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  • So I think I have the values for the resistors needed. Thanks so much for that pi attenuation circuit because as I understand it, it would be an unbalanced circuit with JAMMA audio being 4ohms output impedance and the speaker is 8ohms. So...... Given: - JAMMA audio output is (typically) 8watts @4ohms And the speaker I am planning to use is: - 1mW @ 8ohms I should be looking at attenuating a decibel drop of 19.031 according to this calculator (watts to decibels). Now I have my output impedance va…

  • @ic3b4ll, cool. Question concerning ground for these circuits. Can we consider JAMMA pin L (Speaker-) as ground? Or does this circuit need to be tied to actual ground?

  • Quote from ic3b4ll: “Don't forget to add a voltage divider to attenuate the audio or you'll likely blow the speaker. ” Ok, taking you up on this offer. - I am using this speaker: PB-3212PK What is the best circuit I could build to attenuate audio for that speaker?

  • Quote from ekorz: “I’m fiddling around with a crtemudriver mame build, using a jammaizer via vga for video amp and controls. @acblunden2 suggested the concept. I’m totally digging it!if anyone was looking at other options like jpac I’d suggest thinking about this. I’m in for another one next round. ” Pics of said build once done!

  • I am using EasyEDA. Earlier version of the board had a copper plane for ground, but I couldn't get auto routing to work with this version. I think I have to take it back to the drawing board though because I would like to add a ST3T switch on it for the voltmeter (one meter to display/calibrate all three voltages). Plus, you are right, I should add some circuitry to attenuate audio for the onboard speaker. There is just a switch to channel the "speaker +" from the onboard speaker or to route it …

  • Quote from aimbuster: “I'm just now learning about this treasure! Can't wait to get on the NEXT Pre-order! ” Your timing couldn't be better. But you better be alert quick. These won't last long.

  • Quote from ic3b4ll: “Desoldering is probably the best skill to have in practical terms when it comes to repairs so consider yourself in luck Regarding the probe, it doesn't really matter where you take the 5v from. You don't have to take it from the PSU. For ease of use I just made a small hook with a resistor leg and soldered it to the JAMMA connector on my bench and did the same for ground on the opposite side. This way it's close to the board and easy to move around, while having similar volt…

  • CPS2 Battery Change Day

    acblunden2 - - Capcom's CPS2

    Post

    All good @Murray. We are helping you preserve those boards from battery acid damage is all. Do your thing. If you want to know more about the other methods, we can help you as well. Just ask. Keep the knowledge in the bank for 2025 when hopefully it will be a better world and when you will change out those batteries.

  • CPS2 Battery Change Day

    acblunden2 - - Capcom's CPS2

    Post

    You're an Aussie. Lots of great mates there that would have programmed those chips for you.

  • CPS2 Battery Change Day

    acblunden2 - - Capcom's CPS2

    Post

    Those batteries are just as prone to leaking as axial batteries brutha. Provided you have a programmer, suicide free mod chip, socketed dip pcb, pic chips, is the eay to go. Less expensive than battery plus holder by 80%.

  • Wipes any residual keys. Tiny effort.

  • If it is the B-Board, there is a cap on the B-board that is known to cause audio to fail. Also, could be your Q-Sound EPROM's. But you are going to use this for the multi, so the EPROM's won't matter. So try replacing the caps near the 01 and 02 EPROM's. Still though, your board turned out to be suicided. Don't know why when installing the multi it doesn't work. When you installed the multi previously, did you put it back in the shell when you tried using it? I've seen where the shell touches th…

  • This is where having another working A-Board and B-Board comes in handy. Could be your B-Board. Could be your A-Board. Check again if someone in your area has a working CPS2 set. Try your B-board on the working A-Board. Try the A-Board on a working B-Board. Once you've isolated it to one or the other, then you can troubleshoot further. Welcome to the hobby :).

  • I am good with desoldering. I have a Hakko FR-301 too. Question about the probe as I am awaiting its arrival. The 5v rail that I have to hook it up to can be anywhere between the PSU and PCB? I'll run test mode and see if I get a RAM error and report back.

  • Word. B-board works! Means it should work for the multi. Also means @ArcSys101 sold you the board as described. But getthe B-board audio working before you do the conversion. Eliminate points of possible failure. Make sure you have your audio configured properly for MONO or STEREO. Then try this trick. If that doesn't work, some further surgery is required.

  • Quote from ic3b4ll: “Can you send a picture of the area surrounding the Z80? I want to check what type of RAM it's using. ” photos.app.goo.gl/7tBdLHahCUCQjxgZ8

  • Great rule! Are the previous 742 rules just as fantastic? Probe is on the way.

  • E-SWAT was acquired with dead audio. Converting to the multi did not produce audio either. Replaced the APU with this Z80 from Digikey (I hope that is the correct one). Audio is still dead. Upon turning up volume pot, I get a shrilling sound through the speakers. I can see the voltmeter change consumption as I turn up the volume. Where should I go from here? 1. Replace sound amp 2. Recap I have no probe yet. Thanks!

  • NeoSD MVS Pro has been vaporware for 2.5 years now. It's not the 1st, 2nd, or even 3rd time where they've mentioned it will be out in a month or two. Not being biased either. That has been the honest to goodness truth. I've been holding out on a MVS multi solution until the TO MVS Pro streets and I can make a decision then. It might show up at the end of this month like they've said, but that's been said before. Thankfully, I have lots of other arcade games and MVS carts to hold me over. As for …

  • Quote from LemmyBarnett: “Has anybody else looked at the waiting list, looked at your position in it, looked at the average number shipped per month, and try to work out when yours might get shipped?! #ithinkimobsessed ” See post 2,375.