Philips B1X67U (1956)

This is a rather cheap small mid-fifties radio in a Bakelite case. The U in the type number indicates it is a "universal" (AC/DC) model. It has two wave bands: MW and LW. The round tuning dial bears the reminiscence of other "sunny" Philips types.

It uses "U" types of valves, i.e. valves with a 100 mA heater in series.:

• UCH81 as frequency changer
• UF89 as IF amplifier
• UBC81 as detector and AF pre-amplifier
• UL84 as output amplifier
• UY42 as rectifier.

So all the valves except the rectifier have a Noval base. The UY42 rectifier has the older Rimlock base.

A lot has been done to save cost in this radio. It is an AC/DC model to start with. The circuits have been kept simple. For example, there is no cathode bypass capacitor for the output valve (fine, so it cant't fail). There are only two wave bands. And it is one of the first Philips radios to use a printed circuit board.

This radio came from an elderly woman who was moving to a smaller home. It was in excellent condition. The case was shiny and practically had no scratches. There were traces of a previous repair, though: one half of the ballast resistor was bridged by 4 power resistors.

When I tried it, it gave a strong hum. I switched it off immediately and reprimanded myself for switching on an old radio without checking the power supply electrolytics first. I took the radio out of its case to clean the inside and to be able to get to the printed circuit board, half expecting that I was going to have to change the power electrolytic.

But when I started to reform the electrolytic, the leakage current went down to a very low level quickly. I tried the radio again and now it played with just a little bit of hum. I was pleased to find that, all of the paper capacitors were still in excellent condition! Even for the coupling capacitor the leakage current was very low. This observation combines well with the excellent state of the case. Apparently, the radio has always been in a dry and evenly heated environment. So I decided to leave all the capacitors. I put the radio back in its case and now it is standing proudly there to play every now and then.