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Test Equipment Telepart CRT Tester 4A

 
WayneD
(@wayned)
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Posts: 354

Random Ebay purchase, a "Telepart CRT Tester 4A" made by C.E.Developments which appear to have been a small business. 

IMG 20220630 173147
IMG 20220630 173507

Needs a bit of work as the combined mains/momentary switch is broken. Also, I'm not exactly happy with a CRT neck supporting the weight of this steel socket box! 

IMG 20220630 173421

I'll be trying it out on a sacrificial tube first. I mainly bought this as I fancied reverse-engineering the circuit.

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Topic starter Posted : 30/06/2022 6:16 pm
crustytv
(@crustytv)
Vrat Founder Admin
Posts: 11044

Hmmm, I believe this is the infamous Video Circuits V33 in disguise. Beware, only useful for emission tests, use the reactivation at your peril. I'll say no more than I already added in this thread here https://www.radios-tv.co.uk/community/general-discussion/video-circuits-ltd-panel/

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Posted : 30/06/2022 6:25 pm
freya and WayneD liked
WayneD
(@wayned)
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Posts: 354

@crustytv there's very little to it!

IMG 20220630 191604

Also that grey capacitor on the left absolutely stinks. I doubt I'd use this on anything valuable/rare. 

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Topic starter Posted : 30/06/2022 7:21 pm
Lloyd
(@lloyd)
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Posts: 1592

Reactivate should be re labelled cathode disposal tool! I think I have a similar one in storage, unless it got chucked out. Mine had more bases on it, but no nice steel box!

Regards,

 Lloyd 

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Posted : 30/06/2022 10:19 pm
WayneD and freya liked
WayneD
(@wayned)
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Posts: 354

@lloyd yeah, having studied how this works and heard several warnings I don't think I'll be using it for its intended purpose.

The sockets, case and transformer are all useful.

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Topic starter Posted : 01/07/2022 8:04 am
crustytv
(@crustytv)
Vrat Founder Admin
Posts: 11044

Hi Wayne, why not consider using case, meter and switches, to build a better version of what your new purchase could have been.

How about adopting this very good circuit? You could modify to utilise the one excellent part in the TelePart tester, namely the meter. If nothing else, it would provide you with endless hours of tinkering (which I know floats your boat) and make a very interesting, and much needed project for the forum.

Edit:
I'll put this circuit as a pdf in the technical library (under test equipment/homebrew), I only posted it in here so those without access can mull it over and contribute.

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Posted : 01/07/2022 8:51 am
WayneD
(@wayned)
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Posts: 354

@crustytv Now you're talking my language! 🤩 

I'd been looking at some the circuit diagrams in Television magazine etc but this one seems to have passed me by.

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Topic starter Posted : 01/07/2022 1:24 pm
mfd70
(@mfd70)
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The "Television" article is the basis of the Manor supplies unit, there is an error or modification of the circuit, so probably best check subsequent issues of the magazine if you try to build one.

I made one from the Manor supplies instructions, I never rescaled the meter that I salvaged from a scrap transistor tester but I could tell if a CRT was any good. I made it in about 1992 and used it until the early 2000's at that time, keeping a number of industrial Microvitec monitors displaying enough of a usable image until the machine were upgraded to a VGA display for about £3.5k, so it was worth paying me £150 a few times to keep them going.

 

image

 

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Posted : 02/07/2022 9:58 pm
WayneD liked
WayneD
(@wayned)
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Posts: 354

I did a bit of electrical safety work on this device as I really didn't trust the dodgy mains wiring (the whole thing wasn't earthed either!) and I tried the test function. Have to say the testing side of things is pretty good:

20220708 143245

This is on the tube of my Rediffusion Guildford, which I already knew was pretty flat. Just to emphasise: No way am I using the rejuvenate function on my Rediffusion! I'm tempted to disconnect the rejuvenate functions from the rotary switch.

I've been studying both the CRT Tester and Reactivator in the Television article and the Manor unit mentioned above and I've come up with a rough idea of a rejuvenator that just tickles the cathode rather than strips the thing. I reserve the right to call it "The Tickler" 

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Topic starter Posted : 08/07/2022 6:45 pm