I agree with pretty much everything said here about linears. I prefer the original linear supplies a great deal more than switchers. Switchers may be more power efficient but, for me, restoring classic games or other equipment isn't so much about efficiency as it is about running the game as it was originally intended. There's an LCD replacement for vector monitors available now too but I have no intention of swapping out all my original CRT vector monitors. Transistors are widely available too but I'm not ripping all of the old vacuum tubes out of my classic radios.
Many of my classic games require the POR, the monitor heater 6VAC, spot-kill output, and so forth. Seeing a hacked-in switcher makes me want to kick the guy that cut up the original harness. In many cases, the switcher was a lazy way of "fixing" the game and a poor excuse for a so-called repair or worse, a "restoration". Half the time, the switcher was jammed in with just 1 screw and the old power brick is still sitting there covered with dirt. This is an example of someone who wasn't even trying. Granted, I get why it happens. Not everyone has the skills or equipment (or the patience it appears too) to do the job properly and they just want to get the game going regardless, even if it is just to get rid of it. I am fortunate enough to work on electronics stuff for a living so I have what I need to properly restore the original equipment. If I could not do that, I wouldn't collect the games because for me, the whole point of owning the old games is to be able to operate the original design. Even though many components are now new, I restore them with respect to the original design intent. Replacing all of the PCB headers with brand new ones is a must. Also, it's straightforward to replace all of the harness connector housing terminals with new triple-point contacts (ie: trifurcon). This is the single most commonly neglected step toward getting a linear back into shape.
For more help with your original Sega G-80 power supply...
Power supply list of components with source links: http://www.biltronix.com/Star_Trek_08.html#G80_power_supply
Power supply rebuild pics and tips...
Before: http://www.biltronix.com/Star_Trek_05.html
During and After: http://www.biltronix.com/Star_Trek_06.html
Don't get me wrong here. I'm not ripping on anyone. Not all arcade machines are worth fixing up. Some have seen so much neglect that the power supply is the least of their problems. I'm just saying that I myself prefer to fix up the original stuff wherever possible and that always includes the power supply. I like playing the game while thinking "This is exactly like what I was playing when I was in my teens. It was just like this." I mean, what if it was a 1967 tube-based Hi-Fi radio with phonograph in a beautiful solid walnut or cherry cabinet? Would I rip out the entire radio and amplifier chassis and toss in a cheap $15 solidstate radio board? No. If I want a radio that sort-of looks like a classic but isn't, I'll buy one at Walmart or The Source for $40. If I want an arcade machine that looks like a classic but isn't, I'll go Mame or build a 60-in-1 project. If I'm going to rebuild a Tron, then it's going to get a rebuilt regulator board and the whole nine yards, not just some black spraypaint, a switcher, and a few new cab decals.
Also, I'm all in favor of developing new boards, reproduction boards, chip replacements, or other add-ons that can add value or reliability to a machine without obviously hacking it up. Let's face facts. Sometimes there's just no original parts available or a very-nice-to-have function (like hi-score save or free-play) is missing from the original. The Atari AVG replacement, BPROM replacements, other custom chip replacements, hi-score-save modules, all have their place and make the hobby more fun, and without which, many games might never even run again. What I like about these devices is that they add functionality but they are also easily removed and they do not require modifications to the original boards.
If you are wondering why I first said "I want it all original" and then later said "I like the new add-ons and reproductions" and maybe that sounds like a conflict, well, it kinda is. So there's a line to be drawn I guess. At what point does someone say that an add-on or modification is going too far? For me, if hacking up the original harness or boards is required, that's going too far. I think that plugging in a small module or chip replacement is okay because it can always be easily removed and replaced with an original part. Sticking in a new switcher, hacking up the harness is the process, and neglecting the original supply components is, for me, definitely not okay. However, in the case of the G-80 power supply, if someone designs a brand new board that fits inside the original metal box and presents the original arrangement of header pins and output voltages and is in fact a drop-in & plug-in replacement, then why not? One could always rebuild the original power supply board and put it back in at any time later. If the new repro supply board has a switching heart, that's fine too. It's inside the box where nobody can see it, it requires no hacks, and it's 100% undoable. If it is incapable of outputting an overvoltage on the +5V line (if it were to fail), then that's a bonus too. Or, if the board was a 90% copy of the original linear circuitry but just included a few improvements, that would be great too. Someone produced a completely new board to replace the entire wg6100 color vector monitor chassis and HV box. It's a very nice piece of work. It's certainly a God-send to some people and they are happy to run it inside their Tempest or Space Duel or whatever. Nothing wrong with that at all. Did I buy one? No. I rebuilt all of my original vector chassis'. Anything wrong with that? Not at all. Everybody has to draw their own line and for everyone it is determined by too many factors to list here. So I guess the bottom line of what I am trying to say is that I appreciate a job that is well thought out and neatly executed. I do not appreciate shortcuts or sloppy hacks. If someone makes a nice replacement power supply board for the G-80, hey, kudos. It's about time. I know that many people would put it to good use.
I agree that the G-80 supply has one major drawback and that is when the +5V section shorts, it can/will blow the game boards. This is pretty serious and scary and all on its own is almost reason enough to abandon the whole thing and move to a switcher. However, if you take the time to properly restore the original linear supply & harness, and I mean do it thoroughly and carefully and replace the heatsink grease too and clean everything, the odds that it will fail diminish dramatically. No Atari, Williams, Midway, or Sega linear supply that I have rebuilt has ever failed or caused any problems since. Don't forget, these things ran for more than 20 years in most cases and are still working. They were built like tanks. Properly serviced, they'll go another 20 years without a problem. Okay, so they can be made to be pretty darn reliable... but what if ? Is there a way to add a safety net? I think so. Who would be interested in a simple plug-in add-on circuit that can monitor the +5V and immediately shut it down if it goes over-voltage? I can design and build such a solidstate switch. If there is enough interest, I may go ahead and do it. I've given this idea some thought over the past couple of years because I myself would feel a lot better knowing that the trusty linear supply in my Star Trek can't damage my precious game boards if, God forbid, it actually did fail. If anyone is truly interested in such an add-on, feel free to email me and let me know.
One last thing, and way off the G-80 topic, I have been wondering for some time how many people would be interested in a reproduction of the Atari Major Havoc conversion boards for Tempest and Space Duel. The original boards are exceedingly difficult to find and are usually very expensive. The circuit is documented and not very complex so I know that I could route very nice high quality replacements. I don't have much incentive to go for it because I already have my Space Duel converted to Major Havoc using and original converter board, but if there's enough interest then I may be inclined to produce them.
William Boucher
http://www.biltronix.com
----- Original Message -----
From: Andrew Welburn
To: vectorlist@vectorlist.org
Sent: Friday, March 04, 2011 2:55 PM
Subject: Re: VECTOR: Sega G-80 PSU - Audio Amp
just adding my 'me too' here...
I much prefer repairing linears.. its what games were designed with, and often do include things like POR circuits, isolated audio power supplies, custom sound amps, battery backup voltages. All of which neatly fit and work in the cabinets that we restore everything else on, why slack off here? just cos power supplies aren't glamourous, doesn't mean they should be neglected, but i _know_ most people do neglect them because of the percieved toughness of testing and repairing on your bench.
In essence, i think the reluctance for anyone to rebuild/test an old linear is that the input voltages to linear supplies vary on so many games, you can't make a 'universal' linear PSU test rig. I actually have 3 or 4 transformer rigs taken from scrapped cabients that i use to fix several common models of linear supplies that i come across, and have built a switchable dummy load for load testing of each one. It does take a lot of time and affort to built transformer rigs up so that you can test linears on a bench properly. But when you do, they're dead easy and cheap to fix!
Phooey to switchers i say.
:-)
--
Andrew Welburn
http://www.andys-arcade.com
----- Original Message -----
From: SVerlander@aol.com
To: vectorlist@vectorlist.org
Sent: Friday, March 04, 2011 6:54 AM
Subject: Re: VECTOR: Sega G-80 PSU - Audio Amp
I never under stood why people think a switcher is better than a linear power supply.
I guess I just like to keep a classic original and not hack up the wiring harness. I have 3 star trek games and have never had a problem from the power supply's. I have seen a few that had problems with the inline pins having bad contacts and burning up but just replace the pins and plugs and their good as new.
It can and has been done so good luck.
In a message dated 3/4/2011 1:29:25 A.M. Eastern Standard Time, zittware@hotmail.com writes:
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Received on Fri Mar 4 20:07:38 2011
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