I apologize for what might be a really stupid question, but how come some of the screens seem much darker than the others? On Sat, Apr 2, 2011 at 3:33 PM, terry stewart <terry at webweavers.co.nz>wrote:

On 2011 Apr 2, at 2:37 PM, Marcin Wichary wrote: Presumably some of them have anti-glare screens and some of them don't. I remember when those open-weave-fabric-type anti-glare screens became available in the mid-80s. There were after-market ones available, we had them installed on our Ann-Arbor Ambassador terminals. I don't know whether they were an original or after-market feature for the Lisas.

On Sun, 3 Apr 2011, terry stewart wrote: Is he a collector / restorer sort of person or a "black hole"? I've tripped over a number of folks with large quantities of classic gear who seem to playing the "..he who dies with the most units, wins" game. Drives me crazy when someone who doesn't touch the equipment, doesn't use it or display it (in fact, may not even know where it is), has 6-10 of something you have been desperately looking for and refuses to part with one for any amount of remuneration. Always struck me as sort of a power trip. Steve --

I amy be guilty of this sort of behaviour in that I have what, by some standards, is a ridiculous number of classic computers. On the other hand: I dont; accumulte large numbers of identical machines (yes, I ahve some 'duplicates', but of common stuff). I may have what appear to be similar machines (for example an HP9836A monochrome machine and an identical-looking HP9836CU colour one), but they are different enough interneally for both to be of interest to me. I do like to use my classic devices (not just computers), and as a result I try to get them all working. I can';t claim all my classics just 'switch on' -- there are some I've not got round to working on yet. But I do want to be able to use them. As a result, I figure out how to fix things, and will share this information with anyone who asks. Without wanting to start another flame war, I have difficulty understnading people who collect these machines 'as an ivenstment' and never try to get them working, never use them, in case it damages their value :-(. I would much rather enjoy them while I can. -tony

Well, I only very rarely sell anything, so in a sense once I've got it, you don't :-) Ah, then I _certianly_ don't suffer from that. I am always inside some machine or other. I've even dismanteld soem machins before I've even got them home (I got my HP9180 at an HPCC meeting and dismantled it at the meeting, I even started figuring out what was going on on some of the PCBs). Maybe I take 'fixing things' to ridiculour levels sometimes. Not classic-computer related, but I don't think many people would dismantly a Western Electric telephone dial, inclduing the riveted and staked parts and then machine new parts for it. Not when you can buy a replacement for a few 10s of dollars. But that's what I've been doing for the last couple of afternoons. It's probably as pointless as mot hobbies, but I enjoy it and it appears to harm nobody. Now that I can relate to, as can many others here... More often, though, it's small parts I can't find, as it 'I know I've got a spare type cylinder for an ASR33 somewhere, but where the heck did I put it' -tony

----- Original Message ----- From: "Steven Hirsch" <snhirsch at gmail.com> To: "General Discussion: On-Topic Posts Only" <cctech at classiccmp.org> Sent: Sunday, April 03, 2011 8:52 AM Subject: Re: Speaking of Lisas...this guy has a garageful! Does it matter if you have 10 units of a rare model you restore and keep in your basement so nobody knows about them and they still end up recycled when you die compared to just stacked and neglected till death? I guess you never dealt with hoarders before, you don't offer money to them you offer multiple big grungy junkers for the single item you want. Most people will either trade for something they want more, or take the cash payout that will buy that more desirable item.The problems come when something is rare but not that valuable but the owner thinks it is made of gold and would only trade it for a mint 1971 Hemi Cuda convertible.

On Sun, 3 Apr 2011, terry stewart wrote: That's a steal. The owner of these machines turned down an offer of $500 US for one unit, so we agreed to defer bargaining until such time as the functionality is better known. I'll have a look. Google Lisa list? I'll have to check that out. Wasn't aware of it. The amount of corrosion on these units is just stunning. There's "crust" growing on almost every metal surface surrounding "ground zero" (battery mount point). Some of the screws holding the motherboard to the bottom pan were so grunged up that I had to slice a slot in the head with a Dremel grinder and use penetrating oil to get them out. The rear panel RFI shield of one unit has a "bloom" of rust and crust about five inches in diameter centered on the battery. Even the card-edge connector in the rear of the CRT cage is full of crud, and that's over 6" away! Unlike my Amiga 4000 (a story in its own right), Apple appears to have used very high-quality and thick solder resist on the boards. So far (knock wood) I have not found any dissolved traces - which is just short of incredible given the scope of the disaster. My immediate concern is how to safely remove the green crust from resistor leads, vias and, most importantly, the various bus card-edge connectors. What have folks used to clean the bus connectors without bending contacts? Caig contact cleaner was laughed off - didn't even touch the green stuff. I'll try that later today. One point I'm curious about: Has anyone figured out how to initialize a ProFile for use with a Lisa? The documentation implies that a special procedure is needed to low-level format the unit and write boot blocks. I am setup for Apple /// based low-level format (special Z8 piggyback CPU and firmware), but am unclear as to whether this is the same as what the Lisa expects. No clue how to write boot blocks, though. Steve --

Steven, when I get some device with this level of trouble, I usually disassemble EVERYTHING in the affected area, clean it up with grit pad until I can see only cooper and start to retin the traces with common solder, and repair broken traces with very thin wire-up wire. Replace everything with NEW parts. Usually it works at first and does not break up after. A throught clean-up is primordial for having no problems on the future. I'm sorry I'm so far away (I live in Brazil). I'd love to help you on this matter.

On 04/04/11 02:16, Steven Hirsch wrote: Yuck, and I thought my repair of the 386 motherboard was bad... As I recall, that was two broken tracks, a few broken through-plated holes, some broken solder joints on the resistors and diodes around the battery, and a serious case of disintegrating PCB... The HP16500B was worse. About a dozen broken tracks on the system board which the previous seller neglected to mention, all on the address bus. It "worked"... until I removed and reinstalled the Slot A card (16530A digital scope timebase) while I was installing a CompactFlash card mod. Net result of that was that the system software thought the LAN card was hosed, and wiped the MAC address / LAN settings EEPROM. That was NOT fun to fix. I think I went through about a dozen surface-mount PLCC sockets before I managed to solder one down without melting the baseplate. Those things are evil. Doesn't work that well in my experience. Although a hot-air preheater combined with a soldering iron works wonders. Bring the board up to about 150 Celsius, then use a soldering iron to provide the extra heat required to melt the solder. A similar trick is used when soldering and desoldering small SMD parts with a hot-air station... I think your best bet would be a heated-vacuum tool. Basically a solder-sucker mated to a soldering iron... Some little cheats which might help out: * If the surface of the solder is corroded, scratch into it with a knife. This should reveal a bit of fairly fresh solder: scratch off enough that your iron can make good thermal contact with the joint (oxidised solder doesn't conduct heat particularly well). * Melt some fresh solder into the joint. Rosin flux paste or gel (usually used for SMD soldering) is also worth a try. * Desolder wick will remove most of the solder, but it most likely won't clear a through plated hole unless you make several attempts (desolder, fill with solder, hold iron for a few seconds, repeat). Which brings me onto my next trick... * 24swg tinned copper wire is GREAT for clearing solder out of through holes without damaging the plating. Enamelled copper might work too. * If all else fails you may have to drill out the solder joint. Don't do this on a four-layer board -- it'll ruin the plating. You can fix the plating on a two-layer board using thin tinned copper wire (40SWG or thinner). RoadRunner wire is good for this, especially the tinned-copper stuff. * If you repair tracks with wire, DO NOT use cyanoacrylate glue to stick the wire down! Use a few small pieces of Magic Tape or dots of epoxy. Cyanoacrylate degrades under heat (forming extremely hazardous fumes which WILL burn your eyes, nose and throat quite effectively). Epoxies can be removed with a small heat gun if necessary, or just plain pulled off of the solder resist. Kapton (brown heat-resistant polyimide) tape is good too (buy a few rolls of this stuff if you don't have some already!). -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

Yes, I do that too. I upgraded an HP Integral RAM board from 512K to 1M. This involved adding 16 more 41256 ICs + decoupling capacitors. Of coruse the original board was wave-soldered at the factory so all the holes were blocked. I hat to clean them all out by this method. Me too. The fine stuff is very useful for cleaning up accidental bridges between the pins on an SMD device. -tony

At 04:29 PM 4/4/2011, Chuck Guzis wrote: I've got a full Zeiss surgical stereo scope, 6x to 40x, illuminated and filtered, on the articulated arm and roll-around stand. - John

At 05:10 PM 4/4/2011, Chuck Guzis wrote: Oh yeah. I paid all of $100 for it, too. - John

On Mon, Apr 4, 2011 at 6:49 PM, John Foust <jfoust at threedee.com> wrote: I have had my eyes open (both, since it's stereo ;-) for a deal like that. Nothing yet, but I'm ready to jump on it when I see it. No waffling. -ethan

On 04/04/11 22:29, Chuck Guzis wrote: I'll second that. I have an Olympus SZ30 with 0.9-4x vari-zoom objectives, a 10x eyepiece set and a 20x eyepiece set (I also have a Brunel Microscopes SLR camera adapter for it, but that's another story). It's one of the few pieces of equipment I'd never sell, not in a million years. Optical quality may not be "perfect", and it's a bit of a pig to use (I've never managed to get the dioptre and interpupillary distance adjustments "right"), but it's useful for debugging PCBs which have no obvious cause for failure, and is essential for repairing boards with small SMD parts. I honestly don't know how I've managed all these years without one... Although I do need to bolt on some form of illumination system. The ideal would be one of the Olympus SZ fibre-optic ring lights, although I might try and build an LED illuminator from a couple of Luxeon emitters... After all, the worst case situation is that it doesn't work and I learn something new regardless -- "I haven't failed, I've found a thousand different ways which don't work!" :) -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

On Mon, 4 Apr 2011, Philip Pemberton wrote: For components like a right-angle DE9 connector, the top side of the board is not accessible. Do you think using the hot-air handle for preheat would do any good? If it was set at e.g. 150-200C with medium airflow that might bring things up enough that I won't need a long application of the iron. Or, maybe I should just break down and buy a preheater... Alas, I have two of them. An older OK Industries tool and a new BlackJack Solderwerks thingie from Circuit Specialists. Neither of them is worth a crap from my experience. Occasionally I'm able to clear the hole, but more often it simply doesn't have enough suction to do the job and the heat ends up damaging the via and/or adjacent traces. I do that as a matter of course - it does help a lot. This would be _after_ the component is removed, correct? If not, would you mind elaborating a bit? I picked up a quantity of carbide-tipped PCB drills for just such a purpose. Sort of a last resort, I'll grant you. Is the Kapton tape available from electronic suppliers? I'll take a look at the DigiKey catalog forthwith. Steve --

On 04/04/11 12:55, Steven Hirsch wrote: Well, it'd be worth a shot. The thing about a preheater is that it has a much larger surface area -- so instead of heating a small patch of board (which is what the hot-air gun is for) it'll bring the whole board (or a large section of it) up to a given temperature. The idea being that instead of having to bring every pin on the chip 250C. Less energy required, faster time-to-melt, and as a result less damage to the PCB. Usually the solder joints will stay hot for a little longer too -- meaning you get a few extra seconds to vacuum-pick the part off of the board. Well, that ties in with my experience with the Aoyue one (basically a clone of one of the Hakko workstation-type vacuum solder suckers). I would have thought the OKI one would have been pretty decent though... weren't they Metcal at one point? I suspect the reason that trick works is the flux -- you add extra flux, which helps to remove oxidised solder. The bit of extra solder improves the thermal coupling between soldering iron tip and joint. Yes -- exactly right. You cut the pins off with flush-cutters -- these are the very small wire-nippers that you usually use to cut component pins flush to a solder joint, not the massive (by comparison) side-cutters usually used for cutting wire and cable. Cut the pins and remove as much of the connector frame as possible. I usually use a Dremel and a selection of cutting/grinding bits to go most of the way through, then finish off with hand tools -- needle files and maybe a junior hacksaw blade. Desolder the pins and pull them out, the holes will be filled with solder. Put some flux on the joint, and a drop of solder on your iron tip. Apply to the joint and melt in some fresh solder until you get a convex bubble on both sides. Use desolder wick to remove this -- sometimes you can push a little bit of the wick into the hole, which helps A LOT when wicking solder out of holes. If the hole won't clear after two or three tries at this, remove all the solder you can, then heat a piece of tinned copper wire alongside the joint, like this: wire | ## soldering iron tip | ## |## =============== board Push the wire through the hole while heating it. Again: fresh solder and flux are VERY useful. If it won't go through from one side, try the other side. When the wire goes through, start moving it up and down, and remove the soldering iron. The motion prevents the solder from sticking to the wire. You should now have a clean (or close enough) hole which you can push a new part lead through (and solder it). I've got a box full of the things... only problem with carbide bits is that they break if you look at them funny. Any decent supplier should have it. Farnell stock the 3M stuff, but it's unbelievably expensive (?30 a roll). Their own-brand version ("Multicomp") is about a third of the price. I honestly can't remember if you get 10m or 25m on a roll... but it lasts ages. Just don't let the kids near it! Either the 12.7mm (1/2in) or 18mm wide tape is fine for most things. The thinner stuff (1/4in) is better if you're going to be taping down wires and nothing else... -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

I recently added some sockets and replacement 4164 chips on Lisa RAM boards as Ian and others on the Lisa List will know. (see http://www.classic-computers.org.nz/blog/2011-04-02-fixing-lisa-memory-card… is you want the details.) These multi-layer boards are tricky, and I did manage to nuke a couple of lines. I usually use solder wick to clean out the holes, but these were the most difficult I've come across (then again, I had very limited experience on multi-layer boards). Terry (Tez)

Theyr'e certianly used in the older HP stuff I spend a lot of time repairing (you can see the cross structure aroudn the pin if you hold the PCB up to a storng light source), but even so I do find the pins connected to the power/grounds planes take a little more effort to desolder than the other. -tony

Re: the Keyboard. All three of my Lisa Keyboards had degraded foam pads so much so that between the three of them only one key worked! However, the computer still registered a keyboard as being present. Alll three keyboards are working now. I got my replacement pads off Erik Klein, who is a member of this forum. He might have some more left. Given the battery damage you describe, if you have got the stage where the Profile is seeking then things are going well! (-: Jammed/gummed up floppy disks are also a common, although it's not the only fault these drives can have as evidenced by my long diagnostic conversation with Tony on this mailing list. Terry

On Sun, 3 Apr 2011, Mike Loewen wrote: Thanks for the detailed input, Mike! As it turns out, the Lisa keyboard foam is not degraded at all. Must be the luck of the draw. --

On Sun, 3 Apr 2011, Mr Ian Primus wrote: The anti-static bag had enough conductivity to do the job? I would never have suspected that. I just picked up a Sun 4 keyboard on eBay, since they apparently use the same keytronics arrangement internally. Long run, I'm going to track down the necessary tools to do fabricate from scratch. I have several other old boxen with this style of keyboard, so eventually I'll need to bite the bullet and learn how to do it. Steve --

On 04/04/11 13:02, Steven Hirsch wrote: I wonder if it would be worthwhile making up some form of mass-production rig for these. Sounds like a fun introduction to mechanical design, assuming you could find a punch of the right size, and fabricate the necessary parts. A DC gearmotor would probably be enough to provide motion for cutting the discs of material, followed by a pick-and-place type rig to assemble the cut discs into a keyswitch pad... Hmmmmm.... -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

On Mon, 4 Apr 2011, Philip Pemberton wrote: And... He's off and running at the gate! --

I've had great success using a nromal handheld solder sucker to remove parts from PCBs without damaging either the part or the PCB. it's not uncommon for me to desolder a ROM from a working machine in order to dump it out, and then solder it back in place (actually, I'd problaby put a socket in, but anyray). I wouild recommend a temperature controlelr soldering iron a little hotter than normal (I use a #8 tip in my Weller TCP). A fine tip too. I also find that dismantling the solder sucker and putting a smear of vaseline (petroleum jelly) on the washer helps a lot. As I mentioend in an earlier posting, a new, find nozzle on the sodler sucker helps a lot. When uou;ve remvoed the solder, try to wingle the pins ro break any remaining bond before pulling the part out. This is easy to do on some components, impossible on others. Don't force anything. Alas only experience will tell you how hard you cna pull the compoonent without riskingdamage to the PCB. You may find you can cut up the old DE9F connecotr to remove the pins one at a time. Maybe with a cut-off disk in a Dremel or simuilar. Now that I wasn't sure of... I would recomend taking the keyboard apart anyway and inspecting these disks. You can then see if any are likely to be 'active'. I wouldn't put 'Wanton Destruction 40' anywhere near the floppy drive (or any other aprt of a classic computer). The stuff we get in the UK contains some quite long-chain waxy hydrocarbons whcih will gum things up after a short while. I've never worked on a Lisa drive, but I've worked on plenty of the Sony full-heigfht 3.5" drives, singel and double head, in HP units. They are similar mechancially to the Lisa drive. Some of the odler eject mechansims will come totally apart (the levers are held on with E-circlips), which makes cleaning a lot easier. The later ones are riveted, so you can just rmeove the springs, soak the assmebly in solvent, then work the parts back and forth and wipe off the old grease as it appears. I find propan-2-ol (isporpanol) woeks well for this. There are some photos in my flickr acocunt (tony_duell I think, but searching for HP9820 will find it) which show a Sony double-head drive stripdown. Your drive is similar. -tony

Oops. Hit the wrong key earlier and sent a message with no reply... --- On Sun, 4/3/11, Tony Duell <ard at p850ug1.demon.co.uk> wrote: You don't use the WD40 as a lubricant. You use it as a solvent, on the disassembled eject mechanism to dissolve the old grease. Then you rinse it out with isopropyl alcohol. The eject mechanism can be completely removed from the drive - but not totally disassembled, as some parts are riveted together. You can, however, remove just the one side (the part that attaches to the eject motor) from the rest of the mech, as this is where it always gets frozen. A good soaking in WD40 to dissolve the grease, followed by a rinse in alcohol will de-crud it nicely. WD40 is a terrible lubricant, but it's a fantastic (and easy to get) solvent. -Ian

On 3 Apr 2011 at 13:11, Mr Ian Primus wrote: I prefer Perc (tetrachloroethylene) in the form of automotive degreaser or brake cleaner. Does not appear to affect most plastics; evaporates completely and leaves a grease-free surface. Works particularly well at removing flux from PCBs. --Chuck

----- Original Message ----- From: "Cameron Kaiser" <spectre at floodgap.com> To: <cctalk at classiccmp.org> Sent: Sunday, April 03, 2011 11:50 PM Subject: Re: Advice on Lisa 2 restoration So you are the guy that causes manufacturers to have 1000 warning stickers on everyhting I buy! ;) I wear glasses so they act as safety goggles (polycarbonite lenses will stop pretty much anything that would not take your head off).

You do not know it, but you are. ICs, and to a lesser extent transistors, are made to be soldered *once*, and in a well controlled heated environment. Heating up an IC pin often will stress the die and introduce cracking in the silicon, as the chip expands in a non-uniform manner. Most of the time these microscopic cracks do not immediately kill the device, but they will reduce the expected lifetime of the chip. Basically, the reliability plummets due to these "latent failures" caused by thermal stress. If you need to desolder an IC for reuse, the best thing to do is to mimic the action of the machines that stuffed the boards in the first place. Heat up the entire device gently with a heat gun set on low, so the entire die expands more or less uniformly. Even just raising the chip temperature 30 degrees C over ten or twenty seconds will help immensely. And when the device is removed, let it cool naturally, -- Will

On Mon, 4 Apr 2011, Geoffrey Reed wrote: Anecdotally, I suspect the Hakko unit has substantially better suction than my aging OK or the BlackJack. I'm religous about all of that. <sigh> That was my hope. I add solder, clean the tip, hold it in place until things are heated through and pull the trigger. It burrappps away and just about nothing happens. Except thermal shock to the board, tearing of adjacent traces, etc. Since most of the devices I work on use 60/40 leaded solder, what is the recommended tip temperature? How long do you leave it in place on, e.g. a through-hold IC lead before triggering the vacuum? May be that both these units are substandard. Getting desperate enough that the Hakko is starting look like a good investment. --

On 4/4/11 8:25 AM, "Steven Hirsch" <snhirsch at gmail.com> wrote: When I'm desoldering, I put the edge of the hole against the leg for about 1 to 2 seconds then hit the suction. If it doesn't come clean, I resolder and give it another go. One thing I do is once I start the suction I press the leg against the other edge of the hole with the nozzle, that way I know I get all the solder out. Something you may want to consider if the desoldering isn't going well for you, there are a few low temp alloys made for desoldering, you resolder the pins with the alloy and then can generally completely clean it out using braid or a desolder tool. I have managed to lift traces with my hot air reflow tool, but I chalk that up to not having used one in > 10 years and being WAY out of practice... I am starting to get pretty good at listing surface mount IC's though :)

I raarely damage things either, nd I just use a normal soldering iron and solder sucker. I think the trick is knowing how much force you cna apply to the component before you risk lifting traces. If it won't come out, dont forct it, but resolder and desolder it again. Yes. Puttign a little new solder on helps a lot. Also, if a pin doens;'t desolder fully the first time, it is a waste of time to try to melt the remianing dolder and such it out. It won't coem (there will be sufficient air flow in the clear part that the remining solder will not be moved at all). Resodler the connection and try again. Normally on ther second attempt, it'll come clear. If you are using a nromal soldering iron and solder sucker, make sure the iron is powerful enough and hot enough. You will not desodlerpars from multi-layrer PCBs (with intenral power and ground palnes) wiht a non-temperature-controller iron. So would I, (and I'd pay a lot more to get it), but unfortunately the accountants that run th industry don't see it that way. They'd rather get a little extra profit from em now, even if I'll never buy their crap again. -tony

On 4/4/11 3:30 PM, Tony Duell wrote: Well, with our massive population explosion, the idea of "repeat customers" is much less of a concern. -Dave -- Dave McGuire Port Charlotte, FL

On 4/5/11 4:03 PM, Ian King wrote: Serves 'em right, though I must say I'm surprised. As evil as it is, their logic is sound. -Dave -- Dave McGuire Port Charlotte, FL

On 04/04/11 19:23, Tony Duell wrote: I'm wondering if it would be worth building some form of "small thing disassembly box" to alleviate this problem. Basically, you take a 40-litre under-bed storage box (~?5, Poundstretcher), flip it upside down (thus turning the lid into the base) and use a holesaw to drill two large holes in the side big enough to put your hands through. Optionally attach some thin elbow-length gloves to these holes so your hands go through the gloves and into the box. This way, anything that decides to "ping" off into never-never-land will be restricted to "pinging" into one of the walls of the box. Gravity ensures that any tiny little things which choose to do this will end up in or near the bottom of the box. I've heard of similar things being done for hard drive repair -- though this involves adding a HEPA filter to get rid of particles in the air. The theory being that it's easier to keep a 1ft * 1ft * 2ft box clean than it is to do the same to an entire room... -- Phil. classiccmp at philpem.me.uk http://www.philpem.me.uk/

The Weller TCP is very commonly used by serious enthuiasts, university labs, small companies, etc over here. I find the stnadard #7 tip is colder than I would like. I fit a #8 tip and find it much easier to use. I find it helps a lot. Put a smear on the O-ring of the end cap if you have one in your solder sucker, to imporve the seal there. Sometiems they are :-) Is the silvering OK. The visible (towards the PCB) side of the disk assembly should look metalic, there's a conductinve layer on the top side of that plastic disk (it increases the capacitance between the PCB tracks when you press the key). I've sene keyboards where the foam looks fine, but he silvering has vanaished. Obviously then the keys don't work. If you're unlucky the corrosion will have crept along the wires inside the insulation and you;'ll have open-circuits in the cable? Hos is the cable attached at the other end? Is it possible to replave the cable and connector? I am amazed... Be warned tha the 'gumming up' is not instant, it will occur after days/weeks in my experience. Yes, I thimnk it is. I think this means the disk-inmseted sensort is working, and that you;re using DD (not HD) disks. The latter have a hole in just the 'right' place to avoid tripping the disk inserted sensor. It's certianly worth checking... -tony

Form what I remembner (never having seen a Lisa, alas), this is a normal Keytronics capacitive keyboard. I thought that somebody did sell replacement disk kits for them on Ebay (possibly advertised as being for some other machine, Sol-20 ??) Strictly that's a DE9F connector. The second letter incidates the shell size. I've not seen the old one, but if you can cut off the pins above the PCB, do so. You can then remove the body of the connector and remove the pins one a ta time (the easiest way to do this is to melt the solder on the bottom of the PCB and yank the pins out form the top, then clear the holes by meltign the solder with an iron on one side of the PCB and suckign the solderout from the other). If you can't cut the pins off, you will have to deoslder it in the usual way. A good solder sucker helps, as does a new tip for said succker (They splay out with use, the fine hole in a new tip is a major advantage). I find it helpts ot melt a little new solder onto each connection and then sukc the whole lot off. Wen you've done all the pins, wiggle them around in the holes with a screwdrier or pliers and pull the part out. Normally dead foam disks mean that some or all of the keys don't work, the keyboard should be dectededmy the machine. I think you have another fault. plug?), the connectiuons being a power line, gorund, and a bidirectional serial data line. I would open up the keyboard and check it's getting power, I'd also take the PCB off the key frame (lots of little screws) and try it again. If it fails then, I would see if the microcontroller in the keybaord is running, what the data line is doing, etc. I would always clean such connecotrs, things do not work with bad connections :-) and it's worth eliminating the 'sillies' first. I suspect a dip in citric acid solution, followed by water and then propan-2-ol would help a lot here. If it;s the female mart of the connecotor (rather than the PCB edge fingers it goes onto) that is corroded, I would consider replacing it. Most edge connectors are still avaialble. It's tedious trandfering wires -tony