Hi folks,
in the journey to resurrect my Falcon, I thought it would be good to check the PSU before recapping (and replacing the rectifier). Under load (4.7R on 5V, 22R on 12V) the 5V line was ok (4.96V), but the 12V line was just 10.27V ???
I stumbled over this thread https://www.exxosforum.co.uk/forum/viewt ... p?f=9&t=25, and it seems to indicate that this in "line of expectations" for this PSU? (If so: Is there nothing using the 12 line that needs be within a (+/-) 5-10% window of the nominal 12V, like you would expect it on a modern motherboard?)
Falcon PSU 12V line, what to expect?
Re: Falcon PSU 12V line, what to expect?
I wonder if you're simply overloading the 12V rail. The Falcon service manual mentions 0.2 A max. current.
Re: Falcon PSU 12V line, what to expect?
100R on the 12V would be plenty.
Also (never looked on the falcon psu) but its probably like all the other ST PSU's in that the 12V isn't regulated. The 5V is, and 12V is just whatever turns ratio it ended up on the transformer. Some ST PSU's even had diodes on the output to drop the 12V as it was normally 13V otherwise, then the diode vanished and 12V ended up more like 10V and the diode vanished.
Also (never looked on the falcon psu) but its probably like all the other ST PSU's in that the 12V isn't regulated. The 5V is, and 12V is just whatever turns ratio it ended up on the transformer. Some ST PSU's even had diodes on the output to drop the 12V as it was normally 13V otherwise, then the diode vanished and 12V ended up more like 10V and the diode vanished.
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viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
https://www.exxosforum.co.uk/atari/store2/ - All my hardware mods for sale - Please help support by making a purchase.
viewtopic.php?f=17&t=1585 Have you done the Mandatory Fixes ?
Just because a lot of people agree on something, doesn't make it a fact. ~exxos ~
People should find solutions to problems, not find problems with solutions.
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