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 'Modern' paper caps and two shorted electrolytics.
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 Return to top of page · Post #: 1 · Written at 10:12:41 PM on 6 February 2018.
Ian Robertson's Gravatar
 Location: Belrose, NSW
 Member since 31 December 2015
 Member #: 1844
 Postcount: 2363

Fixing a Kriesler 59 - 3 colour set from 1976 and an HMV PU series chassis from 1967.

First the Kriesler:

Would you expect to find a paper capacitor in a 1976 TV?

Well I did. Made by Rodestein (ERO brand) a .047μF 1250 volt PAPER capacitor!
There is no evidence on the markings that this is a paper cap.
When it fails (as it always will) in this circuit, it behaves as though the tripler has failed. Nasty!

Fixed that, next an O/C 800mA fuse in the rail that supplies the vertical. Linked it out, a 5.6 ohm 5 watt resistor lights up bright orange!
With a current limiting resistor in place, diagnosed the amp - could not find anything wrong except it was biassed up one end.
Fault turned out to be a SHORTED (zero ohms) yoke coupling electrolytic capacitor!

This set has a neat safety feature to protect the CRT from burn if a scan failure happens. It reduces the beam current to nearly zero.

Replaced that electro, now up and running, sort of.. Noise in the video affecting sync.

Then, Phhhttt!! Shutdown!

This turned out to be a bad line tuning cap. One of those green axial ones. Had gone open circuit, bulging and leaking waxy goo.

So much for more modern caps not needing to be changed! And when was the last time you saw a shorted electro?

Just like the HMV PU series set from the night before!

I guess I'm going to see a third S/C electro soon!


 
 Return to top of page · Post #: 2 · Written at 9:45:59 AM on 7 February 2018.
GTC's avatar
 GTC
 Location: Sydney, NSW
 Member since 28 January 2011
 Member #: 823
 Postcount: 6678

Would you expect to find a paper capacitor in a 1976 TV?

Thanks to Whitlam, by 1976 the writing was well and truly on the wall for TV manufacturers in Oz. I guess they were throwing any sort of junk into their sets as the bean counters had conniptions about revenue and expenditure.


 
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