What is going on in the world where windows 10 is required to open a PDF?

I downloaded the J6 file and opened it successfully with Acrobat on Windows 7. I did that by clicking Show in Folder and then right clicking J6.PDF and using "open with".

However, if I click on the J6 file in my Downloads list, I get some Adobe ad in my browser that wants me to download a different version of Acrobat and is going to push McAfee onto me if I don't untick the boxes.

I was also recommended another reader called Sumatra PDF - but again, it failed too. This particular project is open-source, so I logged a bug with them, and they can tell me what's going on. At least, I hope they will.

No luck with Win7 at all.

I'll use the docx when I begin work on the HMV, it will be the most convenient, I think.

I just emailed you a pdf of the J6 circuit that I'm sure can be opened by any PDF reader on any OS.

Let me know if I'm wrong!

I suspect the latest Windows PDF writers are trying to make Adobe look bad. This one is part of the open source suite "Open Office" It's a free download.

I use it all the time in preference to the M$ office suite, it's more compatible and the stuff that used to work in earlier versions of Word, for example, still work in this.

The speadsheet doesn't have the bugs that the M$ one has.

The drawing tools aren't crippled like M$ does, because they want you to pay even more for Visio.

OK, I've been in contact with Kevin and he has recreated the file. It works fine for me now. Give it a try.

Thanks Ian, I tried on Win7 here and it's fine, also works on Sumatra PDF.

Someone called Ken sent me a jpeg and that's fine too.

Just checked on Kevin Chant's page, downloaded J6[F] and J6[J] (not sure what the difference is), and now they both open fine too. So, thanks to GTC too. I now have several ways to view the diagram, thanks to all the members here.

It would be nice if Kevin put the list in alphabetical order, it's easy to miss something the way it is.

Let's hope the radio is actually repairable after all that. The case is good, all knobs are there, no dust inside. Someone replaced the battery with a small black plugpack and added a power cord.

I'll get to work on it next Sunday.

It would be nice if Kevin put the list in alphabetical order, it's easy to miss something the way it is.

Nice I agree, but I wouldn't want to look a gift horse in the mouth.

I use CTRL+F on the relevant page to search for the file that I want.

I got advice from the Sumatra people that the schematic is an embedded attachment within a flash cover. Because flash is banned these days, it didn't know what to do. So, it has to be opened with firefox, then the attachment name shows, click on this and it opens by default, or in my case it saved a file called "pdf" to my download folder. After renaming, it could be opened normally.

So we live and learn.

And to finish this off, I firstly tried Ian Robertson's pdf on my laptop, which is from last century and runs Windows 2000, and Acrobat 7. It opened perfectly, so I used that. A USB wireless mouse was used instead of the dreadful mouse-touch-pad that have plagued laptops for so long.

As for the radio, the main issue was the local osc cut out between 1350 and 1550 kHz. Why? Couldn't really see a reason, and my knowledge of ancient PNP transistors is obviously lacking. Firstly then was to make sense of the circuit. The primary (yes!) of the aerial forms the input direct to the local osc/frequency changer transistor. Since one transistor does both functions, there a little frequency pulling on very strong stations. This is followed by 2 IF stages (so, 3 IFTs), then a diode and the audio section, complete with 2 transformers. The diode provides both the audio and the AGC, which is only applied to just one stage. There's also a mystery diode connecting the osc and the first IF.

After poking about, it did seem this mystery diode was having some effect, so I pulled it out and checked it. The reading was somewhat inconclusive but it did seem there was some reverse leakage. I therefore replaced it with an ordinary 1N914 signal diode. The fixed the odd voltages in the area, but little else. I had noticed that while soldering it in (I left the power on), the osc worked better while the iron was touching the circuit. I tried a few things, and found that by putting a 3.3K resistor (it has to be this exact value) across the diode, the oscillator started working. I know it's a hack, but I really couldn't find anything else wrong.

So, testing the radio, it works on my local station, except with a big antenna it choked up. I wasn't really surprised, since transistor technology was in its infancy back then, it just couldn't handle powerful signals. With the antenna and earth (very important!) there was no trouble picking up the Sydney and Wollongong stations. This is all I expect from valve radios (4 and 5 valve) at my location, about 100km from Sydney. Why 4-valve? The only real difference between common 4 and 5-valve radios is a single triode. If the transistor set can work at least as well as a 4-valve, then I'm happy.

Then of course the radio had a few other issues to fix. Bit of crackle with the volume - spray fixed that. The dial pointer kept jamming. More spray fixed that too. A small crack in the plastic dial where my fat fingers pushed a bit hard when picking it up. And after spending a few years in the garage, it needed a clean. After that, it now lives inside, away from the dust.

So although it was fixed with a bodge, I can call this another successful repair.

The J6 is riddled with .047μF Ducon Red Caps. These are notorious for leaking and can turn into resistors.

I always replace all Red Caps as a matter of course. The higher values, .047μF and above seem to be the most problematic.

That mystery diode is an extension to the AGC. With no AGC applied this Diode MR1 doesn’t conduct. When AGC is applied to the 1st IF transistor, its collector voltage will rise. Once it rises to above 6.8V this diode will start to conduct and shunt signal away from the 1st IF transformer and to ground. Using the silicon diode varient wouldn’t help the radios ability to handle strong stations.

Germanium diodes are buggers of things to test. You can expect reverse leakage, but how much leakage has always been my bugbear.

I did notice a few red capacitors in the radio, I'll swap them out the next time I happen to work on it. It's the only Australian-made transistor radio I have, so I was totally unaware of what issues might be lurking within. I had a pair of Krieslers, one I gave away, the other was a rustbucket when received and was binned immediately. The only reason I even have this radio is a seller at the markets had a table full of Oz transistor radios, but I mistook this as a valve one - it looks like the HMV "Super 5" - and weighs almost as much.

I kept the mystery diode, so it can always be put back in, if the capacitor change makes a difference. I also need to buy some low-voltage greencaps as replacements - it's not normally something I keep in stock.

Still a nice radio to have Robbbert. These early designs with large ferrite rods usually perform very well and sound quite nice also. I have always been on the lookout for the J4-17 Rangemaster model that also shares the same cabinet but has an RF stage in front. I’ll find a nice one eventually.