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Sorry if this has been answered elsewhere - I have searched the net and cannot seem to find any info. Does anyone know how much MVS boards retailed for back when they were mainstream in the arcades? Presumably you could buy the boards seperate from a cabinet? In particular, cost of:- 1 slot 2...

Has anyone seen this behaviour before on an MVS? The error is BIOS Address A13 - A15. The ROM has good connectivity to the CPU. I am speculating the CPU might be the problem.

Hi, I've done a number of MVS 1 slot repairs recently and wanted to share it with people. Backup RAM & Palette RAM Error https://www.youtube.com/watch?v=YYWc4_uM0oA Backup RAM & VRAM https://www.youtube.com/watch?v=xKzP9NdAY8s Z80 Error (MV1A / MV1AX)...

I've done another crusty repair and video, but at the same time I thought I would share this with the community. The cause (74HC259 & HC04) might be the reason others have failed to fix their BRAM faults on the 1FZ. This diagram (and notes on connectivity testing) may help someone...

Anyone seen an AES show a white screen when there's no cart in there? The AES is functional - just got a wierd intermittant PCM issue which I am thinking could be bad caps, perhaps the YM3016D, intermittant connection on a trace (cart slot is super clean and good as new), or maybe a glitchy...

Some of you might already be aware, but you can now pre-order the Neo Geo Pocket SD from www.retrohq.co.uk. I had an early look at one over the last week:- https://www.youtube.com/watch?v=DbZ9Mz36jcQ

Anyone know if the MV-IC (memory card slot) is the same between the different 4 and 6 slot boards? ie. just the 60 pin connector and they are all the same? Also, anyone know where to buy one from?

Just a quick question about the CHA512Y. I've got a boot that was faulty - I've replaced the 273 chip and decided to convert this boot into Diggerman. The board is supposed to use 4Mb or 8Mb chips and I am trying work out how best I can get the C ROMS on there. I've got plenty of 1Mb chips...

Does anyone know of any links to these - assuming they exist? A friend has posted a problem on YT where his up input on both ports is not working. Assuming that the Neo is reading the P1 and P2 inputs in the same way the NEO C1 does on the MVS and AES, then it has to either be a missing data...

Does anyone know what size chip these are? I've got several of them and trying to understand where I can use them. Do they use JEDEC pinout or what? NEC D27C4000D EDIT: I cannot find anything on these chips at all - it's like they don't exist lol. I think I pulled them off a Puzzle Bobble...

Hi, anyone seen a blank screen on a cart before? I am thinking either the 273 has gone completely, or maybe the 74LS174. I've got a 174 on order, but just wanted to float this past people. The sound is there, and the game is working, just nothing on the screen. It's all black for the Neo...

In summary, the SDRMPX and SDPMPX bypass caps (47pF) make the biggest difference to PCM sound on all these carts, but its worth doing all of the mods imo. This has fixed sound problems in many games across all the carts below. The 161 in 1 in general suffers less from the PCM issues, but it IS...

I wanted to ask this of the wider community since I've got limited access to different MVS hardware. I've been wondering about some sound issues on MVS multicarts for a while now and in the first instance I put it down to dodgy NVPROM chips or the odd incorrect byte in the ROM images etc. I've...

Does anyone have a list of connectivity points to check between BIOS, CPU, E0 and anything else the BIOS connects to? Having a nightmare here trying to undo the nightmare that was on Beaps aaa AES and despite checking very carefully tracks before hand and doing diagrams, and comparing to my...

I am posting this in the hope that someone knows what this might be. You can see an example here at 17:21. https://www.youtube.com/watch?v=b3i14NeiBNY&list=UURBWJ9JeJ3Q8ssn_ibii-Cg This has had the bypass mod done - well, the 3 lines to the caps cut. I am wondering if there's mod to fix...

I've recently purchased a Neo Geo Pocket Color which had bad corrosion from acid. I've cleaned it all up and neutralized it etc and the system has been working fine but it seems that it only displays at the right colors / contrast for a short period of time. After a minute or two the contrast...

Does anyone know how these games differ? Was 5+ just a bootleg/pirate 5?

Hi, I've got a Puzzle Bobble that I think has a suspect V ROM. One or two of the sounds dont sound right. Anyway, long story short, I am trying to order a couple of replacement chips (pre programmed) and the emulator copies for the same game I have are 4 x V ROM images. ie. V1, V2, V3, and...

Hi, I've got a really really strange problem where I get some artifacts on the display with one of those dodgy multicarts. And yes, I know they are crap quality and dont last etc etc. But that said I've got a very strange problem that I am trying to understand. The artifacts disappear...

I've got a cart with sound glitches which will need 1 or 2 replacement chips in the form of EPROMS. I've got a couple programmers but neither will accommodate 42 pin chips that it uses. Does anyone know if EPROMs can be programmed in two passes? Say lower 256Kb with relevant address lines...