[Reece]

How bright a tube filament glows is usually not important. Some are dimmer than others by design and work fine. 6X5's can be problematic if there's a heater to cathode short. You may just have had a bad tube. Before you plug a new 6X5 in there you want to look for any excess load in the B+ circuits of this set: any partial shorts to ground or resistors in the plate circuits of tubes that have dropped in value (usually they go up.) Some tubes will get very hot, too hot to touch, in normal operation, but their plates should never glow red which means they are drawing too much current. How does the transformer feel under load? It may get quite warm, but not so hot you can't put your hand on it.

Also be certain that electrolytics are connected correctly with respect to polarity.

With two 1N4007 silicon diodes, you could operate the set without a 6X5 for testing purposes. The cathodes of the diodes (end marked with a band) would go to the tube pin where the tube cathode was connected, and the other ends to the plate pins.

I couldn't find the schematic for this set on the web but if it has a loop antenna, both wires to the loop have to be connected to complete the tuning circuit. The fact that stations were very weak may just be because someone played with the alignment of the set before you got it. Sometimes a person will "tighten all those loose screws" on the I.F. transformers and the tuning capacitor in an attempt to "fix" the radio.