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Re: Reconstructing an AT&T 7300

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On Friday, June 12, 2015 at 3:14:55 AM UTC+3, DoN. Nichols wrote:
> On 2015-06-11, vlaarom@gmail.com <vlaarom@gmail.com> wrote:
> > Hello All,
> 
> > I've found an at&t 7300 and disconnected floppy, hdd and display. When
> > I power it up relays in modem are going crazy.
> >
> > Why  the relays are going crazy?
> 
> 	Well ... it is most likely the connector on the power supply.
> You already have it apart, if you have all of those disconnected, so you
> can look easily.
> 
> 	Pull the wide single-row connector (orange plastic) from the row
> of pins on the power supply.  Look along its side.  If any of the
> plastic over the pins has turned slightly brown, it has developed high
> resistance and is heating, and the voltage is spiking and falling.
> 
> 	If it is *very* brown, or black, it has probably heated things
> up badly enough so the solder has melted from around one of the pins on
> the underside the power supply's circuit board.  (You'll have to pull
> the power supply out of the system to verify this, and to work on it.)
> 
> 	Since it is a 7300, not a 3B1, I suspect that the power for the
> hard disk drive is fed through the system board, so it burns the
> connector a bit sooner.  (Later 3B1 power supplies have a cable soldered
> directly to the board to carry power to the hard disk drive, and thus
> reduce the current through the rest, though it also typically has a full
> 2MB of RAM on the system board, so the current load there increases.
> 
> 	If the connector is dark brown from overheating, it really
> should be replaced.  It is possible to pull the back cover off it, then
> ease the indivdual wires from the stiff ribbon cable out of the
> individual slots, and install them in a replacement connector of the
> same type by pressing down on either side of the metal of each pin, with
> perhaps the tips of some needle-nose pliers.
> 
> 	IIRC, the connector has either 18 pins or 38 pins -- I forget
> which.
> 
> 	But, in any case, spray the pins with a good contact cleaner,
> and slide the connector on and off the pins several times to clean off
> any oxidation.  What I use to really like was something called
> "Cramolin", but it got discontinued because of something toxic or bad
> for the ozone layer, and it was replaced with something called De-Oxit.
> 
> 	Either of them come in two colors, intended to encourage you to
> spray with one, wipe it clean, and then spray again prior to
> reassembling.
> 
> 	Of course, it could be something else, but this is what I would
> check first.
> 
> 	Good Luck,
> 		DoN.
> 
> -- 
>                   Remove oil spill source from e-mail
> Email: <BPdnicholsBP@d-and-d.com> | (KV4PH) Voice (all times): (703) 938-4564
>    (too) near Washington D.C.     | http://www.d-and-d.com/dnichols/DoN.html
>            --- Black Holes are where God is dividing by zero ---

Thank you.
I've replaced power supply with a pc atx power supply. Relays are normal now.
I'm trying to boot at&t, but i see only running green rectangles. All 4 leds are on.
Lithium battery is dead.

I will try to replace battery. I think it will solve boot problem.

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Reconstructing an AT&T 7300 vlaarom@gmail.com - 2015-06-11 05:38 -0700
  Re: Reconstructing an AT&T 7300 "DoN. Nichols" <BPdnicholsBP@d-and-d.com> - 2015-06-12 00:13 +0000
    Re: Reconstructing an AT&T 7300 vlaarom@gmail.com - 2015-06-15 11:01 -0700
      Re: Reconstructing an AT&T 7300 "DoN. Nichols" <BPdnicholsBP@d-and-d.com> - 2015-06-17 01:43 +0000
        Re: Reconstructing an AT&T 7300 vlaarom@gmail.com - 2015-06-17 00:18 -0700
          Re: Reconstructing an AT&T 7300 "DoN. Nichols" <BPdnicholsBP@d-and-d.com> - 2015-06-18 03:42 +0000
            Re: Reconstructing an AT&T 7300 vlaarom@gmail.com - 2015-06-25 01:44 -0700
              Re: Reconstructing an AT&T 7300 "DoN. Nichols" <BPdnicholsBP@d-and-d.com> - 2015-06-26 02:23 +0000
  Re: Reconstructing an AT&T 7300 Convergent MightyFrame <mightyframect@gmail.com> - 2015-06-13 11:46 -0700
    Re: Reconstructing an AT&T 7300 vlaarom@gmail.com - 2015-06-15 11:01 -0700
  Re: Reconstructing an AT&T 7300 vlaarom@gmail.com - 2015-07-07 01:24 -0700
    Re: Reconstructing an AT&T 7300 "DoN. Nichols" <BPdnicholsBP@d-and-d.com> - 2015-07-12 01:06 +0000
      Re: Reconstructing an AT&T 7300 vlaarom@gmail.com - 2015-07-15 07:46 -0700
        Re: Reconstructing an AT&T 7300 "DoN. Nichols" <BPdnicholsBP@d-and-d.com> - 2015-07-18 03:53 +0000
  Re: Reconstructing an AT&T 7300 vlaarom@gmail.com - 2015-08-04 04:36 -0700
    Re: Reconstructing an AT&T 7300 "DoN. Nichols" <BPdnicholsBP@d-and-d.com> - 2015-08-09 02:11 +0000
      Re: Reconstructing an AT&T 7300 "vla...@gmail.com" <vlaarom@gmail.com> - 2021-12-13 14:00 -0800

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