Page 1 of 2 12 LastLast
Results 1 to 10 of 17

Thread: Sproggy PS is not a good choice..

  1. 07-16-2002, 08:17 AM #1
    THEMP3KID
    THEMP3KID is offline
    Banned
    Join Date
    Jun 2001
    Location
    Adelaide, Australia
    Posts
    687
    Send a message via ICQ to THEMP3KID

    Sproggy PS is not a good choice..

    Well, the actual supply is fairly good, but the -12volt line REALLY needs some sort of regulation... :P Upon testing it with a single CDrom as the load (drawing 1.2amps max off the 12volts) the -12volts peaked at OVER -22VOLTS!!!! this can't be good.. :P I think that a simple low dropout -12volt regulator should be added to the -12volt line.... they have a max input of -12.6 and a mix of -26, which should keep it happy even with no load on the 12volts... Perhaps Mastero should include this modification it all the PSs he sells?? Or perhaps a modification should be made to teh board to include this.. also, I thoght I should point out, that even with no load on teh 12volts, my -12volts measured over -13volts..
    2 week temp ban (spam and complaining about deleted posts)
    register another account and you're gone for good.
    Reply With Quote Reply With Quote
  2. 07-16-2002, 08:51 AM #2
    dug1967
    dug1967 is offline
    Maximum Bitrate
    Join Date
    Apr 2002
    Location
    Houston, TX
    Posts
    558
    Well that is a very good observation MP3Kid..... good to see people are really experimenting with this stuff....

    But I think the opening statement of the post is a little extream. You may very well be right and we all should investigate the mod you speak of, any improvement is a good improvement.

    But with the numbers out there succesfully using the Sproggy design it obviously is a GOOD design and all in all is probably the best available right now for people doing this.

    But as I stated above, very interesting observation... I will trinker with the idea. I just got the final parts to build two more Sproggy 2.7 PSU's so I will try to duplicate your finding.
    Reply With Quote Reply With Quote
  3. 07-16-2002, 09:01 AM #3
    THEMP3KID
    THEMP3KID is offline
    Banned
    Join Date
    Jun 2001
    Location
    Adelaide, Australia
    Posts
    687
    Send a message via ICQ to THEMP3KID
    Yeah, the topic title was abit harsh, but I thought it would get peoples attention... Sure, lots of people are using them, but would you really want to feed your expensive mobo with -8volts more than what it is meant to have??
    2 week temp ban (spam and complaining about deleted posts)
    register another account and you're gone for good.
    Reply With Quote Reply With Quote
  4. 07-16-2002, 09:51 AM #4
    Rob Withey
    Rob Withey is offline
    Raw Wave Rob Withey's Avatar
    Join Date
    Apr 2000
    Location
    Bedfordshire, UK
    Posts
    2,139
    Send a message via ICQ to Rob Withey Send a message via MSN to Rob Withey
    Yep, this issue was already identified in this thread:

    sproggy - Testing voltage outputs


    Rob
    Old Systems retired due to new car
    New system at design/prototype stage on BeagleBoard.
    Reply With Quote Reply With Quote
  5. 07-16-2002, 10:03 AM #5
    phil.45
    phil.45 is offline
    Variable Bitrate
    Join Date
    Apr 2002
    Location
    South Coast, UK
    Posts
    437
    MP3KID you posted in that other thread so you must have already known of this problem!!!
    -------------------------------------------
    (=========-) 99% complete
    --------------------------------------------
    AMD K6/2 500 @ 450mhz to keep heat and power usage down, 64Mb, slim CDrom drive, 64mb USB pendrive for MP3 transfer, 10Gb 2.5" drive for MP3, USB>RS232
    All jammed in external CDROM drive case.
    Kenwood KVC-1000r In-Dash LCD. x-10 MouseRemote. Destinator V2 Gps. DC-DC with onboard Shutdown controller.
    ----------------------------------------------
    Reply With Quote Reply With Quote
  6. 07-16-2002, 10:03 AM #6
    MikeHunt79
    MikeHunt79 is offline
    Maximum Bitrate MikeHunt79's Avatar
    Join Date
    Aug 2001
    Location
    Cambridge & Bristol, UK
    Posts
    707
    Send a message via ICQ to MikeHunt79 Send a message via AIM to MikeHunt79 Send a message via MSN to MikeHunt79 Send a message via Yahoo to MikeHunt79
    i`m sure a 7812 linear reg would work, as -12v pulls very little, if any current. I think someone should do a redesign on the sproggy, with this mod, atx startup shutdown (see previous thread) and an optional 10amps on the +5v rail (like the 2.7), and maybe 4 amps on the +12v rail? Call it a sproggy 3.0 or something.
    My Setup
    Reply With Quote Reply With Quote
  7. 07-16-2002, 04:21 PM #7
    Andrew Chappell
    Andrew Chappell is offline
    Variable Bitrate
    Join Date
    Dec 2001
    Location
    Paignton, Devon, UK
    Posts
    315
    Send a message via AIM to Andrew Chappell
    Hehe perhaps that'll be my summer project? I guess it should be easy enough - i think the design is sound, just needs to be more powerful. perhaps a double board with a kinda 2.7 but split in half. But well done mp3kid for bringing this to my attention, i must have missed the previous thread. I'd rather feed my motherboard with -12 rather than -22
    Mediabox Hardware Project
    Current Stage: A complete redesign, although not much happening right now!

    Mediabox Software Project
    Status: Writing Sync Software (still) and playing around with interface
    To do: Far too much!
    Reply With Quote Reply With Quote
  8. 07-16-2002, 05:12 PM #8
    Mastero
    Mastero is offline
    FLAC Mastero's Avatar
    Join Date
    Aug 2001
    Location
    India
    Posts
    1,637
    Send a message via AIM to Mastero
    OK lets get this straight is there even one Mobo which had a problem with the negative 12 volts ??

    Like a properly built sproggy??

    Cause if there was no problem to all the sproggy users i dont think there is much concern for this....

    Cause if this was a major flaw then the sproggy's PSU wouldnt have helped so many

    Mastero
    Reply With Quote Reply With Quote
  9. 07-16-2002, 05:18 PM #9
    Andrew Chappell
    Andrew Chappell is offline
    Variable Bitrate
    Join Date
    Dec 2001
    Location
    Paignton, Devon, UK
    Posts
    315
    Send a message via AIM to Andrew Chappell
    I doubt it is a major problem, but if it was being re-designed i think it would be a good idea. Cheers for the pcb's / shutdown controller - I'm having loadsa fun soldering all the components onto it now.

    Andrew
    Mediabox Hardware Project
    Current Stage: A complete redesign, although not much happening right now!

    Mediabox Software Project
    Status: Writing Sync Software (still) and playing around with interface
    To do: Far too much!
    Reply With Quote Reply With Quote
  10. 07-16-2002, 06:56 PM #10
    eugenen
    eugenen is offline
    Maximum Bitrate eugenen's Avatar
    Join Date
    May 2002
    Location
    Ohio
    Posts
    858
    Send a message via MSN to eugenen
    Since were pulling very little current off the -12v line why not just put a 12.6v zener across the -12v line to cap it. A small zener diode (1A) should be fine. Ahh here we go, did a google for zener, fund this link http://hyperphysics.phy-astr.gsu.edu...ids/zener.html
    middle part shows a simple regulator ckt. zeners are basicaly what is inside a linear regulator, but the linears have extra stuff added. Notice that since a zener operates in the reverse voltage side, it is connected so it appears backwards in this ckt. Basically you want it to not conduct (block) currnet. When the voltage goes over its rating it will conduct shorting the extra to ground. (very un-scientific explanation there). Since we want to regualte negativge voltage we just need to reverse the diode.
    Reply With Quote Reply With Quote
Page 1 of 2 12 LastLast
« Previous Thread | Next Thread »

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Forum Rules