I just finished the circuit work on a Philips 123 and had some questions.

Forgive me if this are simple questions I'm new to this.

The Philips does not have an internal antennal like the others I have done. So I attached a Metre or 2 of wire to the antenna and picked up the local AM station but very quietly. Just for kicks I grabbed the earth wire with my hand and the volume improved some more. I crocodile clipped the earth wire to my metal desk and it got a quieter again. I then clipped it to another length of wire and got equal volume to me holding the earth wire. The question is what do you attach the earth wire to normally?

The other thing is I have the volume up all the way and am receiving the station at an acceptable normal room volume. I would assume the volume turned up all the way should wield horribly loud distorted carnage. Is it normal for a radio of this type or is it my reception and I should add more wire to the antenna? Or of course is there something not quite right still with the radio?

I see not enough detail on what you have not done...............

Just replacing caps does not guarantee that it will work properly.

If you did not check resistors as you went, you cannot guarantee one is not causing distortion, as voltages may be wrong? Methodology is important.

Once parts have been changed in the RF section, it should and is recommended by the manufacturers to re-align (Some IF cans are non adjustable). If it broke down, the Monkeys have a habit of adjusting any thing that moves. If it can be seen that an adjustment has been tampered with, it has to be reset. This requires appropriate equipment.

The biggest cause of set related deafness, particularly in restored sets,( I find) is poor alignment.

As I have been fixing these things for a long time, this means I can justify having certain items. I actually reached the point where I have a metal "black box" that couples a Signal Generator, Oscilloscope & Frequency Counter together as that lot represent the swiftest way of alignment, finding lost signal, spotting distortion & unwanted signal and where it originates.

With most transformer sets, it is good practice to fit an earthed cable to give the antenna an earth return for the antenna. Notwithstanding that in metropolitan areas mains earth may be dirty and a separate earth impossible.

The standard recommended length of the wire antenna, for those sets is 25feet. Insulated wire is preferred for the down wire. As I am in a rural situation, the length is not so critical above this, but there is such a thing as a length that will not work well (big is not necessarily beautiful) There is an RCA chart on this.

Marc

Ah thanks very much. Caps and many resistors were replaced. I have noticed it has improved some after running for some time. Still probably not optimal though.

A Signal Generator and Oscilloscope are on the shopping list as the hobby budget permits. Would you recommend equipment that matches the era or modern gear in this regard?

CRO probably doesn't matter what you use. As long as you have confidence in the unit. Bear in mind a 60 year old CRO will have the same issues as a 60 year old radio with caps and resistors. My CRO is around 20yr old. I also have an older 1966 era CRO with 16 valves, it weighs a tonne, full of wax caps and is very unreliable. Its currently in bits and is likely to stay that way for some time.

An older sig gen such as a Leader, Palec or Advance will probably suit the job better as signal levels and frequency are designed for that era of equipment. Give it a once over and calibrate it against a more modern set and you should be set.

I also have my own 'buggery box' to allow easy connection of siggen, cro and a freq counter.

The stuff is still out there to be found, eventually


Ben

16 Valves! Hardcore

Its a bit of a challenge finding much of this stuff in Tassie so far. Think I will have to bite the bullet and pay some postage costs.

I do tend to salvage a bit of the old test stuff, I am waiting on some Plexiglas to repair the window in a US Philco, BC221-N frequency meter. I have replaced dodgy caps & resistors that just had to go so it will be interesting to see if it stays in calibration with its book?

I have a Leader LSG-11(with original box) That I made go. It has new caps & a new earthed mains cable mains as it was dangerous the way it was. There is also a Sanwa SW0-301, the later was not apparently spectacular according to some in the Radio Club.

Both of these units were basically bought in to save them from scrap, but I did evaluate them to see if they were worth overhauling. I repainted the LSG

These are surplus to requirements. I will send photo's to Brad with more info. One CRO here is a Heathkit OS-1 that seems to need another new set of filter caps. A dual trace BWD 539C I bought at a clearing sale & took over 2 Hrs just to clean and a Jaycar QC1910.

Marc

I had a lot of volume issues restoring my Philips 123. It's a complicated circuit - and was my first valve unit restoration - so I had a lot to learn.

The last thing I found was a problem associated with the centre tap of the volume pot itself. This controls feedback to the automatic gain control. I had to open up the pot, clean and re-lubricate it, and recondition all the soldered connections to that pot - some of the terminals on the pot are rivetted to the insulation base. Those brass rivets can work loose over time and result in unreliable connections.

If the pot is beyond help, there is another thread here about how I found a way to add a centre tap to a standard pot. But stay with the original if possible.

Maven

That's a fairly common arrangement , but the pots are scarce. Astor & many others did that feedback trick. There is a guy in America called Mark Oppat (not sure of spelling) who rebuilds pots.

Riveting can be a pain, I have an audio cable here where the centres have come loose in the plugs & I had a phase issue in a 1929 Lyric (AC filaments) caused by the rivets in a "Humdinger" on the filaments.

If you want ridiculous over complication Radio's like the American "Midwest's" are a good start. 18-36 has four 6F6 Output valves fed by another as the driver and one has a woofer & tweeter, both electrodynamic, as well as other chokes, It drags that much current is has two 5Y3 rectifiers, one in each phase with their plates parallel.

Some of the valve functions (18 of them in one) I wonder about, in some of them shielding is more a decoration, scanting is rife, as for the size, the chassis is quite flimsy & I was always worried about rivets & wires being damaged by the flexing. Capacitor counts are in the order of sixties, resistors similar and to help, several were inside the Hammerlund (ceramic) IFT's which had a terminal plate inside. That means you have to dismantle to get at them. One good thing is that they specify the signal voltages to be fed into the antenna to align & in one case, set the amplified AGC.

Five valve Philips is a wet afternoon breeze, compared to these.

Marc

Hi

I am currently restoring a Mullard badged version of this set: http://vintage-radio.com.au/default.asp?f=1&th=853.

From what I have found so far is that a few of the resistors have gone high in value. In particular R3, R5, R13 and R15.

I still have no life out of mine yet but I have only just started the electrical restore.

Dan

‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
Valve radios, They just don't make them like they used to

Take a careful look at the transformer, 132L & a few others with a similar construction have a bad habit of letting the windings out of the side.

Marc

The Transformer is definitely worth checking, as my 132 the windings are out the side.
As the High voltage had failed wasnt the biggest issue.

Josh

Hi "TheDanger"

Just wondering how you have gotten on with the restore of your radio. I finished the electrical restore last weekend and had a few unusual problems... I actually had valve failures. Its not that common but I had 2 in this set fail!

I am still to polish the cabinet and clean up the knobs.

Hope you got your to go.

Dan

‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
Valve radios, They just don't make them like they used to

Hi Dan

The radio came up very well. Initially had some arcing in the rectifier valve on first start up which was caused by another valve not seated quite right. I had to replace many resistors that were out of tolerance.

http://i.imgur.com/MM0eMYy.jpg

Sorry to be a noob but how do you show an image in the post and not just a link? Nevermind I read the forum guidlines.

Hi

Don't worry about being a noob, you have to start somewhere. I will have a look at the link when I get home.

I have had mine on the bench for the last few weeks and now seems to be performing well. Hopefully this weekend I can polish up the cabinet and re paint in the white stripes.

Dan

‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
Valve radios, They just don't make them like they used to

I'm using this one as my main listener at the moment. Really have to get started on some sort of transmitter sometime. I pick up only one station on AM where I am and lets just say its a pretty boring one.