Murphy 146C

[Restoration73]

Old 1000V dc caps were often used for 300V ac, and if in doubt use a 1250V or 1500V dc
polypropylene type, these will be smaller than the originals.

[Herald1360]

For those two capacitors I would stay with 1000V. One is across the rectifier and could cause mayhem if it failed, the other is the tone correction / transient suppressor across the OP TX primary and is subject to potentially high audio frequency ac voltages.

[HamishBoxer]

Not critical normally unless across the sound o/put transformer,then 1500V might be safer.

Normally 630V modern caps are fine.

Yes,I see it is across the transformer,crossed posts here.

[sparkymike]

I would be interested to know the age of this radio. Serial number is 624478.
Anyone know the year range in which they were produced ?
Mike.

[MurphyNut]

Lovely set, you'll be amazed at how good it will sound when working properly, the bass quality is remarkable! I replaced all the capacitors in mine including the electrolytic cans, I've never been a fan of reforming them.
Easily the most time consuming aspect of restoring one of these sets is replacing the wiring, as you have found.
Good luck, you'll enjoy listening to it when finished.

[sparkymike]

I should be replacing all the capacitors in the amplifier section later this week.
Can this be powered up on its own without the tuner section?
Mike.

[AC/HL]

Not easily, the phase splitter and the rest of the amplifier is on the tuner chassis: https://www.service-data.com/section.php/5113/1/a146c

[sparkymike]

I now have replaced the two high voltage caps and the two electrolytics in the amplifier section and just had a test run and glad to say that now there is no hum as before. The smoothing caps were the ones mainly at fault as capacitance was very low on both sections of the can.
Now when I try to find a station, all I am getting are wolf whistles where I assume are stations on both medium and long. Any suggestions here are welcome.
As I am typing the old brain box is starting to work. The temporary aerial could be quite near one of my garage led strip lights, so will check that first before I reach for the soldering iron !!
The amplifier section sounds as if it will be quite powerful and hum level is quite low unless turned fully up in Gram position.
Mike.

[sparkymike]

Turned all the led lights off and switched on. Good sounding music for a few seconds then whistles took over. Definitely need advice here.

Mike.

[sparkymike]

Got no advice here, so threw all caution to the wind and by tweaking the IF cans a little, got rid of the whistles and an English speaking station is now with clear reception on medium wave low end, but no other stations can be found.
I should be able to identify the station by running another radio next to it to determine where it is on the tuning scale.
Mike.

[sparkymike]

Set now working a lot better. I replaced the interconnect leads where cracked and brittle with new wire and found that the only way to replace them in the tuner section was to solder a draw wire to the old wire and then pull them through. Loosening the tag board at each end was essential as some of the original wires were virtually nipped by the board.
Stations seem a bit sparse on the high end of medium wave but I am now picking up a lot more than at first. A longer higher aerial should improve matters I think. Trying to find a match for the original striped cloth for the speaker grille has proved fruitless so at the moment the speaker is just protected with a bit of scrap cloth.On the original cloth one of the stripes is in a twisted weave and looks much like gold thread.A very vivid yellow colour.
Mike.

[PaulR]

Unfortunately there are fewer stations on MW now. You could invest in an Sstran MW transmitter. I have one permanently connected to a Squeezebox internet radio receiver so can get stations from all over the world on my AM sets. The beauty of my Squeezebox is that the remote control works over the domestic Wi-Fi and so doesn't need to be in the same room as the squeezebox itself. The transmitters are strictly illegal in this country I think but I haven't been arrested - yet.

I have some material which is a good match to pre-war striped Murphy radios. No gold thread and the stripes are much further apart - rather like pin striped suiting which I think it is. You are welcome to a square of it if you would like some.

[Spiga Henry]

Originally Posted by sparkymike

photos before I started.
Mike

Would you be so nice and post here a better photo or scan of the dial of this radio? I have the same set and slowly restoring it, but the dial looks like in the picture ;(

Greetings
HenryK