Continuity tester is always good

they use spare pins on the octal valve sockets as junction points

Yes, the schematic is the "logical" view and the wiring layout is the "physical" view.

Making use of unused pins on valve sockets like that was a common practice.

I have found that the local oscillator coil in my Tasma is not the original! Any ideas were I can get the correct one?

But if you're not painting the chassis, can't you do the new wiring one by one?
You can leave a pigtail on each joint till you solder the new
one so you don't forget where it came from.

Why do you need to strip it back to parts then?

A schematic is a great idea anyway,
as you said, it's harder to look at the radio.
I wonder how hard it would be to produce an optimal schematic from the rat's nest.

The Kicad open-source electronics CAD program has libraries of component images to represent analogue radio schematics, as well as for digitial circuit design. See this link for an Australian source: http://www.philipstorr.id.au/radio/eighteen/kicad.htm.

You can place components anywhere on the matrix, so can make a drawing that is both schematic AND physical layout drawing.

It even has some circuit-checking capability, though I've only used that for simple IC circuits.

For original design, it can also be used to lay out a PCB.

As an amateur, I found it quite easy to learn. Lots of tutorials and contributed component libraries online.

I use Visio do do the drawings. Here is the result so far:

You need to Photobucket images, and then post the link here.

He sent them to me.

Those are certainly nice clear drawings - congratulations. I wouldn't suggest you start again in Kicad after all that good work.

The strength of Kicad and the like is that you get the schematic, the layout, and (if wanted) the PCB template files all generated from the one, electrically-validated source file. Of course, it doesn't stop you putting wrong values or wrong components into the circuit.

Maven

He sent them to me.

I find the images that Brad posts a much better size than some of the recent Photobucket images.

Plus having them appear within the post is more convenient than having to click a link to reveal them.

Additionally, external links can become invalid. Images posted by Brad are hosted here and stay valid (as long as Brad doesn't change them).

(as long as Brad doesn't change them)

Rest assured that won't happen.

Before I upload images I always size them to fit the forums. In future versions of this website they will come to be smaller than the width of the forums because of the gentle, but significant, increases in screen size and resolution we've all witnessed since IBM-compatible computers became commonplace in the home.

I know I've gone from 640x480 up to 1920x1080 over time. Unfortunately, websites have needed similar upgrades so they don't look like a single newspaper column down the middle of the screen.

One of the things I plan on working on in the new year (yep, almost Christmas - again) is the ability for members to upload images to their own posts. New web technologies allow this to happen with good security and the ability for the website to display any uploaded image in a size preferable to the administrator regardless of the dimensions or bytes. If I can eventually succeed with this then it would solve a lot of problems. Images could be seen quicker, less work for me (not that I mind doing it) and members would not have to rely on image hosting sites unless they wanted the images to be available to more than one website.

Unfortunately the upload service originally packaged with the forum software simply didn't have the capabilities I want to be available to members and members were required to possess the skills to resize images, adjust colour, brightness, contrast and sharpness and then upload at exactly the required dimensions for this site. Most didn't have suitable software for this, beyond basic inclusions in Windows at the time or simply ignored the strict requirements for images to be a certain width and this is why that service was given the chop toward the end of 2005. It just didn't work well enough.

Time permitting, the next version of ASP Upload will work quite well though will require a little input from members to ensure quality images. With the popularity of digital cameras these days, imaging software has dropped a lot in price. At the same time I would include a tutorial on taking good photos. The biggest problem with some of the photos I get is sharpness. Photos are sometimes taken in dark light or the camera is too close to the subject and both these issues cause excessive blurring yet it is very easy to overcome.

Progress.
The radio is completely unassembled. Chassis has been cleaned and touched up. See below

Image Link

Image Link

You've done a good job. It's not a task that I would ever consider doing.

Fun job reverse engineering some of these. I am currently drawing the STC model 59 circuit now that I have it making radio noises.

I have an aged "Autosketch" for doing this drawing, albeit I have a copy of TurboCAD.

Beware of tags of convenience. With octal's using pin one as a such a tag can have pitfalls. If there is a chance of a metal valve being used, most of them ground the body of the metal tube via pin one. Some glass ones also do this.

Marc

Yes Marc,
I am thinking of erring on the side of caution and wiring to an insulated post rather than use Pin 1 of the socket. Also, thinking of putting a fuse on the mains side of the transformer. I suppose it’s better to have it safer than original under the chassis.

Cheers,
Gary