Featured
Latest
Ferguson 3629 "...
 
Share:
Notifications
Clear all

Forum 141

Ferguson 3629 "Personal" restore

46 Posts
14 Users
0 Likes
16.8 K Views
AidanLunn
(@aidanlunn)
Posts: 773
Honorable Member Registered
Topic starter
 

Hello all

I had been after one of these for some years due to the design and a few years ago I managed to get one from a very nice seller in Liverpool.

After some time in slumber in my workshop and some persuading that dual standard sets aren't very difficult even for those with relative inexperience (as Sideband suggested), I got it up on the bench. (My hernia recovery helped in this decision, originally I was going to tackle my Ultra V14-53, but as that's heavier, I decided to put that one off and restore this one first, so I could restore for some of the time I was off, when my surgery was well enough to do it).

An inspection inside revealed a set that had been dry stored, but was covered in coal fire dust. More importantly, the standards switch was left untouched, no soldering shut or ripping out! The spring on the standards switch was quite rusty but still had considerable spring in it so has been left alone. It looks a right swine to disassemble just to replace the spring!

A snip of a mains filter cap and first power up, very promising results, just a raster with cramp at the bottom. Applying testcard also revealed a few linearity problems, too.

On the second night, I decided to get down to some diagnostics and component changes. Firstly, a replacement of the cathode bias cap and resistor did bring some improvement to the frame cramp but not enough. Now, the testcard was folding over on itself at the bottom and top and the height and linearity controls wouldn't stretch the raster any further, just cause more foldover. So, the frame linearity circuit was checked and C90 and C88 were tested leaky and replaced. C88 I had a perfect value replacement in stock (0.01uF), but the 0.03uF C90 had to be replaced with a 0.022uF, near enough for almost perfect linearity. Again, the linearity controls didn't sort this, but checking R111 (100K) and R113 (120K) revealed both to be just over tolerance, so they were replaced. Perfect linearity now.

The next night a bit more progress, but a new fault - frame lock very weak, which within 30 seconds disappeared entirely. In the past, the frame area had been repaired before, with Plessey caps. C79 (0.003uF) was faulty so replaced with a 0.0022uF. This restored an oscillator running at half speed, with correct lock only achievable at one extreme end of the vertical hold pot. This was revealed to be the work of the previous repair man, who had put in a 0.015 Mullard tropical fish cap here. Replacing with the correct value restored normality.

Next up, a slight rippling on the line stage which was not viewable on my photos - C100 (1uF) (HT rail decoupler electrolytic for the line and frame stages) was checked and found to be the cause of the fault so replaced. Perfect line scan. Line lock was weak, so the line sync capacitor C104 (0.01uF) was checked and found to be crumbling to bits (well, it's a Hunts). The replacement resulted in strong line lock.

Next up was sound, which was distinctly buzzy in spite of position of the cabling or the system being used or the fine tuning. So, a component fault it had to be!

C77 and C75 had both gone totally o/c so were replaced, slight buzzing on sound now, but nothing more than is normal for a TV of this period.

Testing the UHF tuner, which is of the valve type revealed very good results. I was expecting low gain or something from these, but no, absolutely fine!

Next, on both VHF and UHF, there was a black streaking to the right of anything bright on the screen that didn't show up on testcard. Both C35 and C41 looked distinctly unhealthy so I replaced those. Now that has been resolved.

Next up, a strange fault. Whenever VHF was used with no UHF plug in the socket, the picture would be OK and vice versa on UHF with nothing in the VHF socket. But with both plugged in, a slight buzzing on UHF and severe cross-patterning on VHF. Giving one of the VHF tuner valves a new screening can didn't resolve the issue (the old one was missing when I first took the back off). A close inspection of voltages around V3 revealed the screen grid was at 104V and the anode at 201V. This revealed R15 (39K) and R16 (68K) had both gone to over twice their value! After replacing these but before powering up the set again, I tested C10 (0.001uF) as I thought this could be at fault for the rise in value but nope, it turned out to be fine! As a result, the voltage for the screen grid of the valve was now down to 25V, 20V lower than it should have been, but I thought my digital meter may have been loading the circuit. The anode was now at 190V. This made no difference either, but as this was the point at which I had noticed something else which I was certain to be the cause, I stopped investigating around here.

Purely by chance I had found that the core of the VHF coaxial had split from the core of the VHF aerial socket and that someone had wired in an ordinary cable between the socket and the VHF tuner, with the original cable still present, but only connected by it's screening side.

Taking this cackhanded but well hidden work out and soldering in a new brown 75Ohm coax resolved that problem!

Next was the simple job of resoldering all of the components that were (just about) handing on to their solder at the factory!

One accident with burnt off track, though. Even with my iron down at 25W and the tip being rather small and the iron not touching a joint for more than 4 seconds and the track still began lifting slightly. :aab

A final adjustment of geometry and both linearity controls and height restored picture perfect to 405 and 625.

Now, just a cabinet repair.

What needs doing:
All front panel gold trim, including the gold strip repairing, a new foot and the cabinet revarnishing/restaining and the UHF tuning dial needs looking at, the tuning dial and the fine tuning ring behind it are intermittently twisting each other when one is turned. Do these both turn independently (assuming it has a fine tuner) or is the ring just a backing to make it look a similar design to the VHF tuner?

 
Posted : 02/03/2015 3:51 pm
AidanLunn
(@aidanlunn)
Posts: 773
Honorable Member Registered
Topic starter
 

Verdict of the repair:
Very straightforward, nothing much to be said about it that hasn't been said.

Verdict on the set:
Like most of Thorn's products from the 60s to the 80s, electronically very stable and reliable, however the same can't be said of the cabinet.

More pictures.

 
Posted : 02/03/2015 3:55 pm
Doz
 Doz
(@doz)
Posts: 1485
Prominent Member Registered
 

Cracking. Well done. Will the gold surround just stretch back into position?

 
Posted : 02/03/2015 3:55 pm
AidanLunn
(@aidanlunn)
Posts: 773
Honorable Member Registered
Topic starter
 

More pictures.

 
Posted : 02/03/2015 3:58 pm
AidanLunn
(@aidanlunn)
Posts: 773
Honorable Member Registered
Topic starter
 

Et voila! Picture perfect!

 
Posted : 02/03/2015 3:59 pm
Marc
 Marc
(@marc)
Posts: 2753
Noble Member Registered
 

Hi Aidan,

That looks pretty good to me, Spot on ! :aad

Marc..

Marc
BVWS member
RSGB call sign 2E0VTN

 
Posted : 02/03/2015 4:01 pm
AidanLunn
(@aidanlunn)
Posts: 773
Honorable Member Registered
Topic starter
 

Cracking. Well done. Will the gold surround just stretch back into position?

It seems not unless the grey front panel is removed first as it's quite immovable. Also, the gold strip seems to have snapped, unless it was just wrapped around the front panel without the gold front strip being stuck together?

 
Posted : 02/03/2015 4:02 pm
AidanLunn
(@aidanlunn)
Posts: 773
Honorable Member Registered
Topic starter
 

Oh, the slight greying and lack of contrast on UHF is due to my cheap workshop Maplin UHF modulator. Using my Betamax as a modulator, the contrast looks much more natural.

 
Posted : 02/03/2015 4:03 pm
neil1974
(@neil1974)
Posts: 624
Honorable Member Registered
 

My example had already had most of it's caps replaced when I bought it so works quite well :bba . but it still has the problem of the shrinking and missing trim as it seems most of them do :bbd .

Cheers
Neil.

 
Posted : 02/03/2015 5:58 pm
Refugee
(@refugee)
Posts: 4055
Noble Member Registered
 

That was a nice easy electrical restore. Well done :aap
That trim looks like the bits that went around the wheel arches on the 1960s BMC Mini.
Perhaps you need to give the owners club website a visit and see how they fixed what looks like the same problem.

 
Posted : 02/03/2015 6:04 pm
Lloyd
(@lloyd)
Posts: 1897
Prominent Member Registered
 

Nice job on the Fergy!

I have one too, I never did get round to finishing it after the roof leaked all over it! For the gold trim round the edge of the front panel, I found it easier to remove the front panel completely (just held on with nuts from the inside) and then stretch it back round and superglue it into place a little bit at a time so it doesn't get messy.

Great sets, and cos their so small they fit in just about anywhere!

Regards,
Lloyd.

 
Posted : 02/03/2015 7:22 pm
AidanLunn
(@aidanlunn)
Posts: 773
Honorable Member Registered
Topic starter
 

That was a nice easy electrical restore. Well done :aap
That trim looks like the bits that went around the wheel arches on the 1960s BMC Mini.
Perhaps you need to give the owners club website a visit and see how they fixed what looks like the same problem.

Looks quite different to me, significantly bigger.

http://www.classic-auctions.com/Images/ ... /49003.jpg

 
Posted : 02/03/2015 7:49 pm
Marc
 Marc
(@marc)
Posts: 2753
Noble Member Registered
 

Hi Aidan,

Mini arch and sill trim is way too big I think even gutter trim though smaller will still be too big as well. :aaq

Marc.

Marc
BVWS member
RSGB call sign 2E0VTN

 
Posted : 02/03/2015 7:56 pm
Terrykc
(@terrykc)
Posts: 4005
Member Rest in Peace
 

That trim was quite popular on lots of things in the 60s ...

Try a furniture restorer for the gold trim or a small scale manufacturer who's been around a long time and still has some old bits and pieces knocking around (if you can still find one!).

The easiest way to fit the new trim would probably be with an open stapler - just smack it hard with the heel of the hand to force the staple into the edge of the front panel and repeat as often as required!

When all else fails, read the instructions

 
Posted : 02/03/2015 8:31 pm
AidanLunn
(@aidanlunn)
Posts: 773
Honorable Member Registered
Topic starter
 

I've looked at a few images of the same model online, and it seems that it is probably supposed to have a "break" there:

http://www.radiomuseum.org/images/radio ... 692578.jpg
http://i.ebayimg.com/00/s/NTIyWDEwMjQ=/ ... ~/$_35.JPG
Forum 158
Forum 159
http://collectionsonline.nmsi.ac.uk/det ... &t=objects

 
Posted : 02/03/2015 8:53 pm
Terrykc
(@terrykc)
Posts: 4005
Member Rest in Peace
 

If that is all you've got, I'd leave it alone. It was probably a flush joint originally and the trim has shrunk back.

Alternatively, there was a small additional piece of trim that wasn't well fixed that frequently fell off - which would explain the uniformity of the pictures!

When all else fails, read the instructions

 
Posted : 02/03/2015 9:02 pm
Doz
 Doz
(@doz)
Posts: 1485
Prominent Member Registered
 

That was a nice easy electrical restore. Well done :aap
That trim looks like the bits that went around the wheel arches on the 1960s BMC Mini.
Perhaps you need to give the owners club website a visit and see how they fixed what looks like the same problem.

We buy replacement trim. You can get almost anything for a mini.

 
Posted : 02/03/2015 9:40 pm
Tazman1966
(@tazman1966)
Posts: 382
Reputable Member Registered
 

A nice result! You'll be hooked on this newer stuff now :)

 
Posted : 02/03/2015 11:25 pm
AidanLunn
(@aidanlunn)
Posts: 773
Honorable Member Registered
Topic starter
 

A nice result! You'll be hooked on this newer stuff now :)

Nah, Dual standard sets are still off my radar 😉

Once this is done and dusted, my basket case Ultra V14-53 will be on the bench.

I'd never seen one of those before and I don't think I've seen one either on here or on UKVRR.

 
Posted : 02/03/2015 11:34 pm
colourstar
(@colourstar)
Posts: 632
Honorable Member Registered
 

If that is all you've got, I'd leave it alone. It was probably a flush joint originally and the trim has shrunk back.

Alternatively, there was a small additional piece of trim that wasn't well fixed that frequently fell off - which would explain the uniformity of the pictures!

I had one of these sets years ago. There was a small flat brass 'sleeve' of the same profile, into which the ends of the plastic trim fitted, making for a neat way of covering the join. It was easily lost and of course when it disappears it does indeed look as if the trim has shrunk.

Every one of these sets I've ever seen has been missing at least one piece of brass trim from either the tuning knobs or the smaller controls.

Great little tellies though!

Steve

 
Posted : 03/03/2015 7:32 pm
Page 1 / 3
Share: