Just cut the legs of the part, heat the solder, and pull each leg out at a time, don't try to remove the part with all the legs attached, then you can take a straw ( plastic ) , hold over the region being heating and blow real quick to clear the hole, clean with isopropyl alcohol, and install new part.
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Chris Tofu Sent: Sunday, May 05, 2013 6:10 PM To: [email protected] Subject: Re: hello guys, Hey upgraded LISA I question. Maybe a complete board but not individual transistors. This is an easy fix, after you get the boards out. Static could be a hazard if you're not using a proper desoldering station. I don't own one, and would and have replaced individual components on circuit boards successfully. Just grasp the old component (or lead if the component is cooked) with skinny pliars, heat both leads with say a 15-25 watt iron, either simultaneously or go back and forth quickly, and pull. Hopefully on exit the leads will leave holes for reinserting the new parts. If not just heat the area/pads, but just enough to make the solder flow, don't cook the board, you could create more problems. Then reinsert the new components and add a bit of solder while applying the iron, and that should do it. ------------------------------ On Fri, May 3, 2013 3:45 PM PDT Richard Darner wrote: >Check with vintagemicros via eBay. His name is John Woodall and I guarantee you that he will be able to fulfill your needs. > >Sent from Richard Darner's iPhone > >On May 3, 2013, at 5:09 PM, Hardware Mack <[email protected]> wrote: > >> thank you for that great information! >> >> Can anyone look at their lisa cpu board and let me know what you have in that spot? >> >> Thank You! >> Charles >> >> >> >> On May 3, 2013, at 6:01 PM, Doug McNutt wrote: >> >> At 12:56 -0700 5/3/13, Notgoing Totellyou wrote: >>> I have the CPU card here and its missing a transistor. >>> >>> i can't find a replacement anywhere. >>> >>> Anyone have any lisa parts laying around? >>> >>> it reads : AMPS 4258 EBC >>> >>> you can see the spot behind it, it's missing . >> \ >> Transistor Data Book edition 48, 1980 >> >> MPS4258 CRI, SPS, MOTO p 153 line 15 which says: >> >> Silicon PNP low power >> 350 mw collector dissipation >> V cbo 12 V >> Collector max 800 mA >> Hfe (gain) 15 >> >> >> I would recommend a very common 2N2907 as a replacement. >> >> From the picture it's not altogether clear that transistors Q1 and Q2 >> are supposed to be the same type.. A pretty common circuit uses PNP >> and NPN pairs close together. The pair to the 2N2907 is NPN type >> 2N2222, also very common. (I have a bunch of both here. Use dmcnutt >> at above off list with Lisa somewhere in the subject.) >> >> A look at a working Lisa would be worth while. Anybody here ?? >> >> I also have no idea what the A in front of the very common Motorola MPS means. >> >> >> -- >> >> Fe++ >> // \ >> Fe++ Fe++ >> | || >> Fe++ Fe++ >> \\ / >> Fe++ >> >> -- >> -- >> ----- >> You received this message because you are a member of the Vintage Macs group. >> The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and >> our netiquette guide is at >> http://www.lowendmac.com/lists/netiquette.shtml >> To post to this group, send email to [email protected] To >> leave this group, send email to >> [email protected] >> For more options, visit this group at >> http://groups.google.com/group/vintage-macs >> >> Support for older Macs: http://lowendmac.com/services/ >> --- >> You received this message because you are subscribed to the Google Groups "Vintage Macs" group. >> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> -- >> -- >> ----- >> You received this message because you are a member of the Vintage Macs group. >> The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and >> our netiquette guide is at >> http://www.lowendmac.com/lists/netiquette.shtml >> To post to this group, send email to [email protected] To >> leave this group, send email to >> [email protected] >> For more options, visit this group at >> http://groups.google.com/group/vintage-macs >> >> Support for older Macs: http://lowendmac.com/services/ >> --- >> You received this message because you are subscribed to the Google Groups "Vintage Macs" group. >> To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. >> For more options, visit https://groups.google.com/groups/opt_out. >> >> > >-- >-- >----- >You received this message because you are a member of the Vintage Macs group. >The list FAQ is at http://lowendmac.com/lists/vintagemacs.shtml and our >netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml >To post to this group, send email to [email protected] To >leave this group, send email to >[email protected] >For more options, visit this group at >http://groups.google.com/group/vintage-macs > >Support for older Macs: http://lowendmac.com/services/ >--- >You received this message because you are subscribed to the Google Groups "Vintage Macs" group. >To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. >For more options, visit https://groups.google.com/groups/opt_out. > > -- -- ----- You received this message because you are a member of the Vintage Macs group. 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