K7000 HV shutdown?

sundodger

New member
Joined
Aug 6, 2009
Messages
51
Reaction score
0
Location
Balla, Mayo, Ireland
Have a K7000 with what looks like HV shutdown, IC4 pins 1 and 4 are open (beep test) and i get 163v at R301. have replaced R213 which was bad has a new cap kit flyback and hot and was working till recently.
Have removed D10 (as per randy fromm flowchart) screen static no picture. before i go ordering parts what should i also check to make sure i dont blow another IC4.
New to this so go easy on me ;)
Thanks Mark...
 
Last edited:
okay while waiting for a VR and IC2 from Bob. i was checking diodes looks like D13 and 14 are bad. they test different to D15,16 and 17 which are the same part according to the parts list.
Is this part of the cause of my woes or a victim of the over voltage?
I will need to get the diodes locally (50 miles away) from maplin but being a newbie could do with some help.
which of the diodes at this link are the ones i need.
http://www.maplin.co.uk/Search.aspx?criteria=diode&source=15
Thanks Mark..
 
Last edited:
Is this a 19" or 25" ?

163v at R301 on either end is too high.
Were you measuring the input (pin 1 of IC4) or the output (pin 4 of IC4) ?

If you suspect a shorted or open diode double check them with at least one leg pulled from the board.

Is your H.O.T. insulated properly from the heatsink ?
Also check that it didn't short out.
 
its a 19"
Measured voltage at R301 only, it is all in the game cab and could only access the bottom (blue lead) of R301.
Hot is insulated and seems to check ok. have the old one as a back up as it was all ok before the orginal work.
will check the diodes off the board just in case and report back.
Just to clarify the cap kit fly and hot were done before this problem and the monitor was fine bar weak red.
Thanks Mark..
 
changed voltage regulator and it was blowing fuses, HOT had gone bad. had the old HOT and it stopped blowing fuses.
voltages at R301 now read 162 and 118.5 so still not right?
What should i check next?
 
R102 at 2.8 so Good. D18 seems good. C36 good. Looks like C38 open however.
any advice on a source of parts that will ship international as local sourcing a no go.
 
Last edited:
Do you have a four-legged C36? If so, is it bright green or dark green? I had a chassis that had the bright-green version. I pulled it and found that it was not a 6100pf cap like it was supposed to be, but was in fact a 4600pf cap (or close). Replaced it with a 6100pf like it was supposed to be and it worked...
 
Yep have the four legged version, the green is nearly the same shade as the print dor the trace component side.
It has 1600 612 H
DT SA X
Marked on it.
Things i have noticed since last post R101 gets very hot (normal?)
tested voltage at D1 4 and 4.11
D2 4 and 4.57
D3 10.05 and 5.41
D4 10.97 and 5.39
D5 9.82 and .78
D6 9.78 and .78
D7 9.84 and .84
D8 2.38 and .52
D9 10.97 and 7.46
D11 2.39 and 0
tested these as they were easy to get at.
voltages not as per K700 manual but other than that i dont know what they mean. Do they give someone an idea as to where to point me next.
Thanks Mark.
 
Well things are going backwards. Decided to have another poke around and no static on power being applied to monitor. Checked voltage and i now have 202v going to the monitor.
Transformer gone so need a soiurce for replacement (220/240v)
have i done further damage to chassis by applying this voltage?
Thanks Mark...
 
if memory serves it was around 135v no load before. need to go back to basics now. get correct voltage to monitor and troubleshhot from there.
 
If you've got a 1:1 transformer in there, then the voltage in should be equal to the voltage out. Since you're in Europe, 220 is the norm there, correct?

But you're absolutely correct about getting back to basics; start at the beginning and work your way forward.

Often things will have different voltage output under load then without one - whether this is the case for a transformer, I'm not sure.
 
it was originally a US machine. The transformer looks like it acted as both power and isolation originally. It was worked on prior to my purchase changed to 220/240v and now has an ATX supply for all the low voltage stuff and the transformer was left for monitor and the marquee.
Looking at the original power supply schematic taps 12 and 13 are for the monitor (which they are) but not at 202v ;)
 
K7000 issues

I was having very similar problems with a WG K7401 25 inch

I almost went to hammer after the 8 beers I had didn't work. Then I just bought a new complete chassis installed it on the tube and I was done. It works just great now.Yea I paid like $100.00 for new chassis but the 6 hrs of checking the dam parts. Well worth it.

Sometimes you gotta pay
 
Are you POSITIVE you're going into HV shutdown? You said you were getting 118 at the resistor on the side, that's almost in spec. It's supposed to be 123, and like math class taught us 118 is low voltage when it's supposed to be 123.

Do you have neck glow? A quick way you can tell if the hot is bad or the diodes are bad is that it'll blow the fuse if they are, lol.
 
Back
Top Bottom