LEDs, where the device packaging could be shrunk to the point where more realism is possible.

Whilst the tuning indicator in that set is not a very common one, assuming it is faulty is not a statement I am comfortable with. The circuit has voltages on it; I would like to think these were checked before making the declaration. I would also like to know what was done to it. eg caps.

As noted (elsewhere), the last radio that left here, had only three original resistors left. Why I make that point is that like 6V6 & a few other Output valves, with their grid one resistors; Tuning indicators (eg 6U5) are notorious for wiping out the normally 1 meg resistor/s found on their socket base. Due to the attrition rate these and plate resistors on Det / Audio valves, should never ever, in my book, be left unchecked.

Marc

Don't worry Marc, there are very few original resistors left in this set, and the ones on the magic eye socket are OK. All the papercaps were replaced years ago with polys. The point is, this isn't a restoration, it's a favour for a friend. He just wants the set going again, and he doesn't use the magic eye. So I'll leave it at that.