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Max The Magnificent
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Re: Mysterious Object
Max The Magnificent   6/2/2014 11:22:26 AM
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@David: I'm sure even Max would struggle with 11 G&Ts for breakfast.....

Is that a dare?

Max The Magnificent
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Re: No Problem
Max The Magnificent   6/2/2014 11:21:31 AM
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@salbayeng: On a related note , be wary of metal film resistors > 100k operated at 250v or more (The Tectronix SC501 tiny scope was always having trouble with a set of 4 voltage dividers on the HT) You need to replace with "high voltage" resistors, (and preferably physically bigger resistors as this lowers the electric field)

Good tip -- thanks for sharing

David Ashton
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Re: Mysterious Object
David Ashton   5/31/2014 9:14:51 PM
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@Kfield...."did you see the pictures of him during the EE LIVE! pub crawl?"

No...you got a link??

Good to know I will have some competition if I make to to EELive 2015.....

kfield
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Re: Mysterious Object
kfield   5/31/2014 2:14:32 PM
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@DavidAshton I'm not so sure whether Max would struggle with elevenses, did you see the pictures of him during the EE LIVE! pub crawl? He was going strong late into th evening...

David Ashton
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Re: Mysterious Object
David Ashton   5/31/2014 2:14:51 AM
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@KField....  "Elevenses"....  reminds me of an Andy Capp cartoon (Andy Capp was a working-class British layabout forever shirking work, drinking beer and chatting up barmaids, and a cigarette hanging out of his mouth).  He had a long suffering wife called Flo who had cleaning jobs to bring in a bit of money.   I remember one cartoon with Flo carrying a tray of 11 beers to Andy, with the comment "Elevenses!"

I'm sure even Max would struggle with 11 G&Ts for breakfast.....

salbayeng
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Re: No Problem
salbayeng   5/31/2014 1:29:05 AM
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Yeh when I was ~8 yrs old, my schoolmates dad owneda  radio/TV repair business , we would go dumpster diving and wire up "radios" using old valves , (well we could get the filaments glowing anyway witha 6V battery !).

Built a Tesla coil (first of several) at age 15  used a 806? 810? triode (octal base with top cap anode) it used about 3 scavenged valve radio transformers to get the 1000v B+.   Made a friedd with a tech at the local radio station, he gave me some bigger valves (Used in sets of 4 as the exciters I think? they discarded the whole set when weakest valve couldn't keep up)

Not really done much with valves since.

The 110ohm observation was with a Chinese made hot air station, it had a handful of carbon composition resistors in the triac speed control. One resistor looked kind of heat stressed and was brown brown brown (and measured an erratic 63k)  , while another resistor of the same size nearby showed brown black orange and measured 10k. I swapped the suspect one with a 2W metal film 10k resistor and the speed control worked properly again.  

That sparked a recall from decades back with colleagues who had also noted propensity for drifts in carbon composition resistors that ran hot. By contrast modern metal film resistors can be cooked till the paint flakes off and show no drift.

On a related note , be wary of metal film resistors > 100k operated at 250v or more (The Tectronix SC501 tiny scope was always having trouble with a set of 4 voltage dividers on the HT) You need to replace with "high voltage" resistors, (and preferably physically bigger resistors as this lowers the electric field)

Max The Magnificent
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Re: Mysterious Object
Max The Magnificent   5/29/2014 10:06:52 AM
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@kfield: I thought you might be using it to serve elevenses!

Ah, time for tiffin :-)

Max The Magnificent
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Re: No Problem
Max The Magnificent   5/29/2014 10:05:31 AM
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@salbayeng: Tube radios don't use 110Ω resistors !

You sound like this is a topic that's pretty close to your heart?

salbayeng
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Re: No Problem
salbayeng   5/29/2014 6:08:26 AM
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@mlise: Tube circuits are pretty easy to fix, even for a digital guy. Replace all the caps. Replace all the tubes

And replace any resistors that look to have brown brown brown color bands.

(Tube radios don't use 110Ω resistors ! )

kfield
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Re: Mysterious Object
kfield   5/28/2014 9:40:45 AM
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@Max Oh, I thought you might be using it to serve elevenses!

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