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Most likely would be either R13 on the input side, or R35 on the output side.Would it be correct to say that the only trace left is the output of the contrast red pin on ic1
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duncan campbell scott poems
scopes are out of my skill range and not in my tool box. I'm usually really good troubleshooting these k7000s.Can you see the issue with an o-scope? Choose a pattern screen that's white so all the signals should be the same and do a little bit of comparison testing. Use a 2 channel scope..
Also R30, 31, and 32?darn. Checked r13, r33, r34, and r35. All were reading properly. I replaced c1, c,2, c3, and c7 and q4 even though they read good. Still have the bleeding red. I think I covered the red circuit . I could replace all the green chicklet caps like mecha suggested from a donor chassis.
Ahh. I'll check the voltages late tonight to compare to the manuals voltages. I forgot to do this. I'll check r30-32 tonight as well if I haven't already.Also R30, 31, and 32?
How do the IC1 voltages compare with those listed in the manual? Use gray pattern to test so color signals are (should be) balanced.


The RGB inputs (pins 2, 4, and 6) are all high.ok here are the voltages at input and ouput legs of ic1. The video red input voltage is high like we would expect it be. 3.33 and the manual calls for 2 volts. The contrast video output pins are higher than what the manual calls for as well. Red is the highest at 3.5 and the blue and red are at around 3 volts. The manual states 1.7 R30-32 are all reading as they should.
pin 1. 3.076
pin 2. 3.3
pin 3. 2.78
pin 4. 2.68
pin 5. 2.78
pin 6. 2.69
pin 7. 2.78
pin 8. 2.78
pin 9. 1.42
pin 10.10.5
pin 11. 8.13
pin 12. 0
pin 13. .704
Pin 14. 3.74
pin 15. 11.35
pin 16. 13.03
pin 17. 2.97
pin 18. 3.0
pin 19. 3.01
pin 20. 3.1
pin 21. 3.5
pin 22. 0
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Next time I put this chassis on the bench I will get those readings. Thanks RichardHow do the voltages on the input transistors (Q1, 2, and 3) compare to the manual?
Normal would be OL (overload, or out of range, or open circuit). I just checked one that I have on the bench and reverse polarity reads OL on all 3 of those diodes.There are no mods on the bottom of the board. I went ahead and replaced every green "chiclet" capacitor on there. I replaced D5 and d6 and D7. D5 still reads differently than d6 and d7. So far that's the only thing I've been able to find that reads incorrectly in the red circuit. D5 reads like a normal diode but when I switch the leads I get an ol reading which is different than a 100% working chassis and different than d6 and d7. It's supposed to give me about a 1.9 reading when I switch the leads.
That's odd. Here's another working chassis and I get the 1.9 reading on reverse polarity on all 3 diodes. I get the OL reading on d5 of the "red overdriven problem chassis".Normal would be OL (overload, or out of range, or open circuit). I just checked one that I have on the bench and reverse polarity reads OL on all 3 of those diodes.

Interesting. I used a Beckman 310. I'll try to retest with a Fluke if I get the chance in the next couple of weeks. I really doubt that the diodes are your problem. Hve you been able to check the voltages on the color input transistors?That's odd. Here's another working chassis and I get the 1.9 reading on reverse polarity on all 3 diodes. I get the OL reading on d5 of the "red overdriven problem chassis".
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I'll have some me time tonight to get this one back on the bench. I guess the point I was trying to make is that the only anomaly I have found in the red circuit shows up in the d5 diode which is in indicator that I have missed the faulty component that is effecting the reading of that diode.Interesting. I used a Beckman 310. I'll try to retest with a Fluke if I get the chance in the next couple of weeks. I really doubt that the diodes are your problem. Hve you been able to check the voltages on the color input transistors?
Replacing the vertical IC fixed mine.I have the same issue but I caused mine. I accidentally connected the chassis neckboard wire back to the chassis instead of the neckboard. You know the white and blue wires? Yeah I'm an idiot. I blew r30 on the chassis. Now the red is gone unless I overdrive it. I fixed my r30and ic1. Now I'm replacing all caps from a donor chassis trying to find what else I blew.