#46
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Another technique if you don't want a big power resistor dumping heat under your chassis is to put multiple Silicon diodes in series. I've read that selenium rectifiers drop around 1V per plate( and are effectively a stack of lower rated selenium PN junctions). Silicon drops .7V per plate.
If you are working on a very power hungry set like the nearly 40 tube CT-100 make sure to use 2.5A diodes or make sure there is at least 2-3 component body's worth of lead separating each diode to allow for heat disapation.
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Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#47
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Quote:
I was experimenting with deleting one of the 25 ohm 10 watt dropping resistors because Pin 8 on both the 6X5GT and the 25Z6GT were reading a bit low. My Variac turns out to be a bit over enthusiastic on indicated output. I took one out, leaving one and the factory 18 ohm 2 watt carbon resistor. After doing some power checks the remaining 25 ohm 10 watt resistor (an old wire wound) opened up and killed the power. After that, I took it and the 18 watt carbon 2 watt out and subbed a single hollow core green wire wound rated at 40 ohms and 25 watts. Pin 8 readings are spot-on and stable now. And I like having one large ww doing the job. Neater, too. Last edited by M3-SRT8; 06-27-2019 at 04:13 PM. |
#48
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Just about ready to load the chassis in the cabinet, but I have two minor problems.
1. Horizontal Position Control, when turned fully clockwise, still leaves about a half inch black bar on the right side of the mask. The Pot tests ok. Is there a resistor I can add to it to increase it's reach? 2. Slight Horizontal Linearity issue. I don't recall any pot to adjust it, and all the high meg 2 watt resistors in the sweep circuits were replaced with much closer tolerances than stock. Thanks... |
#49
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There's a couple of Horizontal Deflection Load 2 Watt 4.7 Meg resistors. R88 and R90. Sams 91-6.
Should I go up or down on one/both of these resistors to increase reach? |
#50
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It appears my set doesn't have, or never had, a Horizontal Linearity Adjustment, labeled B2 per Sams, under V17 12SN7GT.
What now, pray tell? |
Audiokarma |
#51
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Hey...where is everybody?
I thought you guys were smart... |
#52
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THEY Are. I, OTOH.....Ain't...
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Benevolent Despot |
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