Kriesler 79-2 dated June 1959.
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Location: Albury, NSW
Member since 1 May 2016
Member #: 1919
Postcount: 2048
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Don't forget to tell them the PAVLOVA is our on invention!!!!
Oh boy I love pavlova!
😆 pete
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Location: Belrose, NSW
Member since 31 December 2015
Member #: 1844
Postcount: 2363
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No problems at all Brad, using an old Android tablet and premises wifi. In Avignon now. Wasn't iuseable on in-flight WiFi but neither was my email.
Kriesleral,
Just looked at the pic of that 1S2. Forget it. If you can wait till about 20th Sept. I have a replacement for you.
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Location: Mile End, SA
Member since 23 February 2014
Member #: 1512
Postcount: 24
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Hello Ian
Apologies for the long delay - I took the time to build your "emissions tester for old CRTs" which you helpfully posted on 11th July this year.
After there being NO reading for about 10 secs, it slowly came up and got no higher than the about 2.5v after a few minutes as the photo shows.
I guess this answers the question of whether the fault is with the CRT, as it would appear to be low emission. I wish I'd been able to test this years ago as now I have a fully re-capped TV with a NBG CRT...oh well. Maybe another will appear one day...
But, the advantage is I now know how to check the CRT before anything else, and to realise that a replacement CRT may still be no good.
Cheers, Alan.
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Location: Belrose, NSW
Member since 31 December 2015
Member #: 1844
Postcount: 2363
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Hi Alan
That should still be a usable CRT. Just a bit slow coming up and emission at about 60%, shouldn't stop you getting a reasonable picture. It might just flare a little on the bright highlights.
Any reading at all on that test will generally give you a picture you can watch.
If it's been out of use for a long time, leave it on the tester (heater powered) for about an hour. It will usually come up a bit more.
I have that 1S2 if you want it.
You still have a problem with the G2 voltage. The CRT is NOT dead, and is DEFINITELY NOT the cause of the low brightness.
G2 is too low and the cathode voltage is a bit too high. That would explain your low brightness.
I note there are some resistors circled on the circuit. These resistors going high were (back in the day) the usual cause of low G2 voltage and hence low brightness. You need to use at least 1W parts there because of the voltage across the resistors - they need to be physically large. 1.5w metal film is a good choice. Carbon film resistors would often fail in that position.
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Location: Mile End, SA
Member since 23 February 2014
Member #: 1512
Postcount: 24
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Thanks Ian - I was contemplating what you've suggested, and will now give it a go. Not sure which resistors you're referring to, but was planning to replace the high rated ones in the horizontal as a start. Any further suggestions?
Cheers, Alan.
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Location: Mile End, SA
Member since 23 February 2014
Member #: 1512
Postcount: 24
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PS - I have a few 1S2s, but thanks anyway!
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Location: Belrose, NSW
Member since 31 December 2015
Member #: 1844
Postcount: 2363
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PLEASE don't use the shotgun approach, i.e. don't go replacing everything. You are more likely to get yourself into more trouble.
If you chase the wire back from G2 on the CRT (using continuity test on your meter) you will find the resistors I'm talking about.
The circuit in this post has the suspect resistors circled in black ink. I can't quite read their values, you have the original and have a better chance.
Note also the same circuit has the G2 voltage on the CRT socket shown as 420V. Yours is much lower than that, it's no wonder the pic is so dark.
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