Hi all having problems with the circuit for this Little General. I have down loaded 3 versions none resemble this .I know there were many versions and the guy who made this may have improvised. Some resistance values seem to be expressed in megohms and some in ohms.
this has the following valve line up and is not the loop aerial version. 6J8,6G8,6V6,80. The cathode of the 6J8 has an 150 ohm resistor to ground bypassed with an 0.025mfd capacitor. there is a 50K ohm between cathode and pin 5 which is the g1 of triode section the circuit shows this as 0.05 I am assuming this is .05 meg ohm. Grid 1 of the 6V6 is shown on the circuit to have a resistor marked as 1. to the power transformer centre tap and negative end of 8 mfd filter cap .
There is an 260 ohm wire wound resistor floating around loose and a 25mfd. electro . I cannot place these. Should I just find a circuit with the same valve line up and rewire this to suit? This makes it a much bigger job than I intended.
Am I correct some of the resistance values are expressed in megohms such as .05 which would be 50K ohm. Maybe I have lost the plot.

looking forward to some constructive advice.
Regards Jim.

Posting this twice is a bit confusing, hopefully you'll see my reply.

0.05 is "old-speak" for 50k, and 1 would be 1M.

The floating loose parts would seem to be those for the 6V6 cathode, to ground. The 25μF (probably 40V) electro is probably shot, replace it with a nice new 22μF 25V job.

Also, like any old radio, replace those old paper/wax caps with new ones.

I have a spare chassis for one of these. you can have it if you want. Just pay postage. My email is open and I will check what's with it in the morning if you like.

Little Generals had 2 broad types.
1/ the early ones with a simple bias control for the volume with a pot in the thousands of ohms
2/ later types with an audio pot around 500kohm for the volume and self bias / AGC on the IF valve.

The value of the "volume" pot will tell you which type you have.
Question: what is the ohms value of your volume pot?
Fred



If it has a 5000 ohm pot use the April 1940 original circuit as the template.
If it has a 500k pot use the January 1946 circuit as the template.

Looking at the set I think its one of the kits supplied by one of many companies.

A picture of the underneath showing the parts would be very handy.


Fred..

Thank you Robbbert, Tallar Carl and Fred.
Firstly Robbbert apologies for the double post. In the first post I was mainly trying to identify what it was and I thought it would be plain sailing from there. However I needed some extra help from the brains trust. Thus the second post.
Tallar Carl thank you. I will email you.
Fred it appears to be based on the latter version the pot is 500K the centre tap goes via a 0.01 cap to grid 1of the 6V6.g1 has a 500K to ground another leg of the pot goes to the cathode of the IF valve 6G8.The other leg goes to the IF can. This again differs from from all these circuits. They all show the wiper grounded and bottom end of pot no connection.
Kind regards Jim

Hi, yep the 1946 version would be the one to use.
Do you have a circuit copy, if not i'll scan the thing and email it to you.
Taking note of the Aegis coil cans and odd layout i'm sure its a kit supplier version although I have not seen that layout in any advert so far in the mags.The 46 circuit was a tad better behaved than the original having AGC added.
I'm sure you will be able to re-wire to the 46 circuit. In that they ditched the 6G8 for a Philips EBsomething, your 6G8 will be fine.
Its just a matter of checking the base pin connections have the correct wires on them.
Its a great little training set to understand how a superhet works.
So long as your parts are good it cannot fail to work!
Fred.

Hi Fred I have a 1947 circuit from the Radio Museum that should do the job, the only valve difference is the rectifier it uses a 6X5.This radio also has a dial light globe to ground on the centre tap of the mains transformer instead of an 400 ohm resistor..Any idea why this would have been used ? I wondered if it acted like a fuse. What power rating did this 400 resistor have , I assume 1 watt would be ok.
Thank you for taking the time with this post.
Kind regards Jim .

Hi, the 1947 circuit uses a 6X5 during Moyles rebuild of the original.
It also has the 5000 ohm bias volume control.
If you have a 5000 ohm control use that circuit or the original as a template.
The dial lamp may have been placed across the 400 ohm resistor to run it at low voltage, but not by itself!
I would not do that, I have not found a LG circuit with that.
I have the original 1947 article but have not seen this radio museum circuit.
I would stick with the articles as published by RH not by someone else.
Cheers Fred.

Thanks Fred not sure if I have a 5k pot will check.
Regards Jim

AWA often used 100 Ohm 1/2W resistors in the plate circuit of 6X5 for a couple of reasons & one would be due to early versions of this valve having a bad habit of shorting, heater to cathode.

Sorry, I forgot to answer your question re the wattage size of the 400 ohm.
As full HT current runs through that continually I use a wire wound 3W in that position.
Probably they used a WW or a large carbon body size.
I make it a rule with valve stuff never to use anything smaller than 1 watt body size resistors anywhere in the chassis, like the Soanar range you get at Jaycar. You can also buy the WW PW3 and PW5 there.
Then you have a compatible voltage and current rating for 250 to 300 volt circuits.

The resistors Marcc mentions are a different application where you WANT the resistor to burn up in a fault condition, I do exactly that with experimental circuits and welcome a stream of smoke from the resistor rather than out of a valve or transformer!

Fred.

One warning here: I stock principally 1Watt resistors for valve radio's (voltage again being the principal reason). However, there are of course others, as that is not all that I fix. Had a "Golf Buggy" recently.

Where sets are "back biased", that is the last resistor that you dare "heavy up": Better to have it marginal & burn up, than destroy the rectifier, or transformer if a short appears.

The globe may also act as cheap Barretter. I often do that sort of thing in battery chargers as a current limiter.

That I copied from "Metz" (commercial flashgun) who actually used a Barretter in the battery holder / circuit for NiCd batteries. These could actually reverse polarity. The Barretter was the current limiter so there was little hope of the transformer being damaged, even when presented with a short circuit.

Marc

Thank you Marcc and Fred.
Regards Jim.

Jimb I will post the chassis off to you on Monday buddy. Will let you know the postage cost then.

Thank you Carl. Much appreciated.
Kind regards Jim.