Recent content by yaryar

Understood about the debounce/cleaning up the coin pulse. So if the CPU7 is seeing the /NMI pulse for coin switch, what could be preventing it from going into the "press start button" routine and out of the attract mode? I know the issue is on the top PCB, as swapping with a known good top PCB...

Thanks Mark. You pointed me in the right direction. Addressing to those RAMs looked good, so I next piggybacked those RAMs one at a time, noticing graphics changes when piggybacking 4J and 5J. Replacing those fixed the graphics issues. Final issue will be fixing a no coin-up issue. Hitting the...

Currently stumped on this Burger Time I'm working on. Graphics are as-seen in the pics. Did some reading on the forums but nothing specific to what I'm seeing. The only thing I read was from a post mentioning grounding the outputs of the LS194s after the graphics ROMs. Doing that doesn't move...

If this were on our bench for repair, in this order: Swap the CPU with known good one (6809EP) Desolder the system RAM (2128 @6A) and check in a dedicated RAM tester Verify system EPROMs using CAT FPGA(this will also verify decoding logic), or using an EPROM reader Always target Fujitsu and...

Yup, it's the one that was found in the Kalamazoo warehouse raid years ago. All original color decal artwork.

Defender upright with the original color artwork.

Are you using the 4116 rams, or did you upgrade to the 41256/4164 RAMs?? The reason I ask is because we ran across a similar issue with a Robotron set using the Arcadeshop 41256 RAM/power adaptor upgrade. The power adaptor they sell has one line floating, which won't work when using 41256 RAMs...

Did you recap the small audio amplifier PCB mounted on the monitor assembly?? If that board has never been recapped, that could likely be your issue.

I use a Dremel reinforced cutting disc. The reinforced ones have fiberglass(?) in them and won't shatter if you put too much force on them, or push at an odd angle.

I've saved probably 150 or so of these over the years. Here's the process I use: 1) Using a Dremel with a reinforced cutoff wheel, cut all legs off flush with the edge of the chip. 2) Using the Dremel, remove 1/16 inch of top material, exposing fresh shiny pads 3) Take a 28 pin machine-pin IC...

It could have been us (Starbase Alpha) that did the work, as we've repaired/refurbed dozens of boards for CudaSales over the past few years......

Of every 20 Galaga PCBs we bulletproof (new IC sockets/resistor networks/capacitors), then power cycle for at least 48 hours, at least half of them come back within the 30 day warranty period with new issues. I've had to start charging more to cover the return warranty shipping. After doing...

Yeah, in a prior reply I told him where the issue was for a previous repair with the exact symptoms he is having. He could have saved himself a ton of time by going into the area I mentioned. If he doesn't have a comparator, piggyback the less than 10 ICs in that area with known good ones, with...

Per a repair i did for a customer 2 years ago, same symptoms you're having. Hope this helps: (From 7/23, PB Shoppe) Centipede repair, this was a fun one to repair, based on the symptoms. Game plays, but when you move your player around, all of the other Motion Sprites move with your player. If...

pm sent on Asteroids Deluxe