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Old 8th April 2015, 07:39 PM   #1
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Default What is this discreate component?

Ever seen this schematic before? I tried to get an answers from several suppliers before and came up with nothing. K25 25ohms comes up as a thyristor, a jfet, a potentiometer with a resistor on the wiper, etc. any body know? I've got bags of NOS germanium that I can use but several of the good schematics have k25, k125 and other that I cannot cross.
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Old 8th April 2015, 08:03 PM   #2
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I would imagine it's a specific type of thermistor, used for controlling the bias.

But it's a really crap antique germanium design, why on earth would you be building one?.

In my experience of repairing old amplifiers, ones which use specific thermistors or bias diodes, they MUST be replaced with the exact original type, or it never ends well!.
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Old 8th April 2015, 08:04 PM   #3
M8e is offline M8e  Sweden
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Looks like a rheostat used as an normal resistor?
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Old 8th April 2015, 08:27 PM   #4
Elvee is offline Elvee  Belgium
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Quote:
Originally Posted by Carl the camera View Post
Ever seen this schematic before? I tried to get an answers from several suppliers before and came up with nothing. K25 25ohms comes up as a thyristor, a jfet, a potentiometer with a resistor on the wiper, etc. any body know? I've got bags of NOS germanium that I can use but several of the good schematics have k25, k125 and other that I cannot cross.
Typically something like that (from Valvo/Mullard/RTC/Philips/MBLE/Elcoma, but other big ones also had their version):
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File Type: jpg NTC2.jpg (281.1 KB, 259 views)
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Old 9th April 2015, 04:26 PM   #5
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Let us keep this thread going. Anyone got any other oddball stuff?
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Old 13th April 2015, 03:44 PM   #6
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This is a puzzler! An ECG84: I tried all internet searches and even got Glen Masline to look it up in his library and he was surprised to come up with Zitch. Masline Electronics - Electronic Component Distributor
I mean Glen's family been in business since Raytheon was making television sets. it has six legs; three by three, a black epoxy top circular with a flat like on an LED. Little help?
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Old 13th April 2015, 05:21 PM   #7
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Default ECG84 Specs

According to my ECG Replacement Guide ECG212P (1987), it's description in the front of the book says : T-PNP, Si, Dual Gen Purp Amp - Discontinued . Figure T13 , both top and bottom rows of wires are the same , E C B No more specs are listed inside the book
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Old 13th April 2015, 06:50 PM   #8
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Wow Michael you got it going on!!! So it could be wired into a darlington function?
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Old 13th April 2015, 07:06 PM   #9
poynton is offline poynton  United Kingdom
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It was replaced with NTE84 when NTE took over Sylvana


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Old 16th April 2015, 01:58 AM   #10
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anybody got a spec sheet?
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