Servicing the Wells-Gardner K4600

a more in-depth guide to disassembly and service of the Wells-Gardner K4600.

removal of the chassis assembly varies depending if your monitor frame is horizontal or vertical. in horizontal configurations there are 2 bolts to remove (roughly marked in image) and the metal tray slides to the right and lifts up and out. vertical configurations I’ve found it easiest to unbolt the entire bottom tray of the monitor frame, there are 2 bolts on either side to remove. for both, a 1/4″ socket can be used, or one of those flexible tools will work.

the flyback transformer assembly is bolted to the right wall of the monitor frame, held in place with 2 bolts. I find it easiest to completely remove the top bolt and loosen the bottom bolt slightly, the flyback will then slide up and out. the flyback is removable from the deflection and neckboards by disconnecting the following: large plug to deflection board, small plug to neckboard, focus wire (requires desoldering), and a ground wire. you can then set the flyback aside in a safe place.

one of the more infamous components of the K4600 due to its potential for getting broken is the width coil, mounted separately from the deflection board and connected by 2 wires. I’m told there’s no polarity here, but if you want to be totally precise like me you can mark one of the wires to put it back the way it was when you’re done with surgery. fully clear out the holes to the width coil for easier reinstallation later. (this part of the process isn’t over yet)

there’s a small metal clip screwed into the wall of the deflection board that must be removed to get the plastic foot half off. a 3/16″ nut driver works well here. this was probably intended as a security lock.

turn the deflection board on its side and underneath are 4 1/4″ head screws to be removed in order to separate the plastic feet from the metal tray. if you’ve followed all the steps in order up to this point, the tray can be set aside in a safe place for the safety and integrity of the width coil.

there are different variations of the K4600, if you have one with the array of red jumper wires here’s a legend of where they all go in case one gets removed accidentally.

the power board wall assembly actually is removable, held in place by the snap-in plastic buttons. to unlock them pull up, and cut the 2 cable ties restraining the power board in place and the entire wall lifts out. I encourage you do this after reflowing solder to the power board header pins however, as you don’t want to do that with the board out (done improperly, the header pins can lift out). the same can be said for the XY and signal cards, don’t reflow the header pins with them removed.

the wall and card clip removed. reiterating once more, don’t take these out until all header pins have been resoldered first.

the XY (top) and signal (bottom) cards. the XY card has probably as many caps on it as the entire deflection board and they’re kind of camoflauged by all the parts around them. permitting the monitor wasn’t capped in 1992 or something, spotting the original grey caps shouldn’t be difficult. the signal card came in multiple revisions, some only supporting positive sync (6 pin header only) and others with negative sync (additional 3 pin header). some have black level pots mounted to the front, some have them on the back, for ideal adjustment they should be reverse mounted on the back. some have different capacitor configurations, I think of all the K4600s I’ve worked on I may have only ever seen them with 2 caps like pictured.

another cap not included in cap kits is C621, which I believe has something to do with vertical retrace. if your monitor has a vertical wobble to it or it pops and you visibly see the vertical refresh, you need a new C621. the replacement cap has thicker legs than the original, I’ve used my picks to bore the holes a little larger to get it to install easier. replacements can be found at APAR here:

visual aid:

don’t be alarmed that the bipolar replacement cap is significantly smaller than the original, it’s the correct one. I angle the legs outward flat and bend straight down at the base of the cap and the legs line up perfectly with the holes.

a number of old timers, including one gamefixer, condone the removal of these rings around the anode legs. sometimes it’s near impossible to get the anode cup back on, but lately I’ve been challenging myself with getting them back on with the rings intact.

I got pairs of K4600s and K4900s to work on twice in the same week. these were washed in the sink, which is another topic for another day.

good luck