Another K7000 blowing fuse thread

Torin

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So, I recently capped it and put a new flyback and HOT and it has been working great. I then recently put in a new PCB in the cab and the picture was upside down. I took the chassis out to swap the yoke wires, put it back in and now the fuse is blowing. I replaced the fuse and it blew again. I don't know if this would cause the blown fuse but the anode clip plate on the new flyback fell off. As a result the anode clip became loose and fell off completely. I am planning on soldering it back on when I can get back to working on it.

Would the loose anode clip cause the fuse to blow?

I know that I didn't swap the wrong yoke wires as I was very careful not to swap the wrong one's.

What else could have caused this and where should I start looking? Any help is much appreciated.

Torin
 
I dont think swithching the yoke wires would do this but swap them back and see what happens, blue and red reversed and green and yellow.
 
try what paul has suggested and if it does not work then you will have to start checking the usual suspects.

H.O.T. , VR, C36-38-39- 69 if there.
D16-23.

it could be something simple.

Peace
Buffett
 
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shorted regulator, polyprop cap(s), shorted diode in bridge rec section, shorted hot or shorted flyback winding.. if you hit a dead end and dont want to deal with it send it in for $100 shipped repair, reconditioned & running the way it should if you already have caps and flyback in.. otherwise $140.00 for the full service.. thanks and good luck!
Chad.
 
7000 chassis

Did you cut the yoke plug in the middle and just turn the two individual plugs 180 degrees?
If not i bet you did something wrong and took out the chassis, otherwise check your hot,caps around it.
 
Did you cut the yoke plug in the middle and just turn the two individual plugs 180 degrees?
If not i bet you did something wrong and took out the chassis, otherwise check your hot,caps around it.

Yes, I cut the yoke plug and just turned each one around keeping green and yellow together and blue and red together on the right pins for both.
 
I am having the exact same problem. What's the easy way with a DMM to tell if one of these poly caps is bad? For instance, my DMM has a cap test, so if I test C36, my meter stars of at about 06.80 and slowly creeps to around 07.80n F. The markings on the cap are F.0061I. Is this within spec or is it going to high. Don't mean to highjack but is there really need for "Another K7000 fuse blowing thread" :)
 
I am having the exact same problem. What's the easy way with a DMM to tell if one of these poly caps is bad? For instance, my DMM has a cap test, so if I test C36, my meter stars of at about 06.80 and slowly creeps to around 07.80n F. The markings on the cap are F.0061I. Is this within spec or is it going to high. Don't mean to highjack but is there really need for "Another K7000 fuse blowing thread" :)

Hijack away. I've taken a break from my k7000 but also need to know what you are asking so I can get back to mine. Not sure about how to measure a poly cap. I have an esr but don't know if they are the same as regular caps.
 
Hijack away. I've taken a break from my k7000 but also need to know what you are asking so I can get back to mine. Not sure about how to measure a poly cap. I have an esr but don't know if they are the same as regular caps.

You are looking for shorted poly caps. Put the meter on continuity setting and put one probe on each lead of the cap. If you get a tone then the cap is shorted.
 
test in circuit.
if it shows shorted pull it and test again.

you can test them with a capacitance meter if you have a good fluke. or a stand alone meter.

Peace
Buffett
 
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Hijack away. I've taken a break from my k7000 but also need to know what you are asking so I can get back to mine. Not sure about how to measure a poly cap. I have an esr but don't know if they are the same as regular caps.

Here's the way mine stands, this monitor was given to me. I powered it up and it had image, but a lot of green. I noticed a small arc coming from the small metal rod on the top of the flyback going to the metal brace above. I ordered a capkit, flyback, HOT, and a VR. And replaced. Just to be clear, I did replace the insulators on the HOT and VR. Still had a lot of green, so I powered down to check some stuff on the neckboard and powered back up, and POP. That's where I am now. Just did a continuity check on C36 and non. Good?
D16-17-18-19-20-21-22 all check good
C36 and 38 check good. I could not find C69, where would it be if it has one?
R103 checks good.
I also checked for continuity between the black and white power just to make sure there was not a short in there. Was OK
 
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Well, I think I found my problem, even though it's a new HOT, I pulled it out and tested. Can someone confirm it's bad. In diode mode, E and C is passing current one way - It shouldn't in any direction?
Also, passing current both directions between E and B. This was a brand new HOT right from Bob, so even though something is new, it can still be bad. A lesson to be learned if this is actually bad.
I think I may be doing this wrong, I have 3 D1398's that are all testing the same.
 
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Using the diode test, black leg to the middle, red leg to each side. Note what you see.

Then reverse the leads. If any of those legs give you a reading forward and backward, it's bad.

Repeat that for the outer legs.

You should also be able to use the Ohms setting to see if it's shorted internally.
 
Using the diode test, black leg to the middle, red leg to each side. Note what you see.

Then reverse the leads. If any of those legs give you a reading forward and backward, it's bad.

Repeat that for the outer legs.

You should also be able to use the Ohms setting to see if it's shorted internally.

Black to middle, red to each side = readings both ways
Red to middle, black to each side = no readings

So this is a good HOT?
Sometimes google and youtube aren't that shithot

I just noticed something as I was putting the HOT back in. I don't know if it was doing this before or could cause this fuse blowing problem, but the middle leg of the HOT was bent back far enough that it was hitting the heat sink which is connected to the frame. Possibility?
 
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I just noticed something as I was putting the HOT back in. I don't know if it was doing this before or could cause this fuse blowing problem, but the middle leg of the HOT was bent back far enough that it was hitting the heat sink which is connected to the frame. Possibility?

not good that will pop a H.O.T. when you fire up the chassis.
this negates using the insulator for the H.O.T. and grounds it out.

correct black lead to center and red to both outside legs you should see the voltage drop thru the diodes.

red lead on center and black to both outside legs you should not see any reading.

Peace
Buffett
 
not good that will pop a H.O.T. when you fire up the chassis.
this negates using the insulator for the H.O.T. and grounds it out.

correct black lead to center and red to both outside legs you should see the voltage drop thru the diodes.

red lead on center and black to both outside legs you should not see any reading.

Peace
Buffett

You can test the HOT without removing it. Conitnuity test---black lead to frame, red lead to middle leg. Continuity = bad.
 
Alright, with the hot out of the monitor, check it like Buffet said so you'll know if it's now shorted too.

One by one, remove parts and test them to see if they're shorted... so for instance, remove the large cap just behind where the hot goes (the safety cap, C38 I believe?) and see it's shorted together from one end to the other. While you do this, check again to see if the middle pad of the HOT is connected to the frame still. One by one remove and then replace the parts behind the HOT until you find the shorted one. When you remove it, it'll test shorted and the board will finally NOT test shorted. there may be more than 1 shorted now though... basically when one piece shorts, it throws both sides of the voltage into each other until something or the fuse or both burns up!
 
One by one, remove parts and test them to see if they're shorted... so for instance, remove the large cap just behind where the hot goes (the safety cap, C38 I believe?) and see it's shorted together from one end to the other. While you do this, check again to see if the middle pad of the HOT is connected to the frame still. One by one remove and then replace the parts behind the HOT until you find the shorted one. When you remove it, it'll test shorted and the board will finally NOT test shorted. there may be more than 1 shorted now though... basically when one piece shorts, it throws both sides of the voltage into each other until something or the fuse or both burns up!

all good points to follow.

if you have re-flowed the chassis you will need to un-solder pads that are close together to see if you have a set of bridged pads.

i fixed a K7000 chassis for a fellow klover that, that happened too.
he did a good job of re-flowing the chassis but a little too good on two pads in the horizontal section. and as a result C38 was shorted across itself in circuit even tho the poly cap tested good out of circuit.

Peace
Buffett
 
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