Ferranti 125 resto - UK Vintage Radio Repair and Restoration Discussion Forum

mancunian69 · 14th Aug 2023, 8:35 pm

Guys,
I'm currently restoring a 125 and it's in really bad shape, but I refuse to senf it to landfill.

I picked this set up locally. It was listed on eBay as a 99p starting auction. I asked the seller how much he wanted for it. To my astonishment, he said I could have it for free. FREE, I love that word.

I collected the set. The guy, in his 50's told me that it belonged to his mum and had been in the family for years. When restored, I am going to send him some images of it up and running again after donkeys years in the loft.

The cab was falling apart and so far, I have done all necessary repairs and now started to refurbish it, but more on that later.

Now, I am startting to restore the chassis. I downloded a schematic and am a bit confused.
The dial light on the chassis I have uses a pigmy type bulb. It is rated at 1.2W 240V
The schematic I have states that it should be a 6.3v bulb.

I have looked on eBay for pigmy bulbs, but all I can find are the types for ovens/microwaves with a much higher wattage. 10W+

I'm stumped here. Any suggestions?

Rgds
Michael.

mancunian69 · 14th Aug 2023, 8:46 pm

FYI

Kentode · 15th Aug 2023, 6:24 am

If the schematic says it should be 6.3v, then it's fed from the heaters. You need to track where the bulb holder in your set is powered from. 240v bulb = fed from the mains.

A previous owner may have altered the circuit...

I've just tried to download the schematic from Radiomuseum but got an error.

John M0GLN · 15th Aug 2023, 7:53 am

Extract from circuit attached, if it is as original it's supplied by a transformer for the valve heaters, the HT is straight from the mains, as Kentode's post you will have to make sure and also be aware that there is no isolation provided from the live mains potential.

John

Paul_RK · 15th Aug 2023, 8:05 am

As Ken says, the bulb could be an owner modification - does the arrangement look original? There's a clear photo of a 125 with the back off at

https://www.snellingsmuseum.co.uk/ar...o/ferranti-125

which appears to show a typical MES bulbholder in the centre of the dial. Are the markings on the pygmy bulb clear enough for you to be confident in those? I only ask because I've never seen a 1.2W 240V bulb, and its power consumption is actually below that of the 6.3V 0.3A MES bulbs typically used - rightly or wrongly I'd expect its filament to be pretty fragile, but for sure it wouldn't be very bright. A few sets - the Ekco U243 comes to mind - did use pygmy 240V bulbs for scale illumination, but I think in that instance it was 15W, whose light was a tad overpowering... or had a previous owner put in a 15W bulb because he couldn't get hold of anything smaller? Long time since I had that set...

Paul

Station X · 15th Aug 2023, 8:21 am

Just measure the AC voltage across the lampholder.

G8UWM-MildMartin · 15th Aug 2023, 10:25 am

I have a very similar-looking Ferranti 745 that has a pygmy bulb in a BC lampholder.
It's probably worth comparing the circuits.

MurphyNut · 25th Sep 2023, 6:25 pm

Quote:

Originally Posted by Kentode

If the schematic says it should be 6.3v, then it's fed from the heaters. You need to track where the bulb holder in your set is powered from. 240v bulb = fed from the mains.

A previous owner may have altered the circuit...

I'm not so sure, I've just picked up one of these and mine contains a 240v 15W pigmy bulb! I think it's going to look too bright so I'll put a low wattage "night light" bulb in it's place. Perhaps there was a modification made on this set by the manufacture, my set looks entirely original and untouched!

PaulR · 26th Sep 2023, 4:30 pm

I have a radio which uses a mains voltage dial light. I have replaced it with a low wattage LED lamp. As it remains switched on for hours at a time I think it is an improvement as it remains cool and uses a lot less electricity. Very easily reversed for the purist of course.

PaulR · 26th Sep 2023, 4:48 pm

Regarding the Ferranti, there must have been two versions. This https://www.youtube.com/watch?v=0momdinNOFM shows a mains powered lamp (not the original in this case)

This https://www.snellingsmuseum.co.uk/ar...o/ferranti-125 doesn't have the fitting for a mains lamp

Radio Tech · 26th Sep 2023, 5:49 pm

That's what I would do replace it with an LED or if you still prefer a bulb then use a 7V 0.3A MES

Ken

PaulR · 26th Sep 2023, 6:56 pm

I think the version the OP has uses a mains voltage bulb. One of the amber 2W LED filament type something like this https://www.ebay.co.uk/itm/113910725...r=414189124377 would probably look good

14th Aug 2023, 8:35 pm	#1
mancunian69 Pentode Join Date: Apr 2013 Location: Manchester, UK. Posts: 175	Ferranti 125 resto Guys, I'm currently restoring a 125 and it's in really bad shape, but I refuse to senf it to landfill. I picked this set up locally. It was listed on eBay as a 99p starting auction. I asked the seller how much he wanted for it. To my astonishment, he said I could have it for free. FREE, I love that word. I collected the set. The guy, in his 50's told me that it belonged to his mum and had been in the family for years. When restored, I am going to send him some images of it up and running again after donkeys years in the loft. The cab was falling apart and so far, I have done all necessary repairs and now started to refurbish it, but more on that later. Now, I am startting to restore the chassis. I downloded a schematic and am a bit confused. The dial light on the chassis I have uses a pigmy type bulb. It is rated at 1.2W 240V The schematic I have states that it should be a 6.3v bulb. I have looked on eBay for pigmy bulbs, but all I can find are the types for ovens/microwaves with a much higher wattage. 10W+ I'm stumped here. Any suggestions? Rgds Michael.

14th Aug 2023, 8:46 pm	#2
mancunian69 Pentode Join Date: Apr 2013 Location: Manchester, UK. Posts: 175	Re: Ferranti 125 resto FYI Attached Thumbnails

15th Aug 2023, 6:24 am	#3
Kentode Octode Join Date: Mar 2015 Location: Yorkshire, England. Posts: 1,269	Re: Ferranti 125 resto If the schematic says it should be 6.3v, then it's fed from the heaters. You need to track where the bulb holder in your set is powered from. 240v bulb = fed from the mains. A previous owner may have altered the circuit... I've just tried to download the schematic from Radiomuseum but got an error. __________________ Regards, Ken. BVWS member

15th Aug 2023, 7:53 am	#4
John M0GLN Octode Join Date: Jan 2004 Location: Southport, Lancashire, UK. Posts: 1,149	Re: Ferranti 125 resto Extract from circuit attached, if it is as original it's supplied by a transformer for the valve heaters, the HT is straight from the mains, as Kentode's post you will have to make sure and also be aware that there is no isolation provided from the live mains potential. John Attached Thumbnails Last edited by Station X; 15th Aug 2023 at 8:05 am. Reason: Please don't post circuits from rm here. They can get very upset! Extract from VRSD attached.

15th Aug 2023, 8:05 am	#5
Paul_RK Dekatron Join Date: Nov 2003 Location: Fakenham, Norfolk, UK. Posts: 4,129	Re: Ferranti 125 resto As Ken says, the bulb could be an owner modification - does the arrangement look original? There's a clear photo of a 125 with the back off at https://www.snellingsmuseum.co.uk/ar...o/ferranti-125 which appears to show a typical MES bulbholder in the centre of the dial. Are the markings on the pygmy bulb clear enough for you to be confident in those? I only ask because I've never seen a 1.2W 240V bulb, and its power consumption is actually below that of the 6.3V 0.3A MES bulbs typically used - rightly or wrongly I'd expect its filament to be pretty fragile, but for sure it wouldn't be very bright. A few sets - the Ekco U243 comes to mind - did use pygmy 240V bulbs for scale illumination, but I think in that instance it was 15W, whose light was a tad overpowering... or had a previous owner put in a 15W bulb because he couldn't get hold of anything smaller? Long time since I had that set... Paul

15th Aug 2023, 8:21 am	#6
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 20,662	Re: Ferranti 125 resto Just measure the AC voltage across the lampholder. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

15th Aug 2023, 10:25 am	#7
G8UWM-MildMartin Heptode Join Date: Jan 2004 Location: Stockport, Greater Manchester, UK. Posts: 822	Re: Ferranti 125 resto I have a very similar-looking Ferranti 745 that has a pygmy bulb in a BC lampholder. It's probably worth comparing the circuits.

26th Sep 2023, 4:30 pm	#9
PaulR Dekatron Join Date: Oct 2003 Location: Southport Lancashire, UK. Posts: 3,136	Re: Ferranti 125 resto I have a radio which uses a mains voltage dial light. I have replaced it with a low wattage LED lamp. As it remains switched on for hours at a time I think it is an improvement as it remains cool and uses a lot less electricity. Very easily reversed for the purist of course. __________________ Paul

26th Sep 2023, 4:48 pm	#10
PaulR Dekatron Join Date: Oct 2003 Location: Southport Lancashire, UK. Posts: 3,136	Re: Ferranti 125 resto Regarding the Ferranti, there must have been two versions. This https://www.youtube.com/watch?v=0momdinNOFM shows a mains powered lamp (not the original in this case) This https://www.snellingsmuseum.co.uk/ar...o/ferranti-125 doesn't have the fitting for a mains lamp __________________ Paul

26th Sep 2023, 5:49 pm	#11
Radio Tech Nonode Join Date: Dec 2012 Location: Bocking, near Braintree, Essex, UK. Posts: 2,018	Re: Ferranti 125 resto That's what I would do replace it with an LED or if you still prefer a bulb then use a 7V 0.3A MES Ken

26th Sep 2023, 6:56 pm	#12
PaulR Dekatron Join Date: Oct 2003 Location: Southport Lancashire, UK. Posts: 3,136	Re: Ferranti 125 resto I think the version the OP has uses a mains voltage bulb. One of the amber 2W LED filament type something like this https://www.ebay.co.uk/itm/113910725...r=414189124377 would probably look good __________________ Paul