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RiscPC CMOS battery replacement advice |
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jonix (12:02 21/8/2010)
ted202 (00:15 22/8/2010)
apdl (06:10 22/8/2010)
RiscAndroid (08:34 4/9/2010)
andypoole (21:22 6/9/2010)
CJE (10:41 7/9/2010)
filecore (11:22 7/9/2010)
CJE (12:13 7/9/2010)
flibble (13:41 7/9/2010)
CJE (14:13 7/9/2010)
apdl (06:07 22/8/2010)
trevj (05:22 23/8/2010)
apdl (06:02 23/8/2010)
jonix (09:37 11/9/2010)
pwx (09:51 18/10/2010)
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Jon Wright |
Message #115059, posted by jonix at 12:02, 21/8/2010 |
Member
Posts: 9
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Hi,
I have 3 RiscPCs and all the CMOS batteries have inevitably corroded.
I have de-soldered the batteries and replaced them with a 1.2V 700mA AAA unit. I seem to be getting a voltage reading across various components although I'm not sure which are supposed to and at what values.
However, after setting the time and rebooting, the year is remembered but the time is not.
I understand that the corrosion can actually damage the motherboard so I am wondering if there are any components I can test with a multi-meter to see why the battery backup is not working.
Can anyone provide a method of diagnosis?
Kind regards, Jon |
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Tommy Durham |
Message #115066, posted by ted202 at 00:15, 22/8/2010, in reply to message #115059 |
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Posts: 12
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Buy the CMOS batteries from CJE micros they are abiut 12 quid...
www.cjemicros.co.uk x |
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David Holden |
Message #115068, posted by apdl at 06:07, 22/8/2010, in reply to message #115059 |
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Posts: 138
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Apart from eating through tracks the gunge often gets underneath components and damages them or their solder pads.
You will find the RiscPC circuit diagram at http://www.riscos.info/index.php/Technical_Reference_Manuals_and_circuits. Working out what's broken shouldn't be too difficult but removing the old components can be very dodgy as the pads and PCB tracks have often been seriously weakened by the battery leakage and 'unpeal' from the board very easily.
We do have exchange motherboards available (as long as you haven't tried a DIY job first and damaged it). |
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David Holden |
Message #115069, posted by apdl at 06:10, 22/8/2010, in reply to message #115066 |
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Posts: 138
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Buy the CMOS batteries from CJE micros they are abiut 12 quid... Was that tongue in cheek? We sell them for just 3.20 GBP. |
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Trevor Johnson |
Message #115075, posted by trevj at 05:22, 23/8/2010, in reply to message #115068 |
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Posts: 660
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...RiscPC circuit diagram at http://www.riscos.info/index.php/Technical_Reference_Manuals_and_circuits. Or, the same link without the rogue full stop. |
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David Holden |
Message #115076, posted by apdl at 06:02, 23/8/2010, in reply to message #115075 |
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Posts: 138
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Or, the same link without the rogue full stop. Apologies. Should have checked I'd got the link right before I posted. |
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Allan Dawes |
Message #115244, posted by RiscAndroid at 08:34, 4/9/2010, in reply to message #115066 |
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Posts: 4
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I think CPC also stock them too. They are based in Preston, but the website is
cpc.farnell.com
n.b. there is no www in front of this. |
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Andrew Poole |
Message #115279, posted by andypoole at 21:22, 6/9/2010, in reply to message #115244 |
Posts: 5558
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Oh fun. I discovered tonight that all four of my RISC OS boxes here have batteries looking like this.
I think I'm going to go for the bapfish procedure. I don't use the boxes much these days, so I can just leave them batteryless until I need them and it won't be too much hassle to bung a battery in when I want to use them again. |
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Chris Evans |
Message #115283, posted by CJE at 10:41, 7/9/2010, in reply to message #115279 |
CJE Micros chap
Posts: 228
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Oh fun. I discovered tonight that all four of my RISC OS boxes here have batteries looking like this.
I think I'm going to go for the bapfish procedure. I don't use the boxes much these days, so I can just leave them batteryless until I need them and it won't be too much hassle to bung a battery in when I want to use them again. From our experience of 20+ RPC M/Bs stored with no battery for a couple of years, the clock chip doesn't seem to like not being powered, about 50% failed to keep time after having a battery refitted.
Replacing the surface mount chip pcf8583t without special equipment isn't fun, we had a go yesterday. Also the chips aren't readily available cpc/Farnell don't do them anymore though RD do!
I hope I'm wrong but battery leakage as in the photo may have allready caused irrepairable damage. |
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Jason Togneri |
Message #115284, posted by filecore at 11:22, 7/9/2010, in reply to message #115283 |
Posts: 3868
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Replacing the surface mount chip pcf8583t without special equipment isn't fun, we had a go yesterday. Also the chips aren't readily available Well, I think the whole point of Andrew's comment was not to try and replace a surface-mount component directly, but to cut it off and replace it with an equivalent powered by an AAA battery somewhere off to the side, on a length of wire. |
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Chris Evans |
Message #115285, posted by CJE at 12:13, 7/9/2010, in reply to message #115284 |
CJE Micros chap
Posts: 228
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Replacing the surface mount chip pcf8583t without special equipment isn't fun, we had a go yesterday. Also the chips aren't readily available Well, I think the whole point of Andrew's comment was not to try and replace a surface-mount component directly, but to cut it off and replace it with an equivalent powered by an AAA battery somewhere off to the side, on a length of wire.
Sorry I wasn't clear the battery isn't surface mounted it is the clock chip that is surface mounted and seems to die if not powered! |
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Peter Howkins |
Message #115286, posted by flibble at 13:41, 7/9/2010, in reply to message #115283 |
Posts: 892
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From our experience of 20+ RPC M/Bs stored with no battery for a couple of years, the clock chip doesn't seem to like not being powered, about 50% failed to keep time after having a battery refitted. There shouldn't be anything in the chip that should degrade (unless it's caused by a battery leak). But it might be worth trying to replace the quartz crystals nearby (little silver cylinders, 32768Hz if I remember right). Technically they shouldn't degrade either, but it's a lot easier to test swap out the crystal than the RTC chip  |
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Chris Evans |
Message #115287, posted by CJE at 14:13, 7/9/2010, in reply to message #115286 |
CJE Micros chap
Posts: 228
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From our experience of 20+ RPC M/Bs stored with no battery for a couple of years, the clock chip doesn't seem to like not being powered, about 50% failed to keep time after having a battery refitted. There shouldn't be anything in the chip that should degrade (unless it's caused by a battery leak). But it might be worth trying to replace the quartz crystals nearby (little silver cylinders, 32768Hz if I remember right). Technically they shouldn't degrade either, but it's a lot easier to test swap out the crystal than the RTC chip
It's unlikely to be the crystal as when they fail the clock still increments over power downs of a few hours or time increases but days and months don't. I am ordering some crystals as they are compatively cheap and easy to replace, but I'm not holding my breath! |
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Jon Wright |
Message #115339, posted by jonix at 09:37, 11/9/2010, in reply to message #115068 |
Member
Posts: 9
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The circuit diagram was useful, but appears to be for the Mk 1 motherboards. I appear to have successfully repaired the RiscPC with the Mk 1 motherboard in it.
I also have two other motherboards which are Mk 3 and their charging circuits appear to differ from Mk 1. I have tried to repair these too but it seems I have a failed component although I'm not sure which one. Is there a source of the circuit diagram for Mk 3 motherboards?
Regards, Jon |
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Philip Webster |
Message #115663, posted by pwx at 09:51, 18/10/2010, in reply to message #115339 |
Member
Posts: 227
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My StrongARM RiscPC with a 1208,000 motherboard had a battery leak after some time in storage. I've ordered a new battery from Dave Holden (great price, by the way) and soldered it in, but I'm still having problems.
The motherboard has been cleaned, but some of the smaller components near the battery look a bit worse for wear, and I have to start the machine with the delete key held down in order to get access to the Desktop. If I try to power it up normally, it stops at the Supervisor prompt and won't accept keyboard input.
Presumably repair would be prohibitively expensive, so I'm on the lookout for a reasonably-priced 1208,000 motherboard, or a complete StrongARM RiscPC with this motherboard revision (surplus bits would be sold off). There are plenty about - I've been bidding them up on eBay over the last few weeks.
Any advice? |
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