modessitt
Volunteer: Encyclopedia Submission Moderator
There are a couple big resistors there near D13 and D14. Are they smoking or getting hot? I had one where D13 measured good but was bad.
Are you still blowing fuses?
K7000 Blowing Fuses :(
- Thread starter zenomorp
- Start date
There are a couple big resistors there near D13 and D14. Are they smoking or getting hot? I had one where D13 measured good but was bad.
Are you still blowing fuses?
racer2e
Member
Well of course my local frys is out of that. Would a 577 or something else work?
Jayme
Jayme
OP
OP
No. Fuses do not blow anymore. Now I have no high voltage. There is only 68VAC at the output of the fuse holder. Nothing at pin 4 of IC4 and nothing at Pin 3 of P202 on the neckboard. I'll check the resistors and replace D13 and D14 just to see what happens. Also, thanks for filling me in about the VR. I have replaced it and double checked it (across pins 1 and 4) and it checks good.
modessitt
Volunteer: Encyclopedia Submission Moderator
Check C36 and make sure that it is actually a 6.1pf capacitor. I recently found a couple that had 4.7pf capacitors there, and that was what was keeping it in HV shutdown....
modessitt
Volunteer: Encyclopedia Submission Moderator
OP
OP
It's 2 separate caps. Not 1. They are blue. Here is a pic..
One of them says .0061G. (C36) The other ones says .0036I (C69) When removed from the circuit, they both read open.
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modessitt
Volunteer: Encyclopedia Submission Moderator
Well, they would read open for a resistance test. You'd need to do a capacitance test to see if they are okay.
I'm not sure if this is your problem or not. Did you replace any of them? If the value of C36 is off by too much, it can keep the chassis from working. the manual lists it as a 6.1pf (.0061).
YOU MAY NOT NEED TO DO THIS!!
if you want to try something, I'd try removing the .0036 cap and adapting it to work with only the .0061 cap, as that is the size the chassis is supposed to work with - and is listed in the manual. You'll need to tie the .0061 cap legs into BOTH holes on each side. If you check these instructions from Bob Roberts, he tells you how to use one two-legged cap where a normal 4-legged or two 2-legged caps are:
http://therealbobroberts.net/csc.html
I'm not sure if this is your problem or not. Did you replace any of them? If the value of C36 is off by too much, it can keep the chassis from working. the manual lists it as a 6.1pf (.0061).
YOU MAY NOT NEED TO DO THIS!!
if you want to try something, I'd try removing the .0036 cap and adapting it to work with only the .0061 cap, as that is the size the chassis is supposed to work with - and is listed in the manual. You'll need to tie the .0061 cap legs into BOTH holes on each side. If you check these instructions from Bob Roberts, he tells you how to use one two-legged cap where a normal 4-legged or two 2-legged caps are:
http://therealbobroberts.net/csc.html
OP
OP
My setup is different. I don't think I can do the mod. Check out the pic below of my setup vs. Bob's...Do you think T2 might be bad?
modessitt
Volunteer: Encyclopedia Submission Moderator
Yeah, that's why I said I wasn't sure. If you pull one end of D10 out, will the monitor work? What's your B+ at right now?
OP
OP
Couldn't tell you. Pulling one leg of D10 out does not make the monitor operate. Also, The big ceramic resistor on the side of the chassis frame (R301?), within 15-20 seconds upon power activation, gets so hot, I can smell it burning. It still reads good after it cools down to room temp (176 ohms). R103 gets hot as well. Not as hot as R301, but still hot to the touch. Still only have 68VAC coming off the fuse. I am about to just give up. This is all caused by something stupid in the first place, not having the chassis secured to the monitor frame while working on it, but the neck was covering the Horizontal Width Coil, and I had to remove the chassis to adjust it. While it as out, I bumped it and the red wire of R301 touched the monitor frame and caused this whole ball of wax rolling.
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OP
OP
Legs 3 and 4 of T2 are shorted to each other. Is that how it's supposed to be?
modessitt
Volunteer: Encyclopedia Submission Moderator
Have you not downloaded the schematic yet? Page 12 shows that pins 3 & 4 of T2 are connecting internally....
OP
OP
Ah. Which schematic? Is there a better flow chart out there besides the one on Wells' site.
modessitt
Volunteer: Encyclopedia Submission Moderator
http://arcarc.xmission.com/PDF_Monitors/Wells Gardner K7000 Manual.pdf
Try this:
http://www.2coinsperplay.com/Tech/Monitors/K7000 HTML/K7000.htm
There are some log files linked at the bottom, too...
OP
OP
Thanks. I removed R103 from the circuit and it read 01.1 ohm. That's a short in my book. It's supposed to read 2.7 ohms. It reads 3.1 in the circuit, but 01.1 out of the circuit. I'll replace it and see what happens.
OP
OP
Nope. No difference.
KenLayton
In Memoriam
I just went through a big problem on a Wells 19k7635 (medium resolution k 7000) that was blowing fuses. Let me fill everyone in on what happened.
Game came into the shop with a blown flyback (hole in the side arcing to the metal frame). I had recapped it a few months ago so it did not need any capacitors. Anyway, checked the horizontal output transistor and it was ok. Next thing I did was replace the bad flyback with a brand new one. Re-installed chassis and powered it up. High voltage was very low, only 8000 volts. Pulled chassis back out. Found capacitor C38 was cracked. Replaced it and re-installed chassis. Powered up and fuse blew immediately. Ok, I pulled chassis out again to start unsoldering things and checked for a shorted component. Could not find anything shorted!
So after much hair pulling and cussing, I decided to grab the other spare brand new k7000 flyback and try it. BINGO! Monitor came up and worked perfectly. High voltage was right on the money and picture looks beautiful.
Moral of the story is that I had a bad brand new flyback right out of the box. It pays to keep a couple of extras around.
Of course if I had the money, I could have used a flyback tester which would have saved a lot of time. But I don't have the money to buy one.
Game came into the shop with a blown flyback (hole in the side arcing to the metal frame). I had recapped it a few months ago so it did not need any capacitors. Anyway, checked the horizontal output transistor and it was ok. Next thing I did was replace the bad flyback with a brand new one. Re-installed chassis and powered it up. High voltage was very low, only 8000 volts. Pulled chassis back out. Found capacitor C38 was cracked. Replaced it and re-installed chassis. Powered up and fuse blew immediately. Ok, I pulled chassis out again to start unsoldering things and checked for a shorted component. Could not find anything shorted!
So after much hair pulling and cussing, I decided to grab the other spare brand new k7000 flyback and try it. BINGO! Monitor came up and worked perfectly. High voltage was right on the money and picture looks beautiful.
Moral of the story is that I had a bad brand new flyback right out of the box. It pays to keep a couple of extras around.
Of course if I had the money, I could have used a flyback tester which would have saved a lot of time. But I don't have the money to buy one.
OP
OP
Good info Ken. Unfortunately, the flyback was one of the first things I replaced. I installed a known good one. Still nothing.
KenLayton
In Memoriam
The high voltage shutdown trimpot is also known to go bad internally.
OP
OP
lol, yup. Replaced that already too. I think there has to be a component shorted that's not normally looked at or maybe one of the other ICs. I already changed IC2.
