Murphy V759 from 1962 - Page 2 - UK Vintage Radio Repair and Restoration Discussion Forum

dazzlevision · 9th Apr 2009, 7:54 pm

Hello Taz,

Nice job. Is the valve next to the HT smoothing can (on the bottom chassis) the correct one? It looks like an EF80 but should be a Mazda 6F23 (2nd vision IF amp). If it is an EF80 (or EF85/EF183/EF184), putting in a 6F23 in might improve the IF response.

Regards,

Dazzlevision

Tazman1966 · 10th Apr 2009, 1:40 pm

Hi Trevor.

Thanks for the kind comments. I'm starting to blush

I do enjoy writing up these resto's but often struggle to try to rein myself in a bit as I could write for England! I only have one more restoration to start and a couple of other sets to sort a couple of small problems out on. I'm not sure what to do after that

Dave, you're bang on about the EF80. I did replace it with a 6F23 quite early on and it did make an improvement. I did think that an EF80 was a good substitute for the Mazda 6F23 though.

I did experiment with a PCL82 in the frame timebase but the linearity wasn't right unless the lin control was right up one end. It seemed to run hot as well

. I'll order a 30PL13 I think.

Cheers,

Tazman1966 · 12th Jul 2009, 8:10 pm

Hi folks

It's me back again with an update.

A week ago I posted a request for help with a CRT equivalent in this thread here as I'd managed to win an A47-14W in the Wooton Bassett auction and wondered if it would replace the original CME1901.

I'm pleased to report that the transplant went well and my patient has improved beyond all recognition. It now focuses right into the corners and it bright and clear

I am however left with one problem and that is that the imporved brightness and contrast now shows up some rather poor EHT regulation. This is especially prevalent after the set has been on for a while. I haven't got another U26 to try but have loads of EY86/87, DY86/87 and DY802. Will any of these do the trick?

Hope to hear from you with your ideas. Meanwhile, I'll leave you with a couple of pics to be going on with

. The first shows the new tube installed, the second the guarantee card that came with it! The third is of the CRT from the back and the last two show the set in operation. One thing I have noticed about the new tube is that when it's switched off, the phosphor is much darker than the original.

Steve_P · 12th Jul 2009, 8:16 pm

Loads better, I agree.

U26 has a different heater voltage and current to a DY or EY. Murphy had to use Mazda valves at the time...

Cheers,

Steve P.

marcus 3500 · 12th Jul 2009, 8:18 pm

Well done mate

looks good as new

Marcus.

murphyv310 · 12th Jul 2009, 9:26 pm

Hi Tas.
Good looking set, a few things to do, firstly make sure you send off the tube guarantee!!
A little more width will up the available drive to the U26 and may cure the EHT regulation.
If it doesn't help have a look at the U26 heaters, if they are dull there is a choke in series with them fitted in the lopty it may be high resistance and this may be the problem, in the 60'-70's the lopty was replaced, now of course we can't but fitting an EHT stick instead of the valve is a 100% cure a TV18 or other EHT stick capable of 18kv will be fine, I have done this with my 320A (16kv) as the choke was o/c and the set is fine.
good luck.
Trevor

Hunts smoothing bomb · 12th Jul 2009, 10:56 pm

Hey Tas,

Looks like yet another quality set you've got there

Tube looks mint - Well done in spotting it

Cheers

BGmidsUK · 12th Jul 2009, 11:06 pm

Nice one !!! Thanks for the pics. Great to see this set working so well! Would be nice if the "tired" tube can be preserved for future rebuild if possible, as these must surely be becoming scarce now.

As for width, this looks about right, maybe shifted to the right but the height could do with being reduced a bit

Brian

Heatercathodeshort · 13th Jul 2009, 7:35 am

Nice receiver you have there! The A47-14W has a dark grey filter faceplate. It gives a very good picture. The date code appears to be around 1970/71. The U26 has a 2v heater, the DY series are 1.4v You can use a DY as a test to prove the goodness of the U26. Regards, John.

9th Apr 2009, 7:54 pm	#21
dazzlevision Dekatron Join Date: Sep 2003 Location: Near Swindon, North Wiltshire, UK. Posts: 3,620	Re: Murphy V759 from 1962 Hello Taz, Nice job. Is the valve next to the HT smoothing can (on the bottom chassis) the correct one? It looks like an EF80 but should be a Mazda 6F23 (2nd vision IF amp). If it is an EF80 (or EF85/EF183/EF184), putting in a 6F23 in might improve the IF response. Regards, Dazzlevision

10th Apr 2009, 1:40 pm	#22
Tazman1966 Nonode Join Date: May 2006 Location: St Albans, Herts, UK. Posts: 2,193	Re: Murphy V759 from 1962 Hi Trevor. Thanks for the kind comments. I'm starting to blush I do enjoy writing up these resto's but often struggle to try to rein myself in a bit as I could write for England! I only have one more restoration to start and a couple of other sets to sort a couple of small problems out on. I'm not sure what to do after that Dave, you're bang on about the EF80. I did replace it with a 6F23 quite early on and it did make an improvement. I did think that an EF80 was a good substitute for the Mazda 6F23 though. I did experiment with a PCL82 in the frame timebase but the linearity wasn't right unless the lin control was right up one end. It seemed to run hot as well. I'll order a 30PL13 I think. Cheers, __________________ All the very best, Tas

12th Jul 2009, 8:10 pm	#23
Tazman1966 Nonode Join Date: May 2006 Location: St Albans, Herts, UK. Posts: 2,193	Re: Murphy V759 from 1962 Hi folks It's me back again with an update. A week ago I posted a request for help with a CRT equivalent in this thread here as I'd managed to win an A47-14W in the Wooton Bassett auction and wondered if it would replace the original CME1901. I'm pleased to report that the transplant went well and my patient has improved beyond all recognition. It now focuses right into the corners and it bright and clear I am however left with one problem and that is that the imporved brightness and contrast now shows up some rather poor EHT regulation. This is especially prevalent after the set has been on for a while. I haven't got another U26 to try but have loads of EY86/87, DY86/87 and DY802. Will any of these do the trick? Hope to hear from you with your ideas. Meanwhile, I'll leave you with a couple of pics to be going on with. The first shows the new tube installed, the second the guarantee card that came with it! The third is of the CRT from the back and the last two show the set in operation. One thing I have noticed about the new tube is that when it's switched off, the phosphor is much darker than the original. Attached Thumbnails __________________ All the very best, Tas

12th Jul 2009, 8:16 pm	#24
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Murphy V759 from 1962 Loads better, I agree. U26 has a different heater voltage and current to a DY or EY. Murphy had to use Mazda valves at the time... 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...?

12th Jul 2009, 8:18 pm	#25
marcus 3500 Retired Dormant Member Join Date: May 2006 Location: South Yorkshire, UK. Posts: 351	Re: Murphy V759 from 1962 Well done mate looks good as new Marcus.

12th Jul 2009, 9:26 pm	#26
murphyv310 Dekatron Join Date: Sep 2006 Location: Kilmarnock, Ayrshire, UK. Posts: 5,422	Re: Murphy V759 from 1962 Hi Tas. Good looking set, a few things to do, firstly make sure you send off the tube guarantee!! A little more width will up the available drive to the U26 and may cure the EHT regulation. If it doesn't help have a look at the U26 heaters, if they are dull there is a choke in series with them fitted in the lopty it may be high resistance and this may be the problem, in the 60'-70's the lopty was replaced, now of course we can't but fitting an EHT stick instead of the valve is a 100% cure a TV18 or other EHT stick capable of 18kv will be fine, I have done this with my 320A (16kv) as the choke was o/c and the set is fine. good luck. Trevor __________________ Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member

12th Jul 2009, 10:56 pm	#27
Hunts smoothing bomb Octode Join Date: Oct 2005 Location: Wimborne, Dorset, UK. Posts: 1,407	Re: Murphy V759 from 1962 Hey Tas, Looks like yet another quality set you've got there Tube looks mint - Well done in spotting it Cheers __________________ Lee

12th Jul 2009, 11:06 pm	#28
BGmidsUK Retired Dormant Member Join Date: Oct 2007 Location: Leicester, UK. Posts: 809	Re: Murphy V759 from 1962 Nice one !!! Thanks for the pics. Great to see this set working so well! Would be nice if the "tired" tube can be preserved for future rebuild if possible, as these must surely be becoming scarce now. As for width, this looks about right, maybe shifted to the right but the height could do with being reduced a bit Brian

13th Jul 2009, 7:35 am	#29
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: Murphy V759 from 1962 Nice receiver you have there! The A47-14W has a dark grey filter faceplate. It gives a very good picture. The date code appears to be around 1970/71. The U26 has a 2v heater, the DY series are 1.4v You can use a DY as a test to prove the goodness of the U26. Regards, John.