Hi everyone,

i have an unrestored Airzone as the title suggests, just have a few questions about it.

First question is about the dial light. it's missing and I cant figure out how it is wired in. theres a red wire leading to where the dial light should be (based on pictures i've seen of similar models) but no globe or even a socket for one to screw into. multimeter doesnt pick up any current flowing between the wire and the chassis either which makes me wonder what the wire is even doing there in the first place. it is soldered into the the electronics underneath but besides identifying individual components I have no idea what I'm looking at.

other issue is the dial paint is flaking off. tried my best not to touch it or anything but just moving it around makes flecks drop off. Is there a way to stop this? maybe something I can spray onto it to hold the paint down? I wouldnt mind replacing it really, even with a scanned image printed on acrylic or something, but I suppose that would really effect the originallity of the radio.

Aside from that the radio actually works amazingly well, I did order some new capacitors though since it's still using those old paper things and the general oppiniun seems to be that they'll die eventually so just replace them before they do and save yourself the hassle. havent touched the capacitors in the metal cans though since I dont know how to get into them and dont want to damage anything.

also cleaned up the case and stuck the pieces back together with araldite, then gave it a bit of a polish. i'm extreamly happy with how it turned out. there are a few bits missing, but they're mainly underneath. it's really affecting the strength of the case though and it's bending a fair bit, so i'll probably fill those with fibreglass resin. also effects how the chassis goes in because it's already such a tight fit and with the pieces missing it just doesnt sit right.

haha that's all I can think of right now, seems like a fair bit but this is the first time i've actually been able to ask about any of this. so far i've just been googling and trawling through forums and articles and that can only get you so far.

thanks very much,

Jarrod

The MES socket for the dial lamp has probably fallen off at some time in the past. If you e-mail me your postal address I'll send you one from the wreck of a 4AIEI, a later model with pretty much the same chassis.

Click on image for larger resolution

The return path for the dial lamp power is through the chassis via the clip on the outer edge of the socket. My e-mail address is on my profile page. There'll be no cost as this item is pretty much too small to charge for. As it's Christmas I'll also chuck in a 6 volt lamp from the same set. The case and dial lamp are smashed so both are surplus to my needs at the moment.

Yes, it is wise to replace all capacitors (also known by their former name, condensers), starting with the electrolytics (the big red ones with the Ducon label) followed by the paper caps (the smaller ones encased in wax or black pitch). Capacitors dry out with age, particularly in hot dry environments like old radios, regardless of the type and without them there are big problems. You'll hear mains hum through the speaker which is aggravating to say the least. The tuned circuit will also most likely not work which means you won't receive any stations.

One thing with capacitors is that they are seldom made today in exactly the same ratings as in the 1940s. This is okay. They don't have to be exactly the same - just very close, making sure that you don't go over the ratings for the large filtering capacitors or you'll cook the rectifier valve when you turn the radio off. Make sure the working voltage ratings are suitable. Types rated at 350VW or even 450VW are most often required. The capacitors you are replacing will have these values written on them.

Whilst under the chassis, check for scorch marks, dry joints and redback spiders. Dry joints are simply solder joints that don't look shiny and can be fixed up with a soldering iron and a dab of fresh solder. If there looks like there's been an explosion under the chassis at some time in the past check to see that the problem was solved with the installation of a new component. Checking the power transformer is also necessary - continuity of each winding (there'll be at least three and in some cases four) and for insulation resistance between any two windings and between each winding and the core. You can use a multimeter for testing transformers but using a Megger (insulation tester) is better as it will run 500 volts (at a tiny current) through what is being tested rather than the 9 volts of a multimeter. If you are using a Megger watch out for the probes - they won't kill you but they still bite.

Note: Transformers can, and often do, work well even with a developing fault. As a rule they are only supposed to get slightly warm. If one gets too hot to touch then there is definitely a problem.

Another item that is probably due for replacement is the power cord. If it is damaged it must be replaced, same with the plug top. Steve Savell from AVW (contact details on Service Directory pages) sells 100 metre rolls of brown cotton covered power cord with earth wire and this stuff looks quite realistic even though most 1950's radios came with 'figure 8' two-core cords. If you are hard up for cash Steve will probably sell you a couple of metres off the roll. Note that it is against the law to retrofit figure 8 cable - all flexible cords must be double-insulated nowadays. You don't need to earth a radio chassis but it is generally the accepted practice now. If you need advice on going about replacing the cord sing out (reply in this thread) and I'll help as much as I can.

I can't help with the dial glass at the moment as the one on this spare receiver of mine is broken but if you'd like me to keep an eye out for one I will do my best.

Hi Brad,

Thanks you've really cleared up a whole lot for me. the power cord was one thing I was wondering about, it's in terrible shape. was just going to replace it with a spare computer power supply cord but i'll definetly ask about the cotton covered cord now. As for the plug, not sure if it's the original but it does look the part and is in near perfect condition so i'll hold onto it.

Checked over and under the chassis and havnt seen anything out of the ordinary. the transformer seems alright and isnt getting hot or anything, but it's making a buzzing sound that is a little louder then what i'd expect.

Thanks for the offer (and explanation) regarding the light but i'll be able to rig something up pretty easily using bits i've got laying around here now that I know how it's supposed to wire in.

As for the dial if you do come across one that'd be great but no need to go to any trouble over it.

really appreciate the advice,

Jarrod