In another thread (that I can't now find) there was discussion of replacing dial lamps with LED substitutes. There are a few problems with that.

1. Many people will prefer the soft candle-light glow of the little incandescent bulbs.
2. LEDs emit a directional beam that is more difficult to dissipate through a wide arc as typically required to light a radio dial from the side(s).
3. LEDs are DC devices so care needs to be taken that putting them in an AC dial lamp circuit does not have unexpected results, say for the AM heater circuit that may be on the same power source.

Having said that, I was finding the standard 6.3v bulbs in my Philips too dim for my eyes, so I tried various options.

I tried to find the small 2mm diameter cold-cathode fluorescent tubes that used to be available from Jaycar, but they seem to have disappeared. These are often found in dashboards, LCD screens or other indirect low-light devices and provide a soft dissipated light.

Instead, I have installed a section of 12v LED strip-light, of the kind used in decorative installations. There was suitable space to surround the rectangular dial with this strip, facing inwards from all 4 sides. It has a self-adhesive backing strip and can be cut up in increments of 10cm x 3 LEDs. The incandescent bulbs s are still in place and add some yellow colour.

The LED strip is not powered from the main transformer. It has its own current-limited PSU ($6.00 post free from Hong Kong, a bit more locally) with the AC input soldered directly to the main power switch in the radio. It mounts on the front baffle, high up to minimise any RFI risk (see pic)

Not everybody's taste - but a good option for me with this particular radio.

If you have the choice, be sure to use warm white LEDs.

There's another discussion on the use of LEDs here.