K7100 complete vertical collapse - anything else to check?

rmcelwee

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K7100 complete vertical collapse - anything else to check?

Spent all day researching and working on this thing:

27V on IC3 pin #6
Swapped out IC2 and IC3
C22, C50 are good
R80, 81, 82, 83, 91, 101 are good
D13, D25 are good
Q7 is good
Continuity from IC2 to Y and G vertical coil pins
Swapped out remote control board
Tried another tube/yoke
Cap kit installed a month ago
C51 reads .6uf with ESR of 5.3ohms. Mentioning this because I don't know what is an acceptable ESR on a tantalum cap.

The monitor was fine for months but went south when cabinet was moved to a friends house. Anything else to check?

zombie31.jpg
 
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the yoke header. I sound like a broken record but I had one that just so happened to have some traces and solder pads not together anymore. you'd never notice if you're not good at identifying that sort of thing. :) if you want the thing like fort knox so it never breaks again, just open the traces to the yoke and lay down some thick wire on the pins and attach it to the traces.

I did a K7000 last night and forgot to reflow the yoke header. one glance I was like "eh, it looks ok". then I looked closer at one of the horizontal pins and it was pretty cracked.

I took it back to the bench and did it properly.
 
check your vertical ic and make sure you have continuity from pin 5 and the ground tab on it. if you do than check for cracks in traces on main and neck pcb or cold solder joints.
 
the flyback outputs 24V (or was it 27?) to power the vertical IC. it runs along the large heatsink wall. if you pull up the K7000 schematic and trace backwards from the source voltage for the vertical IC you will see all the various resistors and diodes in that circuit that could potentially fail. with this information you will know how to test that the supply voltage for the vertical IC is even getting there. if it's missing, you will have to check that circuit. if it's present, then you most likely have a bad vertical IC.
 
the flyback outputs 24V (or was it 27?) to power the vertical IC. it runs along the large heatsink wall. if you pull up the K7000 schematic and trace backwards from the source voltage for the vertical IC you will see all the various resistors and diodes in that circuit that could potentially fail. with this information you will know how to test that the supply voltage for the vertical IC is even getting there. if it's missing, you will have to check that circuit. if it's present, then you most likely have a bad vertical IC.

I checked the power (list above indicates that it was +27V vs the +24V that everyone says it should be). I swapped out the IC with another that I pulled off a chassis some time ago that was having problems but ended up not being the IC. So, it wasn't a new IC but it should have been good. I might take another look and swap it with another. Thanks!
 
check your vertical ic and make sure you have continuity from pin 5 and the ground tab on it. if you do than check for cracks in traces on main and neck pcb or cold solder joints.

No, I do not have continuity from 5 to ground. I see it goes through C66 on the way to ground. Pin5 has continuity to one leg on the cap and the other leg has continuity to ground. I had a K7000 schematic that I was looking at and noticed that Pin5 goes straight to ground on that but does not on the K7100. Not sure what this means.

EDIT - C66 tests fine (0.001 uF).


OH, follow up question. A few people told me to check the neckboard. I was under the belief that the neckboard was only for color. If I am getting a white line on the screen does that not mean all neckboard stuff is working?
 
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NO, I do NOT have continuity from 5 to ground. I see it goes through C66 on the way to ground. I will replace/test C66 and see what happens.

EDIT - C66 tests fine (0.001 uF). I don't understand what this means.

the IC is no good so try flipping the IC chip 180 degrees and see if it works..... i have a feeling i know what is going on. let me know if it works when flipped.
 
the IC is no good so try flipping the IC chip 180 degrees and see if it works..... i have a feeling i know what is going on. let me know if it works when flipped.

I flipped the chip. Still had vert collapse but the line was now wiggling around a bit. I thought I heard something pop and thought I saw a small puff of smoke from that area BUT I was smoking a cigar at the time so I am not sure. I do smell magic smoke around that area of the board.
 
I flipped the chip. Still had vert collapse but the line was now wiggling around a bit. I thought I heard something pop and thought I saw a small puff of smoke from that area BUT I was smoking a cigar at the time so I am not sure. I do smell magic smoke around that area of the board.

i have heard of alot of them that either are remarked (fakes) or the pinout i have read almost seems like its reversed. i have not had the time or found any for sure to test my theory on so its only a theory.

i would replace the IC before going any further because i would bet its bad.
 
check your vertical ic and make sure you have continuity from pin 5 and the ground tab on it. if you do than check for cracks in traces on main and neck pcb or cold solder joints.

Just checking, we were talking about IC3, correct? I was checking IC3 from pin5 to ground on the chassis. Not pin5 and the metal on the back of the transistor. Did I just screw up?
 
i have heard of alot of them that either are remarked (fakes) or the pinout i have read almost seems like its reversed. i have not had the time or found any for sure to test my theory on so its only a theory.

i would replace the IC before going any further because i would bet its bad.

I just looked and the chip was acting just like another K7100 I had sitting there. No continuity from pin5 to any other pins. Again, I am talking about IC3.
 
I just looked and the chip was acting just like another K7100 I had sitting there. No continuity from pin5 to any other pins. Again, I am talking about IC3.

i am sorry, ignore me i am working on too many conversations at once. i would replace the IC3 (UPC1378) with a known working one just to make sure.
 
sub out the vertical IC.

make sure the vertical size pot is NOT broken, give it the wiggle test to see.
be easy as you can break it with to much force.

look again for broken traces in and around the vertical IC, they can be tricky to find in that area.

if/when your ready to hit with a sledge, your welcome to send it in for repair.

Peace
Buffett
 
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