A3010 CMOS issue after battery replacement
A3010 CMOS issue after battery replacement
Afternoon all
I replaced the original CMOS battery on an A3010 I aquired recently with two Eneloop's in an AA battery holder. I'm getting 2.6v when measured from the batteries / terminals but when power is off for more than five minutes then it boots to a black / dark grey screen with no POST just a faint beep. Clear CMOS and it POST's and boots to desktop without issue but obviously all settings are lost.
As the original battery was fairly well depleted (<1v) and I've got no history of the machine I don't know if the CMOS had an issue previously as always had to Del-Power on. Any ideas where to check first?
Should add that the battery had practically zero leakage and the board appears clean enough though still did the standard clean up job on the area first
I replaced the original CMOS battery on an A3010 I aquired recently with two Eneloop's in an AA battery holder. I'm getting 2.6v when measured from the batteries / terminals but when power is off for more than five minutes then it boots to a black / dark grey screen with no POST just a faint beep. Clear CMOS and it POST's and boots to desktop without issue but obviously all settings are lost.
As the original battery was fairly well depleted (<1v) and I've got no history of the machine I don't know if the CMOS had an issue previously as always had to Del-Power on. Any ideas where to check first?
Should add that the battery had practically zero leakage and the board appears clean enough though still did the standard clean up job on the area first
- DutchAcorn
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Re: A3010 CMOS issue after battery replacement
What voltage do you measure over pins 4 and 8 of the cmos chip when power is off?
Paul


- flaxcottage
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Re: A3010 CMOS issue after battery replacement
I've had problems with Eneloop batteries. They show very high self-discharge at times. I'd check them first.
If the CMOS still fails to hold its settings are the correct voltages being applied to the chip when the A3010 is off.
I've also noticed that Axxxx machines need to be powered on for at least 30 minutes first time before they will boot correctly. Maybe leave the machine on for a time before switching off.
If the CMOS still fails to hold its settings are the correct voltages being applied to the chip when the A3010 is off.
I've also noticed that Axxxx machines need to be powered on for at least 30 minutes first time before they will boot correctly. Maybe leave the machine on for a time before switching off.
Re: A3010 CMOS issue after battery replacement
IC5 is not measuring anything...
Re: A3010 CMOS issue after battery replacement
I'll try leaving it on for a while. The batteries are showing 1.3v each and 2.66v in seriesflaxcottage wrote: ↑Sun Jun 10, 2018 12:58 pmI've had problems with Eneloop batteries. They show very high self-discharge at times. I'd check them first.
If the CMOS still fails to hold its settings are the correct voltages being applied to the chip when the A3010 is off.
I've also noticed that Axxxx machines need to be powered on for at least 30 minutes first time before they will boot correctly. Maybe leave the machine on for a time before switching off.
Re: A3010 CMOS issue after battery replacement
Left it on for an hour before leaving it switched off for 7-8 minutes. Turning back on it posts but get blinking underscore prompt or Supervisor prompt. Typing *desktop gives errorsmattdy4 wrote: ↑Sun Jun 10, 2018 1:02 pmI'll try leaving it on for a while. The batteries are showing 1.3v each and 2.66v in seriesflaxcottage wrote: ↑Sun Jun 10, 2018 12:58 pmI've had problems with Eneloop batteries. They show very high self-discharge at times. I'd check them first.
If the CMOS still fails to hold its settings are the correct voltages being applied to the chip when the A3010 is off.
I've also noticed that Axxxx machines need to be powered on for at least 30 minutes first time before they will boot correctly. Maybe leave the machine on for a time before switching off.
Re: A3010 CMOS issue after battery replacement
Thanks Ian and everyone else, found this out which was pretty definitive - viewtopic.php?f=16&t=12245&p=155838&hilit=r73#p155838
I guess that the battery had leaked more than I thought! R60 - R61 link looks fine though at least so hopefully just that. Pads look pretty corroded and not entirely sure if this is in my skill set to replace so will probably have to find a man that can
I guess that the battery had leaked more than I thought! R60 - R61 link looks fine though at least so hopefully just that. Pads look pretty corroded and not entirely sure if this is in my skill set to replace so will probably have to find a man that can
- DutchAcorn
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Re: A3010 CMOS issue after battery replacement
From the picture it seems that R60 is no longer there...
Paul


Re: A3010 CMOS issue after battery replacement
Lookign at the service manual R60 on a A3010 is listed as RES 180R SMD 5%0W100805
Would this be a suitable replacement?
https://www.ebay.co.uk/itm/180ohm-180R0 ... 1807245106
Would this be a suitable replacement?
https://www.ebay.co.uk/itm/180ohm-180R0 ... 1807245106
Re: A3010 CMOS issue after battery replacement
Yup
(Make sure everything's clean/neutralised first, plus you may well have to use hookup wire to connect things up if the traces/pads have died)
d.

d.
- 1024MAK
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Re: A3010 CMOS issue after battery replacement
If the copper PCB pads for R60 no longer exist, you may find it easier to use a normal 0.25W (250mW) or 1/4W wire ended resistor. Carbon film or metal film, any tolerance equal to 5% or better (2% or 1%) will work okay.
Mark
Mark
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Fault finding index • Acorn BBC Model B minimal configuration • Logic Levels for 5V TTL Systems