Recent content by pzlate

Good luck.. if you run across boards with no sound and manage to fix it (outside of it being a bad cap/dead GAL) please tell me how. I have another board in the pile of shame (that I stole my U32 from) that I could never fix the sound on.

So U32 was shorting to ground, I removed the 0ohm resistor before it that goes down to pin 13 on the hex inverter at U75 , and that stopped the short to ground on those chips. So my U32 was faulty, I ended up removing U32, removing the short completely, put in a replacement U32 from a parts...

Decided to work on this board again.. traced it back to U32, replaced U32 and I am now greeted with video, at bootup the screen stays solid purple for about 3 seconds, then the garbage comes up, then it blanks out before rom test.. Kind of stumped on this one

UMK3 board playing blind 7407 inputs shorted to ground Need a bit of guidance here. I have a board where everything works fine, but it's playing blind, it's definitely passing the hardware test and it has sound. It's outputting the correct resolution and refresh rate but just a blank image...

Going around with a logic probe I found that I get nothing on pin 8 and pin 16 on U100. On my other board they show up as high and measure 3.3v. Also I get either weak signals or nothing on the I/O pins for U86.. especially one that leads back to D20 on U1. I still need to learn how to apply...

I think it ended up being the U59. I must have not reflowed it properly but after figuring out how to solder SOJs nicely doing a ram repair I decided to reflow it one more time with a better tip and it now boots at 5v. But both of my boards seem to have bad U86 and no sound sadly. edit...

I have another UMK3 board here that I'm kind of stumped on.. It has no sound/test tones and U86 comes up as bad. I have good -5v and I've already replaced TL084CN at U92 and the 2200uf capacitor. I've tried swapping a U57 from another board but sadly both of these boards seem to have no sound...

Okay this is weird, if I lower my PSU voltage to 4.8v (at the psu so maybe closer to 4.6-7 on the board.) the game will boot with bad U37. At 4.9v it can't get past the rom check, 5v it stops booting (unless I flex it like in the op) Is there any reason why the game would be this picky? My...

I was thinking of that too, or maybe one of the pins of the PLCC socket itself has an issue. Once I have the tool I'll swap those into my working board. The board itself is pretty bowed out, so I'm worried someone screwed down way too hard on the middle of the board, maybe even to force it to...

Negative does have continuity to ground, and there's no cmos error in game. When forced to boot by bending the board the game worked with with the missing smd cap, I put in a 0.1uf cap in its place, and it still works the same way it did before. The dented 2200uf cap, I won't be able to change...

Thanks for info, I didn't have continuity and I tried jumping it. Didn't change much. But I did try checking where my fingers were resting and once I started pushing on the U59 pins themselves, it would boot, so I think I just need to reflow my U59 first and I'll see what else has problems...

UMK3 only boots when pressure applied to corner + missing an SMD cap So I picked a "dead" board but it'll boot when I apply pressure to the corner near the heatsink next to jamma connector. Otherwise it'll just have a black screen and only one led will be lit. I've tried applying pressure to...

Nah it's defintely an issue with the chassis, because it's in songs too, whenever the background video changes the monitor will become either very green, very red, etc. I don't know what causes it, maybe too much of a certain color will cause it to shift, but it's not intended behaviour. I've...

Monitor slightly shifting colors after chassis swap I replaced my dead chassis in a Korean DDR cabinet with a super cheap Chinese chassis from Aliexpress To my surprise it worked, but I get a weird color shift now. The monitor did not do this before on the original chassis. First I thought it...

Thanks for the marquee. Just a heads up for other people these are printed directly to the acrylic, they do not have art inserts. I wonder if these were for the Korean 3rd Mix cabinets.