Repair techniques ... I/O pins and power supplies

From: THETechnoid_at_home.com <(THETechnoid_at_home.com)>
Date: Wed Apr 25 01:50:11 2001

Depends on the switcher you connect to it, but if it it isn't picky, you
might just get power. If it is a picky sort, I often use a spare hard
disk to provide the load required to turn the sucker on. A big motor makes
all the difference. My Atari 8-bit will run off of anything, but
'anything' won't run it if I don't provide a significant load.

Regards,

Jeff


n <3AE62A4A.4558E7FA_at_bresnanlink.net>, on 04/25/01
   at 02:50 AM, Michael Brutman <mbbrutman_at_chartermi.net> said:


>I've always wanted a PCjr with an expansion chassis on it, but they were
>pretty expensive, and I got by without one. 15 years later I have found
>one on Ebay and bought it, but alas it's not a happy ending. There are
>at least two serious problems that I need to fix.

>The first problem is a broken I/O pin on the expansion bus
>that comes off the motherboard. The pin is in a 60 pin
> rectangular connector, and spacing is tight. he broken pin
>is a data line pin, so if I don't fix it, I can't add any
>sidecars to the machine. How does one go about replacing
>a pin? Is it possible? Or am I going to have to desolder the connector
>and try to replace the entire connector? (And I'm not good with a
>soldering iron ... I can't even tin wires.)

>The second problem looks to be a bad power supply. The
>expansion unit has it's own power supply because the PCjr power supply is
>only about 33 watts. The expansion unit has extra memory in it that is
>not being seen by the system unit; I
>suspect that is because the +5 output on the power supply
>is reading about 1.8 volts. (According to a digital
>multimeter.) I measured this with everything connected,
>so there certainly is enough load. (I don't think that
>this is even a switching power supply, so the load issue
>is moot.)

>The power supply has a "pick" line that is
>probably activated from the main unit, so that it doesn't
>have to have an independent power switch. How does such
>a pick line work? Is there a way to fool it on? What
>does it use for a ground? (I didn't see one clearly
>labeled that belonged to the pick line ... perhaps it
>was the same ground as the +5v line?)

>How can I confirm that this power supply is truly
>toast? And it is, then how do I replace it? (I'm willing
>to scab in a reasonable substitute - it probably can't be
>a switching supply though because there won't be enough
>load - it's probably only 512KB of chips on board.

>The expansion unit is a Rapport if that helps anybody.



>Thanks,
>Mike

-- 
-----------------------------------------------------------
Jeffrey S. Worley
President
Complete Computer Services, Inc.
30 Greenwood Rd.
Asheville, NC 28803
828-277-5959
Visit our website at HTTP://www.Real-Techs.com
THETechnoid_at_home.com
-----------------------------------------------------------
Received on Wed Apr 25 2001 - 01:50:11 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:33:29 BST