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B&W TV Marconiphone 4816 (Thorn 1590)

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Doz
 Doz
(@doz)
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Good evening one and all. 

It's been one hell of a few weeks at work. I needed some telly therapy...

Just dug a Marconiphone 4816 out of the garage (Thorn 1590) chassis. Not been powered on in my ownership , and not since the 80's in the last ownership! Seems to date from 1972.

Knowing the issues these used to have with the regulator, I chose to give it 12V, and up it came with a nice bright snowy raster and the world's second most scratchy volume pot (second to almost any Sony 9-90!). Manually depressing a tuner button, I got a good picture, but with no vertical hold.

Tuner washers have disintegrated, and I've never actually done one of these before, but sussed it out. I snipped some suitable poly washers and wiggled them into place. A squid of WD40 to the threads has it moving freely, and latching with a satisfying clunk.

I know I downloaded the service manual from these parts a while back, but I suffered a bad hard disc failure and lost so much. Could someone possibly share it with me?

TIA,

Doz.

 
Posted : 23/09/2023 6:31 pm
crustytv
(@crustytv)
Posts: 11932
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@doz

I've uploaded the service data to the temporary data library for you. Link to library up top. 👍 

CrustyTV Television Shop: Take a virtual tour
Crusty's TV/VCR Collection: View my collection
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Posted : 23/09/2023 6:39 pm
Doz reacted
Doz
 Doz
(@doz)
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@crustytv Thanks as always

 
Posted : 23/09/2023 7:07 pm
Doz
 Doz
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Well, that didn't take much .... 

IMG20230923211133

Stupidly removed the only callins in there (C78) ... measured it , it's supposed to be 1000uF at 16V, ESR meter had it at 1082uF, and an ESR of 0.38 ohms, pretty much perfect , put it back in, carefully examining the polarity mark on the PCB, questioned myself, checked the mark again... put in the correct way to the markings on the board, powered back up , and it leaked all over the board with a second or two, with a massive field shift , and not enough height .... damn marking on the silk screen is wrong. Just ruined a perfectly good 51 year old capacitor. Dammit. Soon resolved however!

 

 
Posted : 23/09/2023 8:46 pm
slidertogrid reacted
slidertogrid
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Brilliant sets! Thorn must have sold thousands in the various makes and models. I had one that survived 240V being put into the 12V socket!  Incredibly the power switch and the LT fuse were the only casualties. 

 
Posted : 23/09/2023 10:23 pm
Doz reacted
Doz
 Doz
(@doz)
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I've cleaned it all up as best I can. It's a bit tatty, but working well enough. Sat here watching Death in Paradise as I type. 

 
Posted : 24/09/2023 12:36 pm
RichardFromMarple
(@richardfrommarple)
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Quite a modern design for the early 1970s, & could have been made into the 1980s without looking old but Thorn replaced them with some other portable designs later in the 1970s.

 
Posted : 24/09/2023 1:37 pm
slidertogrid
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I bought a Ferguson version today from the BVWS bring and buy at Biggleswade. Looks like it has been shed stored as it is mucky with the usual spider poo but at a fiver it had to be bought! It even has the 12 Volt lead with it!  

 
Posted : 24/09/2023 5:48 pm
Cathovisor and Doz reacted
Cathovisor
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@slidertogrid I didn't see you there, Rich? Mind you, I was a bit late arriving (by train) and generally felt a bit out of sorts - I was easy to spot though, I was the lone person with a face mask on!

I bought a couple of items from the auction: one I got to take away and one is being delivered. One is quite fascinating, incredibly rare, dates from the 1920s and uses unexpected technology. I feel a clean-up and write-up is in order in due course.

 
Posted : 25/09/2023 5:38 pm
slidertogrid reacted
slidertogrid
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Hi Mike I was there with a couple of mates from opening time until just after the auction started. We didn't stay for the auction as there was nothing that either of my mates or me wanted to be honest. I bought a couple of things from the bring and buy, and a few useful parts from a couple of stalls. 

"One is quite fascinating, incredibly rare, dates from the 1920s and uses unexpected technology. I feel a clean-up and write-up is in order in due course."

That sounds interesting....?

 
Posted : 25/09/2023 10:35 pm
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