Fair enough – there is something to be said for original.
As an example; my board is showing signs of over use. The Diodes (– I assume are for the 5v/4A circuit... ) are already turning the board brown.
Yes, I can replace them and keep them high off the board to improve airflow due to convention; but this really just a bandaid for a much larger problem.
At least on my machine; I’m seeing over 4.6A of current nominally on the 5V line – as measured across the R25 sense resistor. Not sure if it’s aging components or normal for this game.
The other item of concern is the sheer number of caps on the board; likely stemming from the use of half wave rectifier ckts for the main supplies.
Additionally; I really hate the fact that they didn’t silkscreen that board. Not having the components labels makes for a nightmare in troubleshooting.
Finally; Because I want to.
From: SVerlander@aol.com
Sent: Friday, March 04, 2011 12:54 AM
To: vectorlist@vectorlist.org
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:
All,
I’m about 1/2 the way through my modernizing of the G-80 PSU board in the Sega Vector machines.
I’ve already designed and laid out the 5V/4A and 12V/3A Switcher; I’m now going to focus on the negative voltages and soon the audio amplifier.
I believe the 5V and 12V switchers have a lot more head room than quoted above – but I need to do some bench top testing once I have a PCB back from batchpcb.
My desire is to replaced the discreet transistor amp w/ a more modern monolithic IC – proally from Maxim.
Anyone have any clue what the specs on the transistor amp are? Wattage?
The plan is to “donate” the PSU design to the community under the open hardware TAPR license once it’s validated and functional.
John
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Received on Fri Mar 4 02:05:49 2011
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