Century Super. Help Needed.

[Richard55]

I have an early 1930s 2V five valve radio that I am in the process of trying to renovate, it featured in Amatuer Wireless and was called the Century Super

the major problem is I just cant the thing working, I have done all the obvious checks, replaced components where necessary but it is still dead as a doornail

so I have reached my level of incompetence and was looking for somebody that could spare an hour or two and look at it with me - I am more than happy to bring it over to whoever, I can bring the appropriate power supplies etc.

Is there a member in the Watford, St Albans, Radlett area that knows what they are doing unlike me!

there is no hurry and I am happy to work round any time that is suitable

some advise would be most helpful!

i have attached some photos and the circuit

regards
Dick

[Cobaltblue]

Hi Dick No pictures currently loaded.

If your having trouble there is a guide here.
https://www.vintage-radio.net/forum/...ad.php?t=77650
Cheers

Mike T

[Richard55]

Hi Mike

i am having trouble attaching images - can i edit my existing thread to do this?

regards
Dick

[Station X]

Sorry, but no. Just attach your pictures to a new post in the current thread.

[Silicon]

Have you checked the continuity of the windings in the interstage transformers (if fitted)?

[Richard55]

Hi Silicon

thanks for coming back to me

not sure which bits you are referring to, i can for some reason post any pictures or circuit

i could e mail them to you - my e mail is REMOVED BY MODERATOR

regards
Dick

[Station X]

Please be more specific as to why you cannot upload pictures. Are you getting an error message for example?

[Richard55]

hi

yes error message says i dont have permission to access the page

[Station X]

The procedure for uploading pictures can be found here:-

https://www.vintage-radio.net/forum/...ad.php?t=77650

At what stage do you get the permission denied message?

[Richard55]

when i hit upload

[Cobaltblue]

Whilst the pictures get sorted.
https://www.worldradiohistory.com/UK...1-05-S-OCR.pdf
starting page 710.
Its an early superhet so the first questions I would have:

Is the local oscillator running? this set is shown as having six valves rather than five so is this the correct set?

Cheers

Mike T

[Station X]

Richard55.

Email the pictures to me and I'll upload them for you.

I'll PM you my email address shortly.

[Station X]

Here's the pictures.

Richard has confirmed that this is a 6 valve set.

[Herald1360]

For information.....

[Richard55]

Hi All

given that so far there is nobody available to show me a solution in person can anybody give some advise on next steps

i would like to check that the HT voltages are correct at the right points

wheer should i check and what voltages should i expect

if i can get this right then hopefully we can move on to stage 2!

regards
Dick

[vinrads]

Hi Dick assuming that you have all correct LT and HT voltages to the set I would start by checking for voltage on the anodes of all the valves , also you should have ht on the screen of the two sg valves, let us know your results, have you checked the valves heaters for continuity. What are you using for a speaker. Mick.

[Station X]

This is a battery set. The various HT voltages aren't shown on the diagram, but I assume they're stated in the text?

What power supply arrangements are you using? Something like PP3's in series?

Personally I'd start by checking that all the valves light up, assuming you can see the filaments, this set uses directly heated valves with no separate cathodes.

The first place to check the HT voltages is at the batteries themselves, then you can proceed to test at the point where the battery leads connect to the set. Note that there's a fuse in the HT negative line, have you tested that for continuity?

Assuming the HT is reaching the set, the next place to measure the voltages is within the set. It isn't that difficult to follow the circuit diagram. For example HT+1 should be present at the anode of the first detector valve.

You can measure HT voltages initially without the need to have the LT supply connected.

[Richard55]

thanks Graham and Mick

i am using an Amplion power supply and have checked that correct voltages are present at the terminals on the back of the radio

all valves have continuity and i have checked for 2V at each valve socket (F to F)

i am using SG Brown headphones

i will check the HT voltages as suggested and report back

once again thanks for the help

[Station X]

High Impedance headphones I hope? This set has no output transformer.

Also check that grid bias is present on the grids of the Oscillator and Output Valves.

[Richard55]

Gentlemen

here are the results of my voltage checks

Oscillator Anode = 7.8V

1st Det Anode = 42.4V

1st SG - at the Anode 12.7V, at the SG terminal = 9.2V

2nd SG - at the Anode 12.8V, at the SG terminal = 9.2V

2nd Det - at the Anode 196.6V

Power Valve - at the Anode 0V

i presume i should be worried about the 2nd Det and Power Output?

regards
Dick