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Sega Model 2 and Model 3 problems (VF2 and VF3)

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Sega Model 2 and Model 3 problems (VF2 and VF3)

Postby MangledLeg » December 8th, 2009, 12:36 am

Hi all,

This is my first experience with Model 2 and Model 3 PCBs, so bear with me, hopefully this will make some sense!

A few months back I snapped up VF2 and VF3 from someone interstate (I live in Australia), and have been having some troubles with them, and I'm not sure if it's me, the boards, or maybe a combination of both!

Now, before I go on I'll clarify my setup - Astro City cab with a 15k/24k chassis (Pentranic, previous owner slapped in a generic 15k chassis that belw up, so I replaced with a Pentranic), bog-standard Peter Chou 15A PSU, 3.3v Wei-Ya PSU, JAMMA-ready. To connect the Model 2 and Model 3 boards into my JAMMA setup, I'm using one of these (Model 2) and one of these (Model 3).

In order to boost the 5v and GND lines on the main PSU, I've also increased the amount of wires coming between the PSU and the JAMMA connector as I wasn't getting solid +5v due to some flimsy wiring. After beefing up both lines, I'm getting much better performance across all my PCBs (CPS-I, Neo Geo, CPS-II, System 11 and a few others).

I'll start with VF2 - I'll put the chassis into 24k mode, roll the PSU back, connect VF2 and get the voltage to 5v (maybe 0.05v over). On the PCB, the red LED 11 is lighted up, and I'm getting like a garbled green test pattern thing on the screen. I've pulled the PCBs apart and put them back together again, checked to make everything's in there nice and tight and checked for physical problems on the boards, everything checked out, no change. To test things a bit further, I removed the top ROM PCB, leaving the bottom two boards (since it's a Model 2A system, it's a platter of three boards) and rebooted - same problem, LED 11 is lit up, I think I saw a couple of red LEDs on the bottom board near the filter board light up, and the garbled screen. Turned off, put the ROM board back on, the LEDs on the bottom board are fine, but red LED 11 in the middle board is still lit up. Garbled test pattern remains.

With VF3, it's a bit more tricky, and I have a feeling it's my PSU that's to blame here, as well as some of my wiring before I beefed up the 5v and GND lines. With VF3 when I first tried booting it a month or two back, the 3.3v PSU worked a treat, but the old Peter Chou would crash out immediately - the red light to indicate it was on would light up, then immediately drop out and there'd be no power on the JAMMA adapter when I tested it with my multimeter. I figured my PSU might have been on the way out, so got a new standard arcade PSU (a 16A Min Dong), connected it up and had success... or at least I thought I did. I measured at the JAMMA adapter and it wasn't getting to even +2v on the +5v line; I cranked it, barely got to +2v and the JAMMA adapter was getting really hot. Next thing I knew, it smelt like the PSU was overheating and the little light indicating it was on turned off. The new PSU went and died on me :P Disappointed, I reconnected the old Peter Chou PSU. I noticed a couple of red LED lights come on when I power up the Model 3 off the Peter Chou (even though ti conks out) and the 3.3v Wei-Ya (which I'm going to take as meaning the Wei Ya is working fine, since it doesn't conk out), if that helps. Another thing I noticed is that how much success I have before the Peter Chou PSU gives up depends on the amount of +5v/GND connections - I can have the 5v and GND connections on, say, JST CN13, and it won't kill the PSU, but if I hook up JST CN14 as well, the PSU dies. Does this help?

I was talking a few other people with more experience than I have with arcade cabs, and they mentioned that the fact the JAMMA adapter was heating up indicated there wasn't enough copper between the PSU and the JAMMA adapter on the +5v and possibly the GND connection as well, and suggested beefing up the wiring to fix that part. I've done that and am getting better results when playing the rest of my games, and when I tried loading VF2 or VF3 with the beefed up wiring, VF2 still gave that garbled green test pattern screen thingie (red LED 11 still on), and VF3 still died off. They also mentioned the red LEDs might be indicating a fault with the board or power supply.

The only other variable I can think of is that some of the larger CN plugs on the JAMMA adapter don't connect to the final pin in the row (I can confirm the exact details later tonight since I'm not at home at the moment) - I checked the back of the filter board and it doesn't look like it's connected to anything, but I can double-check that just in case it's possibly the adapter at fault. The connectors on the adapter have all the pin numbers labeled on them and everything's matched up though (e.g. if there are 10 pins on the filter board, the connector on the adapter would say +5v 1-9 or something like that; again, can post pics if it helps, but won't be able to do that until later tonight).

I'm a bit stumped with what I can do to fix up these issues - I'm a huge VF fan, and these two games were part of the reason I wanted to get my own arcade cab. I know there are some very clued up Model 2 and Model 3 people on these forums, but couldn't find anything that coped with these problems. I'm not sure if it's a PCB, PSU or even jumper settings issue that's affecting my PCBs, so any help would be hugely appreciated. If you need me to supply any more info, just say the word! Some other people I've spoken to who run Model 2 boards have done it consistently off standard arcade PSUs for years, but they emphasise that you need to ensure your +5v and GND connections need to be extremely strong in order to do so.

Cheers!

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Re: Sega Model 2 and Model 3 problems (VF2 and VF3)

Postby dj_johnnyg » December 8th, 2009, 6:13 am

Running M2 & M3 stuff straight off the JAMMA is not advised, as you mention due to the high power needed.

I have both VF2 & VF3 (and VS2) sat in my garage, and I use home-built adapters connected to a SUN psu (as found in Sega Naomi Cabs)

I'm thinking of selling my M2 & M3 stuff in the new year, so I'll have the looms available then, or I could probably knock one up for you. Also, I have a spare SUN PSU (It needs a 110v stepdown) which I could probably part with too. P&P shouldn't be too bad with NZ Post.

Let me know if you're interested, or if you want more info. I can try get some picks of my setups.

john
Snakes: They're like bits of rope, only angrier.

myuniversallove

Re: Sega Model 2 and Model 3 problems (VF2 and VF3)

Postby myuniversallove » December 8th, 2009, 9:50 pm

ok here we go. the virtua fighter 2 test pat you get is a low voltage issue. if you crank the volt more it will boot.but be verry carefull with m2 and m3 it is easy to fry 1 or more ic s,. i have 2 stack s of virtua fighter 3 and i am using a jamma harnass and a wei-ya 3,3 powersupply. dont crank that baby to high just in the middle will do fine. make sure you put the power on te m3 board from the jamma and the wei-ya at the same time ! 1 sec later or earlyer the board will not boot and all the light s are burning then but the game does nothing.best is to get the wei-ya 3,3 powersup on the same plug as the cab s jamma powersup. if that still does not work . holla...

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Location: Australia

Re: Sega Model 2 and Model 3 problems (VF2 and VF3)

Postby MangledLeg » December 9th, 2009, 9:40 am

dj_johnnyg wrote:Running M2 & M3 stuff straight off the JAMMA is not advised, as you mention due to the high power needed.


Cool, that's the message I seem to be getting :)

I'm thinking of selling my M2 & M3 stuff in the new year, so I'll have the looms available then, or I could probably knock one up for you. Also, I have a spare SUN PSU (It needs a 110v stepdown) which I could probably part with too. P&P shouldn't be too bad with NZ Post.

Let me know if you're interested, or if you want more info. I can try get some picks of my setups.


Would definitely be interested - I've seen people here mention SUN PSUs around the place - what kind of price do they go for, and is there any particular reason why they're so highly recommended? And would I be able to use the one SUN PSU for both my Model 2/Model 3/JAMMA?

myuniversallove wrote:ok here we go. the virtua fighter 2 test pat you get is a low voltage issue. if you crank the volt more it will boot.but be verry carefull with m2 and m3 it is easy to fry 1 or more ic s,. i have 2 stack s of virtua fighter 3 and i am using a jamma harnass and a wei-ya 3,3 powersupply. dont crank that baby to high just in the middle will do fine. make sure you put the power on te m3 board from the jamma and the wei-ya at the same time ! 1 sec later or earlyer the board will not boot and all the light s are burning then but the game does nothing.best is to get the wei-ya 3,3 powersup on the same plug as the cab s jamma powersup. if that still does not work . holla...


I gave the VF2 board a go this evening, keeping track of the voltages as I was trying different things. I found that the voltage at the JAMMA adapter was different to the filterboard measurements, so if I had it at 5.25v at JAMMA, on the filterboard it would measure around 5.05v; I'm assuming there would be further drain on the line as it went deeper into the stack of PCBs. I managed to grab some measurements off the ROM PCB, and there was definitely movement downwards again. I cranked it as high as 5.4v on the filterboard, but didn't want to go higher than that in case I fried an IC. Still got the test pattern, and only LED 11 on the middle board would light up. With VF3, I run the 3.3v PSU so that it daisychains to the power connection to the standard PSU, so they always come on at the same time; the problem is that my PSU is just not interested in playing with the Model 3 set, it shuts down within 1-2 seconds of powering on.

From what people here are saying, and from what some of the locals I've talked to, it seems to be a recurring theme that the main PSU seems to be the culprit... the problem is that I don't know where else to jump to or what alternatives would work, as most of the online stores I see only sell the Chinese 15A/16A PSUs that I can grab locally-ish, which I figure won't be up to the job. Maybe these SUN PSUs people are mentioning is the way to go? Just afraid at what the price tag might be ;)

myuniversallove

Re: Sega Model 2 and Model 3 problems (VF2 and VF3)

Postby myuniversallove » December 9th, 2009, 4:47 pm

a SUN psu will work i used every psu out ther to power M3 .ATX won t work, get an sun naomi psu and it will go! ;)

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