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Thorn 9650

 
Mikey66
(@mikey66)
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I picked this set up from Colourstar on Saturday.
This set must have been DERs top of the range back in the late 70s, it sports infra red remote control, teletext, 2 speakers and (I think) voltage synthesis tuning.

It really needed a good hoovering out and the many dry joints going over. The only fault I found was the EW diode was in the wrong way round its series resistor was open circuit and a fusible resistor had pinged.

After putting that right I reassembled and switched on. Up came a raster and the channel ident in the top corner. No sign of a picture or sound though, then it dawned on me. Maybe that big empty space on the signals panel should house a plug-in IF module like the later TX9s and TX10s.

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Topic starter Posted : 31/07/2012 12:00 am
Refugee
(@refugee)
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A late 1970s set there for sure.
Those IF units must have been made to plug in once they had a customer and were then aware of the sound offset for PAL I UK 6MHZ or PAL B/G export 5.5 MHZ.
It is indeed missing from that set.

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Posted : 31/07/2012 12:12 am
Mikey66
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I don't remember the original 9600 series having a plug-in IF strip. I was thinking because of the teletext facility that Thorn may have used a SAWF in the IF strip on this version?

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Topic starter Posted : 31/07/2012 12:27 am
Anonymous
(@anonymous)
Illustrious V-Ratter Deactivated Account

they did or some did have a plug in rc reciver.
the touch tunning could be a bit of a pain
as for age i think 1978/9
rob t

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Posted : 31/07/2012 11:10 am
Mikey66
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After some input from a chap "over the road" I think the set is missing its sawf if and demodulator module as Thorn called it in their TX9 chassis. I am assuming that's the major difference between the 9650 and the 9600

In the meantime it's keeping my Marconiphone 3000 company :=D

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Topic starter Posted : 31/07/2012 8:30 pm
neil1974
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Hi Mike, it's nice to see the 3000 working well. cheers,neil.

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Posted : 31/07/2012 9:06 pm
Mikey66
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Hi Neil.

Yes the 3000 has behaved itself for the last 8 months or so. It gets about 2 hours a weeks use and although the tube is past its best. It is great for watching the old TOTP reruns on BBC4.

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Topic starter Posted : 31/07/2012 9:21 pm
Mikey66
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After fitting a donated TX9 IF panel I've now got a picture. The tube measured ok on my 467. The picture is slightly out of focus, adjusting the focus control is a bit "ratchety" so that will need cleaning, but for now I'm just happy to see the old box lighting up :D

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Topic starter Posted : 13/08/2012 11:18 pm
neil1974
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Hi Mike, it's nice to see a reasonable picture on the set before you've actually done any restoration work on it :=D hopefully it will co-operate with you and keep going, and not cause you any headaches. cheers,neil.

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Posted : 14/08/2012 2:35 pm
Mikey66
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Hiya Neil
I had gone over all the pcbs for dry joints before I powered it up.
I think the switch cleaner will be required next.

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Topic starter Posted : 14/08/2012 3:18 pm
EmleyMoor
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Did this have a single "TUNE" button hidden behind a flap? If so, friends of ours had the Baird equivalent in about 1981.

"Yes, a bit of wet string may get you a good TV signal here on four channels, but you'll have to dry it out to get Channel 5!"

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Posted : 03/06/2020 10:49 pm
Jayceebee
(@jayceebee)
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Correct, Thorn called it ramp tuning and it worked very well. When the red button was pressed the voltage ramped from 0 to 33v volts, when the micro saw valid sync pulses the voltage increase would slow then it would look for the AFC S curve from the IF then store the tuning voltage in memory. The only fly in the ointment was that leaking 1.2v Nicad.

John.

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Posted : 04/06/2020 11:49 am
jcdaze
(@jcdaze)
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39A276CB A00E 4355 B346 3CBBEB5A953F

The SAW filter is PCC-001 In the cct diagram.

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Posted : 04/06/2020 1:33 pm
Mikey66
(@mikey66)
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Crikey, I'd forgotten about this set.

You're right, it did have a red button for tuning. I had to replace the back-up battery to cure it's memory loss.

The set ended up with Graham of Imogen fame.

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Topic starter Posted : 05/06/2020 8:38 am
Doz
 Doz
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Posted by: @emleymoor

Did this have a single "TUNE" button hidden behind a flap? If so, friends of ours had the Baird equivalent in about 1981.

Referred to as the "self destruct button" ?

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Posted : 05/06/2020 8:56 am
neil1974
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I've still got my one if anyone would like it ? .

Cheers

Neil.

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Posted : 05/06/2020 12:27 pm
EmleyMoor
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I did like these sets, back in the day, and if I was ever considering a console set, this one would be high on the list (and probably easy to get, unlike the other one I was thinking of).

"Yes, a bit of wet string may get you a good TV signal here on four channels, but you'll have to dry it out to get Channel 5!"

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Posted : 06/06/2020 10:03 pm
EmleyMoor
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Were there sets of this type not in the rental companies' branding?

"Yes, a bit of wet string may get you a good TV signal here on four channels, but you'll have to dry it out to get Channel 5!"

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Posted : 08/06/2020 6:37 pm
Jayceebee
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The Thorn chassis guide here lists 11 Ferguson and 2 Ultra models fitted with either 9600 or 9650 versions. I have to admit that other than the 3734 I've not seen any others in the flesh or even in brochures.

John.

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Posted : 09/06/2020 8:48 pm
EmleyMoor
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@jayceebee I'll probably have to chase up photos of the actual models - I've not actually seen a ramp tune one that wasn't a Baird. Still, it may be a starting point.

"Yes, a bit of wet string may get you a good TV signal here on four channels, but you'll have to dry it out to get Channel 5!"

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Posted : 09/06/2020 9:58 pm