3000 internal clock

3000 internal clock

Post by Daniel J. Andrea » Wed, 31 Jul 1996 04:00:00



Shane Shariff said in comp.sys.amiga.hardware on 30-Jul-96 18:34:17
 SS> Hi,

 SS> my internal clock seemed to die on my A3000. It seems that
 SS> no power is getting to the clock chip, and no power
 SS> goes to the clock battery to recharge it...

 SS> Does anyone know which chip is responsible for charging the battery?

 SS> Also, any ideas on powering the clock chip itself, with say
 SS> a lithium battery, so at least it doesnt lose the time?

 SS> Any help is much appreciated!!! (I am tired of setting the clock
 SS> manually!!!)

 SS> ( it looks like the motherboard may have been slighty damaged
 SS> in this area from corrosion but its very little; some resistors
 SS> have a bit of green stuff on there leads..)

 SS> Thanks..

This info I've pulled from my A3000 service manual (note: this manual was
printed for some version of the motherboard BEFORE the rev 9/x motherboards.
Some items are different on my 9/something motherboard):

The Clock/BattMEM RAM battery (BT190) is charged by two resistors (R190 and
R192, both 470 ohm) and a diode (D191, 1N4148).  The power is supplied from
the main +12v supply thru R190 to D191's anode and then from D191's cathode
thru R192 to the battery + terminal.  There is also a connection to +5v
supply from between R190 and D191 through another diode (D190, 1N4148).  The
power for the clock chip is pulled from between D191 and R192. Since both the
clock and the battery appear to be losing power, I'd first check to see if 12
volts is present on the powersupply side of R190.  If so, then R190 and/or
D191 may be blown.  Another possibility is the battery could be bad, with a
dead short to ground, which may pull the voltage down far enough between R192
and D191 to keep the clock chip from working.

I've repaired electronics for about 6 years at a local shop, and have seen
those types of problems in CD players, stereos, etc., so if you need anymore
help, let me know.


   Amiga 3000 '030 25MHz, 4 meg FastRAM, 1 gig HD, Zip drive, AmigaDOS 3.1
               and.....      *Vision 64 2 Meg video card
  Public PGP key available, Fingerprint = A452EF542E7FFD29 E58E374FFB7AA881

And now...
"Dead or alive, you are coming with me."  Robocop

 
 
 

3000 internal clock

Post by Shane Shari » Thu, 01 Aug 1996 04:00:00


Hi,

my internal clock seemed to die on my A3000. It seems that
no power is getting to the clock chip, and no power
goes to the clock battery to recharge it...

Does anyone know which chip is responsible for charging the battery?

Also, any ideas on powering the clock chip itself, with say
a lithium battery, so at least it doesnt lose the time?

Any help is much appreciated!!! (I am tired of setting the clock
manually!!!)

( it looks like the motherboard may have been slighty damaged
in this area from corrosion but its very little; some resistors
have a bit of green stuff on there leads..)

Thanks..

 
 
 

3000 internal clock

Post by Jill A. Snid » Wed, 07 Aug 1996 04:00:00



>my internal clock seemed to die on my A3000. It seems that
>no power is getting to the clock chip, and no power
>goes to the clock battery to recharge it...
>Does anyone know which chip is responsible for charging the battery?
>Also, any ideas on powering the clock chip itself, with say
>a lithium battery, so at least it doesnt lose the time?
>Any help is much appreciated!!! (I am tired of setting the clock
>manually!!!)
>( it looks like the motherboard may have been slighty damaged
>in this area from corrosion but its very little; some resistors
>have a bit of green stuff on there leads..)
>Thanks..

You _MUST_ remove that old battery as soon as you can!  From your
description it is apparent that it has gone bad and is leaking
corrosive stuff on your motherboard.  Replace it as soon as
possible and hope no other components have been badly damaged!

A lithium battery would be OK (they ARE re-chargeable, aren't
they?), as long as it is rated at the same 3.6 volts.

The batteries in A3000s (and some older A4000s) are now old enough
for this problem to start showing up.  I replaced the battery in
our A3000 with a cell phone battery I bought at a large discount
store for about eight US dollars.  It is rated at about six times
the storage capacity (360 milli-Ampere hours compared to the
original's 60 mAh).

Good luck!

borrowing his roommate's account for USENET
--

 
 
 

1. 3000 Clock and Printer Problems

Hi!

My 3000 has developed a few odd problems:

   1. The system clock will lose time; i.e., it will count
      up to the next minute and then lose a minute.  That's
      when it runs; sometimes it doesn't run at all.  The
      battery backed up clock seems to work great.  I always
      have the right time when I boot up, but that's the
      only time it's right.

   2. If I turn on the printer (attached to the parallel
      port) everything freezes until I *cold* boot.  It will
      not boot with the printer on.

I tried replacing the CIA chips, but that didn't help.
Any ideas?

Thanks,
Mark
--

2. Arexx UUCP mail server

3. Amiga 3000 16Mhz clocked at 25Mhz

4. Export All Messages At Once?

5. Amiga 3000 Battery backed clock

6. How to check if Win or Win-OS/2

7. A-3000 Clock Battery

8. Upgrading Vx to m505. Is it better to install everything from scratch?

9. 3000 built-in clock problem

10. Internal FDD for Amiga 3000

11. Internal modem in 3000?

12. Internal termination on 3000 and Quantums?

13. Internal floptical/MO for 3000?