Westminster Radio Model C.T.A.5350. Circuit.

[Station X]

Not of the best quality, but better than nothing.

If you want an HD version, PM me with your email address.

[Nickthedentist]

As you say, that's better than nothing and will no doubt be handy for someone.

[ms660]

I'll have a go on the resistor values from that pic...

R1...22k...V1&V2 screen feed.
R2...150k...V1 AGC feed.
R3...150 ohm...V1&V3 cathode bias.
R4...56k...Osc grid return.
R5...47k...Osc anode load.
R6...150 ohm...Osc feedback circuit.
R7...2.2 M ohm...Main AGC feed.
R8...56k...IF filter resistor.
R9...0.5 M ohm...Volume control.
R10...1 M ohm (or possibly 10 M ohm?)...V3 grid return resistor.
R11...220k?...V3 anode load.
R12...0.5 M ohm...Tone control.
R13...470k...V4 grid return.
R14...330 ohm...V4 cathode bias.
R15...4,700 ohm?...HT feed.
R16...1,000 ohm...Main HT filter.
R17...5.6 or 56?...V4 grid stopper.

Might need a few corrections....

Lawrence.

[Station X]

No need Lawrence.

They're perfectly clear on the high res version.

[emeritus]

Here's a sharpened version produced in about a minute using the old Microsoft "Photoed" program that used to ship free with Windows 98 and later versions until replaced by the less useful Photoviewer program. (It does work on XP and some later versions if you simply copy the folder containing the program files over and click the .EXE file). Just a question of playing with the Contrast, Brightness, and Gamma sliders under the IMAGE tab. The original image posted is evidently somewhat compressed. With a higher resolution original, the LINE function of the EFFECTS menu can get rid of background intensity variations and just leave only the lines, but the resolution of the copy posted is not good enough for this.

Unfortunately, reposting the images has compressed them even further.

[Station X]

As I said, I'd be happy to send a Hi Res version to anyone who wants it.

I have two of these sets.The Hi Res diagram is perfectly good for servicing them, which is what I'm doing at present.

Would anyone be prepared to pay £1.99 for it though? That is of course a rhetorical question!

[paulsherwin]

Just a reminder that the forum software will not resize images contained in PDF documents or ZIP archives, but the file sizes must comply with the limits for those file types or the upload will fail.

[Station X]

Here's a pdf version.

Looks good when blown up!

[camtechman]

Surely this should be offered in the "Sets, Parts and Service Information Offered" section?

[Station X]

I'm not offering anything. I've just posted the circuit here for information.

[camtechman]

Thanks for that info.

[Station X]

It's a bit borderline I suppose.

I think the pdf version I've posted is perfectly fit for purpose.

[crackle]

During a boring hot evening I had a go at cleaning the schematic.

Mike

[Nickthedentist]

Wow!

[Philips210]

Hi.

That's excellent work Mike.

I have a circuit diagram on the back cover of my Perdio 'Continental' radio which is also somewhat stained and would like to try and reproduce this circuit diagram with all the staining removed. I have used MS Paint but it's awkward for removing stained areas on the scanned image. I was wondering, how do you go about cleaning up this type of scanned image?

Regards
Symon.

[crackle]

Hi Symon
To achieve that result it was a process of brightening the image, changing the contrast and using a Histogram adjustment tool to adjust the highlights, lowlights and overall gamma. The adjustments were made on different areas of the image at different rates as the wanted schematic lines/detail were also of varying intensity. There was also a lot of manual cropping and editing the worst of the stained area.
It took approximately 3 to 4 hours to complete.
There is probably a program that would do all this for you, I have asked my son to see if Photoshop can do it better. (quicker)

Mike

[usradcoll1]

Originally Posted by crackle

During a boring hot evening I had a go at cleaning the schematic.

Excellent job of restoring the schematic.
The set sure looks like a US design. I never thought Locktal base valves were made anywhere else, but here. They were designed by Philco and their main supplier, Sylvania.
The 7S7 frequency changer valve is a lot better choice, than a pentagrid type, at higher frequencies.

[Philips210]

Thanks for the info Mike, it's inspiring to see what can be achieved.

I have a half decent Epson V600 scanner so I'll experiment with the brightness, contrast and gamma settings. For doing the repairs to the image, would a scanner resolution of around 400dpi be suitable or should I go higher?

Regards
Symon

[crackle]

I find 300dpi sufficient, if the image is about A4 size.
I scan and save in 256 grey PNG format. Once editing has been done I save as a new file in about 32 shades of grey.
Mike

[Philips210]

Hi Mike.

Thanks again for the info.

Regards
Symon.