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Old 29th May 2021, 2:28 pm   #41
dazzlevision
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Default Re: Murphy V659/759 restoration

Hello Steve,

Here is a snippet from Murphy Service News, issue 45, July 1962.
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Old 29th May 2021, 8:41 pm   #42
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Default Re: Murphy V659/759 restoration

Hi.
I have a V659 and the full Murphy manual covering all models and the UHF add on.
Re the LOPT, IMHO they never fully recover from years of being damp. I've changed the oil in umpteen Murphy LOPTs with varying degrees of success. My 659 is now on its third LOPT a Thorn 1400 Jellypot. This mod works very well indeed and it can be hidden in the can. Use the stabilised Thorn circuit. The only issue is the Murphy derives a negative supply for the frame from the Line TB. (one reason why after an hours running with a damp Murphy LOPT the linearity and height increases)
I got a negative supply by feeding the heaters from a negative going silicon rectifier and tapping off the heater chain for approx - 35v suitably smoothed and stabilised with a Zener.
Great sets when right.

https://youtu.be/jMKGGdd8ezo
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Old 30th May 2021, 7:23 am   #43
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Default Re: Murphy V659/759 restoration

Thanks Dave and Trevor. Did you mean a 1400 jellypot Trevor?- your excellent video is with a 900 LOPT.
I notice that your set has the direct sync board. Mine has the flywheel version which needs a 300- 0-300V pulse from the LOPT (not 150-0-150V as I said earlier). I have wound this on and by shear luck the number of turns I tried (about 30) gives me a nice pulse of about 320V when dummy loaded, so I will wind on the other half then coat the whole LOPT in HV silicon. Adding the winding has meant changing the values of the S-bend caps again. I think also it will just about fit in the bottom of the LOPT enclosure.
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Old 30th May 2021, 8:25 am   #44
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Default Re: Murphy V659/759 restoration

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Originally Posted by murphyv310 View Post
Hi,

I have a V659 and the full Murphy manual covering all models and the UHF add on.

Great sets when right.

Cheers,

Trevor
Full service information on the UHF converter plinths for the Astra series seem to be "unobtanium". The only information I have ever come across are circuit diagrams for the two versions (sets with and without VHF/FM radio).

Do you have a full service manual for these UHF converters? If you do, I'm sure the vintage TV people on this forum would be very pleased if you could share it.
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Old 31st May 2021, 8:28 am   #45
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Default Re: Murphy V659/759 restoration

Hi.
Yes the LOPT I fitted was the earlier type but a 1400 would be the best choice.

Here is a quick photo of the info I have. Is this of use?

PS. The jellypots have a separate winding for flywheel sync reference so there is no issue for flywheel versions.
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Old 31st May 2021, 8:46 am   #46
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Default Re: Murphy V659/759 restoration

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Hi.

Here is a quick photo of the info I have. Is this of use?
I have checked my Murphy Radio issued documentation and I have all of the items in your photo except the remote control circuit diagram - for the V659XS or V683XDS (image not clear enough to tell)?

In an issue of Murphy Service News, a full service manual for the UHF converter kits was promised, but I don't think it ever appeared. All that seems to have been issued outside Murphy were the two UHF converter circuit diagrams - unless anyone else knows different...
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Old 31st May 2021, 8:55 am   #47
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Default Re: Murphy V659/759 restoration

Hi.
Here is the remote diagram.
This may be clearer

Unfortunately it's limited by the forum software.
Is there a way I can upload it or should I scan the whole manual and send it to Paul?
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Old 31st May 2021, 9:02 am   #48
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Default Re: Murphy V659/759 restoration

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Originally Posted by murphyv310 View Post
Hi.
Here is the remote diagram.
This may be clearer

Unfortunately it's limited by the forum software.
Is there a way I can upload it or should I scan the whole manual and send it to Paul?
I scanned the whole official Murphy V659/V653 series manual for Steve. If Paul lets me know where to email it, I'll happily do so.

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Old 31st May 2021, 9:12 am   #49
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Default Re: Murphy V659/759 restoration

Interestingly this one doesn't include the V683/689.
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Old 31st May 2021, 9:17 am   #50
dazzlevision
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Default Re: Murphy V659/759 restoration

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Interestingly this one doesn't include the V683/689.
Oops! My mistake.

The manual I scanned is the same as the one shown in your photo - with the grey cover.

Murphy produced a separate model for the Astra V683X, V683XDS, V689 and V689X models with VHF/FM radio facilities.
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Old 31st May 2021, 5:19 pm   #51
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Default Re: Murphy V659/759 restoration

Quote:
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Quote:
Originally Posted by murphyv310 View Post
Hi.

Here is a quick photo of the info I have. Is this of use?
I have checked my Murphy Radio issued documentation and I have all of the items in your photo except the remote control circuit diagram - for the V659XS or V683XDS (image not clear enough to tell)?

In an issue of Murphy Service News, a full service manual for the UHF converter kits was promised, but I don't think it ever appeared. All that seems to have been issued outside Murphy were the two UHF converter circuit diagrams - unless anyone else knows different...
I worked on these from new, and also cannot recall ever seeing a manual or supplement for the UHF converter. One of my jobs was to file the Murphy News.
As regards the LOPT I do remember replacing quite a few even only after a couple of years. One enduring memory of this model, is that for some unknown reason, there were a number of our engineers who used to twiddle the IFT's & make a complete mess of the alignment. We worked on shifts, so one night (they used to keep their hex-trimmers in their white-coat top pockets) so I cut both the ends off all their trimming tools! I wasn't very popular next morning.

It was me that had to use the Samwell & Hutton wob to rectify their misdeeds.

David
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Old 2nd Jun 2021, 1:48 pm   #52
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Default Re: Murphy V659/759 restoration

As a matter of interest Dave, I'm curious why are you after the full manual for the converter? I have not had to do any serious work on mine, but the layout is very simple and straightforward in a way which makes me think it would be very easy to find anything- vision valves all in a row on one board, sound valves in a row on another.
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Old 2nd Jun 2021, 2:51 pm   #53
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Default Re: Murphy V659/759 restoration

I think the alignment twiddling problem was probably caused by a poor AGC system resulting in signal overload on quite moderate settings but guys working on these should have been well aware of it. I.F. twiddling was far too common back in the 60's. I don't think it employs a V/U valve as a common sound on vision amplifier.

My example is fine with a 18DB attenuator in the aerial input that other receivers do not require. These is a preset 'set AGC' slider inside but it's not 'nice'. John.
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Old 2nd Jun 2021, 6:36 pm   #54
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Default Re: Murphy V659/759 restoration

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Originally Posted by Niechcial,Steve View Post
As a matter of interest Dave, I'm curious why are you after the full manual for the converter? I have not had to do any serious work on mine, but the layout is very simple and straightforward in a way which makes me think it would be very easy to find anything- vision valves all in a row on one board, sound valves in a row on another.
Hello Steve,

I always like to have the full manufacturer's service information for anything I work on.

With Murphy Radio products, I'd expect a circuit diagram, modifications list, detailed parts list, drive cord stringing diagram, component layout diagrams (often photos with component references added), circuit description and alignment details - as per their full TV service manuals. In the case of their UHF converters, this was promised, but (it would appear) never issued.

I can manage with a circuit, but to have all the rest is really helpful and speeds up any work, especially alignment, as Murphy loved to use "damping units" in their TV alignment processes.

Bush Radio published full service manuals of all their UHF/625 conversion kits, so I'm surprised Murphy didn't. I expect it was an "economy measure", as Murphy sold out to Rank in 1962, due to increasing annual losses.

It does seem strange that Murphy didn't use a vari-mu valve as the first common vision and sound IF amplifier in the Astra (and previous chassis, IIRC). Setmakers in the Mullard camp would be using either an EF85 or EF183 (in later designs). Although it is now a long time ago, I do seem to recall that, when these sets were in everyday use, changing a 6F23 in a Murphy Astra did cause a noticeable change in IF alignment. Of course, there are three 6F23s in the vision IF strip of the UHF converter!

Last edited by dazzlevision; 2nd Jun 2021 at 6:45 pm.
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Old 2nd Jun 2021, 7:07 pm   #55
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Default Re: Murphy V659/759 restoration

Further to my previous post (#54), I've just had a look at the Murphy UHF converter plinth circuit and see that the 6MHz inter carrier sound IF amp is an EF184 - presumably a Mazda branded one!
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Old 3rd Jun 2021, 5:39 am   #56
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Default Re: Murphy V659/759 restoration

Fair points Dave! I guess I have been very lucky with all the 60s stuff and come across very little that needs re-aligning.
I don't know these early D/S Murphys very well, but things like the 6F23, oil filled transformer, no VHF fine tuner, partial system switch and switched heaters do add up to make them a bit quirky. I love the appearance of them- must have been one of the slimmest cabinets on the market. I haven't run my one long enough to test out the VHF tuning. Is it stable?
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Old 3rd Jun 2021, 7:03 am   #57
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Default Re: Murphy V659/759 restoration

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I haven't run my one long enough to test out the VHF tuning. Is it stable?
Yes, I'd say the local oscillator in then Astra sets is stable enough to do away with a front panel fine tuner, although the non-VHF/FM radio sets usually had a fine tuning (translucent Nylon) adjusting "screwdriver" fitted into that black piece projecting out of the tuner unit at the rear, which you pushed in and turned.

Astra sets with VHF radio had AFC (only when radio was selected), which had to be carefully set up by the Murphy dealer upon first installation. So, if there was a rear fine tune shaft fitted, the customer would fiddle with it and mess things up!

The Astra is a typical Murphy - doing it their own unique way!
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Old 3rd Jun 2021, 7:45 am   #58
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Default Re: Murphy V659/759 restoration

To be honest I never liked the Astra series. Great to play with today but back in the 60's they were to be avoided if you reconditioned receivers for resale.

The nasty Mazda CME19/2301 CRT was always as flat as a pancake. Add to this the expensive oil filled transformer that could only be obtained from another Murphy dealer, even if you were RTRA registered. Add to this the considerable cost and you had a spares bill well in excess of what you could sell it for!

Murphy seemed to have a dislike for AGC. The 6F19 vari/U common I.F. valve was the Mazda equivalent to the Mullard EF85 and was certainly available. The earlier V310 lacked AGC having twin RF gain controls for Band 1 & 3 but I must say the oscillator stability was 100%. The 'A' fringe versions did have full AGC and flywheel sync.

The models with FM radio used a double superhet arrangement to produce a second I.F. of 6.31mc/s. I remember there were a couple of tiny switches near the voltage selector panel that aided setting up the FM stations. In the set up position the AFC was disconnected and a low level AC 50c/s introduced into the RF stages. You tuned for minimum hum [AM rejection] then switched back the AFC and the hum off with the tiny rotary switches. The Astra series probably has the same system but was easily overlooked unless you were a Murphy dealer and knew all the Murphy tricks. John.
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Old 3rd Jun 2021, 7:55 am   #59
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Default Re: Murphy V659/759 restoration

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The models with FM radio used a double superhet arrangement to produce a second I.F. of 6.31mc/s. I remember there were a couple of tiny switches near the voltage selector panel that aided setting up the FM stations. In the set up position the AFC was disconnected and a low level AC 50c/s introduced into the RF stages. You tuned for minimum hum [AM rejection] then switched back the AFC and the hum off with the tiny rotary switches.

The Astra series probably has the same system but was easily overlooked unless you were a Murphy dealer and knew all the Murphy tricks. John.
Hello John,

Yes, the Astra series used the same VHF radio tuning set up - there were three little “switches” involved.

I certainly agree that the MAZDA CRTs fitted didn't last long, unfortunately.

I sometimes wonder - if Murphy Radio had continued as an independent company - what the next chassis after the Astra (presumably a fully dual standard one) would have been like.
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Old 4th Jun 2021, 6:11 am   #60
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Default Re: Murphy V659/759 restoration

I have coated my KB LOPT in solid setting silicon insulant, fitted a new EHT rectifier winding, and the whole thing runs well. When I have got time I will now fit it in the existing EHT can, but not use the width inductor control
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