how many of those orange electrolytics actually test as faulty
When tested on my Peak ESR70, all except one had either doubled or halved in capacitance. As you rightly pointed out in another post, I should remove them all, so I did, and you were right. 👍
I might be tempted to re-form them, and if tested ok, keep any good ones for future spares.
Well, one was going back into the pulled spares tray, a 22uF @40V, that tested OK. Then, upon reflection, that too joined the rest in the bin. I'm hardly short on spares, and you can bet if pressed that cap into service, it would end up failing. Then someone would say, “why on earth did you use that! You can get brand new 22uF 40V caps for pennies”.
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Fair point.
To understand the black art of electronics is to understand witchcraft. Andrew.
Gosh, they were a bit rubbish then! I mentioned purely because I replaced a load in some Quad 50s and on test, they were pretty reasonable.
No matter - they can't do any harm now they're out of circuit.
Had any rain to cool the air yet? Had about an hour here, but no celestial fireworks.
Had any rain to cool the air yet?
No, I was very miffed. Though it's a cooler outside, the workshop was still 26C at 06:00 this morning. It reached 28C just after lunch and is now back down to 26.6C. We're forecast for a good downpour Sunday. I've still got the fan running to keep me cool.
Gosh, they were a bit rubbish then!
Indeed, I was quite surprised too. For example, two of the 470uF, one was 890uF the other 230uF
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Indeed, I was quite surprised too. For example, two of the 470uF, one was 890uF the other 230uF
Technically speaking, just about in tolerance for older electrolytics which were +100/-50%...
Those orange things were used extensively in the Thorn 3000 and were very troublesome early in the life of the set. The two 22uF ones in the line oscillator were responsible for line drift, not enough to drift out of lock but enough the cause trouble in the chroma due to mistiming of the line feedback pulses
John.
The leading edge of the "bath-tub curve" then.
A great rare set indeed. During my time at Thorn (Multibroadcast-mid 1980s), I saw only two 4K sets out on rental. Pretty reliable at the time. I wonder where they went. these were 22" models I think.
Good to see you have a Telefunken 743 in your collection too!
Best Regards
Paul
Last night I spent many hours following your experience with the 4000. Brought back so many memories.
The colour decoder module was always a problem. We saw so many variations of it, including one on a bigger board that used (from memory) Philips TBA510, TBA540 and TBA660(?). None of them ever really worked properly.
The weekly service bulletins are another memory.
The experience of keeping AWA 4KAs running I liken to the scene from the movie Titanic where the engineers were furiously resetting breakers to keep the lights on.
Later production used local IRH metalglaze resistors and Japanese-sourced capacitors.The thick film modules were gradually replaced with discrete equivalents. The reliability improved. AWA worked very hard trying to make the 4KA a success. They had to, they were to build about 200,000 of them.
And those CRTs from RCA. The reds were luminous dark orange and the white screen purity was abysmal. They flashed over like mad and destroyed the most unlikely parts. I replaced more than one of these CRTS under warranty with Mazda tubes which, despite being not as bright, at least had reasonable colours.
Eddie Charlton (Pot Black) had a 4KA. I installed it.
