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#1 |
Precious & fragile things
Join Date: Feb 2009
Location: Victoria, Australia
Posts: 1,946
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A500 / A600 / A1200 PSU Tester
The last thing anyone wants to do is plug in their precious Amiga to a bad PSU. I have made a little tester which puts moderate loads onto the + / - 12 volt lines and +5 volt lines
I grabbed a few of the power resistors I have lying around and snagged a power connector off an old A600 scrap board I have here and a 4 pin Molex socket off an old dead PC PSU. 8R2 @ 5W for +5 to GND 66R @ 6W ( 2 x 33R 3W Series ) for +12 to GND 500R @ 1/2W ( 2 x 1K 1/4W Parallel ) for -12 to GND |
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#2 |
Global Moderator
Join Date: Aug 2008
Location: Sidcup, England
Posts: 10,300
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Thanks for the idea, Paul!
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#3 |
Moderator
Join Date: May 2012
Location: Stockholm / Sweden
Age: 49
Posts: 1,575
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Ohh sell a kit =)
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#4 |
ex. demoscener "Bigmama"
Join Date: Jun 2012
Location: Fyn / Denmark
Posts: 1,642
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but that doesn't load anything (unless you short out pins in the molex connector)..
also, overvoltage is what usually kills things, which this thing doesn't test.. or am I missing the point of this thing? |
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#5 | |
Precious & fragile things
Join Date: Feb 2009
Location: Victoria, Australia
Posts: 1,946
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Quote:
610mA on +5 ( 4.3A max) 181mA on +12 ( 1A max ) 2.4mA on -12 ( 100mA max ) Not ideal by any means but with what I had lying around. Better values would be; 3.3R 10W for +5 ( 1.51A 7.57W ) 18R 10W for +12 ( 667mA 8W ) 150R 2W for -12 ( 80mA 0.96W ) The resistors will get hot so keep this in mind when running cabling and use appropriate wire for the current capacity. |
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#6 |
ex. demoscener "Bigmama"
Join Date: Jun 2012
Location: Fyn / Denmark
Posts: 1,642
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ahh, of course.. I had a quick glance at the photo and it looks like the resistors are in series with the power rails ;-)
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#7 |
Precious & fragile things
Join Date: Feb 2009
Location: Victoria, Australia
Posts: 1,946
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#8 |
Moderator
Join Date: May 2012
Location: Stockholm / Sweden
Age: 49
Posts: 1,575
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http://www.amistore.de/Amiga-Hard-un...eu::28462.html
Dont know if that is reliable or how many they have in stock. My german suck a bit. |
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#9 | |
Global Moderator
Join Date: Aug 2008
Location: Sidcup, England
Posts: 10,300
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Quote:
![]() However, they do still have the CD32 version! ![]() http://www.amistore.de/Amiga-Hard-un...eu::28463.html |
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#10 |
Moderator
Join Date: May 2012
Location: Stockholm / Sweden
Age: 49
Posts: 1,575
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Hrmp. The link certainly worked yesterday. They must have run out and removed the link. And no, it wasn't me =)
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#11 |
Registered User
Join Date: Jun 2010
Location: PL?
Posts: 2,877
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Resistors can be replaced by bulbs (car standardized are preferred).
Nothing can be comparable with something like this http://www.edn.com/design/analog/436...power-supplies http://www-d0.fnal.gov/hardware/cal/...nfo/curr_load/ http://www.eevblog.com/forum/project...y-load-tester/ http://www.edn.com/design/power-mana...s-as-low-as-2V |
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#12 |
Registered User
Join Date: Apr 2011
Location: birmingham
Age: 55
Posts: 2,827
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i had a quick look at the schematic in the third link you posted pady71,the zener at point d1 is shorted by the look of it.(it should of went to ground i think)
i didnt read the comments in thread though to see if anyone noticed it. using car bulbs is a good idea for low amp supplys for load testing,brake lights are good for this.(its sinple to setup for multiple rails) |
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#13 |
Registered User
Join Date: Jun 2010
Location: PL?
Posts: 2,877
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For low amp - LM317 or similar configured as current source can be used - this is one resistor, one LM317 (and counterparts - LM337, LM350 - or for voltage higher than reference even 7805 etc)
Just set this on decent radiator/heatsink (those from Pentium 4 can be bought as real bargain on ebay and most of them is capable to spread over 100W easily). http://www.eevblog.com/2010/08/01/ee...ttery-testing/ I mean my earlier links are just example relatively easy, high quality active load can be made if someone is interested in real power supply testing. http://www.eevblog.com/2010/08/01/ee...ttery-testing/ I mean as a contradictory example - resistor load for PC PSU testing http://techreport.com/review/13271/e...ies-compared/4 - it looks quite odd but works... |
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#14 |
Precious & fragile things
Join Date: Feb 2009
Location: Victoria, Australia
Posts: 1,946
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It was just a quick tester and I have included resistor values for the A500 brick ending in 05.
Bulbs are good because they have a low resistance at start up and increase over time as the filament heats up / lights up. |
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#15 |
Junior Member
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This is what I need!
I tested my nos 1200 psu and I now know the wrong method was used, I had no load on it. The trouble is that means having an amiga connected, if the psu is bad then I will kill things doing so. Would be brilliant to have a tester in kit form. Heck I would buy one and salvage the square din socket and solder it all myself ![]() |
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#16 | |
Precious & fragile things
Join Date: Feb 2009
Location: Victoria, Australia
Posts: 1,946
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Quote:
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#17 |
Unregistered User
Join Date: Sep 2012
Location: Copenhagen / DK
Age: 44
Posts: 4,190
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I found these a while ago, and it seems pretty cheap, although I haven't tried them yet:
http://imall.iteadstudio.com/open-pc...ototyping.html |
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#18 | |
Precious & fragile things
Join Date: Feb 2009
Location: Victoria, Australia
Posts: 1,946
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Quote:
A show of hands, if I get interest from 10 members I'll sort it out. |
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#19 |
Moderator
Join Date: May 2012
Location: Stockholm / Sweden
Age: 49
Posts: 1,575
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*Hand up*
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#20 |
Unregistered User
Join Date: Sep 2012
Location: Copenhagen / DK
Age: 44
Posts: 4,190
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I don't think ROHS is mandatory for DIY projects. If you were building and selling them, then that's a different story. However, I think all PCB production today is ROHS since most markets require it.
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