Ever ready radio with A type chassis.

[davidgem1406]

This first thread is covering the historic aspect of this radio.
The first posting was in December 2012 and mainly covering the identification of this set.

https://www.vintage-radio.net/forum/...ad.php?t=91371


A second posting covering the faults with the set was made on November 2013

https://www.vintage-radio.net/forum/...261#post642261


I then shelved this set until now because of other things that needed attention. As far as this set was concerned I thought I only needed to make a rear panel to finish it completely. It has now spent a few years on a shelf in my lounge

This story is now continued in the next thread.

Dave

[davidgem1406]

I have now eventually got round to finishing this radio, mainly because of the interest a friend showed in it. I remember at that time having it working for him and finding it to be quite poor on reception, but working, although I did nothing about it at that time.

The first thing I did was to make a rear panel (See Picture) for it as I had obtained some thin plywood to do so.
Also I ordered a ready made power board to run it that could be mounted inside the cabinet, and awaited the arrival.

The power board arrived so I set about mounting that into the cabinet without making any changes to the existing construction. The power board was mounted on an L shaped aluminium bracket that sat on top of the frame aerial frame, and was held in place by 2 wrap around brackets that hooked to the front edge of the frame, ran under the frame, and then secured by the 2 lower screws holding the board to the bracket. (See Picture).

I then powered it up and checked it out.
First I noticed that the Medium Wave was very low on gain, then the Long Wave was much louder but poor and noisy with a lot of crackling interference. I also found that If I touched the chassis the noise and especially the crackling would reduce considerably.
I connected the chassis to the AC earth and all that pretty much vanished. The AC lead was changed to a 3 core with the earth connected via a capacitor to the chassis and the power supply bracket.

Then I turned back to why the reception was at such a low level, and looked up my previous postings on this radio.
Because of the problems I had with the IF transformers at that time I decided to check the IF alignment.

Connecting the signal generator produced nothing, absolutely nothing, I even tried connecting directly to the IF amplifier valve, but still nothing.
I did a voltage check on the valves, they were a bit down, but not enough to stop the set dead.
For good measure I also tested all the valves, they were all OK and usable.

My next thought was about the AGC (AVC as they call it) could this have a fault that had everything turned off?
The circuit and the wiring was checked finding that I had made an error in the wave-change switch wiring (S1). (The way the poles are shown on the circuit is rather stupid. It shows all the switch poles as 1 way when they are 3 way. That can be a bit confusing).
As S1 has the AGC for the front end connected to it if the wiring is incorrect maybe that is the problem.
The wiring was corrected but the problem remained.
Also any trace of a station had vanished, I checked the switch wiring again, and again, but I make it correct now.

I then turned to the IFT’s again. First I measured the DC resistance of the winding’s (Reading my previous posts I don’t seem to have done that before). These are the results:

IFT1 Primary 25.1R Secondary 74.4R with 100pf max. trimmers for each winding.
IFT2 Primary 26.9R Secondary 26R with 100pf max. trimmers for each winding.

Could that be correct?
Or is that way to high?

Could somebody having a Type A chassis make a check on the IFT windings DC resistance please?
Also if possible the readings for the oscillator coils L5, L7 is not possible, L8 and L9.

All the information I have been able to find say that IFT windings should be very low or SC (SC I don’t believe)

I have 2 other sets of IFT’s both from valve sets, all be it mains not battery, both sets read low on all windings, between 5.5R to 9.2R.

Also how does one determine the winding that is primary as to the one that is secondary?
Or does it not matter if both windings have the same, or nearly the same, DC resistance and capacitor?

Regards
Dave

[Mike. Watterson]

Secondary to a grid, Primary to an anode.

I have the Lissen equivalent of the Ever Ready 1939 model the A is based on. It works well.

I do have an A. The only significant differences are the valve bases, the tuning drive mechanics and some details of the case.

Do make sure the PSU is about 1.35V +/- 0.02V and the HT is about 80V +/- 5V. The 90V and 1.5V of the battery pack is the nominal FRESH voltage. It should work down to just under 1.1V LT and about 55V HT.

Do have a 25mA fuse on the HT.

IFTs are rarely "a bit high". They are either OK or open circuit.

Note that the original service information was for a very basic analogue meter.

You can measure the AVC. At 0V (on a parallel filament set, series are different) the gain is max. The dectector produces a negative voltage, so a stronger signal is AVC line negative and gain off.

If it was working on LW & MW, put the switch back as it was.

I'd use an Alkaline battery pack (2 x D cells in PARALLEL from same batch) and 60 x AA cells in 6 x 10 way holders for HT. Shelf life over 5 years if decent alkaline. Huge run time.

Unless the PSU is super good and filtered. Mains adds a lot of noise.

Originally the loop aerials were "tuned" to take account of the battery pack, thus service info usually mentions to have it at normal location compared to the loop.

A different model may have quite different IFTs. I'll check the Model A and Lissen later.

[Mike. Watterson]

I presume if this is an A chassis with Octal valves in a Bakelite case, then it's the Model D.
The rarer G uses B7G.
The original Bakelite table models (Ever Ready & Lissen branded) look identical, but usually have P8 edge connect valves, though some might have been changed later, the wires go to same place and valves are identical. The original versions also have direct disc drive tuning, the A, D and G have a cord drive, so pointer goes the correct direction.*
All these and the C series use the AD3 pack, which was probably F cells in parallel for LT (the cells in a 996 and an Alkaline D is slightly higher capacity) and probably 60 of the B cells, as per the three in a 1289 style flat torch pack. An Alkaline AA cell is a similar capacity.

Search Radios Only, GB, Ever Ready, 1945 to 1949 and photos on the Radio Museum home page.
The 1949 Model K is the first to use what was later the Sky Queen style Chassis and it used the B103, a pack with layer cells for HT.
https://www.radiomuseum.org/

I'd never use a vintage battery eliminator on a battery valve set. Built mains PSUs by the maker are a different story.

* Vidor had a direct drive using a slot in the main tuning drum so knob and pointer are in sync on a direct drive.

[Mike. Watterson]

Some valve IFTs have identical primary and secondary. I'd have to check some sets.
I have loads battery valve superhets.

[davidgem1406]

Hello Mike,

Thanks for all the information.

With the Primary and Secondary I realise the Primary is the Anode and Secondary is the Grid.
What I was meaning is that having an IFT that is not in a radio and the 2 windings having the same, or near same, resistance how does one decide on the winding to be the Primary or the one to be the Secondary? Or does it not matter and either winding can be Primary or Secondary?

The power supply is fully stabilised at 1.4V using an IC stabiliser, whilst the HT supply is set to be 90V of load, this drops to 80 on load. The power supply is built for the purpose.

The meter used for all resistance and voltage check is an AVO 8 MK V.

It was working very poorly on MW and LW with MW extremely weak and LW stronger but out of tune and noisy. Most of the noise was cured by earthing the metalwork.
When I rewired the switch it was wrongly wired and I corrected it to the circuit diagram.

I do not have a battery pack to use. I have the original Vidor eliminator that came with the set and I fully refurbished. I also modernised it to have stabilised supply for the 1.4V, whilst the 90V was held at 90V of load by a zener diode. This dropped to 80V on load It is to big to be inside the set permanently. However I could put it in place to do the final alignment.

Yes, it is in a Bakelite case with octal valves and is the model “D”.

Thanks Mike for your offer to check some sets to see what the IF’s are on the battery sets.
The DC resistance for the IF’s of an A type chassis would be good.

Regards,
Dave

[govjohn]

Hello Mike, you say that the set has not worked since you rewired the W/C switch to match that shown in the diagram. It is possible that the diagram is wrong, it would not be the first time. Just a thought.
John.

[Mike. Watterson]

I have an A.
A battery pack is really easy to do and scans of the AD3 are available.
Just for fun, I made a B137 pack. The Sky Prince can take the B136 used in the Sky Queen, King, Lord etc. However it also takes the monster B137. I think half a year of occasional use. Perhaps the largest UK All Dry pack. The USA had some larger packs for their "Farm" radios. The D, G, T, Sky Prince, L26, Sky Monarchs (x2) and Sky Lord are all for homes with no electricity, what the USA called "Farm" radios.
There were some larger UK models 1945 to 1950 that used 2V lead Acid as those are cheaper to run. About 1/5th, 20%, of UK homes still had no mains in 1948.

Battery models (2V LT) in the same case as mains models were common 1935 to 1940.

[TrevorG3VLF]

The IF transformers usually have similar primary and secondary coils. The capacitors will then be the same but they may be tuned slightly differently due to valve grid and anode capacitance being slightly different.
The two tuned circiuts will be spaced in such a way as to get the correct coupling inductance. Critical coupling will give optimum gain and bandwidth. This works either way round so either winding can be primary or secondary.

[Mike. Watterson]

True for valves. Later Transistor IFs are single tuned and not critically coupled.

[davidgem1406]

Hello John,
The diagram does appear to be correct. S1 contact just bridges out the LW aerial coil when in MW band. S2 bridges out the primary of the LW oscillator coil L7 and C13 when in MW band.

Hello Mike,
Thanks for the battery information it is certainly worth knowing about. However for this radio I wish to use the power unit I purchased for it. I need to get it up and running before anything else. The fact that the battery is not sitting there will not stop it from being aligned once it is working.

Hello Trevor,
Thanks for that information and confirming that either of the windings can be Primary or Secondary if they are both the same.

Thanks,
Dave

[Mike. Watterson]

I have returned from the attic. I found some Pye & Vidor sets I'd forgotten about. No sign of the Model A, or the similar 1939 Lissen, or indeed my BEREC version of the Sky King (which is really a Sky Queen, which is really a model K with 25mA type valves).

I'd agree the diagram looks correct.

I'll look again over the weekend. It's reminded me that I need to sort out up there.

I'd only use "add on" power units for transistor models. Radios suitable for everyday use.

But then I do have maybe about 300 sets. I have one AEG AM/FM valve set I use regularly, nearly everyday. I have a 1929 suitcase set with replica batteries that gets a demo on special occasions. The 1929 breadboard model does go, but I don't usually demo it.
I have some 1940s & 1950s battery valve sets that see occasional use, either World Band models, or ones with VHF-FM. The S72 is a nice battery set for SW and SSB, but I have a VR500, ICF-2001D, FT817ND, VX5R and FT101ZD MkIII, so I'd not be using any of the battery valve sets on a regular basis. The valve life of them is a fraction of the 1950s & early 1960s mains models, so it makes no sense to use them regularly.

Edit: You do know that Vidor PSU isn't for a model A?
I do sometimes use external PSUs for testing battery valve sets. The 80V is loads for the HT. The set is designed to perform well at 75V HT & 1.35V LT and should work at 1.1V LT and 56V HT (though poorly). The connector socket is the B4 valve base, even using the same convention, separate pin is HT and the pins either side are LT. Though I often make sockets from two layers of marg tub plastic and cut up coffee tin.
Note the LT- and HT- on any 1.4V LT / parallel filament set with no GB battery must be isolated as the HT- current via LT- (chassis 0V) generates the negative bias for the output valve (470 to 680 Ohms resistor). Shorting LT- and HT- results in a short life for output valve or transformer, whichever is more fragile.

[davidgem1406]

Hello Mike,
You are a very avid collector, you must have been doing it for a long time. I wish I was able to do that but space and finances will not allow for it.

Yes I realise the Vidor eliminator is a generic device not particular to any set. It is just an addition that came with the radio when I bought it. Its model number is 366.

I have noticed that the HT- does not go directly to chassis and supplies the output valve bias. I have no intention of shorting it.
By the way, the AF stages are working fine, it is only the RF that is not working.

Best regards,
Dave.

[Mike. Watterson]

The Vidor probably IS for a particular set because of the difficulties of regulation, especially LT regulation. That's why German 1.4V valve sets (from the Y8 series in 1940s to 25mA B7G types till the end) used an NiCd as a regulator (DEAC) and UK & USA battery sets with built in mains used series filaments, easier to regulate (7.5V nominal battery is about 6.8V on mains PSU). Series models could be from nominal 7.5V battery (4 valves = 5 filaments) to 12V (added series resistance). The battery sets with very large numbers of valves like the Hallicrafters S72 used two parallel series chains.
It was better precision diamond dies that allowed series battery filaments in the USA from 1938 with the larger Sylvania 1.4V valves. The Germans (Telefunken, later owned by Philips) went for most efficiency, so the filaments were all different currents and could not be used in series.

Even the LM317 is marginal for parallel 1.4V filaments and fine for series filaments.

Many earlier 1.4V 50ma (0r 100mA on the output with one or two filaments) valves used Nickel filaments which are less forgiving to voltage variation than tungsten and also much lower life. All the later B7G 25mA types are tungsten and thus are a bit longer life. Later production of filaments was also more consistent. The ballast resistors then on series filaments only had to compensate for HT currents.
You'll find the filament resistance on Loctal, P8, Octal and Mazda Octal 1.4V valves actually is quite variable.

I don't have the space or finances either. Many cost x3 for the shipping than the radio. I've bought very few expensive ones. Many cost £5 to £10.

Do check switch and all wiring is per diagram.
Also C6 on R1 and V1 (pin4?) will kill gain if leaky. 10nF ceramic or plastic 150V is OK

[davidgem1406]

Hi Mike,

I started refurbishing radios as something to keep me occupied but not to retain them, but rather to sell them on and help with my pension.
Its some 2 to 3 years now since I bought any as the prices to buy the, in any condition, has risen a lot, to the point they have become unviable to sell on.

I will be checking all the wiring against the circuit just in case I have made another error somewhere. All the capacitors were replaced when I rebuilt it and the resistors checked and replaced where required.
I will check the components you have mentioned.

Regards,
Dave.

[Mike. Watterson]

It's not viable at all as a money making scheme unless you find a model worth hundreds, very cheap. It's a hobby. Very few models will fetch much. Also it's impossible to give a warranty. I used to service electronics as the day job many years ago and we'd have been wary of more than 1 week warranty even repairing something "recent".

It's very rare resistors need replaced. The tolerance of the design is more than the typical 20% of the parts new. Some high value resistors can go off. Some low ones can too. Cathode resistors in mains sets and the -LT to -HT bias resistor in battery valve sets are the only critical ones.

Though I haven't found the actual radio sets, I did check the R&TVS book, the circuit in it looks correct. At a glance the Trader 450 looks similar

[davidgem1406]

Hi Mike,

I have now checked all the rewiring and components, everything check out correct to the diagram.
My conclusion is first that both IF's are faulty due to a lot of damp in the past. Comparing the winding resistance with other IF's, from mains valve radios, the resistance of the existing IF's is very much higher. I either have to try and find out what the correct DC resistance is or chance to pull and replace them.

Secondly that the oscillator coils are faulty due to a wiring error that took the HT to chassis via those coils, this is mentioned in my original posting in 2013. I need to know what the DC resistance of these coils is to get any idea if they have sustained some damage. I don't think that just pulling them and inspecting them will show me anything.

The original IF's peak at 452KHz, whilst the others I have 1 set peaks at 465KHz and the other at 471KHz.

Regards,
Dave.

[ms660]

Is the Ever Ready 5214 circuit/chassis similar? If so the coil resistances for that are given on the Trader sheet for that one.

Lawrence.

[peter_sol]

Hello
I dont know that particular ever ready model but I think the IF coils should measure around 9 ohms for them all.
Have you tried measuring with the trimmers disconnected?
Almost any IF transformers would substitute.
Can you post some pictures?

[Mike. Watterson]

Originally Posted by ms660

Is the Ever Ready 5214 circuit/chassis similar? If so the coil resistances for that are given on the Trader sheet for that one.

Lawrence.

Very similar.
Edit: all 27 Ohm. Though that might not be 100% correct.
The later 5214 models had the same valves as the A & D, and the characteristics are the same. The main difference is the tuning drive arrangement. There are two damping resistors in the osc part dropped and minor changes to other values.