Hello,
       I've just bought a 770R for restoration which seems to be in
reasonable condition except for two fairly big problems. The flywheel
friction drive to the tuning mechanism is missing and the dial cord has
been removed.Does anyone have any decent pictures/diagrams showing
these components. and the route for the dial cord.
Cheers
Keith Harvey

----- Original Message -----

From: harv54

To: eddystone_radio_users@...

Sent: Wednesday, February 07, 2007 4:46 PM

Subject: [eddystone_radio_users] Eddystone 770R

Hello,
I've just bought a 770R for restoration which seems to be in
reasonable condition except for two fairly big problems. The flywheel
friction drive to the tuning mechanism is missing and the dial cord has
been removed.Does anyone have any decent pictures/diagrams showing
these components. and the route for the dial cord.
Cheers
Keith Harvey

Thanks for that information. Lokking at the drive cable layout, it
seems that I'm also lacking the two pulley gears so I'll probably
need a scrapper
Cheers
Keith




--- In eddystone_radio_users@..., "GRAEME WORMALD"

<g3ggl@...> wrote:
>






> Hello Keith.
>
> The drive cord lacing is described in the handbook.
> The friction drive is considered to be a factory servicing job and
isn't described.  The only way to deal with it is to look at another
Eddystone with a slide-rule dial (most early fifties to late sixties
sets).  Acquiring the parts may be difficut; try Ian Nutt (website)
or acquire a model which is otherwise scrap.
>
> Good luck,  Graeme  Wormald,  G3GGL
>
>
>   ----- Original Message -----
>   From: harv54
>   To: eddystone_radio_users@...
>   Sent: Wednesday, February 07, 2007 4:46 PM
>   Subject: [eddystone_radio_users] Eddystone 770R
>
>
>   Hello,
>   I've just bought a 770R for restoration which seems to be in
>   reasonable condition except for two fairly big problems. The
flywheel
>   friction drive to the tuning mechanism is missing and the dial
cord has
>   been removed.Does anyone have any decent pictures/diagrams
showing
>   these components. and the route for the dial cord.
>   Cheers
>   Keith Harvey
>

The EUG website is in the process of uploading the service manual for
the IMR54 receiver. However the circuit we are working from is rather
poor and difficult to clean up prior to digitising. Does anyone have a
clean copy of the IMR54 circuit we can borrow/copy/use so that we can
complete the upload

Regards

Chris G0EYO
EUG Webmaster
www.eddystoneusergroup.org.uk

----- Original Message -----

From: g0eyo

To: eddystone_radio_users@...

Sent: Saturday, February 10, 2007 2:20 PM

Subject: [eddystone_radio_users] Circuit for IMR54 required

The EUG website is in the process of uploading the service manual for
the IMR54 receiver. However the circuit we are working from is rather
poor and difficult to clean up prior to digitising. Does anyone have a
clean copy of the IMR54 circuit we can borrow/copy/use so that we can
complete the upload

Regards

Chris G0EYO
EUG Webmaster
www.eddystoneusergroup.org.uk

EC10 Mk. II seems rather insensitive on all bands: any suggestions,
please? A circuit diagram would also help: and suggestions, please?

Al / G8DLH

----- Original Message -----

From: g8dlh

To: eddystone_radio_users@...

Sent: Sunday, February 11, 2007 2:14 PM

Subject: [eddystone_radio_users] EC10 Mk. II

EC10 Mk. II seems rather insensitive on all bands: any suggestions,
please? A circuit diagram would also help: and suggestions, please?

Al / G8DLH

----- Original Message -----

From: Alan Ainslie

To: eddystone_radio_users@...

Sent: Sunday, February 11, 2007 3:45 PM

Subject: Re: [eddystone_radio_users] EC10 Mk. II

EC10 Mk2 service info is available for download on the excellent EUG web site

http://www.eddystoneusergroup.org.uk/

Alan

----- Original Message -----

From: g8dlh

To: eddystone_radio_users@yahoogroups.co.uk

Sent: Sunday, February 11, 2007 2:14 PM

Subject: [eddystone_radio_users] EC10 Mk. II

EC10 Mk. II seems rather insensitive on all bands: any suggestions,
please? A circuit diagram would also help: and suggestions, please?

Al / G8DLH

--- In eddystone_radio_users@..., "Gerry O'Hara"
<gerryohara@...> wrote:
>
> Al,
>
>
>
> I think Graeme means the OC171 transistors in the RF and IF stages
(the OC71
> is in the AF stage).  The OC171's have four leads, one of which is
an earth
> connection.  These transistors tend to grow 'whiskers' in the can
that
> effectively short the transistor to earth.  Chopping the earth wire
of the
> faulty transistor can effect a cure.
>
>
>
> 73's
>
>
>
> Gerry, G8GUH
>
>
>
>   _____
>
> From: eddystone_radio_users@...
> [mailto:eddystone_radio_users@...] On Behalf Of
GRAEME WORMALD
> Sent: February 11, 2007 9:32 AM
> To: eddystone_radio_users@...
> Subject: Re: [eddystone_radio_users] EC10 Mk. II
>
>
>
> Hello Al / G8DLH,
>
>
>
> Assuming that the IF is properly aligned, the most likely problem
will lie
> with one of the OC71 transistors.  These have now become very dated
(ie
> about 40 years old) and are known to develop internal 'whiskers'
which can
> short to the can, (which is earthed) or other electrodes.
Determine which
> stage has lost most gain (using sig gen with calibrated output) and
then
> snip the earth wire to that stage.  It may work.  If not, I
believe 'new'
> transistors are available from Birketts in Lincoln.
>
>
>
> Good Luck,  Graeme  G3GGL
>
>
>
>
>
> ----- Original Message -----
>
> From: Alan <mailto:alan.ainslie@...>  Ainslie
>
> To: eddystone_radio_
<mailto:eddystone_radio_users@...>
> users@...
>
> Sent: Sunday, February 11, 2007 3:45 PM
>
> Subject: Re: [eddystone_radio_users] EC10 Mk. II
>
>
>
> EC10 Mk2 service info is available for download on the excellent
EUG web
> site
>
> http://www.eddyston <http://www.eddystoneusergroup.org.uk/>
> eusergroup.org.uk/
>
> Alan
>
> ----- Original Message -----
>
> From: g8dlh <mailto:alanhall@...>
>
> To: eddystone_radio_
<mailto:eddystone_radio_users@...>
> users@...
>
> Sent: Sunday, February 11, 2007 2:14 PM
>
> Subject: [eddystone_radio_users] EC10 Mk. II
>
>
>
> EC10 Mk. II seems rather insensitive on all bands: any suggestions,
> please? A circuit diagram would also help: any suggestions, please?
>
> Al / G8DLH

Gerry; Graeme,
Thanks guys. I had a vague notion that OC171 "whisker trouble" was
likely to be suggested as a prime suspect! However, having never been
down this road before, I needed some confirmation that I was thinking
along the right track.
In the IF stages I can see that the screen lead to the OC171's have
been cut through. I wonder if this is where someone has been here
before - I find it a bit difficult to believe that this is an
original "feature". There are other clear signs of previous
maintenance efforts.
Somewhere in the "archive junk box" I have a collection of OC171's
(not new)- but I suspect that they are likely to have the
same "whisker" problem by now. Perhaps fitting new ones is best.
So, a general replacement of these OC171's followed by a general re-
alignment & routine service seems to the way forward.

Alan:
Thanks for the tip, re: service info. @ the EUG Web Site. Will look
there now.

Thanks to all for the help: will keep you posted.

Al / G8DLH
>

----- Original Message -----

From: Gerry O'Hara

To: eddystone_radio_users@...

Sent: Sunday, February 11, 2007 6:03 PM

Subject: RE: [eddystone_radio_users] EC10 Mk. II

Al,

I think Graeme means the OC171 transistors in the RF and IF stages (the OC71 is in the AF stage).  The OC171’s have four leads, one of which is an earth connection.  These transistors tend to grow ‘whiskers’ in the can that effectively short the transistor to earth.  Chopping the earth wire of the faulty transistor can effect a cure.

73’s

Gerry, G8GUH

---

From: eddystone_radio_users@yahoogroups.co.uk [mailto:eddystone_radio_users@yahoogroups.co.uk] On Behalf Of GRAEME WORMALD
Sent: February 11, 2007 9:32 AM
To: eddystone_radio_users@yahoogroups.co.uk
Subject: Re: [eddystone_radio_users] EC10 Mk. II

Hello Al / G8DLH,

Assuming that the IF is properly aligned, the most likely problem will lie with one of the OC71 transistors.  These have now become very dated (ie about 40 years old) and are known to develop internal 'whiskers' which can short to the can, (which is earthed) or other electrodes.  Determine which stage has lost most gain (using sig gen with calibrated output) and then snip the earth wire to that stage.  It may work.  If not, I believe 'new' transistors are available from Birketts in Lincoln.

Good Luck,  Graeme  G3GGL

----- Original Message -----

From: Alan Ainslie

To: eddystone_radio_users@yahoogroups.co.uk

Sent: Sunday, February 11, 2007 3:45 PM

Subject: Re: [eddystone_radio_users] EC10 Mk. II

EC10 Mk2 service info is available for download on the excellent EUG web site

http://www.eddystoneusergroup.org.uk/

Alan

----- Original Message -----

From: g8dlh

To: eddystone_radio_users@yahoogroups.co.uk

Sent: Sunday, February 11, 2007 2:14 PM

Subject: [eddystone_radio_users] EC10 Mk. II

EC10 Mk. II seems rather insensitive on all bands: any suggestions,
please? A circuit diagram would also help: and suggestions, please?

Al / G8DLH

Hi All,

I found one Eddystone 5500 in a surplus shop. I made a search in
Google for the technical manual but I found nothing.

Since this transceiver Xtal controlled I want to modify to use PLL or
DDS controllled.

Any help for technical manual for this radio will be appreciated.

Regards,

TA2LJ Hakan GUNER

Hakan
I think you might mean Orion 5000, 6 channel 100W transceiver. You can
view data sheet in our website www.eddystoneusergroup.org.uk in Data
sheet section. We have a manual here which we could upload if that is
the set you are referring to.

Chris G0EYO
EUG Webmaster
--- In eddystone_radio_users@..., "ta2lj" <ta2lj@...>
wrote:
>
>
> Hi All,
>
> I found one Eddystone 5500 in a surplus shop. I made a search in
> Google for the technical manual but I found nothing.
>
> Since this transceiver Xtal controlled I want to modify to use PLL or
> DDS controllled.
>
> Any help for technical manual for this radio will be appreciated.
>
> Regards,
>
> TA2LJ Hakan GUNER
>

----- Original Message -----

From: g0eyo

To: eddystone_radio_users@...

Sent: Wednesday, February 14, 2007 6:12 PM

Subject: [eddystone_radio_users] Re: ABOUT EDDYSTONE 5500

Hakan
I think you might mean Orion 5000, 6 channel 100W transceiver. You can
view data sheet in our website www.eddystoneusergroup.org.uk in Data
sheet section. We have a manual here which we could upload if that is
the set you are referring to.

Chris G0EYO
EUG Webmaster
--- In eddystone_radio_users@yahoogroups.co.uk, "ta2lj" <ta2lj@...>
wrote:
>
>
> Hi All,
>
> I found one Eddystone 5500 in a surplus shop. I made a search in
> Google for the technical manual but I found nothing.
>
> Since this transceiver Xtal controlled I want to modify to use PLL or
> DDS controllled.
>
> Any help for technical manual for this radio will be appreciated.
>
> Regards,
>
> TA2LJ Hakan GUNER
>

To: Alan Ainslie.
Thanks for that.
From the EUG Web Site I was indeed able to get a copy of the Service
Manual for the EC10 - including the supplement for the Mk.II, which
contains the cct. diag. . .  or rather 95% of it! - The "left-hand
side" of the cct. is missing! Can anyone suggest any alternative
sources, please?

Rgds., Al / G8DLH


--- In eddystone_radio_users@..., "Alan Ainslie"
<alan.ainslie@...> wrote:
>
> EC10 Mk2 service info is available for download on the excellent EUG
web site
> http://www.eddystoneusergroup.org.uk/
> Alan
>   ----- Original Message -----
>   From: g8dlh
>   To: eddystone_radio_users@...
>   Sent: Sunday, February 11, 2007 2:14 PM
>   Subject: [eddystone_radio_users] EC10 Mk. II
>
>
>   EC10 Mk. II seems rather insensitive on all bands: any suggestions,
>   please? A circuit diagram would also help: and suggestions, please?
>
>   Al / G8DLH
>

If you send me your email address then I will post you a cct.

Maybe I better scan a copy of the cct for the web site.

Alan.




--- In eddystone_radio_users@..., "g8dlh"
<alanhall@...> wrote:
>
> To: Alan Ainslie.
> Thanks for that.
> From the EUG Web Site I was indeed able to get a copy of the
Service
> Manual for the EC10 - including the supplement for the Mk.II, which
> contains the cct. diag. . .  or rather 95% of it! - The "left-hand
> side" of the cct. is missing! Can anyone suggest any alternative
> sources, please?
>
> Rgds., Al / G8DLH
>
>
> --- In eddystone_radio_users@..., "Alan Ainslie"
> <alan.ainslie@> wrote:
> >
> > EC10 Mk2 service info is available for download on the excellent
EUG
> web site
> > http://www.eddystoneusergroup.org.uk/
> > Alan
> >   ----- Original Message -----
> >   From: g8dlh
> >   To: eddystone_radio_users@...
> >   Sent: Sunday, February 11, 2007 2:14 PM
> >   Subject: [eddystone_radio_users] EC10 Mk. II
> >
> >
> >   EC10 Mk. II seems rather insensitive on all bands: any
suggestions,
> >   please? A circuit diagram would also help: and suggestions,
please?
> >
> >   Al / G8DLH
> >
>

Graeme

It could be the 5500 but we sold so few of those and only to Ghana
military. We certainly never had it trialled by NATO it was styled
just to give a more rugged look.

Regards

Chris G0EYO

--- In eddystone_radio_users@..., "GRAEME WORMALD"
<g3ggl@...> wrote:
>
> Hello Chris, been looking at this one; the 5500 is the military
version (shown in QRG).  I think it was trialled by NATO but not
adopted.  There is a big NATO prescence in Iceland . . .   Graeme.
>   ----- Original Message -----
>   From: g0eyo
>   To: eddystone_radio_users@...
>   Sent: Wednesday, February 14, 2007 6:12 PM
>   Subject: [eddystone_radio_users] Re: ABOUT EDDYSTONE 5500
>
>
>   Hakan
>   I think you might mean Orion 5000, 6 channel 100W transceiver.
You can
>   view data sheet in our website www.eddystoneusergroup.org.uk in
Data
>   sheet section. We have a manual here which we could upload if
that is
>   the set you are referring to.
>
>   Chris G0EYO
>   EUG Webmaster
>   --- In eddystone_radio_users@..., "ta2lj" <ta2lj@>
>   wrote:
>   >
>   >
>   > Hi All,
>   >
>   > I found one Eddystone 5500 in a surplus shop. I made a search
in
>   > Google for the technical manual but I found nothing.
>   >
>   > Since this transceiver Xtal controlled I want to modify to use
PLL or
>   > DDS controllled.
>   >
>   > Any help for technical manual for this radio will be
appreciated.
>   >
>   > Regards,
>   >
>   > TA2LJ Hakan GUNER
>   >
>

Had not realised that the circuit of the EC10 Mk2 was missing the
left hand bit. We now have better copy of the EC10Mk2 manual
available to put on the web site so will do this over the next couple
of days.

Regards

Chris G0EYO Webmaster

PS if anyone needs a manual not on our website then just send me an e
mail and I will see if we have copy here to digitise.

www.eddystoneusergroup.org.uk


--- In eddystone_radio_users@..., "g8dlh"
<alanhall@...> wrote:
>
> To: Alan Ainslie.
> Thanks for that.
> From the EUG Web Site I was indeed able to get a copy of the
Service
> Manual for the EC10 - including the supplement for the Mk.II, which
> contains the cct. diag. . .  or rather 95% of it! - The "left-hand
> side" of the cct. is missing! Can anyone suggest any alternative
> sources, please?
>
> Rgds., Al / G8DLH
>
>
> --- In eddystone_radio_users@..., "Alan Ainslie"
> <alan.ainslie@> wrote:
> >
> > EC10 Mk2 service info is available for download on the excellent
EUG
> web site
> > http://www.eddystoneusergroup.org.uk/
> > Alan
> >   ----- Original Message -----
> >   From: g8dlh
> >   To: eddystone_radio_users@...
> >   Sent: Sunday, February 11, 2007 2:14 PM
> >   Subject: [eddystone_radio_users] EC10 Mk. II
> >
> >
> >   EC10 Mk. II seems rather insensitive on all bands: any
suggestions,
> >   please? A circuit diagram would also help: and suggestions,
please?
> >
> >   Al / G8DLH
> >
>

Hi all!

EC10 Mk. II. Tuning cord broke whilst other repairs were being
undertaken! The manual (from the EUG Web Site) describes the re-
stringing procedure for the Mk.I, but it doesn't work for the Mk.II!
I don't believe that the alumininium pulleys are out of sync with the
anti-backlash gear train, (which could explain my troubles with this)
since all was fine - until ping!

Can anyone help with this, please?

Rgds., Al / G8DLH

----- Original Message -----

From: g8dlh

To: eddystone_radio_users@...

Sent: Thursday, February 15, 2007 10:46 PM

Subject: [eddystone_radio_users] EC10 Mk. II re-stringing

Hi all!

EC10 Mk. II. Tuning cord broke whilst other repairs were being
undertaken! The manual (from the EUG Web Site) describes the re-
stringing procedure for the Mk.I, but it doesn't work for the Mk.II!
I don't believe that the alumininium pulleys are out of sync with the
anti-backlash gear train, (which could explain my troubles with this)
since all was fine - until ping!

Can anyone help with this, please?

Rgds., Al / G8DLH

Hi Graeme -

Yes . . . Drive cord trouble . . "Apply the ol' grey cells". There
speaks the Voice of Experience. So I did - and fixed it!

When I studied the mechanical arrangements closely, I could see that
the position of the pulleys relative to the anti-backlash gearing (to
which the pulleys are geared to) has to be just right, because the
drive cord is fixed to these pulleys in a non-adjustable position.
What was giving me such a hard time was that when the tuning
condenser was at full mesh, the pulley closest to the tuning
condenser appeared to be in the wrong postion relative to the
gearing, because the cord would first wind on to the pulley for half
a turn - then wind the other way on the pulley! - And ditto at the
other pulley! Net result was that the total length of cord between
the pulleys VARIED as the tuning condenser was varied over its entire
range!
So I thought "Can't be right! Even if it WAS working before!" So, off
comes the circlips, and to summarise, I repositioned both pulleys
relative to the gearing such that the total length of cord between
the pulleys remained constant over the whole tuning range - which, of
course, it couldn't have been before, even if it DID appear to work -
which is probably why it snapped.

All goes to prove the old motto - don't assume that just because you
can SEE that someone has been there before, that they've done it
right! I know that you've experienced that scenario (especially with
drive tuning mechanisms) from articles that I've read of yours in
past issues of the "Lighthouse".

Right- where was I? Oh, yes - attention to the IF strip: suspected
low gain. I can see that the screening wire to all the OC171's has
been cut through (prob. whisker trouble) - and after that drive cord
scenario, with this set, I'm now ready to believe anything! Gremlins!
Grrr!

73
Al / G8DLH


--- In eddystone_radio_users@..., "GRAEME WORMALD"
<g3ggl@...> wrote:
>
> Hello Al,
>
> I've repaired drive cords on EC10 Mks I & II (not at the same
time!) and haven't been aware of a difference.  As I no longer have
either I'm afraid I can't open and compare.  Hopefully someone will.
In the meantime apply the grey cells and I'm sure you'll work out a
viable system . . .
>
>  vy 73,  Graeme  G3GGL
>
>
>   ----- Original Message -----
>   From: g8dlh
>   To: eddystone_radio_users@...
>   Sent: Thursday, February 15, 2007 10:46 PM
>   Subject: [eddystone_radio_users] EC10 Mk. II re-stringing
>
>
>   Hi all!
>
>   EC10 Mk. II. Tuning cord broke whilst other repairs were being
>   undertaken! The manual (from the EUG Web Site) describes the re-
>   stringing procedure for the Mk.I, but it doesn't work for the
Mk.II!
>   I don't believe that the alumininium pulleys are out of sync with
the
>   anti-backlash gear train, (which could explain my troubles with
this)
>   since all was fine - until ping!
>
>   Can anyone help with this, please?
>
>   Rgds., Al / G8DLH
>

I KNOW this sounds awfully bland, but was not the 730/4 particularly
designed to a rather exacting spec. issued by the M.O.D.? If that
spec. specifically called for a single conversion - then there you
are. One reason for this might have been to reduce the complexity
compared to a dual conversion, so that maintenance tasks would be
easier / quicker, etc.
Why did the 730/4 cost so much more than the 750 to produce? After
all, the 750 is no mere "short-wave radio" in the classical domestic
sense. Was it due to specially selected components, tropicalisation,
extensive testing to exacting specs & the extended design input to
meet these specs?

Just a few thoughts.

Al / G8DLH

~~~~~~~~~~~~~~~~~~~~~~~~


--- In eddystone_radio_users@..., "GRAEME WORMALD"
<g3ggl@...> wrote:
>
> Hello Chris,
>
> The 730/4 cost four times the price of the 750, so that's no reason!
> The 750 was adopted by Marconi as a land station Rx called HR100.
> A bit of a mystery . . .
>
> Vy 73,  Graeme  G3GGL
>
>
>   ----- Original Message -----
>   From: m0hmr
>   To: eddystone_radio_users@...
>   Sent: Friday, January 19, 2007 4:56 PM
>   Subject: [eddystone_radio_users] Why is the 730 series single
conversion?
>
>
>   My Eddystone collection stared out with a 730/4, and I also have a
>   750. It seems reasonable to assume that the 750 dual conversion
>   technology would have been available to Strattons when the 730 was
>   being designed. Now, there are many nice features on the 730/4
that I
>   wouldn't do without and which were pricey at the time, so I
wonder why
>   it was a single 450kc/s IF and not 1.6Mc/s + 85kc/s and hence 888
>   selectivity? The MOD was especially penny pinching in those days.
>   Regards to all: we've been busy with elderly parent problems so I
>   apologise for perhaps not maintaining this site as I should!
>
>   73, Chris Harmer M0HMR.
>

----- Original Message -----

From: g8dlh

To: eddystone_radio_users@...

Sent: Friday, February 16, 2007 1:36 AM

Subject: [eddystone_radio_users] Re: Why is the 730 series single conversion?

I KNOW this sounds awfully bland, but was not the 730/4 particularly
designed to a rather exacting spec. issued by the M.O.D.? If that
spec. specifically called for a single conversion - then there you
are. One reason for this might have been to reduce the complexity
compared to a dual conversion, so that maintenance tasks would be
easier / quicker, etc.
Why did the 730/4 cost so much more than the 750 to produce? After
all, the 750 is no mere "short-wave radio" in the classical domestic
sense. Was it due to specially selected components, tropicalisation,
extensive testing to exacting specs & the extended design input to
meet these specs?

Just a few thoughts.

Al / G8DLH

~~~~~~~~~~~~~~~~~~~~~~~~

--- In eddystone_radio_users@yahoogroups.co.uk, "GRAEME WORMALD"
<g3ggl@...> wrote:
>
> Hello Chris,
>
> The 730/4 cost four times the price of the 750, so that's no reason!
> The 750 was adopted by Marconi as a land station Rx called HR100.
> A bit of a mystery . . .
>
> Vy 73, Graeme G3GGL
>
>
> ----- Original Message -----
> From: m0hmr
> To: eddystone_radio_users@yahoogroups.co.uk
> Sent: Friday, January 19, 2007 4:56 PM
> Subject: [eddystone_radio_users] Why is the 730 series single
conversion?
>
>
> My Eddystone collection stared out with a 730/4, and I also have a
> 750. It seems reasonable to assume that the 750 dual conversion
> technology would have been available to Strattons when the 730 was
> being designed. Now, there are many nice features on the 730/4
that I
> wouldn't do without and which were pricey at the time, so I
wonder why
> it was a single 450kc/s IF and not 1.6Mc/s + 85kc/s and hence 888
> selectivity? The MOD was especially penny pinching in those days.
> Regards to all: we've been busy with elderly parent problems so I
> apologise for perhaps not maintaining this site as I should!
>
> 73, Chris Harmer M0HMR.
>

Graeme - Thanks for that.

I'm always fascinated by the history of individual Eddystone designs,
and that has helped fill another gap!

Al / G8DLH

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


--- In eddystone_radio_users@..., "GRAEME WORMALD"
<g3ggl@...> wrote:
>
> Hello Al/Chris,
>
> The 730 series was an Eddystone private venture which was adopted
by the MoD.  It had to be beefed up a little from a mechanical point
of view but otherwise was all home grown.
> It was, of course, a development of the 680X as close inspection of
the sets and the circuits soon makes apparent.
> It never even had a military number!  The army also called it the
730/4.
> I suspect that the extra four valves impressed the MoD!
> Remember that the 730/1a had been in service for some years with
the Dip W'less Svce for some years before the army ordered it.
>
> Vy 73,  Graeme  G3GGL
>
>
>   ----- Original Message -----
>   From: g8dlh
>   To: eddystone_radio_users@...
>   Sent: Friday, February 16, 2007 1:36 AM
>   Subject: [eddystone_radio_users] Re: Why is the 730 series single
conversion?
>
>
>   I KNOW this sounds awfully bland, but was not the 730/4
particularly
>   designed to a rather exacting spec. issued by the M.O.D.? If that
>   spec. specifically called for a single conversion - then there
you
>   are. One reason for this might have been to reduce the complexity
>   compared to a dual conversion, so that maintenance tasks would be
>   easier / quicker, etc.
>   Why did the 730/4 cost so much more than the 750 to produce?
After
>   all, the 750 is no mere "short-wave radio" in the classical
domestic
>   sense. Was it due to specially selected components,
tropicalisation,
>   extensive testing to exacting specs & the extended design input
to
>   meet these specs?
>
>   Just a few thoughts.
>
>   Al / G8DLH
>
>   ~~~~~~~~~~~~~~~~~~~~~~~~
>
>   --- In eddystone_radio_users@..., "GRAEME WORMALD"
>   <g3ggl@> wrote:
>   >
>   > Hello Chris,
>   >
>   > The 730/4 cost four times the price of the 750, so that's no
reason!
>   > The 750 was adopted by Marconi as a land station Rx called
HR100.
>   > A bit of a mystery . . .
>   >
>   > Vy 73, Graeme G3GGL
>   >
>   >
>   > ----- Original Message -----
>   > From: m0hmr
>   > To: eddystone_radio_users@...
>   > Sent: Friday, January 19, 2007 4:56 PM
>   > Subject: [eddystone_radio_users] Why is the 730 series single
>   conversion?
>   >
>   >
>   > My Eddystone collection stared out with a 730/4, and I also
have a
>   > 750. It seems reasonable to assume that the 750 dual conversion
>   > technology would have been available to Strattons when the 730
was
>   > being designed. Now, there are many nice features on the 730/4
>   that I
>   > wouldn't do without and which were pricey at the time, so I
>   wonder why
>   > it was a single 450kc/s IF and not 1.6Mc/s + 85kc/s and hence
888
>   > selectivity? The MOD was especially penny pinching in those
days.
>   > Regards to all: we've been busy with elderly parent problems so
I
>   > apologise for perhaps not maintaining this site as I should!
>   >
>   > 73, Chris Harmer M0HMR.
>   >
>

Gentlemen,

Recently acting as a distance learning apprentice to Gerry O'Hara in
Vancouver I made a succesfull full RF, IF and discriminator alignment
of my 770U MkII using a Marconi 2022E synthesized signal generator
and a EP17R Panadaptor as a wobulator/sweep generator. (see Gerry's
Detector and Discriminator Tech Short).

All first and second IF cores were set to the correct first peaks
without problem. However the second mixer stage Tx is very sensitive
and has multiple peak positions of core settings and there is no
specific information in the manual as to which is the correct one. I
wonder if anyone out there has any guidance to offer on this subject.

Also there is an adjustable core on the internal crystal calibrator
but again no guidance on corect set up. Likewise if anyone has any
info on this I would appreciatte it.

As a point of information I removed each core in turn, cleaned them
up and refitted them using Rocol Kilopoise 0868S as a locking
compound. We used this product when I was an apprentice Radio and TV
engineer in the 1960's. It is none solidifying, very viscous (and
very sticky) and avoids problems of jammed cores from perished
elastic or other old solidified grease products.

Mike C

Hi, any pointers on how to get an 840C out of its case?  I've removed
the four rear screws but nothing has become free or even looser.  Do I
need a hammer and goose fat?

I've posted a couple of pics in the pics section.  Nothing too exciting.

Nick

----- Original Message -----

From: Nick Pettefar

To: eddystone_radio_users@...

Sent: Sunday, February 18, 2007 5:27 AM

Subject: [eddystone_radio_users] 840C Dismantling

Hi, any pointers on how to get an 840C out of its case? I've removed
the four rear screws but nothing has become free or even looser. Do I
need a hammer and goose fat?

I've posted a couple of pics in the pics section. Nothing too exciting.

Nick

I have decided to sell my working, unmodified, good condition 940.   Willing to
deliver within
a radius of 50 miles from Holmfirth in West Yorkshire (specifically HD9 2NY)
This includes
Hartshead Moor services between junctions 25 and 26 of the M62.  If you live
further away I
guess some mutually conveneint arrangement might be worked out.  £170 o.n.o.