#61
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I am curious about a few things.
1. where and how are you measuring the regulator current? 2 what is the actual B+Boost voltage? Should be ~1000 - 1200volts if I recall correctly. 3. Have you checked the screen grid resistors in the Horizontal output tube. I think there is a 47 ohm and 13K ohm that if they drift high at voltage cause low High voltage. One thing that bothers me is that all the controls seem to have to be at one end of their range. This indicates a voltage problem in the B+ or Boost voltage. Possibly not enough drive from the horizontal output stage. 4. Have you checked for leaky caps in the horizontal yoke windings? The 1.5 meg resistors in the regulator circuit are a matched pair. I would not change them to different values. Since they are 20% they are not out of spec. The key is they should be the same value. Yours are about 7% high, but they are very close to the same value. |
#62
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Enter ye the 10th circle of hell,
Timmy CTC-12 clone HV regulation. |
#63
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Sams can have mistakes, bounce the schematic against an RCA one?
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Evolution... |
#64
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Quote:
Last edited by timmy; 01-14-2015 at 10:32 AM. |
#65
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Quote:
Last edited by timmy; 01-14-2015 at 10:18 AM. |
Audiokarma |
#66
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Hey, Had a black-out for a few hours this morning... Someone took their pickup a few
quarts of alcohol and went out to get some wood........ Now we got 2 phone poles on this street cut in half and hangin in the air.... Bill is right about the H-output tube screen voltages, I'm not sure but I think we went over it before on another thread.... But you better check, the 47ohm, and 13K resistor off pin 4-8 of 6dq5 also suppose to be around 145V there.... My schematic don't have the number, but off the cathode of the damper tube somewhere should be a test point for B+ Boost, and it should be around 1KV like bill said... Check your Sams it may have a test point and a number.... 1Kv ~ 1200V ?? Also, since you said you are not a tech, I want to be sure you are aware B+, and B+ Boost are two different things.... B+ Boost does not come off the power supply section of the tv, it is part of the voltage from the horiz. output section of the tv..... Generated off the Damper tube.... They may have a point where they show a test spot, and a Voltage number, so use their test point.... Did you check or replace the caps on the yoke... C 105 ?? Good one to look at.... .
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Yes you can call me "Squirrel boy" Last edited by Username1; 01-14-2015 at 11:26 AM. |
#67
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Quote:
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#68
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those 2 resistors are 100 ohm and a 47 ohm at the hot , i think i replaced the 100 ohm after getting the set and recapping as i went over this and found that resistor drifted very little and probably didnt even have to change it. just checked the sams it shows pin 2-7 385 volts pin 9 is the one with the hv and it says do not measure. im showing only a 720 v boost source but that dont tell it all.
Last edited by timmy; 01-14-2015 at 12:23 PM. |
#69
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This pic shows B+ Boost, where it's made, but not necessarily where
to measure it..... And the screen grid resistors. .
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Yes you can call me "Squirrel boy" |
#70
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ok yes i have the same here but this sams is alittle different by the numbers your 3 is my 9 but same location. ok the 13k 7 watt i probably checked that one already but i will again. so now ill have to find out where to test this boost voltage because i believe i hit that spot already by accident and burned another fluke dvom out so i dont want to do that again.
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Audiokarma |
#71
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NO - be careful, there are very high voltage spikes there ! !
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Yes you can call me "Squirrel boy" |
#72
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my mistake there is no c105 in the yoke the sams i have dont show it nor does the rca schematic but shows it in the color board as a disc cap. the yoke appears to have c 123 caps
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#73
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horz pos pot wired right, not open?
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#74
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horiz pot new and wired, came with the fly.
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#75
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I don't know for sure on your set, but on CTC-15 clones I have the boost supplies the high voltage side of the CRT screen/G2 potentiometers, and IIRC the vertical linearity control pot.
On my Silvertone CTC-15 clone there was an SS boost diode that was bad when I repaired my set. Your set may be the same or different so take this with a grain of salt.
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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 |
Audiokarma |
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