getting low readings on 12V Falcon supply

Repairs & upgrades.
jacolover
Posts: 47
Joined: Sun May 03, 2020 6:40 am

getting low readings on 12V Falcon supply

Post by jacolover »

the -12V rail is down to -10.59 v and the 12V is 11.59, +-5V is good, fan spins up but the 12V is too low, any ideas? This is a Skynet supply with Chemicons so I haven't replaced any caps on it, maybe I need to? Would be good to have a schematic but that doesn't appear to be available anywhere, so any suggestions would be good, thanks!
User avatar
frank.lukas
Posts: 660
Joined: Fri Jan 19, 2018 11:52 am

Re: getting low readings on 12V Falcon supply

Post by frank.lukas »

This is normal and good.
Steve
Posts: 2570
Joined: Fri Sep 15, 2017 11:49 am

Re: getting low readings on 12V Falcon supply

Post by Steve »

Yes as Frank said this is within tolerance and fine
User avatar
frank.lukas
Posts: 660
Joined: Fri Jan 19, 2018 11:52 am

Re: getting low readings on 12V Falcon supply

Post by frank.lukas »

The + 12v from the powersupply has only a few milliamps and is not loadable ...
User avatar
exxos
Site Admin
Site Admin
Posts: 23499
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: getting low readings on 12V Falcon supply

Post by exxos »

12v 200mA. Falcon pulls 130mA from it.

https://www.exxosforum.co.uk/atari/last/ ... htm#FALCON
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
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.
jacolover
Posts: 47
Joined: Sun May 03, 2020 6:40 am

Re: getting low readings on 12V Falcon supply

Post by jacolover »

OK, but is that acceptable for the -12 rail, a -10.69 sounds awfully out of tolerance, thanks!
User avatar
exxos
Site Admin
Site Admin
Posts: 23499
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: getting low readings on 12V Falcon supply

Post by exxos »

jacolover wrote: Wed Mar 17, 2021 10:17 pm OK, but is that acceptable for the -12 rail, a -10.69 sounds awfully out of tolerance, thanks!
There is probably no regulation on the 12V, only the 5V. 12V is just pot luck on winding ratios of the transformer itself. So "normal" could be 10V-14V etc.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
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.
jacolover
Posts: 47
Joined: Sun May 03, 2020 6:40 am

Re: getting low readings on 12V Falcon supply

Post by jacolover »

Thanks exxos, I plan on using this supply with a Mega STe as they have the same connector and looks like the same voltage requirement, does that sound OK?
User avatar
exxos
Site Admin
Site Admin
Posts: 23499
Joined: Wed Aug 16, 2017 11:19 pm
Location: UK
Contact:

Re: getting low readings on 12V Falcon supply

Post by exxos »

jacolover wrote: Wed Mar 17, 2021 10:50 pm Thanks exxos, I plan on using this supply with a Mega STe as they have the same connector and looks like the same voltage requirement, does that sound OK?
Falcon PSU's are nothing like MEGA STE PSU's... They are not compatible.
https://www.exxosforum.co.uk/atari/ All my hardware guides - mods - games - STOS
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.
jacolover
Posts: 47
Joined: Sun May 03, 2020 6:40 am

Re: getting low readings on 12V Falcon supply

Post by jacolover »

Thanks for the heads up, just looking at them I thought they were, good to know!
Post Reply

Return to “PSU (power supplies)”