Amiga.org
Amiga computer related discussion => Amiga Hardware Issues and discussion => Topic started by: OSS542 on June 16, 2003, 03:30:41 AM
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I have several dead A2000 300W Bigfoot power supplies I'd like to repair if possible. Does any one know where I might find schematics for these ? Are they similar to the A2000 stock power supply ? Is there a schematic available for the stock supply ? I don't have access to the A2000 user's manual, so I can't check that. I don't think the power supply schematic is included there with the rest of the A2000 schematics anyway, as a number of slightly different models are said to have been used. I'd like to find some sort of example to work from if I am unable to find a Bigfoot schematic.
Thanks......:-)
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The Bigfoot power supplies for the Amiga 2000 are JUNK! Get an original 225 watt Amiga power supply. They are much higher quality. Just remove the top cover, blow out the dust with a can of compressed air, and replace the fan with a new fan from Japan, Germany, or England. Getting a really good fan is VERY important! If the fan ever goes bad, then the power supply will quickly over-heat and burn up. The best power supply fans are made in Japan, Germany or England. Check for any dark areas on the board, there should be none. Check for puffy or fat caps. If there are any, replace them with new caps. Check for darkened resisters. If any are darker then normal, replace them with new resisters. Also, check the power ICs. Make sure they are firmly secured to the heatsinks. You may have to loosen them up, clean away the old heatsink compound and replace with new compound and tighten back up. If these visual inspections pass, and you do blow out the dust and replace the fan, the power supply should last another 10+ years. :-D
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My electronics isn't amazing, being limited to a being a bit of an occasional hobby, but I wouldn't go fiddling with anything like PSUs unless you really know what you are doing
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..... or you goanna share Doomy's hairstyle :-D
(o.k. I stop here ;-) )
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@DoomMaster, please don't call others possessions "JUNK ! ", it is offensive.
And as a so called "professional" you should realize that power supplies are only to be serviced by qualified persons. There are others that will read your posts (the unexperienced and kids) that do not have the knowledge needed to understand what can be touched and what should not.
Warning label # 1 on A2000 power supply reads...
CAUTION: DISCONNECT POWER
You neglected to state this in your advice, and even with power disconnected you will still get a very nasty zap if you short the wrong contacts.
Warning label # 2 inside of A2000 power supply on transformer reads...
DANGER HIGH VOLTAGE
Warning label # 3 on heatsink reads...
CAUTION Hazard of Electric Shock-Heatsink is Live !
The A2000 power supply contains two 200 volt caps
that'll give a real jolt even days after having no power supplied, so it is ill advice to tell complete strangers in a public forum to go digging into a power supply.
Advice like yours will get some unexperienced person or kid hurt. This is a public forum, please keep that in mind when you post advice.
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Kronos wrote:
..... or you goanna share Doomy's hairstyle :-)
:lol:
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I've got a poor quality schematic for one of the A2000 PS models. (the Eltek) I can email it, if you want it... about 600K
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Maybe if I just tap this capacitor with my screwdriver...
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ZZZZZZZZZZZT!!!!!!!!
Check the fans too... The Amiga PS at least has current sensing on the fan. If it stalls out, or opens up, the current changes and the power supply will shut down for protection.
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What everyone else said. PSUs are not meant to be serviced in a casual manner. If you want them working again, find an electrical repair shop and see what they can do. Don't try it at home!
Oh, and once again Doomasster has everything all backwards. The 2000's stock PSU is junk. Otherwise there wouldn'tve been replacements for it.
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Why does doommaster always drop a burning torch in a thread like this and then disappear from it?
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To tony23:
I call things what they are! And I AM qualified to work on power supplies. The 200 volt caps will not hurt you because there is not enough current, they may zap you one time, but that is all. I did NOT "neglect" anything. COMMON SENSE should tell people to unplug the power cord before working on a power supply! :-P
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And I AM qualified to work on power supplies.
Maybe you are, but the ppl you give advice to are likely NOT.
The 200 volt caps will not hurt you because there is not enough current, they may zap you one time, but that is all. I did NOT "neglect" anything.
I doubt all 200V PSUs are identical. Also not every power supply is 200 volt. And how do you know if ppl have a pacemaker or other condition that makes them vulnerable to even smaller zap? Giving instructions like that IS dangerous and should be avoided on public forum.
COMMON SENSE should tell people to unplug the power cord before working on a power supply!
Like said, that is not enough. The caps can still hold a lethal charge.
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@ DoomMaster
Quote..
"I call things what they are!"
Well DON'T ! they are just your opinions NOT FACTS !
Nobody should have to suffer your opinions as Facts .
Quote...
" I AM qualified to work on power supplies"
So what if you are !
Others, that may heed your advice are not. This is a public forum with people of all ages and even all levels of intelligence.You should not assume that everyone comprehends the dangers of high voltage electronics.
Quote...
"The 200 volt caps will not hurt you because there is not enough current"
I don't care if you think there is not enough current . As Piru said above, you do not know the conditions of other peoples health.
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"they may zap you one time"
And that's all it would take.
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"but that is all"
No , that is not all.
Quote...
"I did NOT "neglect" anything."
Yes you did. You did neglect to give fair warning not to attempt to service power supplies unless you know what you are doing. Any professional would know to give this safety advice in a public forum.
Quote...
"COMMON SENSE should tell people to unplug the power cord before working on a power supply!"
Emergency wards are full of people without common sense.
It seems to me that your post in a public forum lacked the COMMON SENSE to include any warning what so ever.
Nuff Said .
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Boy, you guys sure like to pick on me, don't you?! Well, have fun. :-D
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@"DoomMaster"
May I just ask you a few tech. questions:
First, when you say a fan made in Japan, Germany or England, are there any particular brands that you are reccomending? Are there specific technical reasons as to why fans from these countries are better? Could you please give us the reasons that these fans are superior - and back it up.
Second, How specifically are commodore brand PSU's better than the "BigFoot" PSUs?
Explain all of this to us in detail - for now at least you seem to have an emotional bias toward anything commodore from the 80's.
Please prove us wrong.
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I don't care if you think there is not enough current . As Piru said above, you do not know the conditions of other peoples health.
God forbid Mr. McEwen should decide to start working on power supplies ;-)
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DoomMaster
Quote:
Boy, you guys sure like to pick on me, don't you?! Well, have fun.
end
You must remember when talking about mains power on an open forum that
not everyone has the experience with technical things, also there are
some very young people who read these forums. Whenever someone post
something involving mains power they should place a disclamer,
something to the effect of:
Danger! You will be dealing with mains power voltage if you attempt
this. The device may have Very Dangerous Voltages in it EVEN when
disconnected from the wall outlet. Do not attempt unless you know
what you are doing!
I would note that by not doing so could lead to you being sued!