Re: [cctalk] Replacing the Flyback Transformer From My VAXmate
Rob - It has been 35+ years since I worked for an Apple dealer, during the Macintosh announcement (and Apple sales, service training). I no longer have any of those documents. The Apple Community is extensive, and a quick Google search turned up many comments about Flyback, Damping Diode, & CRT replacements for early Macintosh. One individual acquired a replacement Flyback from Spain ($16 USD) for his Apple. Suggest you research those Apple owners for Mac specifications — possible replacement. https://macgui.com/news/article.php?t=446 greg > On May 18, 2020, at 4:54 PM, Rob Jarratt wrote: > > Thanks for this. I am having trouble finding any information on them, such > as datasheets. Any ideas where to find this kind of information? > > Regards > Rob >> == >> From: "Rob Jarratt" >> To: "General Discussion: On-Topic and Off-Topic Posts" >> Subject: Replacing the Flyback Transformer From My VAXmate >> >> I am about as certain as I can be that the flyback transformer from my >> VAXmate monitor board has failed. I know this is probably impossible, but I >> am >> wondering if there is a way to find a more modern equivalent? How >> standardised are these things? I do see a lot that appear to have the same >> circular arrangement of the pins. >> >> The VAXmate one is a Tai-Ho TH-1802B and according the Technical >> Description has a primary voltage of +28V and produces auxiliary voltages as >> follows: >> >> +13.1kV @85uA max >> +950V @200uA >> +45V @75mA max >> -100V @1.2mA >> >> Regards >> Rob
[cctalk] Re: Replacing the Flyback Transformer From My VAXmate
Tai-Ho (Taiwan) was the OEM supplier for flyback transformers used by Apple in the early Macintosh computers (1984+). Russell Industries (New York, USA) produced replacement flyback transformers for monitors and TVs, these appear on eBay and remaining TV repair supply houses. As noted, while the circular pin-out is often standardized, the voltages need to be double-checked. greg chicago == From: "Rob Jarratt" To: "General Discussion: On-Topic and Off-Topic Posts" Subject: Replacing the Flyback Transformer From My VAXmate I am about as certain as I can be that the flyback transformer from my VAXmate monitor board has failed. I know this is probably impossible, but I am wondering if there is a way to find a more modern equivalent? How standardised are these things? I do see a lot that appear to have the same circular arrangement of the pins. The VAXmate one is a Tai-Ho TH-1802B and according the Technical Description has a primary voltage of +28V and produces auxiliary voltages as follows: +13.1kV @85uA max +950V @200uA +45V @75mA max -100V @1.2mA Regards Rob
Re: [cctalk] Replacing the Flyback Transformer From My VAXmate
Rob - A DEC Part Number would speed up your Part Search. Radwell, a surplus dealer in New Jersey, lists a DEC terminal Flyback Transformer. DEC Part number: 16-27975-01 (supposedly used in the DEC VT320 terminal) https://www.radwell.com/en-US/Buy/MONITOR%20TECHNOLOGIES/MONITOR%20TECHNOLOGIES/16-27975-01 A quick search on eBay produced this flyback candidate by Dalbani, a Miami, FL reseller. eBay auction # 123532693525 Replacement 16-27975-01 Flyback Transformer for DEC CRT TVs. Please verify the part number to ensure compatibility. These Items are not manufactured anymore. Order before we are out of stock permanently. All items are new old stock and guaranteed for functionality.
RE: [cctalk] Re: Replacing the Flyback Transformer From My VAXmate
> -Original Message- > From: cctech On Behalf Of Gregory Beat via > cctech > Sent: 18 May 2020 20:08 > To: cct...@classiccmp.org > Subject: [cctalk] Re: Replacing the Flyback Transformer From My VAXmate > > Tai-Ho (Taiwan) was the OEM supplier for flyback transformers used by Apple > in the early Macintosh computers (1984+). > > Russell Industries (New York, USA) produced replacement flyback transformers > for monitors and TVs, these appear on eBay and remaining TV repair supply > houses. > > As noted, while the circular pin-out is often standardized, the voltages need to > be double-checked. Thanks for this. I am having trouble finding any information on them, such as datasheets. Any ideas where to find this kind of information? Regards Rob > > greg > chicago > == > From: "Rob Jarratt" > To: "General Discussion: On-Topic and Off-Topic Posts" > Subject: Replacing the Flyback Transformer From My VAXmate > > I am about as certain as I can be that the flyback transformer from my > VAXmate monitor board has failed. I know this is probably impossible, but I am > wondering if there is a way to find a more modern equivalent? How > standardised are these things? I do see a lot that appear to have the same > circular arrangement of the pins. > > The VAXmate one is a Tai-Ho TH-1802B and according the Technical > Description has a primary voltage of +28V and produces auxiliary voltages as > follows: > > +13.1kV @85uA max > +950V @200uA > +45V @75mA max > -100V @1.2mA > > Regards > Rob=
Re: LK201 emulation
If anyone is interested in taking over my PS/2 mouse to DEC mouse adapter (tested working on VAXStation, should also work on VT340+, etc) https://bitbucket.org/tinyscsi/decmouse/raw/fc73c57dce5926ac1ab9f0958ba82cf1e8cbe88e/DECMouse.ino You could implement both keyboard and mouse on one controller that has two serial ports (I use Teensy's) On Mon, May 18, 2020, 8:34 PM Ethan Dicks via cctalk wrote: > On Mon, May 18, 2020 at 6:34 PM Steve Malikoff via cctalk > wrote: > > There is a project that seems to be going along the same idea, > http://www.kbdbabel.org/ > > Interesting starting point, but I tried to browse the code and it > flashed up instructions for how to use cvs or rsync to pull the code > down. > > Last substantial update seems to be from 2009. Lots of 8051 source. > Not impossible to still find those, but a little on the chunky side > for this decade. > > One could learn much from reading the code and inspecting the > schematics, I'm sure. > > -ethan >
Re: LK201 emulation
Sophie Haskins wrote: > A long term dream of mine is to build some sort of general-purpose box > that can make connections to arbitrary vintage computer > keyboard/mouse/video ports, and connect in to modern HDMI & USB > peripherals to make it easier to just pull a machine off the shelf and > get going. I'm kind of moving in this direction a tiny bit. I have a set of software emulators that I install on Raspberry Pis. My idea is that they should boot straight into the emulator and connect to a host computer over the network.
Re: LK201 emulation
If anyone wants a PS/2 keyboard adapter that emulates an LK201, there's Peter Bosch's Arduino Nano based lk201emu: https://github.com/peterbjornx/lk201emu His writeup on this is still in the Wayback Machine: https://web.archive.org/web/20180703165508/https://peterbjornx.nl/vtkbd/ I can no longer find a copy of Peter's schematic for this online, but at some point I grabbed a copy of it. I've renamed it from schem.pdf to lk201emu-schem.pdf and made it available at: https://drive.google.com/open?id=1XmRClTCoIedfXDcUbcaJi-A9QXr7SCEo -- Ron
FTGH - Decstation 5000 plus many extras
Lets have another go (but this time I have some pictures) Decstation 5000/125 – also houses a CD drive. Two expansion storage boxes – one has a tape drive and the other one has a floppy drive. Two very large and heavy RGB Digital monitors – one has both Digital and Sony branding on the back of it. I haven’t dug the other one out as its in a corner and is dam heavy but it looks the same as the other one. Box of spares (RAM, CPU's, HDDs etc.) I’ve never powered it up – it was a rescue – I believe it was a server in a TAFE college in Adelaide. This is all I got from the rescue bar the box of spares. The original owner had tossed all the documentation and software. Please note that the stand is not included in my offer and its located in south western Victoria (Australia). Photos: http://koken.advancedimaging.com.au/index.php?/albums/decstation/ Kevin Parker
Re: LK201 emulation
On Mon, May 18, 2020 at 6:34 PM Steve Malikoff via cctalk wrote: > There is a project that seems to be going along the same idea, > http://www.kbdbabel.org/ Interesting starting point, but I tried to browse the code and it flashed up instructions for how to use cvs or rsync to pull the code down. Last substantial update seems to be from 2009. Lots of 8051 source. Not impossible to still find those, but a little on the chunky side for this decade. One could learn much from reading the code and inspecting the schematics, I'm sure. -ethan
Re: LK201 emulation
On Mon, May 18, 2020 at 6:47 PM sales--- via cctalk wrote: > On 2020-05-18 17:34, Steve Malikoff via cctalk wrote: > > There is a project that seems to be going along the same idea, > > http://www.kbdbabel.org/ > > > > Steve. > > Except that I can tell you from experience that not all 4p4c terminal > keyboards are interchangeable. I you plug a Wyse into a Televideo, or > vice versa, the keyboard will not work, and sometimes causes a small > fire That is very true. DEC LK201/LK401, etc, and compatibles are all +12V devices with +12V and gnd on specific pins (not mirrored or mirror-safe). I have, as I mentioned, a Planar terminal, an ELT-320. It is a third-party device with an LK201 socket (and a PC-AT keyboard socket - either one can be used). Other vendors are free to do as they please because they expect to sell you a device with their keyboard. I'm sure some are +5V devices and many are +12V. Doesn't take much of a difference to cause problems, especially if your +12V line isn't current-limited. Making a universal keyboard interface definitely faces some physical challenges. -ethan
Re: LK201 emulation
On 2020-05-18 17:34, Steve Malikoff via cctalk wrote: Sophie said I would absolutely be interested in this - while I'd love to use original hardware where possible, it's not always easy to get peripherals at the same time as machines. A long term dream of mine is to build some sort of general-purpose box that can make connections to arbitrary vintage computer keyboard/mouse/video ports, and connect in to modern HDMI & USB peripherals to make it easier to just pull a machine off the shelf and get going. There is a project that seems to be going along the same idea, http://www.kbdbabel.org/ Steve. Except that I can tell you from experience that not all 4p4c terminal keyboards are interchangeable. I you plug a Wyse into a Televideo, or vice versa, the keyboard will not work, and sometimes causes a small fire Cindy
Re: LK201 emulation
Sophie said > I would absolutely be interested in this - while I'd love to use original > hardware where possible, it's not always easy to get peripherals at the same > time as machines. A long term dream of mine is to build some sort of > general-purpose box that can make connections to arbitrary vintage computer keyboard/mouse/video ports, and connect in to modern HDMI & USB peripherals to make it easier to just pull a machine off the shelf and get going. There is a project that seems to be going along the same idea, http://www.kbdbabel.org/ Steve.
RE: LK201 emulation
Readymade cables exist to allow Wyse and other terminal keyboards to work on USB. Would a reverse of this work? -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Warner Losh via cctalk Sent: Monday, May 18, 2020 4:48 PM To: Ethan Dicks; General Discussion: On-Topic and Off-Topic Posts Subject: Re: LK201 emulation On Mon, May 18, 2020 at 3:46 PM Ethan Dicks via cctalk < cctalk@classiccmp.org> wrote: > On Mon, May 18, 2020 at 5:28 PM Paul Koning via cctalk > wrote: > > What I was talking about is a way to use a PC USB keyboard in place of > an LK201, when your last remaining real LK201 has just failed. That > involves a USB jack, a LK201-compatible handset jack, some electronics, and > software to speak the protocols involved. That's what I have just > prototyped. > > I would make a few of these. Could be handy at a VCF if your LK201 > dies, or doesn't fit in your luggage. > I'd want a couple of these, especially if it let my Rainbow boot 'headless' otherwise. I've been experimenting with different LCD displays in an effort to replace the VR201 display with that. If I could then plug in any old keyboard I had laying around (USB or PS/2) that would be really nice... Warner -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Re: LK201 emulation
On Mon, May 18, 2020 at 3:46 PM Ethan Dicks via cctalk < cctalk@classiccmp.org> wrote: > On Mon, May 18, 2020 at 5:28 PM Paul Koning via cctalk > wrote: > > What I was talking about is a way to use a PC USB keyboard in place of > an LK201, when your last remaining real LK201 has just failed. That > involves a USB jack, a LK201-compatible handset jack, some electronics, and > software to speak the protocols involved. That's what I have just > prototyped. > > I would make a few of these. Could be handy at a VCF if your LK201 > dies, or doesn't fit in your luggage. > I'd want a couple of these, especially if it let my Rainbow boot 'headless' otherwise. I've been experimenting with different LCD displays in an effort to replace the VR201 display with that. If I could then plug in any old keyboard I had laying around (USB or PS/2) that would be really nice... Warner
Re: LK201 emulation
On Mon, May 18, 2020 at 5:28 PM Paul Koning via cctalk wrote: > What I was talking about is a way to use a PC USB keyboard in place of an > LK201, when your last remaining real LK201 has just failed. That involves a > USB jack, a LK201-compatible handset jack, some electronics, and software to > speak the protocols involved. That's what I have just prototyped. I would make a few of these. Could be handy at a VCF if your LK201 dies, or doesn't fit in your luggage. -ethan
Re: LK201 emulation
On Mon, May 18, 2020 at 5:20 PM Electronics Plus via cctalk wrote: > Do you guys want original LK201s, or other keyboards that LOOK like LK201s > in the caps and layout, or converters? > I am a little confused... LK201 clones do not have the clip offset on the > terminal connector, so you would have to replace the connector. I have no > idea if the protocol, voltage, etc is the same. LK201 keyboards and variants (LK401, clones, etc) have a narrow 4p4c "handset jack" connector, not offset like an MMJ serial connector. The power is +12V, the serial protocols are the same. I've used LK401s on VT220s and Rainbows, I've used LK401s and LK201s on a Planar terminal with an "LK201" input jack. That part is standard. Speaking for myself, I have a pile of devices (DECmates, Professionals, Rainbows, VT220, VT240...) that have a 4-place narrow handset jack for a keyboard, and most of them are expecting an LK201. I also have a large assortment of LK201s (with and without the WPS/EDT "Gold Key" keycaps) and 1-2 smaller but compatible keyboards. Every time I pull an LK201 off the shelf, I'm wondering if it's going to work. I have 2-3 dead ones for sure. I think at least one of them has a dead matrix because IIRC, it was causing "4 - keyboard error" until I dismantled it and unplugged the mylar keyboard matrix sheet. I suspect that the paint layer has either oxidized to high resistance/open circuit or there's a short somewhere. I haven't investigated that further. I am also aware of some electronics failures. I can obviously mix and match bits to have as many working keyboards as possible, but that is a finite decreasing number. What I would find handy in one regard is being able to use a PS/2 or USB modern keyboard on 1980s DEC equipment as if I was plugging in an LK201. I would also probably employ a device that I could plug a real DEC keyboard into but that talked PS/2 or USB to be able to use that with a modern machine. One application would be to use it with Simh or even just a dumb terminal emulator (Glass, etc) with a real terminal feel. I might employ a device that replaced the electronics in a dead LK201 but I wouldn't need that many of them. -ethan > -Original Message- > From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Sophie > Haskins via cctalk > Sent: Monday, May 18, 2020 3:41 PM > To: Paul Koning; General Discussion: On-Topic and Off-Topic Posts > Subject: Re: LK201 emulation > > I would absolutely be interested in this - while I'd love to use original > hardware where possible, it's not always easy to get peripherals at the same > time as machines. A long term dream of mine is to build some sort of > general-purpose box that can make connections to arbitrary vintage computer > keyboard/mouse/video ports, and connect in to modern HDMI & USB peripherals > to make it easier to just pull a machine off the shelf and get going. > > > On May 17, 2020, at 5:13 PM, Paul Koning via cctalk > wrote: > > > > Gentlepeople, > > > > I've been having problems with broken LK201s, so as a workaround I created > an adapter that connects to a standard PC USB keyboard and makes it look > like an LK201. It's based on an Arduino (specifically, Adafruit Trinket M0, > an amazingly tiny yet powerful small microprocessor). > > > > It's working at this point, though it needs a few small software tweaks to > make it complete. I'm going to turn my breadboard into something slightly > more polished. > > > > Question to the list: is this something that would be of interest to > others? If yes, I can make the design available. Perhaps the PCB layout > and parts list. I don't think I want to get into building units for others, > though. > > > > paul > > > > > -- > This email has been checked for viruses by Avast antivirus software. > https://www.avast.com/antivirus >
Re: LK201 emulation
Paul Koning wrote: >> On May 18, 2020, at 9:09 AM, Peter Coghlan via cctalk >> wrote: >> >> ... >> I also find myself with several flakey LK201s. >> >> To be honest, I wouldn't be interested in replacing them with PC keyboards. >> I'd prefer to get my LK201s back in action. >> >> If the issues are in the keyswitches or the flexi-print stuff connecting them >> to the electronics, it looks like it will be nearly impossible to do anything >> with them. > > Yes, and that is the case with mine. I know from years past that those > switches are vulnerable to contamination. > I fear it may be the same with mine. Most of mine seem to behave as if keys are intermittently stuck down but no amount of tapping, shaking etc seems to help. > >> However, if it turns out that the issues are in the electronics part of the >> keyboard and they are not easily repairable for one reason or another, I may >> be interested in a drop in replacement for the original electronics. > > Since that wasn't my scenario I haven't tried to do that. It seems easy > enough. The main issue is that you need a controller with enough I/O lines > to run the scan. A BeagleBone would be ample; an Arduino might not be. > Fair enough. Sorry for the digression. Regards, Peter Coghlan. > paul >
Re: LK201 emulation
> On May 18, 2020, at 5:20 PM, Electronics Plus via cctalk > wrote: > > Do you guys want original LK201s, or other keyboards that LOOK like LK201s > in the caps and layout, or converters? > I am a little confused... LK201 clones do not have the clip offset on the > terminal connector, so you would have to replace the connector. I have no > idea if the protocol, voltage, etc is the same. I think you're confused between terminals and keyboards. LK201 keyboards don't have offset clips (MMJ connectors). Instead, they use a standard telephone handset connector. What I was talking about is a way to use a PC USB keyboard in place of an LK201, when your last remaining real LK201 has just failed. That involves a USB jack, a LK201-compatible handset jack, some electronics, and software to speak the protocols involved. That's what I have just prototyped. paul
RE: LK201 emulation
Do you guys want original LK201s, or other keyboards that LOOK like LK201s in the caps and layout, or converters? I am a little confused... LK201 clones do not have the clip offset on the terminal connector, so you would have to replace the connector. I have no idea if the protocol, voltage, etc is the same. Cindy -Original Message- From: cctalk [mailto:cctalk-boun...@classiccmp.org] On Behalf Of Sophie Haskins via cctalk Sent: Monday, May 18, 2020 3:41 PM To: Paul Koning; General Discussion: On-Topic and Off-Topic Posts Subject: Re: LK201 emulation I would absolutely be interested in this - while I'd love to use original hardware where possible, it's not always easy to get peripherals at the same time as machines. A long term dream of mine is to build some sort of general-purpose box that can make connections to arbitrary vintage computer keyboard/mouse/video ports, and connect in to modern HDMI & USB peripherals to make it easier to just pull a machine off the shelf and get going. > On May 17, 2020, at 5:13 PM, Paul Koning via cctalk wrote: > > Gentlepeople, > > I've been having problems with broken LK201s, so as a workaround I created an adapter that connects to a standard PC USB keyboard and makes it look like an LK201. It's based on an Arduino (specifically, Adafruit Trinket M0, an amazingly tiny yet powerful small microprocessor). > > It's working at this point, though it needs a few small software tweaks to make it complete. I'm going to turn my breadboard into something slightly more polished. > > Question to the list: is this something that would be of interest to others? If yes, I can make the design available. Perhaps the PCB layout and parts list. I don't think I want to get into building units for others, though. > > paul > -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus
Re: LK201 emulation
I would absolutely be interested in this - while I'd love to use original hardware where possible, it's not always easy to get peripherals at the same time as machines. A long term dream of mine is to build some sort of general-purpose box that can make connections to arbitrary vintage computer keyboard/mouse/video ports, and connect in to modern HDMI & USB peripherals to make it easier to just pull a machine off the shelf and get going. > On May 17, 2020, at 5:13 PM, Paul Koning via cctalk > wrote: > > Gentlepeople, > > I've been having problems with broken LK201s, so as a workaround I created an > adapter that connects to a standard PC USB keyboard and makes it look like an > LK201. It's based on an Arduino (specifically, Adafruit Trinket M0, an > amazingly tiny yet powerful small microprocessor). > > It's working at this point, though it needs a few small software tweaks to > make it complete. I'm going to turn my breadboard into something slightly > more polished. > > Question to the list: is this something that would be of interest to others? > If yes, I can make the design available. Perhaps the PCB layout and parts > list. I don't think I want to get into building units for others, though. > > paul >
Re: LK201 emulation
On Mon, May 18, 2020 at 8:32 AM Paul Koning via cctalk < cctalk@classiccmp.org> wrote: > > However, if it turns out that the issues are in the electronics part of > the > > keyboard and they are not easily repairable for one reason or another, I > may > > be interested in a drop in replacement for the original electronics. > > Since that wasn't my scenario I haven't tried to do that. It seems easy > enough. The main issue is that you need a controller with enough I/O lines > to run the scan. A BeagleBone would be ample; an Arduino might not be. > Yea. I have one LK201 that I fried the controller board on by connecting 12V to the wrong lead and popping a few components off the board... I've replaced the exploded ones and it still doesn't work :( Would be cool to be able to use it again... Warner
RE: Evans & Sutherland PS-2?
I have one, but no documentation I'm afraid. The last time I turned it on was 20 years ago. The last thing I remember is the fuse in the display blowing. I ordered replacements, but never got it going again. They take a lot of power, where mine is currently sitting I don't have the power to bring it up. In the next year or so I plan to build a special room with lots of power for my old graphics devices. I'll get back on it then, hopefully I'll be at least semi-retired by then. -Original Message- From: cctalk On Behalf Of Brad Parker via cctalk Sent: May 18, 2020 2:15 PM To: General Discussion: On-Topic and Off-Topic Posts Subject: Evans & Sutherland PS-2? Does anyone have, or know of low level documentation for Evans & Sutherland Picture System 2 hardware? I walk past a PS-2 monitor all the time and some of us started talking about bringing it back to life. I'm not sure if more of the system exists, but it might. I plan to check. I looked on bitsavers and there's nothing I could find on the picture system. Other E&S hardware, but not PS. Anyone know if any systems still exist? I'd have to think the CHM has at least one. Back in the day they were sort of required for anyone doing commercial animation (or at least, that's what I could claim/recall but it was a long time ago) Brad
Re: Evans & Sutherland PS-2?
Brad Parker wrote: > Does anyone have, or know of low level documentation for Evans & > Sutherland Picture System 2 hardware? Sorry, I can't help. Is there any software for it? I do consider making an emulator for the E&S LDS-1.
Evans & Sutherland PS-2?
Does anyone have, or know of low level documentation for Evans & Sutherland Picture System 2 hardware? I walk past a PS-2 monitor all the time and some of us started talking about bringing it back to life. I'm not sure if more of the system exists, but it might. I plan to check. I looked on bitsavers and there's nothing I could find on the picture system. Other E&S hardware, but not PS. Anyone know if any systems still exist? I'd have to think the CHM has at least one. Back in the day they were sort of required for anyone doing commercial animation (or at least, that's what I could claim/recall but it was a long time ago) Brad
Re: LK201 emulation
> On May 18, 2020, at 9:09 AM, Peter Coghlan via cctalk > wrote: > > ... > I also find myself with several flakey LK201s. > > To be honest, I wouldn't be interested in replacing them with PC keyboards. > I'd prefer to get my LK201s back in action. > > If the issues are in the keyswitches or the flexi-print stuff connecting them > to the electronics, it looks like it will be nearly impossible to do anything > with them. Yes, and that is the case with mine. I know from years past that those switches are vulnerable to contamination. > However, if it turns out that the issues are in the electronics part of the > keyboard and they are not easily repairable for one reason or another, I may > be interested in a drop in replacement for the original electronics. Since that wasn't my scenario I haven't tried to do that. It seems easy enough. The main issue is that you need a controller with enough I/O lines to run the scan. A BeagleBone would be ample; an Arduino might not be. paul
Re: LK201 emulation
Paul Koning wrote: > > Gentlepeople, > > I've been having problems with broken LK201s, so as a workaround I created > an adapter that connects to a standard PC USB keyboard and makes it look > like an LK201. It's based on an Arduino (specifically, Adafruit Trinket M0, > an amazingly tiny yet powerful small microprocessor). > > It's working at this point, though it needs a few small software tweaks to > make it complete. I'm going to turn my breadboard into something slightly > more polished. > > Question to the list: is this something that would be of interest to others? > If yes, I can make the design available. Perhaps the PCB layout and parts > list. I don't think I want to get into building units for others, though. > I also find myself with several flakey LK201s. To be honest, I wouldn't be interested in replacing them with PC keyboards. I'd prefer to get my LK201s back in action. If the issues are in the keyswitches or the flexi-print stuff connecting them to the electronics, it looks like it will be nearly impossible to do anything with them. However, if it turns out that the issues are in the electronics part of the keyboard and they are not easily repairable for one reason or another, I may be interested in a drop in replacement for the original electronics. I've opened up one of mine just now and extracted the PCB. There are eight 10 microfarad axial electrolytic capacitors on it. Each of them has some green salty corrosion deposits on one or both of their leads while the leads on the other components are bright and shiney. If I had spares available, I would try replacing these components and see if it makes a difference. I unsoldered them anyway in case they cause damage to the PCB. Most of them measured ok on the capacitance range on my multimeter but one of them reads only 3.5 microfarads. Regards, Peter Coghlan. > paul >
Re: LK201 emulation
Paul Koning wrote: > Question to the list: is this something that would be of interest to > others? If yes, I can make the design available. Perhaps the PCB > layout and parts list. Yes, I'm interested. I also have a broken LK201, and I have a Trinket lying around.
