Wells Gardner D279410 - no picture

roothorick

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We have four Fast & Furious DRIFT sit-down dedicabs. Each was outfitted at the factory with a Wells Gardner D279410. Anywho, one day, one of the monitors went dark. The blue disappeared, and the picture was distorted. So, I took out the neckboard and mainboard and sent the lot to WG. They looked at it, repaired it (I later found out they only replaced the microcontroller and EPROM...) and sent it back. Here's where the fun begins.

So I get it back, and reassemble the monitor. What I didn't know was the pins on the anode cap were bent out of shape, and not properly seated. I also made the mistake of not connecting the four wires running from the yoke to the main board (four big pins next to the flyback... not labeled in the diagram, maybe P201?). When I turned it on, it gave its usual startup whine, but never snapped into action. I turned it off, took another look, and noticed the one connector loose. I seated that one, tried it again. This time, I was greeted by a loud CRACK! and a blue flash. "Lovely, I just fried something!" At this point I just turned it off and went home.

Now today, after a phone conversation with John Pruski at WG, I discovered the bent pins on the anode cap. Bent them back, put the cap on correctly and.... not so much. No picture on the tube. I get the usual whine then quiet snap, but the whine doesn't go away and I hear a faint crackling, kinda like an old CRT cooling off. John says it's probably something in the Horiz Output that shorted out, but I'm looking for details and second opinions. Anyone?
 
I don't think you fried anything by having the deflection coil disconected. If the pins on the anode were mashed, it may not be making good contact, this is why you hear a slight crackling. You may need to take the cap off and check the connection under the cap, and make sure it is making contact, if your HV comes up and then shuts down, then you may have an issue in the horizontal section. You will know if your HV comes up if you can feal a static field at the front of the tube. Remember the monitor is self checking itself. If it senses lack of or no HV it will assume a fault and shut down the horizontal section.. hope this helps
 
I just took both boards out of the machine -- yes, the big 4-pin connector is P201.

John questioned the horizontal section too, and gave me a few transistors to test (901, 903, 206, 207). That's what I'll be doing... when I find time. Between these two monitor boards and the upcoming card system I'm going to have my hands VERY full.
 
I finally have a proper soldering iron :) Weller WESD51. It's a world of difference, I can actually solder now :)

Anyway, I started pulling suspect components and found a blown through MOSFET (Q903). As you know, MOSFETs invariably take things with them, which means repairing would be extremely time-consuming and cost a little bit. After talking with WG and my boss we concluded our best choice is to buy a whole new replacement chassis from WG. Sorry for the anticlimactic finish :(
 
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