Wartime Utility Radio - UK Vintage Radio Repair and Restoration Discussion Forum

deco-doctor · 31st Aug 2008, 12:43 pm

Split from this thread:-

https://www.vintage-radio.net/forum/...d.php?p=198341

Graham. Station X. Forum Moderator.

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Quote:

Originally Posted by Avro626

A while ago I bought an old Wartime Utility Radio in need of restoration from one of our Forum members (he'll know who he is). Well I have now completed the 'Cosmetic' restoration and thought I would show you it. The cabinet was sanded down,restored and revarnished and the speaker cloth replaced. The internals still need more restoration work but so far so good! Cheers Dave.

Hi Dave

Nice job! how are you getting on with the internals?

I am wondering if you or anyone else can help me out with one of these sets?

I am in need of a circuit diagram so I (or a willing volunteer

)can repair the one my father has.

My fathers set has just packed up, I replaced all the valves for him last year and it has been working fine, but he turned it on this week to listen to the cricket on LW and sadly there is no output.

The radio has much sentimental value to him, as after the war he worked at the McMichael radio factory making the chassis for these very sets. One of his jobs was job was to put in the eyelets into the chassis with a fly press.

I really need to get it going again for him.

Many thanks

Martin

Station X · 31st Aug 2008, 12:46 pm

The service data is available by clicking the link at the top right of this page.

deco-doctor · 31st Aug 2008, 12:51 pm

Quote:

Originally Posted by Station X

The service data is available by clicking the link at the top right of this page.

Hi Graham

Is this available as an individual download? If so how do I find it?

Thanks

Martin

Patrick Dixon · 31st Aug 2008, 1:04 pm

If you click on the link and type 'wartime' into the search box you'll see that there are three sets available - battery, AC and a supplementary sheet for LW.

You can then buy each of these individually for £1.99 if you wish.

PJL · 31st Aug 2008, 4:18 pm

Before you go further I would recommend you check the mains transformer primary and secondaries continuity and output transformer primary continuity.

deco-doctor · 31st Aug 2008, 4:52 pm

Quote:

Originally Posted by PJL

Before you go further I would recommend you check the mains transformer primary and secondaries continuity and output transformer primary continuity.

Thanks, I have not even looked at it yet, so I don't know whats occurred. I will check the transformer windings first as you suggest.

I downloaded the service sheet which is very good.

Steve_P · 31st Aug 2008, 4:53 pm

First, unplug and put an Ohmeter (Mulitmeter on ohms range) across the plug terminals. With it switched off there should be nothing. If when it's switched ON there's nothing, then check the plug fuse, cable and On-Off switch.

The secondary goes to the rectifier valve. Check the reading across both the anodes. Also, the valves are wired in parallel, so whip out V1, V2, V3 and V4. The rectifier, V4 is on a separate heater chain, so check continuity between the heater pins of all valves as you put them in. V1 to V3 go to deck, V4 does not.

If you don't get a reading, check wiring to the mains transformer and the secondary itself.

Put the valves back in and switch on. They should light up. Allow time to warm up and listen to see if you can hear anything. If you don't hear anything, check from the cathode of the rectifier valve through R14 and R15.

Check the AFC is OK too - a very insensitive radio if you don't. And you have changed C14 haven't you?

If you hear hissing but no stations, check the Aerial is OK and the install of the LW part. Might also be an idea to check the oscillator circuit and R4.

Cheers,

Steve P.

deco-doctor · 31st Aug 2008, 5:58 pm

Quote:

Originally Posted by Steve_P

Check the AFC is OK too - a very insensitive radio if you don't. And you have changed C14 haven't you?

Hi Steve. I have not checked anything yet. The set is at my dads house. I put a new set of valves in about a year ago and everything was fine then.

C14 looks like it is the coupling cap to the grid of EL33 output valve, yes if thats leaky there will be positive grid voltage on the EL33 which would not be good! I guess the original could be a high voltage PIO judging by the size of it in the picture in the service sheet. I have some nice Russian PIO caps here I can replace it with.

Thanks for the advice on what to check first.

Regards

Martin G4IYA

Studio263 · 31st Aug 2008, 9:44 pm

AFC? On a set in this class? I think you mean AGC. The bias from this came from a "westector" diode which if it still there has probably gone very high resistance by now. A suitably rated germanium diode makes a good replacement.

Station X · 31st Aug 2008, 10:58 pm

Or even AVC.

McMichael · 8th Nov 2008, 12:23 am

Quote:

Originally Posted by deco-doctor

I am wondering if you or anyone else can help me out with one of these sets?

My father's set has just packed up, I replaced all the valves for him last year and it has been working fine, but he turned it on this week to listen to the cricket on LW and sadly there is no output.

The radio has much sentimental value to him, as after the war he worked at the McMichael radio factory making the chassis for these very sets. One of his jobs was job was to put in the eyelets into the chassis with a fly press.

Hi Martin,

Was your father's set made by McMichael? If so, it should have U20 stamped on the chassis label. You say that your father made the chassis for these radios after the war - I thought that they were made in 1944, but perhaps they carried on producing them until they brought out the Model 451 in February 1946. How long did he work there (and did you manage to fix the set)?

73, David

31st Aug 2008, 12:46 pm	#2
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Wartime Utility Radio The service data is available by clicking the link at the top right of this page. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

31st Aug 2008, 1:04 pm	#4
Patrick Dixon Hexode Join Date: Aug 2007 Location: Bristol, UK. Posts: 480	Re: Wartime Utility Radio If you click on the link and type 'wartime' into the search box you'll see that there are three sets available - battery, AC and a supplementary sheet for LW. You can then buy each of these individually for £1.99 if you wish.

31st Aug 2008, 4:18 pm	#5
PJL Dekatron Join Date: Sep 2005 Location: Seaford, East Sussex, UK. Posts: 5,997	Re: Wartime Utility Radio Before you go further I would recommend you check the mains transformer primary and secondaries continuity and output transformer primary continuity.

31st Aug 2008, 4:53 pm	#7
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Wartime Utility Radio First, unplug and put an Ohmeter (Mulitmeter on ohms range) across the plug terminals. With it switched off there should be nothing. If when it's switched ON there's nothing, then check the plug fuse, cable and On-Off switch. The secondary goes to the rectifier valve. Check the reading across both the anodes. Also, the valves are wired in parallel, so whip out V1, V2, V3 and V4. The rectifier, V4 is on a separate heater chain, so check continuity between the heater pins of all valves as you put them in. V1 to V3 go to deck, V4 does not. If you don't get a reading, check wiring to the mains transformer and the secondary itself. Put the valves back in and switch on. They should light up. Allow time to warm up and listen to see if you can hear anything. If you don't hear anything, check from the cathode of the rectifier valve through R14 and R15. Check the AFC is OK too - a very insensitive radio if you don't. And you have changed C14 haven't you? If you hear hissing but no stations, check the Aerial is OK and the install of the LW part. Might also be an idea to check the oscillator circuit and R4. Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

31st Aug 2008, 9:44 pm	#9
Studio263 Octode Join Date: Apr 2007 Location: Hampshire, UK. Posts: 1,577	Re: Wartime Utility Radio AFC? On a set in this class? I think you mean AGC. The bias from this came from a "westector" diode which if it still there has probably gone very high resistance by now. A suitably rated germanium diode makes a good replacement.

31st Aug 2008, 10:58 pm	#10
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,288	Re: Wartime Utility Radio Or even AVC. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.