EverReady SkyLeader Resurection & Repair
EverReady SkyLeader
The EverReady SkyLeader radio was introduced in 1958 and went though a few revisions with the last versions being turned out in the early 1960s. The early versions had socketed transistors (OC44, OC45) in the RF stages and were point to point wired. I was looking for a repair challenge, and happened up one of these radios on eBay. I bid and won it for £10 plus postage. When it arrived I discovered it was a later model with a PCB and soldered in transistors, but on searching for something else in the shed, I discovered a 1958 vintage version I didn’t even know I owned.
Initial observations
The hinges on the case are broken and there are two missing transistors, and I’m further checking, one of the other transistors has been pulled out of the socket and collector snapped off (this may be because it was soldered on the backside of the socket on some of these radios.)
Another observation is that the antenna coil has some broken connections.
The section of the chassis that the audio amplifier is on is not screwed to the case or the rest or the chassis any more. Someone has been playing with this radio before me.
Disassembly
Getting the Radio chassis out of the wooden case we can see it’s a bit cruddy with lots of fluff and junk around the switches.
Undoing the two screws on top, allows you to take out the chassis from the case; the chassis is pretty filthy
With the RF and the audio boards out, the speaker is left in place and the external antenna Jack is left in place
Testing on the bench
It’s a six transistor radio: Oscillator, First and Second IF, Audio Pre-driver and Push-Pull Audio amplifier. Existing parts in the radio are all Mullard Germanium PNP parts.
On the back of the chassis, the band select switches look oxidised, but also silver plated, so the oxide shouldn’t be a problem. Again making me think someone else has had a play with this radio before me, I can see a mix of original resistors and one suspiciously (relatively) new looking part.
New and old resistors
The detector diode is hiding down in a gap under a resistor.
No obvious shorts on the tuning capacitor, so I’ll dig in my box of crap old transistors and see if I can find parts to make this radio work.
I dug out some OC44s and connected up a small speaker for testing. The transistor sockets are not great, so I ended up soldering in the transistors on the backside of the socket.
Waggling the transistors around in the socket did manage to make the radio draw about 10 mA at 9 V and there was a little bit of crackling in the speaker but nothing actually being received. So I looked at the schematic to start to see where the broken wires from the antenna coil should connect.
At this stage, and in this area I should be able to pick up BBC Radio 5 live on medium wave with literally just a diode and a crystal earpiece. This radio is not receiving anything yet. Some deoxit it on the band switch helps, and two stations are received at low volume. Some more contact cleaner on the volume control improved the volume to the stage where I could use the radio to listen to a friend’s album launch listening part on it. Long story, but the only way I had to listen was to stream the album over a lash-up medium wave transitor and listen on this not-yet-fixed radio.
The Radio kind of works on medium wave but long wave is totally dead. There’s a broken wire on the longwave section of the antenna coil so I need to find where this goes. Again, the schematic helps here.
Looking at the schematic, we can see that the broken coil is labelled L3 or L5. One end of it goes to a switch and the other end goes via R2 and C4. Checking the connections I can see that the end that goes to the resistor and capacitor is still soldered so the end that goes to the switch must be broken end. It should go to a tag on the coil which connects to a wire that goes to the underside of the chassis, so I soldered it back.
In an effort to improve the audio, I start checking the capacitors in the order amplifier. At least one has been changed before and one other needs changing as it measures completely open circuit..
There is now a horrible squealing as you tune between stations. This is almost certainly on auto volume control (AVC) / auto gain control (AGC) capacitor so back to looking at the schematic to see where this may be. C11 is fed by a sniff of detected audio from the detector diode via R11, the voltage developed on this capacitor is combined with the signal into the base of TR2 and controls the gain of that transistor.
I pulled the capacitor and it wasn’t a capacitor any more. It tested open circuit. I replaced it by a 10µF 16V part and the radio is much happier.
Alignment
The IF of the radio is 470kHz. I’m using a TinySA as the signal source and coupling it in via a 0.1µF capacitor. The service manual wants me to connect to a part of the radio that’s not easy to disconnect (several parts soldered to one tag), so I connect in my signal source a bit further up the chain.
The core of the second IF transformer was broken, so I had a hunt for something similar.
I’m able to hear the IF signal down to -48dB with an initial tuning of the IF stage. I end up checking the end of the bands and adjusting the trimmers around the tuning capacitor to set the correct oscillator frequency and set the band limits.
I had to play around with the radio a bit more, there was an intermittent fault, where the volume would drop to very low levels, even on a very strong station like BBC Radio 5. 1 foot but took some head scratching to find was that I’d left one transistor in the socket and soldered another one underneath this caused issues when the transistor in the socket actually made contact. I also realised my LED light panel I was using caused lots of interference and stopped the radio really receiving much.
I made a second attempt at aligning the IF stip, the replacement core I used in IF2 was too small and would move in the transformer, I glued a small bit of cocktail stick to it to position it more easily, and secured it with some wax when it was in the best place. I got the sensitivity down to -57dB, much better than before.
Finishing up.
I removed the speaker and the grill cloth from the case, and gave the case a good scrub with soap and water and a wipe with some IPA. I tired flattening the grill cloth over night under a weight, but didn’t get the deep dent in it entirely removed.
This was an enjoyable complicated fix, it took a couple of evenings over a couple of weeks to get the radio operational and then get it properly aligned and back in the case. While I was repairing this radio, there was definite evidence that someone had played around inside before. From the missing transistors to the replaced resistors and capacitors, and the broken wires on the antenna coil.
This article in other media forms
If you’d rather watch me fix this radio and ramble on, instead of read what I did, there are three videos on my YouTube channel.
Part 1: https://youtu.be/nd4Vfxm_c2k?si=tER616k5qwBvGKnh