PRAM Battery Source + Bypassing Battery test on Titanium

Discussion in 'PowerPC Macs' started by AmestrisXServe, Mar 5, 2014.

  1. AmestrisXServe macrumors 6502

    Joined:
    Feb 6, 2014
    #1
    Good source for coin batteries with tabs?

    I'm looking for a supplier of coin-type batteries, with tabs, for Powerbook units. I need them in bulk (10 to 20 units at a time), and would like to find a supplier with discount pricing for quantity.

    I have a stack of Powerbook and iBook models that need new PRAM batteries, including some TItanium (400-500MHz VGA models) that will not power on, which I expect is due to faulty PRAM batteries.

    Does anyone recall if there is a way to bypass the PRAM battery check, to turn on a Titanium with a bad PRAM battery? I recalled that Command + Shift, Option + Shift, or Control + Shift did something like this, but it has been a very long time since I was required to recall exactly what these did.

    Do any of you know a way to jumper the mainboard, so that the system will allow a power-on without a PRAM battery module?

    I hate to replace batteries in systems that I can't test at all, just to test them. I need to inspect the modules, to see if the same module is used on the VGA (400MHz and 500MHz) systems, and the DVI (800MHz to 1GHz) systems. I should have some DVI systems with no displays, from which I can rob components.
     
  2. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #2
    iBook's don't have PRAM batteries and Tibooks will boot with a dead one or without one installed. The PRAM battery in Tibooks is a rechargeable lithium coin cell. Leave it plugged in with the main battery out for a few hours to charge the PRAM battery.
     
  3. AmestrisXServe thread starter macrumors 6502

    Joined:
    Feb 6, 2014
    #3

    You know, you;re right It's probably a bad capacitor for the iBook units.

    The TiBook batteries are rechargeable, but the first line, of 400/500MHz units are at a point, where the battery no longer properly retains current. It has been twelve to thirteen years, after all.

    I was rather certain that a failing PRAM battery would cause a TiBook not to power-on. Unless this is come grand conspiracy, there is a decent amount of documentation on that being a probable culprit of a system refusing to start.

    I seem to recall some key combination, or removing the module and pressing a key combination, or something odd along these lines, would fix this problem.
     
  4. jrsx macrumors 65816

    jrsx

    Joined:
    Nov 2, 2013
    Location:
    Tacoma, Washington
    #4
    As Intell said, iBooks don't have PRAM batteries. Many people think they do, but it's really just a little capacitor that holds up to 20 minutes. Many people also think that the capacitor only holds about a minute tops, but that's not true. I think the iBook G4s had a lot of bad PRAM capacitors, my previous G4 held time for about 15 seconds without the main battery, and you constantly see people on the web asking about their ibook forgetting time if they've had the battery out for a very short time, maybe just switching batteries, even.
    My current iBook holds it for several minutes, but I'm not sure exactly how long.
     
  5. AmestrisXServe thread starter macrumors 6502

    Joined:
    Feb 6, 2014
    #5

    I don't really know why the iBook is a topic of conversation here, at present. I admitted a fault, in that I had forgotten about the cap in the iBook series, and that the single iBook that I have with a PRAM problem, likely has a bad capacitor.

    That is not the case with the sixteen Powerbook Titaniums that I have one hand, of which an assortment do not hold PRAM settings (and will not recharge the PRAM battery), and two refuse to start at all, which I recall being a known problem for VGA units with bad PRAM modules.

    I still need any source references for buying bulk PRAM batteries for the TiBook (Titanium Powerbook G4), and anything on the topic of the PRAM battery in those units (particularly the 400MHz and 500MHz versions) being a culprit in the system refusing to start.

    I believe there was a process to fix, or to bypass, this singular problem, and I will try a few more things before I resort to waiting on any other response.
     
  6. jrsx macrumors 65816

    jrsx

    Joined:
    Nov 2, 2013
    Location:
    Tacoma, Washington
    #6
    Sorry, just wanted to chime in on iBooks. Didn't mean anything personal to you, just trying to help and solve confusions. :(
    Have you checked iFixit for PRAM batteries? They have a lot of Ti parts that might be helpful for you. I don't know about bulk, though.
     
  7. AmestrisXServe thread starter macrumors 6502

    Joined:
    Feb 6, 2014
    #7
    Don't worry about it any further mate: I gave this the old school try, with al the voodoo, and sorcery that I had in me, and it is still a problem. Disconnecting the PRAM battery, and button combinations of every kind hadn't any effect, and as the 400Mhz system the power module integrated on the mainboard, tracing power faults becomes a nightmare.

    I need to look through my files to see if I have a magical schematic for the pre-DVI TiBook, or at least, a power diagram.

    I need to check the PMU battery discs to be certain, but I may have been wrong in what type of coin battery they use. There used to be a variety of replacement modules, but most of these were over-the-top, and I don;t know what, if any effect, changing it would have.

    It is routed to the PMU system, but may not have any effect on power-on; or it may, and I don't recall the incantations to resurrect one of the early models. I rarely worked on these, as they were rather solid systems, and I usually received repair orders on the 800MHz through 1GHz models; that of course, have a modular power board.

    When I have more time, patience, and can see better, I will try tracing the power routing, and see if I can find a fault anywhere. It is odd though, that two, identical units, of the same age, have an identical problem. That is partly why I associated it to the PRAM module.

    For ordering the batteries, the prices from mainstream resellers is absurd. The coin batteries should be no more than £3-4 as a generic part. I'm going to ask my fobwatch supplier if he has any of the same spec, as he also repairs clocks, and other timekeepers.

    I don't even remember if the battery has a soldered tab, or if it is held behind a tab. I believe I have had to replace two of these in the past thirteen years...and none in the last eight.

    My main reason to swap them, is to do every system at one time, so that I am positive that the PRAM batteries are fresh, and I'm going to rebuild the main battery packs at the same time. I know that the after-market, Chinese battery packs should be about £10 wholesale, however I don't know what wholesalers have them on hand, although I can place a 10-unit order, to meet that typical minimum for batteries of this kind.
     
  8. Intell macrumors P6

    Intell

    Joined:
    Jan 24, 2010
    Location:
    Inside
    #8
    The coin cells in those are soldered to the board. They are expensive because the coin cell itself it expensive due to them being a rechargeable one.
     
  9. AmestrisXServe thread starter macrumors 6502

    Joined:
    Feb 6, 2014
    #9
    Right, but even rechargable coin cell batteries of this size should be less than £4.

    This one, for example, is $3 (£2): https://www.sparkfun.com/products/10319

    Charging £15 or more for one part is sheer robbery.

    I can always flux the battery and apply the tab to it, if the privileged of having it pre-soldered is a £12 difference.
     

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