Ultra 6813 (Thorn 1500) - UK Vintage Radio Repair and Restoration Discussion Forum

Restoration73 · 5th Dec 2020, 8:38 pm

I recently acquired this set, the last Ultra 1500 (thanks Andy) as I gave away
all my 1500s about 30 years back. Careful examination revealed only
1. A dropper section wired across the o/c dropper
2. Pinnacle PCL805 and PCL82
3. The track between the mains fuse and filter cap had blown and linked
across. The filter cap was a blue/white Dubilier. Someone had kindly wound
some fuse wire across the 1.6A fuse.
I decided to replace the filter cap and fuse and switched on to get quite a
good picture, although the contrast control had no effect (wiper not making
contact) All the updates were already fitted except for the 120pF across the contrast control.
Now it is possible to get soot and whitewash if desired.
I had a load of PCL805s which I tested, 10 good, 3 low emission, and a BNIB
Pinnacle with no output. John HCS gave me 2 30PL15s which gave an even
greater amplitude here. This must be one of the the easiest sets to work on.
It took me longer to polish out the scratches in the cabinet !

Heatercathodeshort · 6th Dec 2020, 12:21 pm

Thorn receivers were one of the best for overhaul and resale.
Their cabinets were always simple with good control quality control knobs that cleaned up to new appearance with the aid of 'FLASH'. The much later 'painted grain' plastic cabinets if handled roughly would look scruffy but could be either recovered or sprayed to give an acceptable finish. It only took a couple of minutes to remove the chassis, tuners and CRT.

I had my shop divided down the middle with the counter in the middle. It was a deep shop. All new receivers were displayed on the right and the reconditioned ones on the left. They were always well received by the customers who very often thought they were also new stock! Thank you Thorn, you served us well. John.

Richard_FM · 6th Dec 2020, 1:21 pm

The 1500 chassis seemed be designed with the rental trade in mind, which isn't surprising as Thorn owned Radio Rentals and had interests in some others.

I do like how the main board swings out on them so engineers had easily access both sides for in-situ repairs.

Welsh Anorak · 7th Dec 2020, 10:42 am

The 1500 was an improvement on the 1400 with regard to accessibility, if not picture quality. Moving the line output stage to the hinged side of the chassis was much appeciated - I doubt many engineers who serviced 1400s survived without 'bullet holes' on their hands from the top caps of the output valves!
I was always surprised the valves didn't work loose from being mounted horizontally, but only the frame transformer used to suffer from this orientation.

Restoration73 · 7th Dec 2020, 1:40 pm

I have two knobs missing. This set has not had a lot of use, and the UHF tuner plastics
are fine. It's a shame Thorn economised with a 5x3 speaker. The mystery of the new Pinnacle PCL805 is solved. I thought to check for interelectrode shorts when pin 1 fell out of the glass. None of the pins was bent. I have a mint Ultra 6660 (1400) to compare with.
After getting a nip from our old Skantic hybrid I wore a rubber glove on my right hand !
On to the next one, Tony

5th Dec 2020, 8:38 pm	#1
Restoration73 Nonode Join Date: Jun 2013 Location: Surbiton, SW London, UK. Posts: 2,801	Ultra 6813 (Thorn 1500) I recently acquired this set, the last Ultra 1500 (thanks Andy) as I gave away all my 1500s about 30 years back. Careful examination revealed only 1. A dropper section wired across the o/c dropper 2. Pinnacle PCL805 and PCL82 3. The track between the mains fuse and filter cap had blown and linked across. The filter cap was a blue/white Dubilier. Someone had kindly wound some fuse wire across the 1.6A fuse. I decided to replace the filter cap and fuse and switched on to get quite a good picture, although the contrast control had no effect (wiper not making contact) All the updates were already fitted except for the 120pF across the contrast control. Now it is possible to get soot and whitewash if desired. I had a load of PCL805s which I tested, 10 good, 3 low emission, and a BNIB Pinnacle with no output. John HCS gave me 2 30PL15s which gave an even greater amplitude here. This must be one of the the easiest sets to work on. It took me longer to polish out the scratches in the cabinet ! Attached Thumbnails

6th Dec 2020, 12:21 pm	#2
Heatercathodeshort Dekatron Join Date: Jun 2005 Location: Warnham, West Sussex. 10 miles south of DORKING. Posts: 9,147	Re: Ultra 6813 (Thorn 1500) Thorn receivers were one of the best for overhaul and resale. Their cabinets were always simple with good control quality control knobs that cleaned up to new appearance with the aid of 'FLASH'. The much later 'painted grain' plastic cabinets if handled roughly would look scruffy but could be either recovered or sprayed to give an acceptable finish. It only took a couple of minutes to remove the chassis, tuners and CRT. I had my shop divided down the middle with the counter in the middle. It was a deep shop. All new receivers were displayed on the right and the reconditioned ones on the left. They were always well received by the customers who very often thought they were also new stock! Thank you Thorn, you served us well. John.

6th Dec 2020, 1:21 pm	#3
Richard_FM Nonode Join Date: Sep 2017 Location: Stockport, Cheshire, UK. Posts: 2,004	Re: Ultra 6813 (Thorn 1500) The 1500 chassis seemed be designed with the rental trade in mind, which isn't surprising as Thorn owned Radio Rentals and had interests in some others. I do like how the main board swings out on them so engineers had easily access both sides for in-situ repairs. __________________ Hello IT: Have you Tried Turning It Off & On Again?

7th Dec 2020, 10:42 am	#4
Welsh Anorak Dekatron Join Date: Apr 2005 Location: North Wales, UK. Posts: 6,927	Re: Ultra 6813 (Thorn 1500) The 1500 was an improvement on the 1400 with regard to accessibility, if not picture quality. Moving the line output stage to the hinged side of the chassis was much appeciated - I doubt many engineers who serviced 1400s survived without 'bullet holes' on their hands from the top caps of the output valves! I was always surprised the valves didn't work loose from being mounted horizontally, but only the frame transformer used to suffer from this orientation. __________________ Glyn www.gdelectronics.wales

7th Dec 2020, 1:40 pm	#5
Restoration73 Nonode Join Date: Jun 2013 Location: Surbiton, SW London, UK. Posts: 2,801	Re: Ultra 6813 (Thorn 1500) I have two knobs missing. This set has not had a lot of use, and the UHF tuner plastics are fine. It's a shame Thorn economised with a 5x3 speaker. The mystery of the new Pinnacle PCL805 is solved. I thought to check for interelectrode shorts when pin 1 fell out of the glass. None of the pins was bent. I have a mint Ultra 6660 (1400) to compare with. After getting a nip from our old Skantic hybrid I wore a rubber glove on my right hand ! On to the next one, Tony