McMichael 135.

[Nickthedentist]

Loved your Youtube video too, well done!

The chassis looks particularly impressive.

I hope those new caps make it sound as good as it deserves to, i.e. miles better than it does at the moment.

You also seem to have a lot of "hash" on the signal. Have you tried routing the aerial wire away from your telly? Even when off but on standby, these often create a lot of radio interference.

Nick.

[chipp1968]

Yes the chassis looks great , sound s like a Darlek Hope the caps improve it . Im my experience here a good eath and aeriel works wonders , thats as well as a mains earth

[therave]

only have two of the new caps left so i ran it up with two new ones and one of the old wax ones it is now almost listen able just a slight hum. but something is not ringing right as you now i have run a ground wire to the speekers now when i got the set there where no sines that any such wire had ever been there the only wires that where there are the feild coils and speeker thats just 4 no ground but yet the data sheet shows the caps at ground thats what you get for not takeing photos of the speekers so does any one know how to wire them right as you can see the data sheet shows ground but there is none help

[therave]

thats c21 c22 are mounted with the speekers that has no ground but also now that i have added a ground wire the tone control rv2 does not work and like i say there is only 4 wires

[Steve_P]

The ground wire shouldn't matter, but if you aren't sure, leave it out. It's not there on either of my diagrams.

I notice you have the Broadcaster sheet, so that's the one I'll use. Change C21 and C22, that may improve it. So may C19 and C20.

Have you had the speaker winding connected between C21 and C22. This is intended to reduce hum and energise the speaker. If it's connected the wrong way round, it will INCREASE the hum.

Cheers,

Steve P.

[therave]

hi thaks all caps in the set have been replaced the bad photo was how i had them first .but i dont know how they where origionaly

[Steve_P]

Still got problems here?

That diagram looks wrong to me, try tracing the wiring through on the main diagram. If the tone control does nothing, check it's wiring - One leg to the non-valve anode end of R18. The other end to C20. The other end of C20 to deck/earth/chassis.

The control could be faulty of course.

Cheers,

Steve P.

[therave]

hi yes still having probs with this i know its somthing simple so if any one has any ideas plez make a simple diagram and post it but i must admit i think i have tryd most ways that it can be setup like i posted before the service sheet is wong when it comes to how the caps and speekers are wired..
thanks david

[therave]

hi now that i have rewired it to the same as post 66 the tone now works having removed the ground from the speekers

[Top Cap]

Hi Dave, the Pink wire should be the un-smoothed HT from the rectifier and should connect to only two places! These are 1) one side of the larger speakers Field coil and 2) the Positive connection of one of the capacitors (or two if you are using parallel pairs of 4.7uF). The Cream wire is the smoothed HT that feeds the HT line of the receiver and is fed from the other side of the larger speakers Field coil. Also connected here is the other smoothing capacitors Positive connection. Note that the larger speakers field coil (1500 Ohms) operates by the HT current drawn by the set, the smaller speakers field coil (7500 Ohms) is fed directly from the smoothed HT line via a 3000 Ohm 2W resistor.
I have altered your original sketch. There must have been a chassis connection of sorts which not only grounded the negative of the smoothing block but also grounded the field coil of the smaller speaker. If there is a wire already on this smaller speaker that goes to chassis, then use this wire as a return for the smoothing capacitors. Without any knowledge of this radio myself I am out on a limb but I cannot see how a chassis connection here is affecting the tone control. The tone control is a simple top cut with a variable resitor and capacitor from the output valve anode to chassis.
Did you check the two capacitors on the anode circuit?
Does the tone control go to earth via its metal mounting bracket? If so, is this itself connected to chassis or is it somehow related to the missing earth on the smoothing block and field coil 2?
Hope this may help, Les

[therave]

hi i have just tryed this and i could have used it as a wacking plate lol. thanks

[Top Cap]

Hi Dave, I am not sure whether your reply is complementary or derogatory.
If the former then I am glad I was able to help and how does the radio perform now? If the latter then maybe, with my limited amount of circuit information, I think it best to just concentrate on my own collection from now on.

[therave]

hi sorry if it sounds that way i was only trying to give you a idea of what it sounds like i can only apologise if it sounds derogatory that was not my intenton i have now tryed somany ways i am now at a dead end.

thanks
David

[Nickthedentist]

So it made a banging noise when you tried Les' suggestion?

[therave]

not banging when i get time tomorrow i will draw all the ways i have tryd may do them again with the db meter i think one of mine made the most nose with service data been second

thanks
david

[Nickthedentist]

Don't give up on this. You've done so well so far, even if the very ambitious deadline came and went.

[therave]

iav it at last ok there is no ground wire but there is a L.T. set of wires that run net to the speekers for the 6.3v top light i have just tried it and yes it works top caps way but not runing ground but runing it to one side of the L.T it must act as a bias on ac2. still a hum only when set warms up just a little one must be one of the new caps..

[Top Cap]

Hi Dave, you may well have another fault so that when you wire it right, it still does not work and you blame your wiring instead. I have tried to place the connections on the manufacturers circuit, you will see that it is as I sent before, I only used your sketch as I thought you might be able to read it better. The old circuit diagrams were poor at times with no dots to show actual connection points and also they had connections in a cross, i.e. 4 ways, which are never used now. I note that one of the pilot lamp wires goes to chassis but it is shown very weird on the circuit, as if it passes through the mains transformer. I have guessed this as tag 1 but you may find that it is tag 2. Could this be the missing chassis return wire?

I agree you should carry on with this beast, it may seem daunting at times, especially radios with energised speakers. Just concentrate on getting the HT correct and smoothed, then try audio input to the GRAM sockets and get the Audio output stage working correctly. You will then have a level playing field for checking out the rest of the radio.
Les

[Top Cap]

Sorry Dave, we must have been posting at the same time .

There is an additional coil in the main speaker, at least thats what it looks like on the circuit and could be a hum bucking coil (see attached). As was mentioned in an earlier post, make sure you have not inadvertently reversed the main speakers FIELD winding connections. If you have, this may induce more hum instead of cancelling it, just a thought!
Les

[therave]

hi thanks top cap you have seen what has been my problem the only way i came to this is i went over some not to good photos and 5 tags had been used the top light not being used at all but just one side of the L.T but if i put the meter on them none goes to ground but the diagram shows it runing to ground with t1. if tomrrow gives me some time i am going to remove the if out of circuit and see where my hum is comeing from

anway top cap i thank you much for your help

in my new world we only play at board level.

thanks