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Workshop Thorn Rentals CRT tester/rejuvenator kit.

 
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

Wonder if there is anyone else over here that remembers the Thorn CRT tester/rejuvenator self build kit? Back in the delta gun days, sets were often mistakenly being brought in by field engineers, for soft CRTs. When in fact it was often the tripler at fault, especially those blue German skeleton ladder types (example below) used in the 3000/3500.

20211020 073359[1]

Every field engineer was given an afternoon on the bench to build their own from a kit to carry out an emission test and rejuvenate both colour and mono CRTs. Does anyone still have an example or the kit instructions, I wonder? One did appear on eBay some years ago. Don't remember much about the design other than it used a BDX32 which was used as line output in the 8500.

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Topic starter Posted : 19/10/2021 10:16 pm
crustytv liked
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crustytv
(@crustytv)
Vrat Founder Admin

Hi John, sounds very intriguing, it would be good to see the circuit.

If one could be sourced, it might even be fun to build it, more so for those without a tester. They'd have a way to check emissions and have the ability to tickle their cathodes, without the need to fork out for a B&K et al.

What did it use as an indicator for emission, was it just a simple hook-up to your meter?

Were there any protection circuits to ensure the overzealous field tech did not strip the cathode bare?

There was a simple emission checker cct in Jan 1979 'Television', no ability to tickle.

https://www.radios-tv.co.uk/vintage-electronics-blog-forum/build-a-simple-crt-tester/

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Posted : 20/10/2021 9:25 am
Doz
 Doz
(@doz)
Noble V-Ratter Registered

Our local RR had a B&K 467, which a tame engineer would "borrow" for us occasionally. 

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Posted : 20/10/2021 3:44 pm
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

Hi Chris, fairly basic and certainly compact but a bit better than the Video Circuits model which was around at the time. Originally it was only possible to use with mono and delta CRTs but later the mono base was removed and the connector for the RCA PIL tube used in the 9000 was fitted. With the advent of other CRTs such as the AX51 and 30AX the workshop unit was replaced with the B&K467.

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Topic starter Posted : 20/10/2021 9:04 pm
jcdaze
(@jcdaze)
Trusted V-Ratter Registered

I have got a copy of the T.T.R. book containing the circuit and components and usage of the tester/rejuvenator. I will scan and upload it soon, it's contains about 30 pages. I never could chuck things away!

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Posted : 22/10/2021 8:12 pm
Jayceebee liked
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

I was hoping you may have had a copy. It will be interesting to see that document again, cheers👍

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Topic starter Posted : 22/10/2021 8:36 pm
crustytv
(@crustytv)
Vrat Founder Admin

Jim has scanned the Thorn manual for the tester, and submitted it via the upload service. 👍 I've just this second moved it to the data library. It can be found under 'test equipment', there is a Thorn folder.

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Posted : 23/10/2021 4:11 pm
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

Thanks for that Jim, not quite as simple as I remembered but I was correct about the BDX32. Forgot about the emission test time limit also and I noticed it was Pat Pending, wonder if one was ever obtained?

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Topic starter Posted : 23/10/2021 5:24 pm
jcdaze
(@jcdaze)
Trusted V-Ratter Registered

@jayceebee Good old Pat Pending. 

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Posted : 23/10/2021 5:48 pm
Jayceebee
(@jayceebee)
Noble V-Ratter Registered

@jcdaze Snazza frazza rashin' fashin' Rick Rastardly

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Topic starter Posted : 23/10/2021 6:09 pm