schematic AAAAGH!!!

[redrooster]

I'm getting really frustrated with this old tube radio schematic! (Philips 168) I am trying to repair and restore it but the schematic doesn't relate to the radio itself very well,like there are no numbers, symbols or markings on the chassis to orientate myself? Is there someplace around where I can find out how to relate to points/numbers of say a coil on the schematic to the reality of the hardware? Some of it just doesn't make sense to me at all. How can I tell which pin is which on the tuning capacitor or what is what anywhere for that matter? It looks like its going to be a long road if I do indeed stick to it.Any help will be appreciated. Redrooster.

[Reece]

Take a look under the chassis at V1, the first 1T4 tube socket. It's a 7-pin tube. The pins are numbered clockwise from the underside of the socket, starting with the first pin to the left of the wide space: that's number 1. On the schematic, see that the first grid G1 has the number 6 by it: that's pin 6. Count around to pin 6 and follow the wires from it and you'll see that one of them goes to the stationary (stator) plates of one of the gangs of the tuning capacitor C1. C4 is also associated with C1 and is probably the trimmer on the tuning capacitor. Also that same line continues to terminal 1 on L2, which I am guessing is a ferrite core.

Then look at pin 2, the plate, on that same 1T4 tube. It's wired to a two-coil transformer L5/L6 that sends the RF signal to V2, the 1R5. And so on.

What I like to do with a tricky schematic is print it out and then trace each wire one by one, and when located, mark it off on the paper with a highlighter. That way you know you didn't miss something and you get familiar with how that set is wired. Hope this helped. If you get lost somewhere check back in.

[redrooster]

Hi Reese,Whats happened is that I started to recap it, like for like and then I checked it with the schematic and it is like its the wrong schematic for it because some of it just doesn't make sense at all. It looks like Ill have to learn the hard way like everyone else must have done in the old days LOL.

[Reece]

If you just change the old wax paper caps and the electrolytics (being careful on those to observe polarity!!) you should be OK.

Those little 1-volt filament tubes are delicate. Have you tested them to see if they are OK? Any overvoltage on the filament can burn them out. If you don't have access to a tube tester, you can test the filaments with your ohmmeter for continuity. The pin numbers are on the schematic.

Is your line voltage 240 or what? Check it at the socket with your AC voltmeter. I see from the partial schematic that the set has various taps for different line voltages. I think on a set like this, even if I had a 240 volt mains, I would set the tap at 250. This would lower the voltage a bit coming into the radio for starters, just for a little extra caution. If it plays OK like that, leave it that way as the power supply and tubes would be less stressed.