test-drb

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101090 discussions

Software preservation (Was: Seeking reverse-engineers - Apple II VisiCalc)

by csquared3＠tx.rr.com

On Fri, 30 Jan 2009 at 09:49:34 Chuck Guzis said > It surprised me that the micro types took so long to figure basic > things like SCCS and regression testing out. I think I can partly explain that. For one thing, though we may all be brilliant ;) we are not necessarily all that wise! Wisdom hopefully accumulates with experience, and perhaps with the agony of recreating something that was lost that should have been carefully preserved - especially things like batch files, make files and little utilities written for example because the available software tools could not produce deliverable binaries in the desired form. More seriously, most of the places I have worked for the past 45 years have been what I call "Mom and Pop" operations with all the problems that produces, including tight budgets and razor-thin resources. BTW, just because it is a fair size company does not prevent it from being run in "Mom and Pop" mode. The thin resources in my experience usually result in a very fast transition to the next project once the current one is done, which does not leave a lot of time for reflection about what all should be preserved. Even the quite large company for whom I currently work, though sadly only until next Friday, :( has run our soon-to-be-dissolved group on razor-thin resources IMHO. The other common problem I have seen is that usually no one in the chain above my immediate manager has the vaguest idea as to the importance of the work I have just completed. During some unfortunate periods, even he had no clue! I've been quite pleased for about the past 14 years to have had the use of MKS and more recently VSS to provide an archive and history information on the file servers. Allegedly these are backed up frequently off-site as well, on tape cartridges I believe, though I have never had an occasion to test that theory. At one time the IT guy would whine about how much space I was taking up on the server and I would have to give him a list of folders that could be written to CD's to make space on the file server. In at least one case, I recall one of those was partly unreadable when I tried to access it only maybe a year after it was burned. It has now been probably 10 years - anyone want to bet any of them are still readable? Since they are sitting in my bookcase at work, anyone care to guess what will become of them once I leave next Friday? The good thing is that they are all very old versions and it probably does not matter all that much. No longer needing to keep card/mag-tape/floppy backups has indeed been pleasant. (I sort of hate to admit I once even had some punched paper tape backups.) The history information the source control software provides is invaluable as well, even though I do keep written notes regarding software changes as they are made. I've been a bit amazed at how often I've found myself looking in the MKS and VSS archives to search for the answer to a question like "Exactly when was _this_ particular tiny change made". These are usually changes that seemed almost inconsequential at the time, but turned out much later to have been rather important. Later, Charlie Carothers

17 years, 4 months

ebay: 2 vintage cards for apollo workstation

by legalize＠xmission.com

Relisted with reduced buy-it-now ebay item # 260354394197 'course since the last listing expired with no bids, you could probably low-bid on this and get the two cards with no competition. I guess people aren't really collecting Apollo workstation stuff. A shame, really. -- "The Direct3D Graphics Pipeline" -- DirectX 9 draft available for download <http://www.xmission.com/~legalize/book/download/index.html> Legalize Adulthood! <http://blogs.xmission.com/legalize/>

17 years, 4 months

decmate

by nierveze＠radio-astronomie.com

hello everyone,I have a working decmate3, working well with floppies of os278 made with putr (thanks) ,I'd like to have hardware documentation about that machine ,I found the vr101,the lk201,but nothing about the cpu box, also I'd like to find documentation about os278 that seems different from os8.thanks for your help Alain Nierveze 492 All?e Montesquieu 33290 Le Pian Medoc France web:www.radio-astronomie.com email:nierveze at radio-astronomie.com

17 years, 4 months

Replacing failed powersupplies on qbus PDP-11s

by csquared3＠tx.rr.com

On Fri, 30 Jan 2009 Chuck Guzis said: > Read about it: > > http://www.smpstech.com/filter00.htm > > Interestingly, the real-world example cited is the addition of an > input filter to a PDP 11/40... The part of this that really amazes me is where it says something like "long power supply input lines" can also cause problems or oscillation. I suppose this includes for example all the wiring in my house or at the office, over which I have no control and very little detailed knowledge. I wonder if the effective length of the AC input line is all the way back to the transformer on the pole or wherever? If my guesses are correct then it is sort of scary to plug in any SMPS anywhere! I would hope that most SMPS these days have an input circuit that is reasonably immune to most of these problems, but I certainly don't know that. BTW, I have been reading the digest form of this group for a couple of years now but I think this is the first time I have posted a reply of any sort. If I goofed it up, profuse apologies in advance! Later, Charlie C.

17 years, 4 months

REPLY - Re: KAYPRO 10 - Need Help Please

by FJGJR1＠aol.com

Steven, Yes, it sounds like they are looking for boot software. It should be on the hard drive, but maybe it is corrupted or someone took it off. Check with "Sharkonwheels" on _www.vintage-computer.com_ (http://www.vintage-computer.com) , he is more expert in Kaypros after 1983. I am more into the 1983 versions. The Kaypro 10 came after 1983. You can post on this site and maybe someone will offer to buy them from you. They could be used just for parts of course. Note if you have anything else for them - software, accessories, cables, etc. That can help the sale, along with any other info - where did you get them, past history if known, etc.. This is probably the best overall site for such vintage computers. I post under GADFRAN. Good luck. Keep us informed on how you progress. Frank _www.kayprosts.org_ (http://www.kayprosts.org) In a message dated 2/1/2009 2:09:24 A.M. Eastern Standard Time, steven.alan.canning at verizon.net writes: I rescued two ( more like 1 3/4 ) KAYPRO 10 machines headed for euthanasia. I repaired the LVPS in the first unit and it comes up (?) but I think it is waiting for something ( like a BOOT disk ? ). They both ( machines ) have one half-height 5 1/4 floppy drive and one half-height 10 MByte hard drive. So far both of the CPU boards do exactly the same thing, after RESET it puts up the following prompt on the CRT; * KAYPRO 10 v1.9e * Anyone know what if anything it is waiting for ( I can't believe it wouldn't BOOT off of the hard drive, but I don't know any better ) ?? The 10 MB Ready light for the hard disk does come on ( for what it is worth...). Better yet, anyone want a couple ( or one ) KAYPRO 10s to screw around with and add to your collection ? They are built pretty tough ! Make an offer that will cover my Super Bowl beer fund and you're in business ! Because of their weight, probably limited to domestic USA shipping ( from Southern CA ). Best regards, Steven **************From Wall Street to Main Street and everywhere in between, stay up-to-date with the latest news. (http://aol.com?ncid=emlcntaolcom00000023)

17 years, 4 months

Looking for used EPROM chips, 2, 4 and 8 megabit

by ian_primus＠yahoo.com

I've been working on some projects lately that require larger EPROM chips than the ones I have scavenged over the years. I am primarily looking for 8 megabit (27c080) chips, but I also need 4's and 2's as well. Anyone have some extra 'bugs' they would part with? Thanks! -Ian

17 years, 4 months

Storage Media ( was: Seeking reverse-engineers - Apple II VisiCalc )

by wdonzelli＠gmail.com

> Holographic memory has been right around the corner for *HOW* long? I first > heard of working prototypes sometime between '88-90. Late 60s, maybe. IBM has been looking into holographic memory for a long time. -- Will

17 years, 4 months

LCD projection panel-Sharp QA 50

by Knglng＠aol.com

LCD projection panel-Sharp QA 50 I HAVE ONE WITH A REMOTE, IF YOU WANT IT EMAIL ME OR CALL ME @ 203 530 6896 I WILL ONLY SELL THE WHOLE THING, NOT JUST THE REMOTE **************Great Deals on Dell Laptops. Starting at $499. (http://pr.atwola.com/promoclk/100000075x1217883258x1201191827/aol?redir=htt… ntent/products/features.aspx/laptops_great_deals?c=us%26cs=19%26l=en%26s=d hs%26~ck=anavml)

17 years, 4 months

FSOT: two Lear Siegler ADM-3A terminals

by dave＠drcircuits.com

Advise availability of ADM-3 or 3A dave at drcircuits.com

17 years, 4 months

Stack Depth requirements for CP/M 2.2 CBIOS

by ajp166＠bellatlantic.net

> >Subject: RE: Stack Depth requirements for CP/M 2.2 CBIOS > From: "ROBO5.8" <robo58 at optonline.net> > Date: Sat, 31 Jan 2009 07:54:55 -0500 > To: "'General Discussion: On-Topic Posts Only'" <cctech at classiccmp.org> > >Hi Chuck, > >Thanks for the reply. > >My IDE drive is about 2GB which is overkill and beyond the capacities of >CP/M 2.2. So I'm only using 20MB of the drive for this project. My system >uses Interrupts for Floppy but polling for the IDE. Anything under 16drives of 8mb will fly (128mb) and not using the full drive is not an issue. >In the mid 70's and early 80's I did lots of CBIOS work and never ran into >stack problems with CP/M. Maybe the code was simpler and I used fewer >Calls, Pushes and Pop's. > >I am currently using a Private Stack for some of my CBIOS debug routines >since they are more stack intensive. > >Did you find that you had to make any other changes to the >Blocking/Deblocking code other than the recommended CP/M 2.2 patches for >success? I'dn look at drive selection and allocation vector (alloc) for a 8mb logical drive that nees to be at least for 4kb allocation size should be at least 256bytes for each drive! You can make it smaller by making the allocation chunks larger (8kb would only need 128bytes). I've never had stack size issues for just disk IO but interrrupt handlers yes always on creatign private stack. I generally develop the disk IO with minimal polled IO to limit the number of things that can go wrong and ones the disk IO is up then roll in the interrupt IO and added features. Allison > >Thanks Robo > > >-----Original Message----- >From: cctech-bounces at classiccmp.org [mailto:cctech-bounces at classiccmp.org] >On Behalf Of Chuck Guzis >Sent: Friday, January 30, 2009 7:29 PM >To: General Discussion: On-Topic and Off-Topic Posts >Subject: Re: Stack Depth requirements for CP/M 2.2 CBIOS > >On 30 Jan 2009 at 19:08, ROBO5.8 wrote: > >> I have rewritten my old systems CP/M 2.2 CBIOS to add an IDE Drive. >> >> I've run into a problem that has me stumped. Everything works as long as >I >> don't try and copy or assemble a large Assembly file (>80KB). >> >> I will be going along fine and then out of nowhere I will see CP/M request >> access to Drive "T". My debug info says SELDSK is requesting Drive >0FF00h. >> >> I have added debug code to all the CBIOS routines so that they report what >> they are doing to the console (slow but nice). >> >> I've gone through my code many times and tested each routine via an >embedded >> debug monitor. I believe I have added every CP/M 2.2 patch (1-6 and >9)that >> is specific to the CBIOS including those dealing with Blocking/Deblocking. > >What do you mean by "large"? I've run 2.2 with disks up to 20MB with >no problems. > >CP/M's stack can't be depended upon for much space at all. Since my >BIOS code was interrupt driven, every interrupt service routine >started with a change to a private "system" stack. I recall having a >lot of problems before doing that. > >Cheers, >Chuck > >

17 years, 4 months

Stack Depth requirements for CP/M 2.2 CBIOS

by ajp166＠bellatlantic.net

> >Subject: Re: Stack Depth requirements for CP/M 2.2 CBIOS > From: "Chuck Guzis" <cclist at sydex.com> > Date: Fri, 30 Jan 2009 16:28:52 -0800 > To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at classiccmp.org> > >On 30 Jan 2009 at 19:08, ROBO5.8 wrote: > >> I have rewritten my old systems CP/M 2.2 CBIOS to add an IDE Drive. >> >> I've run into a problem that has me stumped. Everything works as long as I >> don't try and copy or assemble a large Assembly file (>80KB). >> >> I will be going along fine and then out of nowhere I will see CP/M request >> access to Drive "T". My debug info says SELDSK is requesting Drive 0FF00h. >> >> I have added debug code to all the CBIOS routines so that they report what >> they are doing to the console (slow but nice). >> >> I've gone through my code many times and tested each routine via an embedded >> debug monitor. I believe I have added every CP/M 2.2 patch (1-6 and 9)that >> is specific to the CBIOS including those dealing with Blocking/Deblocking. > >What do you mean by "large"? I've run 2.2 with disks up to 20MB with >no problems. I have many systems with a minimum of 10mb drives and one has a two 32mb and the other has 45mb SCSI/ However partitions are limited to 8Mb as its' CP/M2.2. >CP/M's stack can't be depended upon for much space at all. Since my >BIOS code was interrupt driven, every interrupt service routine >started with a change to a private "system" stack. I recall having a >lot of problems before doing that. > Nominally one should preserve the stack and have one locally for that reason. Howeer if the BIOS is using the minimal IO drivers (no interrupts) the stack should be fine. Hoever is acc to drive "T" says he either has more than 16 partitions or he is crushing drive select. Allison >Cheers, >Chuck > >

17 years, 4 months

Can anyone identify this terminal?

by sethm＠loomcom.com

A friend forwarded me this YouTube link today: http://www.youtube.com/watch?v=5WCTn4FljUQ It's a KRON Channel 4 news (San Francisco, CA) report from 1981 about the San Francisco Examiner (and others) making themselves available online via BBS. My favorite line: "Of the estimated two to three thousand home computer owners in the Bay Area..." Ah, those were the days! I spy a Tandy TRS-80 Model I, a TRS-80 Color Computer! But I'm mainly interested in the Space-Age looking terminals being used by the SF Examiner staff in the video. They've got swooping, rounded corners, white shells, and what looks like an integrated 9 or 10 inch green phosphor display. Screenshot is here: http://www.loomcom.com/misc/examiner_terminal.jpg Anyone know what kind of terminal this is? I'd freaking LOVE to have one of those on my desk. -Seth

17 years, 4 months

Tektronix 4014-1 & unknown cards

by aek＠bitsavers.org

> There was > also a 4115 that used a raster display instead of the vector display. - 4115/4125 uses an x86 processor At one time, I had the full set of manuals for the 4115, while the company I was working for was trying to write an emulation for it. The service manual in particular seems very hard to find now.

17 years, 4 months

Good resource about Alan Kay

by evan＠snarc.net

Stumbled onto this web site tonight. Looks very good. http://thinkubator.ccsp.sfu.ca/Dynabook

17 years, 4 months

Software preservation (Was: Seeking reverse-engineers - Apple II VisiCalc)

by mc＠media.mit.edu

Date: Thu, 29 Jan 2009 09:07:20 -0600 From: John Foust <jfoust at threedee.com> Subject: Re: Seeking reverse-engineers - Apple II VisiCalc To: cctalk at classiccmp.org Message-ID: <6.2.3.4.2.20090129085638.05e74420 at mail.threedee.com> Content-Type: text/plain; charset="us-ascii" At 01:00 PM 1/28/2009, Tim McNerney wrote: > >I am looking for volunteers to help reverse-engineer and document Apple II VisiCalc. > >I have three versions of the Apple II software. I know one of them still boots (1983?) > >and have some confidence that the other two versions (1979 and 1981) work too. > >I have been in contact with both Bob Frankston and Dan Bricklin. > >Of course you ask, well then why do you need volunteers? > >The answer is because no one can find the sources. > No matter how many times I hear stories like this, or lived through stories like this, I still shake my head and can't understand how the source code gets lost. All these corporations, all the lawsuits, all the programmers, all the marketing money, and so often no one, NO ONE, preserves arguably the most important bits. - John In the case of Personal Software, I believe Lotus bought them to reduce competition, not to preserve VisiCalc. At the time, people seldom think about the historical significance of source documents. The Intel 4004 schematics would have been lost if it hadn't been for some Intel engineer who realized they needed to be saved. True, there are some engineers who take stuff home and store it in their basement, but in the case of the 4004, Federico Faggin couldn't hold on to any schematics when he left Intel because he was going off to found Zilog and had to protect himself legally. The problem with packrats is that, even when you are unusually organized, like Bob Frankston, you still end up with boxes that are mis-labeled. Even Hewlett Packard has thrown out some important engineering documentation. When the calculator division moved from Santa Clara to Corvalis, the threw out dumpsters full of drawings on their very first RPN calculator, the 9100. --Tim

17 years, 4 months

Software preservation (Was: Seeking reverse-engineers - Apple II VisiCalc)

by mc＠media.mit.edu

Date: Thu, 29 Jan 2009 11:08:15 -0800 From: Guy Sotomayor <ggs at shiresoft.com> Oh, I completely understand how it happens (after having seen it happen a few times). Typically all of the source for a project is kept on a server(s) that run the SCM (source code management) system. Yes, they are backed up but in many cases it's just a rotating backup set (ie they get overwritten). When the project is EOL'd usually the server(s) are either re-tasked (involving a complete re-install and wipe) or scrapped (which involves wiping). The backups are usually scrapped at that time as well. Almost no one does an archive of those backups. If they do, then that's were to look because they are kept in an off-site location for disaster recovery. In many cases the off- site storage is mostly write-only (ie tapes/whatever go in but are never asked for and not purged). Most of this stuff gets "lost" because of apathy on the part of the owners rather than malicious intent. TTFN - Guy People have always been sloppy about old backups. Even companies like Thinking Machines, who were careful and kept off-site backups using Iron Mountain, or somesuch, when the company went out of business, all these tapes ended up in a dumpster. (I know this for a fact). --Tim P.S. Back in the 70's version control systems were rare. Personal Software's backups were done on floppies.

17 years, 4 months

My GRiD 1109 screen is shot

by tosteve＠yahoo.com

I have acquired a GRiD 1109 laptop from 1983(?), but the screen mostly shows only every-other scan line. Schematics may help, but I haven't found any. Does anyone have a screen (or more) to donate? Thanks- Steve. P.S. The 1109 circuit boards are different than those of the 1101. Anyone know the differences between the two?

17 years, 4 months

cctalk Digest, Vol 65, Issue 65

by mc＠media.mit.edu

From: "Jeff Walther" <trag at io.com> Subject: Re: Seeking reverse-engineers - Apple II VisiCalc What I find particularly irritating, is that the loss of the source code, arguably, defeats the implicit reason that copyright and patent protection exists in the first place. The U.S. constitution states: "To promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries;" Now one could argue that securing the exclusive rights promotes progress all by itself. But the fact that it is meant to be for a limited time, implies to me that at some point the full benefit of that advancement should become available to everybody. If no copy of the source code is required to be filed with the government, then the copyright and/or patent laws are not securing the benefits of that progress for society at the end of the exclusive period. Patents have become similarly lame. Chips get patented with no description language at any level required to be filed. Sigh. Bad congress. Bad bad congress. No cookie. Jeff Walther I don't think it ever occurred to our founding fathers that "authors" would copyright something with no intent of ever publishing it. Or, in the case of software, publishing the binaries, but not the sources. Even the pre-1976 requirement of copyright registration was perverted in the case of software. The Copyright Office allows you to submit only a fraction of what was being copyrighted, and you can block out parts that you consider trade secrets. So much for the public good. --Tim

17 years, 4 months

ebay: 2 vintage cards for apollo workstation

by aek＠bitsavers.org

> I guess people aren't really collecting Apollo workstation stuff. DN3xxx et. al. are just coming out of the bottom of the bathtub curve. Same with VME Sun 3 and 4. Most of the mid-80's workstations have been recycled now. There is also the little problem of software for them, if you don't want to run NetBSD. To be honest, the first lot with the disk controller and network card were of more use than the memory and video card. Keeping Apollo gear going is going to be tricky. At least the Sun 3 hardware docs have mostly leaked out. I've heard of very little detailed Apollo HW info out there. A couple of years ago, I was trying to get the guy who was working adding more driver support to BSD to get the info he had reverse engineered, but didn't get anywhere. I've been in contact with the person responsible for Apollo product support at HP about what hardware info they got for the machines, and it doesn't sound like much made it out there from the east coast. Similar things happened when HP took over the 68k-based 1500 product line from TI.

17 years, 4 months

Replacing failed powersupplies on qbus PDP-11s

by tiggerlasv＠aim.com

Since I'm not aware of your electronics/troubleshooting knowledge, I thought I'd make mention of one of the known BA23/BA123 issues. When the boxes were first introduced, they were shipped with backplane power cables that had a major design flaw. They used IDC-style connectors on each end of what was basically a heavy-gauge ribbon cable. The Insulation Displacement Connectors tended to add significant resistance to the connection, and couldn't carry their rated loads. Depending on the load, the connectors would either discolor from the heat. . . . start to melt, or, in extreme cases, start on fire. An FCO was issued, and the "proper" power cables have individual wires, and crimped-on pins. I don't think it would be unreasonable to speculate that, if your particular power supply had an old-style connector at some point (which chose to melt) that the solder joints for the header could have been compromised from the heat. Check the circuit board where the header is soldered, to make sure there aren't any cold or bridged solder joints. A shorted pin could prevent the power supply from coming up. . . If you have the old ribbon-style power connectors, I would recommend replacing them immediately. I "rolled my own" with parts readily available at MCM Electronics. I'm sure suitable connectors could also be obtained from Jameco, Digikey, etc. T

17 years, 4 months

Tektronix 4014-1 & unknown cards

by stephane.tsacas＠gmail.com

Hi, I just bought a Tektronix 4014-1, almost unused, for 10 euros ! The guy who sold it to me told me that it was connected to a "computer" which was located under a desk. He had removed the cards of this "computer", and had them stored, he gave them to me with the 4014. The inside of the 4014 and those unkown to me cards are displayed there : http://picasaweb.google.fr/sur.le.tas/Tektronix40141?feat=directlink (the "loupe" button on the top right might be useful). Also, in the 4014 docs, it seems I have one extra cards in the 4014, maybe the first one from the left ? Any idea what the other cards are ? Thanks -- Stephane Paris, France.

17 years, 4 months

Seeking reverse-engineers - Apple II VisiCalc

by trag＠io.com

>Date: Thu, 29 Jan 2009 09:07:20 -0600 >From: John Foust <jfoust at threedee.com> >Subject: Re: Seeking reverse-engineers - Apple II VisiCalc > At 01:00 PM 1/28/2009, Tim McNerney wrote: > > >> >I am looking for volunteers to help reverse-engineer and document >> Apple II VisiCalc. >> >I have three versions of the Apple II software. I know one of them >> still boots (1983?) >> >and have some confidence that the other two versions (1979 and >> 1981) work too. >> >I have been in contact with both Bob Frankston and Dan Bricklin. >> >Of course you ask, well then why do you need volunteers? >> >The answer is because no one can find the sources. >> > > No matter how many times I hear stories like this, or lived through > stories like this, I still shake my head and can't understand how the > source code gets lost. All these corporations, all the lawsuits, all > the programmers, all the marketing money, and so often no one, NO ONE, > preserves arguably the most important bits. What I find particularly irritating, is that the loss of the source code, arguably, defeats the implicit reason that copyright and patent protection exists in the first place. The U.S. constitution states: "To promote the progress of science and useful arts, by securing for limited times to authors and inventors the exclusive right to their respective writings and discoveries;" Now one could argue that securing the exclusive rights promotes progress all by itself. But the fact that it is meant to be for a limited time, implies to me that at some point the full benefit of that advancement should become available to everybody. If no copy of the source code is required to be filed with the government, then the copyright and/or patent laws are not securing the benefits of that progress for society at the end of the exclusive period. Patents have become similarly lame. Chips get patented with no description language at any level required to be filed. Sigh. Bad congress. Bad bad congress. No cookie. Jeff Walther

17 years, 4 months

Annals of the History of Computing: "bitsavers" is referenced

by aek＠bitsavers.org

> Ye gads... If that's the leading publication on Computer History, it > looks like the market could stand another. Something more along the > lines of the excellent UK magazine "Retro Gamer" perhaps, with > articles written by (and for) normal (if a bit fannish) humans and > lots of pictures of old hardware and stuff. One thing I have learned working at a museum is there is a lot more to the discipline of the history of computing than being a fan and having nostalgia for the subject. I was fortunate to have the chance to have long talks with Doron Swade on what it is like to be a curator at an institution that has existed for hundreds of years, and the responsibility that is involved with that position. There was a very good article on the problems of creating an institution to preserve computing history (in particular, the Charles Babbage Institute) "Arthur Norberg, the Charles Babbage Institute, and the History of Computing" in the Oct-Dec 2007 issue of the Annals, in particular, the collections policy and focus that they created at CBI. "Retrocomputing", nostalga, and eye candy seem to be more of what you are interested in, than the discipline of historical preservation and interpretation, which is where the Annals and other journals on the history of technology are focused.

17 years, 4 months

Annals of the History of Computing: "bitsavers" is referenced

by madcrow.maxwell＠gmail.com

Ye gads... If that's the leading publication on Computer History, it looks like the market could stand another. Something more along the lines of the excellent UK magazine "Retro Gamer" perhaps, with articles written by (and for) normal (if a bit fannish) humans and lots of pictures of old hardware and stuff. You could call it "Classic Bits" or something actually catchy. I'll bet the inhabitants of this list could cook up a better product almost overnight. Mike

17 years, 4 months

Repair of damaged/corroded gold connector 'fingers'?

by ian_primus＠yahoo.com

Recently, I've run across some circuit boards with damaged connector fingers. Some are badly scratched and worn, the gold plating almost gone, and others are actually corroded - the copper has corroded, possibly due to previous damage to the gold plating. The circuit boards in question are the ones in Nintendo cartridges, but the same problem applies to any printed circuit board edge connector. The scratched/worn connectors seem to still work, at least most of the time. The corroded ones wouldn't work until I cleaned off the corrosion. Not an easy thing to do - I ended up resorting to Brasso, a brass polish. Now, this is NOT the thing to use to clean edge connectors! DON'T DO IT! It WILL take the plating off. In this case, the plating was already gone, and the copper track underneath was corroded. Cleaning the corrosion off with the Brasso, and subsequent cleaning with alcohol to clean off the Brasso, removed the corrosion leaving a shiny copper track. The board worked fine, but for how long? How long until the corrosion comes back, or the copper oxidizes? Is there any way to repair or replate fingers like this? Obviously, tinning them with solder would prevent oxidization, but this would make that 'finger' much too thick, and risks damaging the connector it plugs into. (Operators loved to "fix" burnt edge connectors on arcade boards like this, and it works for a while, until you go to unplug and replug it, and the destoyed connector no longer mates with the board correctly.) Just something I thought that others might have an input on - I mean, in this case, these Nintendo cartridges are not worth the effort of any complicated repair, but it raised the question in my mind, and I know I've run into this on computers before. So, any thoughts? -Ian

17 years, 4 months

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test-drb