Re: DECpc 425SE
On 07/12/2019 18:10, Antonio Carlini via cctalk wrote: I'm going to set it to one side for now and get to the same stage with the Acorn A3000 (which looks OK but the battery really has to come out now ... it will eventually fail I suppose). I might as well tackle both at the same time ... I've unsoldered the battery lugs from the PCB and removed the battery that way. The PCB has the +ve side marked (it's the end by R337). Once I mechanically peeled the lugs off the battery I could see the battery is a 3V Panasonic VL1220 rechargeable Lithium Vanadium Pentoxide and they're still available on eBay and Farnell (and probably everywhere else too ...). If I'm going to replace it I'd prefer to do it in a way that leaves it (more) easily removable, so that if I decide that the machine goes back in a box, it can do so without a ticking time-bomb in it! I think I want to find a suitable "IC-socket-style" connector (well, connectors I guess) that I can solder to the PCB and then slot a battery into. I guess it needs to be quite low profile to avoid fouling when it all gets put back together. An alternative might be to use a small push-fit socket for the battery, hide that somewhere convenient in the system (I think there is room by the HDD) and then use flying leads back to the PCB. Any ideas (I'm not sure of what terms to feed a search engine ...) Antonio -- Antonio Carlini anto...@acarlini.com
Re: DECpc 425SE
On 05/12/2019 14:18, dwight via cctalk wrote: With the solder tabs you are not soldering directly to the case, you are soldering to the tab. If you try to solder to the case, the electrolyte will evaporate causing excess pressure in the case. This will burst the seal. For a lithium coin cell this can mean a fire. As was mentioned, the solder tabs are usually spot welded to the case. The heat is momentary and little pressure is created in the cell. I've dismantled the machine enough now to get the mainboard out. Right behind the cell on the opposite side of the PCB are expansion memory boards. Between those and the PCB is a black square of insulating plastic that is tackily glued to the PCB. That lifts up easily enough. There are plenty of components on this side of the PCB too. It looks like one tab is right by the label "R337" and the other is between the "R346" and "R351" labels. Just in case anyone else ever follows this path :-) I'm going to set it to one side for now and get to the same stage with the Acorn A3000 (which looks OK but the battery really has to come out now ... it will eventually fail I suppose). I might as well tackle both at the same time ... Maybe I'll take photos as I put it back together, sort of "Haynes manual in reverse". Antonio -- Antonio Carlini anto...@acarlini.com
Re: DECpc 425SE
With the solder tabs you are not soldering directly to the case, you are soldering to the tab. If you try to solder to the case, the electrolyte will evaporate causing excess pressure in the case. This will burst the seal. For a lithium coin cell this can mean a fire. As was mentioned, the solder tabs are usually spot welded to the case. The heat is momentary and little pressure is created in the cell. Dwight From: cctalk on behalf of Adrian Graham via cctalk Sent: Wednesday, December 4, 2019 5:17 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: DECpc 425SE >> Many years ago I removed the soldered coin cell from the control board of >> the Compaq 7000 series and replaced it with a 2032 coin cell holder, worked >> nicely so I can’t see why it wouldn’t work in this DECivetti monstrosity. >> > > Well I suppose removing it means unsoldering the two tabs from the > motherboard rather than unsoldering the tabs from the cell, so maybe I'll > give that a go. Then I could work out what the battery is, get a suitable > holder and solder that in. Yep. I’d never try and fasten tabs to batteries, they’re flash welded rather than soldered. Someone on hackaday reckoned they had a procedure to do it but fitting holders instead is so much easier. > It would, however, be much more useful if a manual turned up and I could just > perform a system reset and get past the password that way! I wish I could help. I only ever worked on those when they were new. -- Adrian Graham Owner of Binary Dinosaurs, the UK's biggest private home computer collection? t: @binarydinosaursf: facebook.com/binarydinosaurs w: www.binarydinosaurs.co.uk<http://www.binarydinosaurs.co.uk>
Re: DECpc 425SE
>> Many years ago I removed the soldered coin cell from the control board of >> the Compaq 7000 series and replaced it with a 2032 coin cell holder, worked >> nicely so I can’t see why it wouldn’t work in this DECivetti monstrosity. >> > > Well I suppose removing it means unsoldering the two tabs from the > motherboard rather than unsoldering the tabs from the cell, so maybe I'll > give that a go. Then I could work out what the battery is, get a suitable > holder and solder that in. Yep. I’d never try and fasten tabs to batteries, they’re flash welded rather than soldered. Someone on hackaday reckoned they had a procedure to do it but fitting holders instead is so much easier. > It would, however, be much more useful if a manual turned up and I could just > perform a system reset and get past the password that way! I wish I could help. I only ever worked on those when they were new. -- Adrian Graham Owner of Binary Dinosaurs, the UK's biggest private home computer collection? t: @binarydinosaursf: facebook.com/binarydinosaurs w: www.binarydinosaurs.co.uk
Re: DECpc 425SE
> On Dec 4, 2019, at 7:53 PM, Antonio Carlini via cctalk > wrote: > > On 05/12/2019 00:36, Adrian Graham via cctalk wrote: ... The button cell looks very much like it is soldered in. It's approximately 12mm in diameter. I've read numerous warnings not to go to near a button cell with a soldering iron so I'm not really keen to do that, especially as I don't know for sure that it will fix the problem. >>> I'm curious what the reason is for that warning. After all, the thing was >>> soldered in to begin with; it certainly won't mind the heat. You'd want to >>> make sure you don't short it out while doing it, of course; some insulating >>> tape might help with that. >>> > > There are plenty of warnings, e.g.: > http://www.cr2032.co/soldering-article.html Ok, but that's different, it talks about soldering directly to the cell. >> Many years ago I removed the soldered coin cell from the control board of >> the Compaq 7000 series and replaced it with a 2032 coin cell holder, worked >> nicely so I can’t see why it wouldn’t work in this DECivetti monstrosity. >> > > Well I suppose removing it means unsoldering the two tabs from the > motherboard rather than unsoldering the tabs from the cell, so maybe I'll > give that a go. Then I could work out what the battery is, get a suitable > holder and solder that in. > > It would, however, be much more useful if a manual turned up and I could just > perform a system reset and get past the password that way! Indeed. But clearly a solder-tab coin cell is meant to be soldered :-) so unsoldering those solder joints has to be safe by definition (so long as you are reasonably prompt). And if the cell is still good, you could then solder it right back in if you want. paul
Re: DECpc 425SE
On 05/12/2019 00:36, Adrian Graham via cctalk wrote: ... The button cell looks very much like it is soldered in. It's approximately 12mm in diameter. I've read numerous warnings not to go to near a button cell with a soldering iron so I'm not really keen to do that, especially as I don't know for sure that it will fix the problem. I'm curious what the reason is for that warning. After all, the thing was soldered in to begin with; it certainly won't mind the heat. You'd want to make sure you don't short it out while doing it, of course; some insulating tape might help with that. There are plenty of warnings, e.g.: http://www.cr2032.co/soldering-article.html Many years ago I removed the soldered coin cell from the control board of the Compaq 7000 series and replaced it with a 2032 coin cell holder, worked nicely so I can’t see why it wouldn’t work in this DECivetti monstrosity. Well I suppose removing it means unsoldering the two tabs from the motherboard rather than unsoldering the tabs from the cell, so maybe I'll give that a go. Then I could work out what the battery is, get a suitable holder and solder that in. It would, however, be much more useful if a manual turned up and I could just perform a system reset and get past the password that way! Antonio -- Antonio Carlini anto...@acarlini.com
Re: DECpc 425SE
>> ... >> The button cell looks very much like it is soldered in. It's approximately >> 12mm in diameter. I've read numerous warnings not to go to near a button >> cell with a soldering iron so I'm not really keen to do that, especially as >> I don't know for sure that it will fix the problem. > > I'm curious what the reason is for that warning. After all, the thing was > soldered in to begin with; it certainly won't mind the heat. You'd want to > make sure you don't short it out while doing it, of course; some insulating > tape might help with that. > Many years ago I removed the soldered coin cell from the control board of the Compaq 7000 series and replaced it with a 2032 coin cell holder, worked nicely so I can’t see why it wouldn’t work in this DECivetti monstrosity. -- Adrian Graham Owner of Binary Dinosaurs, the UK's biggest private home computer collection? t: @binarydinosaursf: facebook.com/binarydinosaurs w: www.binarydinosaurs.co.uk
Re: DECpc 425SE
> On Dec 4, 2019, at 5:46 PM, Antonio Carlini via cctalk > wrote: > > ... > The button cell looks very much like it is soldered in. It's approximately > 12mm in diameter. I've read numerous warnings not to go to near a button cell > with a soldering iron so I'm not really keen to do that, especially as I > don't know for sure that it will fix the problem. I'm curious what the reason is for that warning. After all, the thing was soldered in to begin with; it certainly won't mind the heat. You'd want to make sure you don't short it out while doing it, of course; some insulating tape might help with that. paul
DECpc 425SE
I'm working on a DECpc 425SE right now and I've not been able to find any useful documentation. The laptop seems to work but has a BIOS password set. I suspect that if I remove the button cell then it will forget the password (or at least that's my hope). The main battery comes out. There's no sign of leakage. It's a SANYO 8HR-4/3A (510295-001). The button cell looks very much like it is soldered in. It's approximately 12mm in diameter. I've read numerous warnings not to go to near a button cell with a soldering iron so I'm not really keen to do that, especially as I don't know for sure that it will fix the problem. I've looked for a password reset jumper of pads but I can't see one. I think someone has been here before me as the four screws that hold the two halves of the unit together are all missing. Any hints welcome. Thanks Antonio -- Antonio Carlini anto...@acarlini.com
