Eddystone 640 - UK Vintage Radio Repair and Restoration Discussion Forum

peter.sables · 11th Oct 2008, 3:55 pm

hi

For my next project I've picked up a "not bad" Edison 640. Is there any pitfalls with this set that I should know about..

Thank you

Pete G4MRU

dave walsh · 11th Oct 2008, 4:14 pm

If you mean the Eddystone 640 Rx circa 1947 Peter and not the famous inventor [although he was fairly electrical

] I've coincidentally, just got one myself in a similar condition! It's still in Bognor Regis so I have not dug out various restoration articles yet that I know are around in the mags although I'm sure there will be direct experience available on here. Mine has a long history incuding twenty years or so out of the country and I even have the call sign of the first owner. It's complete with the original handbook so I should be able to do you a copy in due course, if you require it.
I told the seller that I last had one of these back in 1977 when a personal "credit crunch" forced it's sale although the overall econmy wasn't brilliant then either I suppose.
Cheers Dave W

PS If you do mean the comms rx we might be in the wrong section but I 'm sure the mods will sort it.

Brian R Pateman · 11th Oct 2008, 4:48 pm

Dave is right, so I've re-located it to a more appropriate section.

Regards,

XTC · 11th Oct 2008, 8:14 pm

Peter,

Check the "Useful Vintage Amateur and Military Radio Info (read only)" link, current in the read only section.One of the links from there is to the Eddystone User's Group site and there are numerous copies of "The Lighthouse" which you can access on-line.

Of course, you may also get help on here if someone has special knowledge, but the EUG site and publications are well worth a look.

Pete.

peter.sables · 11th Oct 2008, 9:06 pm

hi.

Thanks.

Yes that's a good start. Yes it looks much used. So will be nice to power it up again....

Pete

Skywave · 11th Oct 2008, 11:26 pm

Hi!

Eddystone 640; I've renovated a few of these.

Apart from the usual replacement of old capacitors & high-value resistors, check that the metallizing on the EF39 IF amp. is intact - otherwise the IF amp. will go unstable.
If you re-align the IF amp., don't forget to do it on the phasing crystal frequency.

Apart from that, four specific headaches that spring to mind are:
1. The AF amp. is on its own little sub-chassis, making measurement of the 6V6 electrode voltages impossible. I've always removed this sub-chassis, replaced all the Rs & Cs en-bloc & then re-assembled & re-fitted it. Less hassle in the long run.
2. If re-stringing the drive mechanism is required, this is difficult without the info.
3. It's rare for the IF gain pot. to give trouble, but if it needs replacement, it's a problem: it's a wire-wound reverse-log. pot.

4. General maint. is difficult in places, but in-line with most Eddystone radios.

Good luck with it!

Al. / Skywave.

peter.sables · 13th Oct 2008, 6:55 pm

Thank you all.

Right its project time on this Eddystone S640. It's now on the bench and I've not put power to it yet. It looks as though its not been used for some time and all bits are as should be. Yes I can see I'll need three EF39 s as the red is almost off. The cord is ok. Bit worid about the main trasformer as I see some black pitch that has dripped out! Could be ok but not checked.

Some info:-

Eddystone S640

Regd. Pat. 57443

EY 0722

Thanks Dave yes I'll need any copy's you can give. Think they will be very handy.

Pete G4MRU

peter.sables · 15th Oct 2008, 12:03 am

hi

Inspection complete. After a slow run up the set works very well. Stations heard even without a antenna fitted. Apart from the three valves that really should be replaced. Work needs to be done one the switches (they do not work every time) , the tuning and band spread mch. are in need of some grease. They have that dry feall to them. But also all the pots are scratchy.

So. question is...

How do I fix the switches and how do I fix the pots...

I suppose in the end it only need some T L C.

Pete

Skywave · 20th Oct 2008, 10:00 pm

Short answers are:

Pots.: try switch cleaner. If that fails, replace them.
Wave-change switch: switch cleaner.
Toggle switches: replace them.

If you have a need (& are stuck

) for a replacement 10 k-ohm RF gain pot., send me a PM. I have a stock of suitable (not original) w/w 10k reverse log. types: these are a common feature in Eddystone valve receivers.

Al. / Skywave.

peter.sables · 25th Oct 2008, 11:03 pm

hi

Thanks for that. I've sent for a set of valves for it as they looked shot. I only need one valve then it can be turned back on. Ha new switches,,, OK I'll look out for them. Al. I'll get back to you when I've got it up and running. It has though cleaned up really nice.

Very nice set..

Pete

Skywave · 26th Oct 2008, 11:19 am

Switches: have a look at Farnell 120-3336; product code 2BL63-63. £4.96 ea.
Traditional chrome toggle, DPDT, 3A a.c., 6A d.c., approx 1/2" dia. through-chassis fixing, solder tag wiring.
I'm sure that these are ones I've used in the past when overhauling Eddys.

Two further thoughts . . .

As 'standard build', there are no fuses fitted in the PSU.

I strongly recommend fitting fuses in the mains. transformer pri. and HT sec'y. The d.c. HT current is about 75 mA when the set is warmed-up.

Check the front-panel mains switch. In some Eddys., only one side on the incoming mains is switched - and sometimes that is the "N"

. I always fit a DPDT switch to break both sides on the incoming mains, with heat-shrink fitted over the switch solder tags. As with all Eddys. with this type of layout, it is too easy for a finger to come into contact with the wiring to the the mains switch when doing maintenance - and if you've forgotten to switch off / disconnect at the mains source . . .

Al.

peter.sables · 27th Oct 2008, 11:40 pm

hi Al.

Thanks for the very good info. I've printed it off. Never thought to look for fuses.

Pete

squier · 28th Oct 2008, 10:38 pm

the phasing control switch can be a bit dodgy too causing signals to "leak" around the phasing xtal rather than through it!. Otherwise they're not a bad little set. Must get around to fixing mine sometime.

Mark

PS: I wonder if you're the same Pete Sables from Skellow that I knew 20 odd years ago?

Skywave · 30th Oct 2008, 1:20 am

Yes - I've had that trouble too (faulty phasing switch). And - ISTR - it's a rather fiddly job replacing it, too

Al.

Skywave · 30th Oct 2008, 1:36 am

The above Posts on phasing reminded me of selectivity issues I've experienced with this receiver . . .

Not that it's a maintenance issue, per se, but I do find that for Amateur Radio ssb reception, the relatively wide IF of the 640 leaves quite a lot to be desired in the way of selectivity.

(I've often contemplated wiring up an external Q-multiplier to help with this . . . maybe, one day . . .)

But - having said that - my other two main receivers for that purpose being an Eddystone 888A (double conversion, last IF 85 Kc.) and a Racal RA-17 (triple conversion, 100 Kc last IF), so perhaps I'm not being fair to this 60-year old veteran! After all, there wasn't a lot of ssb around in 1947 (date of manufacture of my current 640). And considering that is was designed and built just after the end of WWII, when stuff was scarce . . . .

Your thoughts are cordially invited . . .

Al.

MichaelR · 30th Oct 2008, 2:53 am

Al,

I agree with your sentiments, in fact the 888 and the Racal were not far behind timewise when they were designed.

The Military stuff I find a joy to work on and use and it is all credit to the designers that with some skill you can use designs that are over 60 years old on modern band conditions.

I think the Q multiplier idea would work very well and worth a try

Mike

peter.sables · 30th Oct 2008, 9:23 pm

hi All.

New valves and switches arrived and fitted. Looks really nice. I cannot report on how well it works yet. But Ill let you know. But so far it works fine. Im hopping to marry it up with my Tinker box Mk3. So thinking that for CW it will do the job.

Thanks every one for your help... brill.

Pete

Skywave · 31st Oct 2008, 1:27 am

"How well it works yet . . ."
Just a quick report about that - hopefully, by way of encouragement

Apart from one particularly nasty example that came my way, the few I've overhauled have all come pretty close to the published specs. after the necessary work had been completed. (Which, of course, really says something, considering the age of these radios

). 'Specs'. - such as sensitivity, signal/noise ratio, image rejection, and similar. It's the image rejection spec., at 30 MHz, that seems to be the most difficult to obtain, although I usually end up with a figure that is fairly close.

It would be nice to see a pic. of yours when it's all done.

HTH

Al.

peter.sables · 31st Oct 2008, 1:40 pm

Hi

Not a report yet (but it will come) This is just some pics as I got it. The only bit that I think needs a look at is a capacitor has been cut but no sign of from where!! (Black arrow is the capacitor and white is the cut end)

Pete

Skywave · 1st Nov 2008, 1:05 am

Hi Pete -

Well one things for sure - it's either an originally-fitted component with one end cut or a later added item! If original, C58, C59 & C60 seem likely candidates: a study of the cct. diag. should reveal all. However, looking more closely at your large-scale photo, I think I can see one or two other components that don't look like they are in the right place / right connections, either

A thorough check-out of all the wiring / component fit would seem in order.

TTFN.

Al.

11th Oct 2008, 3:55 pm	#1
peter.sables Rest in Peace Join Date: Dec 2007 Location: Doncaster, South Yorkshire, UK. Posts: 385	Eddystone 640 hi For my next project I've picked up a "not bad" Edison 640. Is there any pitfalls with this set that I should know about.. Thank you Pete G4MRU

11th Oct 2008, 4:14 pm	#2
dave walsh Dekatron Join Date: Jan 2006 Location: Ramsbottom (Nr Bury) Lancs or Bexhill (Nr Hastings) Sussex. Posts: 5,817	Re: Edison 640 If you mean the Eddystone 640 Rx circa 1947 Peter and not the famous inventor [although he was fairly electrical] I've coincidentally, just got one myself in a similar condition! It's still in Bognor Regis so I have not dug out various restoration articles yet that I know are around in the mags although I'm sure there will be direct experience available on here. Mine has a long history incuding twenty years or so out of the country and I even have the call sign of the first owner. It's complete with the original handbook so I should be able to do you a copy in due course, if you require it. I told the seller that I last had one of these back in 1977 when a personal "credit crunch" forced it's sale although the overall econmy wasn't brilliant then either I suppose. Cheers Dave W PS If you do mean the comms rx we might be in the wrong section but I 'm sure the mods will sort it. Last edited by dave walsh; 11th Oct 2008 at 4:19 pm.

11th Oct 2008, 4:48 pm	#3
Brian R Pateman Nonode Join Date: Jun 2005 Location: Western Lake District, Cumbria (CA20) - UK Posts: 2,136	Re: Eddystone 640 Dave is right, so I've re-located it to a more appropriate section. Regards, __________________ Brian

11th Oct 2008, 8:14 pm	#4
XTC Retired Dormant Member Join Date: Oct 2004 Location: Bristol, UK. Posts: 837	Re: Eddystone 640 Peter, Check the "Useful Vintage Amateur and Military Radio Info (read only)" link, current in the read only section.One of the links from there is to the Eddystone User's Group site and there are numerous copies of "The Lighthouse" which you can access on-line. Of course, you may also get help on here if someone has special knowledge, but the EUG site and publications are well worth a look. Pete.

11th Oct 2008, 9:06 pm	#5
peter.sables Rest in Peace Join Date: Dec 2007 Location: Doncaster, South Yorkshire, UK. Posts: 385	Re: Eddystone 640 hi. Thanks. Yes that's a good start. Yes it looks much used. So will be nice to power it up again.... Pete

11th Oct 2008, 11:26 pm	#6
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Re: Eddystone 640 Hi! Eddystone 640; I've renovated a few of these. Apart from the usual replacement of old capacitors & high-value resistors, check that the metallizing on the EF39 IF amp. is intact - otherwise the IF amp. will go unstable. If you re-align the IF amp., don't forget to do it on the phasing crystal frequency. Apart from that, four specific headaches that spring to mind are: 1. The AF amp. is on its own little sub-chassis, making measurement of the 6V6 electrode voltages impossible. I've always removed this sub-chassis, replaced all the Rs & Cs en-bloc & then re-assembled & re-fitted it. Less hassle in the long run. 2. If re-stringing the drive mechanism is required, this is difficult without the info. 3. It's rare for the IF gain pot. to give trouble, but if it needs replacement, it's a problem: it's a wire-wound reverse-log. pot. 4. General maint. is difficult in places, but in-line with most Eddystone radios. Good luck with it! Al. / Skywave.

13th Oct 2008, 6:55 pm	#7
peter.sables Rest in Peace Join Date: Dec 2007 Location: Doncaster, South Yorkshire, UK. Posts: 385	Re: Eddystone 640 Thank you all. Right its project time on this Eddystone S640. It's now on the bench and I've not put power to it yet. It looks as though its not been used for some time and all bits are as should be. Yes I can see I'll need three EF39 s as the red is almost off. The cord is ok. Bit worid about the main trasformer as I see some black pitch that has dripped out! Could be ok but not checked. Some info:- Eddystone S640 Regd. Pat. 57443 EY 0722 Thanks Dave yes I'll need any copy's you can give. Think they will be very handy. Pete G4MRU Last edited by Sean Williams; 13th Oct 2008 at 7:36 pm. Reason: Pitch starts with a P........not B :-)

15th Oct 2008, 12:03 am	#8
peter.sables Rest in Peace Join Date: Dec 2007 Location: Doncaster, South Yorkshire, UK. Posts: 385	Re: Eddystone 640 hi Inspection complete. After a slow run up the set works very well. Stations heard even without a antenna fitted. Apart from the three valves that really should be replaced. Work needs to be done one the switches (they do not work every time) , the tuning and band spread mch. are in need of some grease. They have that dry feall to them. But also all the pots are scratchy. So. question is... How do I fix the switches and how do I fix the pots... I suppose in the end it only need some T L C. Pete

20th Oct 2008, 10:00 pm	#9
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Re: Eddystone 640 Short answers are: Pots.: try switch cleaner. If that fails, replace them. Wave-change switch: switch cleaner. Toggle switches: replace them. If you have a need (& are stuck ) for a replacement 10 k-ohm RF gain pot., send me a PM. I have a stock of suitable (not original) w/w 10k reverse log. types: these are a common feature in Eddystone valve receivers. Al. / Skywave.

25th Oct 2008, 11:03 pm	#10
peter.sables Rest in Peace Join Date: Dec 2007 Location: Doncaster, South Yorkshire, UK. Posts: 385	Re: Eddystone 640 hi Thanks for that. I've sent for a set of valves for it as they looked shot. I only need one valve then it can be turned back on. Ha new switches,,, OK I'll look out for them. Al. I'll get back to you when I've got it up and running. It has though cleaned up really nice. Very nice set.. Pete

26th Oct 2008, 11:19 am	#11
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Re: Eddystone 640 Switches: have a look at Farnell 120-3336; product code 2BL63-63. £4.96 ea. Traditional chrome toggle, DPDT, 3A a.c., 6A d.c., approx 1/2" dia. through-chassis fixing, solder tag wiring. I'm sure that these are ones I've used in the past when overhauling Eddys. Two further thoughts . . . As 'standard build', there are no fuses fitted in the PSU. I strongly recommend fitting fuses in the mains. transformer pri. and HT sec'y. The d.c. HT current is about 75 mA when the set is warmed-up. Check the front-panel mains switch. In some Eddys., only one side on the incoming mains is switched - and sometimes that is the "N" . I always fit a DPDT switch to break both sides on the incoming mains, with heat-shrink fitted over the switch solder tags. As with all Eddys. with this type of layout, it is too easy for a finger to come into contact with the wiring to the the mains switch when doing maintenance - and if you've forgotten to switch off / disconnect at the mains source . . . Al. Last edited by Skywave; 26th Oct 2008 at 11:42 am. Reason: Add "further thoughts"

27th Oct 2008, 11:40 pm	#12
peter.sables Rest in Peace Join Date: Dec 2007 Location: Doncaster, South Yorkshire, UK. Posts: 385	Re: Eddystone 640 hi Al. Thanks for the very good info. I've printed it off. Never thought to look for fuses. Pete

28th Oct 2008, 10:38 pm	#13
squier Retired Dormant Member Join Date: Jul 2006 Location: gloucester Posts: 7	Re: Eddystone 640 the phasing control switch can be a bit dodgy too causing signals to "leak" around the phasing xtal rather than through it!. Otherwise they're not a bad little set. Must get around to fixing mine sometime. Mark PS: I wonder if you're the same Pete Sables from Skellow that I knew 20 odd years ago?

30th Oct 2008, 1:20 am	#14
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Re: Eddystone 640 Yes - I've had that trouble too (faulty phasing switch). And - ISTR - it's a rather fiddly job replacing it, too Al.

30th Oct 2008, 1:36 am	#15
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Re: Eddystone 640 The above Posts on phasing reminded me of selectivity issues I've experienced with this receiver . . . Not that it's a maintenance issue, per se, but I do find that for Amateur Radio ssb reception, the relatively wide IF of the 640 leaves quite a lot to be desired in the way of selectivity. (I've often contemplated wiring up an external Q-multiplier to help with this . . . maybe, one day . . .) But - having said that - my other two main receivers for that purpose being an Eddystone 888A (double conversion, last IF 85 Kc.) and a Racal RA-17 (triple conversion, 100 Kc last IF), so perhaps I'm not being fair to this 60-year old veteran! After all, there wasn't a lot of ssb around in 1947 (date of manufacture of my current 640). And considering that is was designed and built just after the end of WWII, when stuff was scarce . . . . Your thoughts are cordially invited . . . Al.

30th Oct 2008, 2:53 am	#16
MichaelR Retired Dormant Member Join Date: Mar 2006 Location: Sheffield, South Yorkshire, UK. Posts: 1,587	Re: Eddystone 640 Al, I agree with your sentiments, in fact the 888 and the Racal were not far behind timewise when they were designed. The Military stuff I find a joy to work on and use and it is all credit to the designers that with some skill you can use designs that are over 60 years old on modern band conditions. I think the Q multiplier idea would work very well and worth a try Mike

30th Oct 2008, 9:23 pm	#17
peter.sables Rest in Peace Join Date: Dec 2007 Location: Doncaster, South Yorkshire, UK. Posts: 385	Re: Eddystone 640 hi All. New valves and switches arrived and fitted. Looks really nice. I cannot report on how well it works yet. But Ill let you know. But so far it works fine. Im hopping to marry it up with my Tinker box Mk3. So thinking that for CW it will do the job. Thanks every one for your help... brill. Pete

31st Oct 2008, 1:27 am	#18
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Re: Eddystone 640 "How well it works yet . . ." Just a quick report about that - hopefully, by way of encouragement Apart from one particularly nasty example that came my way, the few I've overhauled have all come pretty close to the published specs. after the necessary work had been completed. (Which, of course, really says something, considering the age of these radios ). 'Specs'. - such as sensitivity, signal/noise ratio, image rejection, and similar. It's the image rejection spec., at 30 MHz, that seems to be the most difficult to obtain, although I usually end up with a figure that is fairly close. It would be nice to see a pic. of yours when it's all done. HTH Al. Last edited by Skywave; 31st Oct 2008 at 1:29 am. Reason: add comment on pic. at end

31st Oct 2008, 1:40 pm	#19
peter.sables Rest in Peace Join Date: Dec 2007 Location: Doncaster, South Yorkshire, UK. Posts: 385	Re: Eddystone 640 Hi Not a report yet (but it will come) This is just some pics as I got it. The only bit that I think needs a look at is a capacitor has been cut but no sign of from where!! (Black arrow is the capacitor and white is the cut end) Pete Attached Thumbnails

1st Nov 2008, 1:05 am	#20
Skywave Rest in Peace Join Date: Jun 2006 Location: Chard, South Somerset, UK. Posts: 7,457	Re: Eddystone 640 Hi Pete - Well one things for sure - it's either an originally-fitted component with one end cut or a later added item! If original, C58, C59 & C60 seem likely candidates: a study of the cct. diag. should reveal all. However, looking more closely at your large-scale photo, I think I can see one or two other components that don't look like they are in the right place / right connections, either A thorough check-out of all the wiring / component fit would seem in order. TTFN. Al.