UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Amateur and Military Radio

Notices

Vintage Amateur and Military Radio Amateur/military receivers and transmitters, morse, and any other related vintage comms equipment.

Closed Thread
 
Thread Tools
Old 4th Nov 2015, 5:35 pm   #1
Wendymott
Octode
 
Wendymott's Avatar
 
Join Date: Jun 2013
Location: Huddersfield, West Yorkshire, UK.
Posts: 1,782
Default Eddystone 888A.

Hi peeps. Just thought this might be of interest, bought on ebay a few days ago, a garden shed "find". Went to Felixstowe not knowing the condition, 232 miles each way, didn't pay a lot. Virtually untouched since made. Maybe a new mains lead. PLENTY of deceased spiders, this was the receiver, as a young amateur that was unreachable. 50 years on, winter refurb.
Attached Thumbnails
Click image for larger version

Name:	chassis underside.jpg
Views:	443
Size:	72.3 KB
ID:	115189   Click image for larger version

Name:	Front dial.jpg
Views:	499
Size:	55.2 KB
ID:	115190   Click image for larger version

Name:	Rear 1.jpg
Views:	502
Size:	63.3 KB
ID:	115191   Click image for larger version

Name:	Rear int 1.jpg
Views:	423
Size:	58.2 KB
ID:	115192  
__________________
Should get out more.

Regards
Wendy G8BZY
Wendymott is offline  
Old 4th Nov 2015, 6:30 pm   #2
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
Default Re: Eddystone 888A.

Nice! Even if they do tend to run a bit hot because there's so much valvery packed into such a small space! (Consider replacing the rectifier with a couple of silicon diodes fitted into the base salvaged from a dead octal valve to reduce the heat a bit).
G6Tanuki is offline  
Old 4th Nov 2015, 7:05 pm   #3
carnivalpete
Tetrode
 
Join Date: Dec 2014
Location: Pembrokeshire, Wales, UK.
Posts: 68
Default Re: Eddystone 888A.

Hi Wendmott,
Ref your ''888A''
Not sure if you mind or not, but it is almost certainly not a 888A
If I have this right its a S888 - which is much rarer, but also different.
I think you bought the Rx I enquired about.

Is it serial number GH003?
If so its a type S888

The S888 has a bfo and usually a black crackle case.
The S888A has a product detector and usually a hammer grey case.

The S888 was made around 1956-57.
The S888A was made around 1958-1961.
Total production (for both) around 550 sets.

Best of luck with the restoration.
pete
carnivalpete is offline  
Old 4th Nov 2015, 7:21 pm   #4
David G4EBT
Dekatron
 
David G4EBT's Avatar
 
Join Date: Feb 2003
Location: Cottingham, East Yorkshire, UK.
Posts: 5,737
Default Re: Eddystone 888A.

If you don't have the manual you can download it from the Eddystone User Group here:

http://eddystoneusergroup.org.uk/Man...e%20OE3SBN.pdf

If you trawl the site you might also find hints, tips, faults etc, but really, if it works, much depends on how far you want to go to restore it to peak performance.

Given that it's a double superhet it has a high component count - 111 caps, many of which should be fine (tuning gang, silver mica & tubular ceramic), but some of the 28 or so tubular paper caps might be suspect, as will the smaller low voltage electrolytics used for such things as cathode bypass, (eg, C111 on V8). Given the recent discussions on reforming smoothing/reservoir caps, if - as you say - it's going to be a winter project, you'll probably want to show a little kindness to those and reform them slowly over a period of several hours, keeping the current down, while slowly upping the voltage, rather than adopting the 'whap 'em on a variac or whatever and see what happens' approach.

Some of the close on sixty carbon composition resistors will inevitably have drifted high in value, and it depends on your view as to how far out of tolerance you're prepared to go before replacing out of spec resistors.

I doubt whether any of the 11 valves will be duff - the set may have been used extensively, but a lot of Eddystone receivers have spent far more time switched off than on, gathering dust. That said, it wouldn't hurt to pull the valves, clean the pins and give the sockets a light squirt of Servisol/Deoxit or whatever, and likewise and pots and switches. Same goes for the tuning gang and dial drive mechanism - pulleys etc.

Ultimately, realignment is called for - or at least checking the alignment.

Just my thoughts.

I went through an 'Eddystone phase' that lasted about 25 years from my mid thirties and have had most at one time or another, having vowed as a teenager, with my nose pressed against the shop window: "when I grow up if I'm really, really rich, I'm having one of those". By the time I could afford them, the sun had set on Eddystones and the receivers were vintage. Nostalgia overcame common sense and they just mounted up, but I'm over it now - the last to go were an EA12 and a 940. The nastiest little components, which I hated with a passion, (I can't recall in which models), were little red Hunts egg-shaped caps about the size of a Smartie, laughing at me from deep inside the chassis.

Hope that's of interest.

Have fun with it!
__________________
David.
BVWS Member.
G-QRP Club member 1339.
David G4EBT is offline  
Old 4th Nov 2015, 7:28 pm   #5
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Eddystone 888A.

It indeed is a 888 Not 888A and the first time I have come across one,so good buy.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Old 4th Nov 2015, 10:49 pm   #6
Wendymott
Octode
 
Wendymott's Avatar
 
Join Date: Jun 2013
Location: Huddersfield, West Yorkshire, UK.
Posts: 1,782
Default Re: Eddystone 888A.

Hi peeps....thanks for all the input.....Pete.. Yes the serial is GH0037... and is indeed a S888... hey ho Ebay.... I am sure it was advertised as a 888A, but no matter...
Tanuki.... Yes I will replace the 5Z4 or whatever...with silicon devices.
David, I totally agree with your comments.... I had all that to do with my 750...in a similar state to start with... My Eddy phase.. I thought had burned out.. but this was too good to miss at £69...plus a tank of "go gass". I downloaded the 888a manual but I did notice the 888 as well so its on the list...I am away for a few days now... so I will get into it when I get back. In my 750 I fitted an ex computer psu fan over the mains transformer, and it stays fairly stable, Ok about the current threads on reforming electrolytics... all noted.
The tuning drive is totally seized up at present, but as with the 750 it will be stripped and totally restored... looks like the case will be bead blasted and powder coated...
From the "First coat of looking at"............ schematic wise.... the only real difference, that I can see is that the "S" uses ECH42's whereas the "A" uses ECH81's...... there is no product detector as suggested by "carnivalpete" ....Oh yes V3 is a 6BA6 in the "S" whereas its a 6C4 in the "A"... ah well sun, sea and sangria calls.....
__________________
Should get out more.

Regards
Wendy G8BZY

Last edited by Wendymott; 4th Nov 2015 at 11:15 pm. Reason: More info
Wendymott is offline  
Old 5th Nov 2015, 12:06 am   #7
Skywave
Rest in Peace
 
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
Arrow Re: Eddystone 888A.

Eight comments based on my experience of owning & maintaining the S888A. Most of what follows is applicable to the 888 also.

1. Some S888A receivers have a tuning dial marked '888'. Never yet seen the 'reverse'.
2. The ECH81 has a nasty habit of going distinctly noisy. I'm not sure if that is limited to the S.888A / 888 or a 'characteristic' of the ECH81 itself.
3. You may find, during re-alignment, that no matter how hard you try, repeated adjustment of the osc. coil and the osc. trimmer won't give correct calibration. Usual cause is drift in the effective value of the capacitance across the LC osc. tuned cct. Usual fix to to change the value of any fixed small-value cap. that is in parallel with the trimmer or acting as a series padder. An increase - or a decrease - in that small-value cap. is usually required.
4. Re-alignment of the 85 kHz IF strip can be a tedious affair - mainly because access to the cores of the IFTs, from below chassis, is so difficult. My fix is to use a long plastic knitting needle that has had its diameter reduced and the end so shaped to as to fit the slot in the slug - plus lots of patience!
5. The osc. coil that provides for the 1620 kHz to 85 kHz conversion is very 'sharp' in its adjustment. Be careful that you choose the correct position for that slug: there are two positions. The manual does advise about selecting the correct one.
6. The Eddy. cct. diag. for the S888A and the 888 is not easy to 'decipher'. If you have the time - and the inclination - a manual re-draw of it can make subsequent fault-finding much easier.
7. Very short-term instability of the BFO (S.888A only) can be caused by a defective VR150/30. You won't notice that instab. on the local oscs. - at first.
8. Many valve heaters are by-passed using Hunts 0.25 uF caps. I've never found one of those to be faulty yet - but I always change them 'on sight' - just to be sure.

Best of luck with it. With the S.888A and the 888, due diligence is usually rewarded.

Al.
Skywave is offline  
Old 5th Nov 2015, 12:08 pm   #8
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Eddystone 888A.

Reses have always been highly suspect on all my Eddystones.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Old 5th Nov 2015, 12:42 pm   #9
G6Tanuki
Dekatron
 
G6Tanuki's Avatar
 
Join Date: Apr 2012
Location: Wiltshire, UK.
Posts: 13,953
Default Re: Eddystone 888A.

Yes - the kind that are a white ceramic tube with the carbon 'stick' retained inside by a pinkish or terra-cotta-coloured cement at each end [were these made by Erie?] are notorious for going high.
Example: the RF amp and frequency-changer of my Eddystone 840A worked a lot better once I'd replaced the gone-way-high screen-feed resistors (when you only start with 100V of 'HT' in the first place you can't afford to waste it!). I at first thought the valves were 'tired' but testing showed they were all OK: replacing the resistors recovered at least 10dB of gain.

Also- any very small brown-bodied decoupling capacitors that look like a brown rat-turd-with-colour-bands - replace them on sight!
Eddystone often used these as decouplers on the AGC line - and when they leak you get overloading on strong signals.
G6Tanuki is offline  
Old 5th Nov 2015, 12:45 pm   #10
HamishBoxer
Dekatron
 
HamishBoxer's Avatar
 
Join Date: Aug 2007
Location: W.Butterwick, near Doncaster UK.
Posts: 8,923
Default Re: Eddystone 888A.

Yes I think Erie did make them.
__________________
G8JET BVWS Archivist and Member V.M.A.R.S
HamishBoxer is offline  
Old 7th Nov 2015, 11:48 am   #11
Barraman
Tetrode
 
Join Date: Mar 2011
Location: Western Isles of Scotland, UK.
Posts: 52
Default Re: Eddystone 888A.

I wonder what those pin heads on the scale plate, Band 3, are?
Never saw anything like that before.
The model number plate, on the tuning condenser cover, will tell you 888 or 888A.
I wouldn't change the valve rectifier, for obvious reasons. Just run the set with the top open.
73 Richard gm0ogn
Barraman is offline  
Old 7th Nov 2015, 7:56 pm   #12
Skywave
Rest in Peace
 
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
Question Re: Eddystone 888A.

Quote:
Originally Posted by Barraman View Post
I wouldn't change the valve rectifier, for obvious reasons.
O.K. Now I'll appreciate it if, in your opinion, you'd like to tell what those "obvious reasons" are, please.

Thank you.

Al.
Skywave is offline  
Old 7th Nov 2015, 8:21 pm   #13
Barraman
Tetrode
 
Join Date: Mar 2011
Location: Western Isles of Scotland, UK.
Posts: 52
Default Re: Eddystone 888A.

A) Eddystone made their radios that way

B) Old components prefer to be woken up slowly

Richard GM0OGN
Barraman is offline  
Old 9th Nov 2015, 4:01 pm   #14
Skywave
Rest in Peace
 
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
Arrow Re: Eddystone 888A.

Quote:
Originally Posted by Barraman View Post
A) Eddystone made their radios that way
Richard GM0OGN
Indeed. But that doesn't mean that they can't be improved. As we all know, elevated temperatures can dramatically reduce the life of many components. Replacing the valve rect. with solid-state diodes will substantially reduce the heat build-up in the cabinet. Of course, you can always run the Eddy. with its top door open, but with regard to your stated sentiment, they weren't designed to be operated that way.
In my 888A, I replaced the valve rect. with diodes during 1967. Have regularly used that radio since then. Never had an 'H.T' failure yet (temps fate! ) I have also done same on many an RA-17 that has passed through my hands: same conclusion reached.

Quote:
Originally Posted by Barraman View Post
B) Old components prefer to be woken up slowly.
Richard GM0OGN
Ah, yes! At my age, I understand that only too well! (And I'm substantially older that my Eddy.!)
However, to wax seriously, when regular preventative maintenance is done (replacing 'iffy' capacitors and resistors) and painting the valve screening cans matt black (inside and out - and yes, that is worthwhile), your concerns on 'waking up' time, in my experience, fail to become significantly relevant.

As for 'keeping things original', I've already stated my viewpoint on that related topic.

Al.

Last edited by Skywave; 9th Nov 2015 at 4:16 pm.
Skywave is offline  
Old 9th Nov 2015, 4:15 pm   #15
Skywave
Rest in Peace
 
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
Arrow Re: Eddystone 888A.

Quote:
Originally Posted by Barraman View Post
I wonder what those pin heads on the scale plate, Band 3, are?
Never saw anything like that before.
Richard gm0ogn
Hmm: interesting. I have two 888A here. Both have scale plates stating 'MODEL 888'. I know that that labelling is original on each. However, neither have the 'pin heads' visible to which you refer. Perhaps those pin heads are not original. To the best of my knowledge, the scale plates for the 888 and the subsequent 888A are identical, although for a few late productions of the 888A, that labelling was changed to 'MODEL 888A'.

Al.
Skywave is offline  
Old 9th Nov 2015, 5:48 pm   #16
Herald1360
Dekatron
 
Herald1360's Avatar
 
Join Date: Feb 2007
Location: Leominster, Herefordshire, UK.
Posts: 16,528
Default Re: Eddystone 888A.

Maybe its history includes a blind amateur active on 20m?

Two pins on 14.1 would provide a reference point to count up/down from.

Is it relatively easy to remove the glass?
__________________
....__________
....|____||__|__\_____
.=.| _---\__|__|_---_|.
.........O..Chris....O
Herald1360 is offline  
Old 11th Nov 2015, 12:59 pm   #17
turretslug
Dekatron
 
turretslug's Avatar
 
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
Default Re: Eddystone 888A.

Depends on how one defines "relatively easy"! Assuming that there's little difference in front panel mechanical detail between 750 and 888 (and Eddystone very much worked on the basis of one being derivative from the other), then there's the removal of knobs, followed by removal of shaft bush nuts and switch/headphone socket retaining collars, unclipping dial lights, then 4x 2BA panel retaining screws associated with the panel handles, 4 more associated with the coil-box front under the finger-plate. If the 888 has the same linearising ratio arm as the 750, this then just unclips from the tuning drive peg without the need to loosen grub screws or maintain indexing as the front panel lifts away. Finally, the four 4BA screws securing the panel glass retaining tabs can be undone. (I have to admit that I filed these brass tabs smooth and rounded and covered them in thin heatshrink, I really didn't like the thought of re-tightening stamped, burred tabs onto a large piece of thin glass.... )

So, a fair few simple steps but all mounting up, time-wise.

I'm re-assured to find a table of 888 internal voltages where the e.g. HT corresponds far more closely with my experience of the 750 than with the 750 manual, i.e. at around 255V rather than 235V. I'd wondered if there was a primary short, though the transformer doesn't run worryingly hot Maybe the mains was a bit low back when they checked their sample 750.
turretslug is offline  
Old 11th Nov 2015, 1:58 pm   #18
Skywave
Rest in Peace
 
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
Arrow Re: Eddystone 888A.

Re above post: Magnitude of the HT and that of the incoming a.c. mains.

I have recently performed routine corrective and preventative maintenance on two 888A receivers. Once the essential work had been done - replacing defective / suspect Rs and Cs; checked / adjusted alignment; checked sensitivity and SNR, etc., I measured various HT voltages and compared same to those figures stated on the Eddy. cct. diagram: nearly all HT and heater voltage were substantially high. The a.c. input voltage was 245 v.; the mains adjustment transformer was set for its greatest voltage: 230 v. However, when the mains input was reduced to 230v. (by use of a Variac), the HT voltages were then a close match to the published figures - which were measured using an Avo 8 (20k-Ohms / volt.).

One of those receivers has been used on a nominal 230 / 240v. a.c. supply for most of its life. I do not believe that the difference between 230v.a.c. and 240v.a.c. has had any significant effect on the components within that receiver, nor on its measured performance figures.

Al.
Skywave is offline  
Old 11th Nov 2015, 2:10 pm   #19
Skywave
Rest in Peace
 
Join Date: Jun 2006
Location: Chard, South Somerset, UK.
Posts: 7,457
Arrow Re: Eddystone 888A.

Removing the glass from an Eddy. 888, 888A and similar Eddys. of that style of construction (the 730/4 being another example).

Generally speaking, that's not what I call an "easy task" . But that doesn't mean to say that it cannot be done: care and detailed notes made during dismantling are a great help - plus taking photos. Turretslug's above remarks are relevant & apposite: I will add one additional comment. Once the black front bezel is removed, it is necessary to remove the coarse threaded bolts which are fitted and recessed below that aluminium casting then visible. These can be very difficult to shift. Use a flat blade screwdriver whose blade is wide enough and with a blade that is in excellent order - together with persistence and patience! There is often a loud 'crack' as those bolts 'give way'.

Al.
Skywave is offline  
Old 11th Nov 2015, 6:08 pm   #20
turretslug
Dekatron
 
turretslug's Avatar
 
Join Date: Nov 2011
Location: Surrey, UK.
Posts: 4,385
Default Re: Eddystone 888A.

In fact, a task like this makes one appreciate the attributes of sturdiness and precise construction that is a hallmark of many Eddystones and surely contributes to their popularity in the vintage world.

I'm not familiar with typical mains supply voltages extant in the early 'fifties but I was surprised that the primary wasn't wound with nominal 210V and 240V tappings to better span a 200-250V possible supply range. This model 3937P transformer seems to have appeared approximately concurrently with the 750 and it was subsequently used in many models, even when the advent of solid-state rectifiers and noise-limiter diodes meant that either or both of the 5V, 2A and 6.3V, 0.3A secondaries was redundant. Perhaps the manufacturer (whose name I won't mention lest the search engines find it....) offered a quantity price quote that was too good to miss and Eddystone had a warehouse stacked up.

Last edited by turretslug; 11th Nov 2015 at 6:22 pm.
turretslug is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 7:07 am.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.