WG k7000 vertical Collapse???

JJ

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This is a 19" K7000 p448 board that had just a horizontal line across it ( horizontal tube line acros the longest part of it). had a new flyback gave a new cap kit double checked everthing still there just brighter, sharper with more color... Bob had sugested the vertical out and not follow the schematic to eyball it.. only issue is I'm not even totally sure what I'm looking for. any suggestions?
thanks,
JJ
 
Cold solder joints at the yoke header pins on the main board.

Bad vertical output IC. You must replace it with like-for-like number of what's in it now.
 
I'll double check the joints this morning, IC 3 seems to be the vertical so I'll see what I can figure with it. thanks Ken!!
 
Well changed the IC3 (upc1378H) with no change I've resoldered about 40% of the board. only odd thing so far is the blue wire on the vertical circut leading to the front of the board had a resistor tied in to the vertical hold, not unusual but the resistor looks like its from the 60's the bands call for 680 ohms +/- 5% I have no idea what wattage it should be at, but it measures at 703ohms ..
while at the Electrical store today I did learn something though; the solder on this board acts odd when melting it, which the guy said it's probably lead free solder and to watch out for dendrite, as there is some tanis caking around a few of the solder joints.
heres what I looked up on his advise;
http://www.emtworldwide.com/article.aspx?ArticleID=8504
http://www.era.co.uk/news/rfa_feature_05a.asp
http://www.scientific.net/MSF.580-582.229
http://en.wikipedia.org/wiki/Dendrite

http://nepp.nasa.gov/whisker/background/
http://www.nist.gov/mml/metallurgy/thermodynamics_kinetics/lead-free_surface_finishes.cfm

which would explain the ghost in one of my older k7000 boards that damn near everything was changed on and it still ate parts!
 
You should check for 24v on pin no. 6 if IC3. For me the easiest/safest way to do this is to solder a insulated wire to the bottom of the chassis on pin 6 and run it long enough to get it out from under the chassis. That way you don't risk shorting that voltage elsewhere. If pin 6 doesn't have 24volts then R91 may be open.
 
Well after a couple weeks of race truck repair I finnally got back to this board checked pin 6 got a healthy 24v out of her. anyother thoughts? I'm totally brain fried on this now..
 
Did you check the V-size pot on the remote board. I had a broken one that caused the same problem.
no remote board and yeah I was looking it over didnt see anything wrong with it but am thinking of pulling it and checking just to be sure..
 
check to make sure the yoke wires aren't broken somewhere. i had a 9" K7000 with vertical collapse that was giving me fits until i realized that one of the wires from the chassis to the yoke (the yellow, i believe) had been snagged on something and snapped near the yoke. since the wire was stiff and stayed mostly in place on a casual glance it looked like it was still connected.
 
check to make sure the yoke wires aren't broken somewhere. i had a 9" K7000 with vertical collapse that was giving me fits until i realized that one of the wires from the chassis to the yoke (the yellow, i believe) had been snagged on something and snapped near the yoke. since the wire was stiff and stayed mostly in place on a casual glance it looked like it was still connected.

it's all good with another 7000 board, but I did check them just because..
 
Well after desoldering and resoldering across the board and changin parts from a know good board, still same issue, but I found lits of solder pads with no circutry to solder to and patchesall over so striped it out and gave up. Saved the good stuff trimmer pots, width coil and such. it just wasnt worth that much trouble!
 
If you didn't stip it out completely and still have it, check D13 or R91. I had one with vertical collapse and IC3, C50 and R91 checked out fine but D13 was broken, replaced it and the issue cleared up.
 
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