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Vintage Television and Video Vintage television and video equipment, programmes, VCRs etc. |
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11th Jun 2007, 9:36 pm | #1 |
Dekatron
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Ferguson 24" 3834 1500 chassis.
I sold the first Marconi 4800 20" sets fitted with the Thorn 1500 chassis as early as August 1969. Only BBC2 was receivable until early November, but the sets were an immediate success, and proved to be very reliable and more importantly, predictable.
One of the last models in the 1500 range I sold in 1976 was the Ferguson 3834 24" model and was in fact one of the last monochrome sets sold from my South London shop. I was recently presented with three sets from an old customer, a Philips 21TG100U from 1959, a 19TG170A from 1967 and the Ferguson 3834. Just for the fun of it I decided to get the old 1500 working. It's hard to believe that these sets will soon be forty years old and this example is over thirty! The main smoothing capacitor had a section O/C resulting in a breathing picture and sound hum. A NOS Radiospares replacement was fitted together with several preset controls and a general clean. That was it! The picture shows the set working on a very low signal provided by an eight element aerial screwed inside the roof of my single story workshop. I am 25 miles from Midhurst so the old timer is well up to standard. The tube fitted in the final production run was sourced from the old Eastern block and did not give as good a definition as the original Mullard A61-120WR, the screen material being more like blotting paper! All the same it is very old so cannot be criticised. This must be the best chassis ever produced from a servicing aspect. Happy days. John. |
11th Jun 2007, 11:10 pm | #2 |
Octode
Join Date: Apr 2007
Location: Hampshire, UK.
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Re: Ferguson 24" 3834 1500 chassis.
That's very smart (for a British set...), I don't remember that cabinet style. The ones we had were all the 20" sort in plastic "wood effect" cabinets with a 4-button mechanical tuner at the top and (usually totally flat) Mazda gold star tubes.
I never really got on with the chassis folding out sideways rather than down, it always seemed to swing about as if the top caps of the line output valves were following your hand! The circuit looks so simple now but judging by the amount written about them in "Television" I am not the only one who occaisonally struggled with them. I think the problem was that a lot of the small components were poor quality so more or less everything (except the LOPT) was suspect (a bit like the later TX90, though the LOPT did go in those). Happy days! They are an ideal collector's set for the beginner now of course, I'd recommend them to anyone starting out and wanting to learn how to look after an older set. |
12th Jun 2007, 8:16 am | #3 |
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Re: Ferguson 24" 3834 1500 chassis.
Spot on Studio 263, and thanks for your response. Of course there were a lot of small components, mostly capacitors [Callins] in the early models that failed. Presets and the mains dropper were short lived.
I used to do a mass overhaul of these sets on a Saturday morning while the customers waited! All known weak components were replaced and the whole lot added up to just a few pounds. I had an A4 hand written sheet I had compiled listing all the suspect components and known faults. I had a similar one for the 1400, another first class chassis. I will dig this out and post it when I have time. The 1400 chassis certainly had the line output valve in a nasty position but this was reversed with the 1500. These sets also 'scrubbed up' well for resale.The Mazda 'Gold Star' tube was a beast - fantastic screen but low emission and O/C cathode connections were common. Regards, John. Last edited by Heatercathodeshort; 12th Jun 2007 at 8:21 am. |
12th Jun 2007, 8:34 am | #4 |
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Re: Ferguson 24" 3834 1500 chassis.
John
Nice job! I thought I had seen all the 1500 cabinet designs, but apparently not. I would wholeheartedly agree that the 1500 was one of the best monochrome 625 chassis for ease of service and reliability.
__________________
Mike. |
12th Jun 2007, 8:53 am | #5 |
Retired Dormant Member
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Re: Ferguson 24" 3834 1500 chassis.
Simple and reliable but AC coupled video so fade to black = fade to grey. Suppose it meant that any poor EHT regulation went unnoticed. It's sad comment on the viewing public that most of them neither knew nor cared about what made a good quality picture. But that's a different subject.
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12th Jun 2007, 3:45 pm | #6 |
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Re: Ferguson 24" 3834 1500 chassis.
Ah - that's the one with the tuning preset adjusters that needed a screwdriver. Or else the customer's spade, so it seemed, when the metal crossbar's welds failed....
Anyone remember the Ultra that - oh luxury - had a varicap tuner, slider controls and SIX sloping silver buttons - whatever could you possibly need six for?? Glyn |
12th Jun 2007, 7:56 pm | #7 |
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Re: Ferguson 24" 3834 1500 chassis.
Thanks for all your comments. It just occured to me that a number of Forum members may have never handled the Thorn 1500 chassis. Well it was nearly forty years ago. I have attached a couple of pictures as they are worth many words. The second picture shows the chassis opened for servicing where every single component can be located at a glance. What an absolute pleasure it was to service these fine receivers.
Jeffrey is very correct when he mentions the lack of 'black level'. I never had a single complaint about this so to put it in a rather no nonsense way the BUSH 640 chassis could be described as 'Pearls before Swine' with its superb picture. I will save this one for another thread. [They thought the set had gone wrong when the screen faded to black in these models] Growing old fast! John. |
12th Jun 2007, 9:45 pm | #8 |
Octode
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Re: Ferguson 24" 3834 1500 chassis.
Looks like Plessey scan coils which also suggests a later model.
I remember seeing a 1500 with a GREEN PCB many years ago! They really are super sets. Brian |
12th Jun 2007, 9:59 pm | #9 |
Dekatron
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Re: Ferguson 24" 3834 1500 chassis.
Its a 1976 model Brian. I have a 20" 1500 chassis that has a green board. They must have run out of red varnish..J
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13th Jun 2007, 1:38 am | #10 |
Dekatron
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Re: Ferguson 24" 3834 1500 chassis.
Hi John,
I remember that set. Late production 1500 series sets were modified to BEAB specification. In receivers of various makes any 1 1/4" fuses were replaced by 20mm types. Also fusible resistors were introduced into critical parts of the circuit. The printed circuit board had to meet certain standards. It will be noticed that the earlier dark brown boards were changed to a light brown material. In the late production 1500 series receivers the valves and CRT were no longer sourced from Mazda, by 1975 production had ceased. Thorn Consumer Electronics bought in the valves from East European manufactures, except for the for the 30FL1, Mullard made the 30FL2 for TCE. To sum up, 1500 receivers were reliable and easy to to fix. OK, the picture could have been better. DFWB. |
13th Jun 2007, 7:36 am | #11 |
Octode
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Re: Ferguson 24" 3834 1500 chassis.
I understand the BRC 1400s made a brief comeback in the mid 70s to cater for those areas without UHF facilities, BEAB approved as well!
The 30FL2 is, I understand, an improved version of the 30FL1 and can be fitted in its place. Brian R |
14th Jun 2007, 2:32 pm | #12 |
Octode
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Re: Ferguson 24" 3834 1500 chassis.
I was employed by DER when the first Thorn 1500 receivers came on line. I liked the chassis immediately - far better than the 1400 which preceded it and better than the earlier 800, 850, 900, 950 et al, all of which had multitudinous stock faults (or so it seemed): tuner problems, board burn-ups, underrated caps etc. Working on the 1500 was easy. Fault-finding was straightforward. Tubes certainly were a little iffy as were the triplers and lopts but all straightforward to replace. Although obviously built down to a price, definitely my favourite monochrome chassis, lack of black level clamping notwithstanding.
-Tony |