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  • Quote from stj: “if you want to convert from a potentially BTL speaker signal, to a line-level then you can get cheap adapters intended for fitting between car stereo's and booster-amps ” I started another thread for the test bench PCB. Keep this one on topic of fixing the S16b audio.

  • Thanks @pacoarcade & @ic3b4ll. I think I will just use a different speaker. I'll start another thread on this subject and page you guys there. I am derailing my own thread. So let's get back to fixing the S16b audio.

  • Jamma Fingerboards

    acblunden2 - - Project Sentinel

    Post

    Right now, it is just a personal project with my wants and to suit my available tools and spare parts. The block of power connectors is for powering auxiliary devices. Original intent was just to have a +5v connection for the Gonbes 8200 (GBS modded) to be powered for PCB repair. Then with some manual switching, I can pipe the video into a CRT for CRT repair and calibration. There is enough room on the board that I added extra taps for +5v and +12v to power what ever else might be needed: optica…

  • Unbalanced isn't correct? JAMMA audio is 4ohms and my speaker is 8ohms. Shouldn't it correctly be calculated for unbalanced impedance?

  • Jamma Fingerboards

    acblunden2 - - Project Sentinel

    Post

    Alrighty then. Auto-route, then manually fine tune it is. Almost done. Just need to beef up some traces and ensure the audio attenuation circuit is correct for the onboard speaker, then I can put in the order and test the sucker out. Added JAMMA edge test points in this latest rev, moved the test points away from anything it could ground to, and made it a bit wider. arcade-projects.com/forums/ind…b993caabc5ca1a5f97761b986

  • Jamma Fingerboards

    acblunden2 - - Project Sentinel

    Post

    Silly question for you @Frank_fjs, do you ever use the auto router? Or is that beneath you?

  • Jamma Fingerboards

    acblunden2 - - Project Sentinel

    Post

    Quote from xodaraP: “I like this a lot. What connection are you using for video? ” 2.50mm spacing, so JST NH or JST XH will work. Test points will use these clips.

  • Jamma Fingerboards

    acblunden2 - - Project Sentinel

    Post

    I've been fiddling with Easy EDA a lot lately too, pivoting off of Frank's work. Getting better with it (I think). Working on this right now: arcade-projects.com/forums/ind…b993caabc5ca1a5f97761b986 Just want my test bench to be uncluttered. The one I've used for so long has just been a stripped out harness from a cab. I put a 3P3T switch for all 3 voltages. A hole for calibrating the meter. A DPDT switch for onboard audio to output to an external speaker or to attenuate the signal for the onboa…

  • 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…