[M100] LCD Lines
I've had a Model 102 for years that I enjoy tinkering with and I've often thought I should pick up a Model 100 as well but never had a real need. Now with new forthcoming REXCPM on the horizon I figured I might start watching eBay looking for a deal. I ended up picking up a nice clean (on the outside anyway) m100 that has some screen issues. There isna large horizontal band of missing pixels all the way across the screen as well as some vertical lines missing for about half the screen. https://imgur.com/JHnyrUB I've seen the repair video linked below fixing similar issues. Squeezing the bezel fixes part of the widest section of missing vertical lines near the middle of the screen but leaves every other line missing still. No amount of pressure anywhere around the bezel seemed to affect the missing horizontal lines, nor the alternating section of missing lines. My question is, is there anything else I should check before removing the LCD bezel and examining the elastomer strips? The NiCad has just begun leaking but has not reached the board. All but one of the smaller black electrolytic caps have leaked quite a bit though. Is there any way that damaged traces on the main PCB would produce the issues on the LCD? https://imgur.com/JHnyrUB https://www.youtube.com/watch?v=bYa-zT75N9s
Re: [M100] LCD Lines
I recently had very good luck fixing an LCD. With careful inspection with a microscope I found corrosion on the traces that drive the LCD from a particular driver. The corrosion was right under the rubber conducting gasket. I disassembled the LCD, removed the gasket, carefully repaired the traces, reassembled and voila all good. you could have a similar issue. On Tue, Mar 3, 2020 at 9:58 AM Kevin Becker wrote: > I've had a Model 102 for years that I enjoy tinkering with and I've often > thought I should pick up a Model 100 as well but never had a real need. > Now with new forthcoming REXCPM on the horizon I figured I might start > watching eBay looking for a deal. I ended up picking up a nice clean (on > the outside anyway) m100 that has some screen issues. There isna large > horizontal band of missing pixels all the way across the screen as well as > some vertical lines missing for about half the screen. > > https://imgur.com/JHnyrUB > > I've seen the repair video linked below fixing similar issues. Squeezing > the bezel fixes part of the widest section of missing vertical lines near > the middle of the screen but leaves every other line missing still. No > amount of pressure anywhere around the bezel seemed to affect the missing > horizontal lines, nor the alternating section of missing lines. My > question is, is there anything else I should check before removing the LCD > bezel and examining the elastomer strips? The NiCad has just begun leaking > but has not reached the board. All but one of the smaller black > electrolytic caps have leaked quite a bit though. Is there any way that > damaged traces on the main PCB would produce the issues on the LCD? > > https://imgur.com/JHnyrUB > https://www.youtube.com/watch?v=bYa-zT75N9s >
Re: [M100] LCD Lines
It ‘could’ also be a driver issue, i.e. the driver for one row is flakey or not being enabled. You would have to try and match the missing row up to the matching driver(s) and check for the proper signals. Looking at the schematic there are several signals marked ‘CS’, i.e. PA0-PA7, PB0-PB1. These are the enable signals for each driver so you could check at the LCD connector to see if they are all being twiddled. This is a classic issue with the ‘zebra strip’ on the LCD though. You may be able to fix it by releasing the bezel and cleaning the LCD, PCB and elastomer strip well. I did a video on recapping a M100 and made up a color-coded capacitor list with part numbers. There is a link in the video description to download the list. I used a super-cap instead of a new battery on this machine as an experiment. On subsequent M100s I have used NiMh cells though as they have a much longer back up time. Arcadeshopper (another list member) carries the batteries as do I. https://youtu.be/IGTdNMx1V1w Jeff Birt (Hey Birt!) From: M100 On Behalf Of Kevin Becker Sent: Tuesday, March 3, 2020 8:59 AM To: m...@bitchin100.com Subject: [M100] LCD Lines I've had a Model 102 for years that I enjoy tinkering with and I've often thought I should pick up a Model 100 as well but never had a real need. Now with new forthcoming REXCPM on the horizon I figured I might start watching eBay looking for a deal. I ended up picking up a nice clean (on the outside anyway) m100 that has some screen issues. There isna large horizontal band of missing pixels all the way across the screen as well as some vertical lines missing for about half the screen. https://imgur.com/JHnyrUB I've seen the repair video linked below fixing similar issues. Squeezing the bezel fixes part of the widest section of missing vertical lines near the middle of the screen but leaves every other line missing still. No amount of pressure anywhere around the bezel seemed to affect the missing horizontal lines, nor the alternating section of missing lines. My question is, is there anything else I should check before removing the LCD bezel and examining the elastomer strips? The NiCad has just begun leaking but has not reached the board. All but one of the smaller black electrolytic caps have leaked quite a bit though. Is there any way that damaged traces on the main PCB would produce the issues on the LCD? https://imgur.com/JHnyrUB https://www.youtube.com/watch?v=bYa-zT75N9s
Re: [M100] LCD Lines
I've seen your part 1 of this repair and I believe you also saw leaking from all the smaller black electrolytic caps, didn't you? I haven't seen the part 2 but I'll check it out. The capacitor list is great, I was going to go through the service manual and assemble a list today at work if I had the chance but this saves me the effort. I also used a NiMh in my T102 and was planning to do the same for this guy. -- Original Message -- From: "Jeffrey Birt" To: m...@bitchin100.com Sent: 3/3/2020 10:15:07 AM Subject: Re: [M100] LCD Lines It ‘could’ also be a driver issue, i.e. the driver for one row is flakey or not being enabled. You would have to try and match the missing row up to the matching driver(s) and check for the proper signals. Looking at the schematic there are several signals marked ‘CS’, i.e. PA0-PA7, PB0-PB1. These are the enable signals for each driver so you could check at the LCD connector to see if they are all being twiddled. This is a classic issue with the ‘zebra strip’ on the LCD though. You may be able to fix it by releasing the bezel and cleaning the LCD, PCB and elastomer strip well. I did a video on recapping a M100 and made up a color-coded capacitor list with part numbers. There is a link in the video description to download the list. I used a super-cap instead of a new battery on this machine as an experiment. On subsequent M100s I have used NiMh cells though as they have a much longer back up time. Arcadeshopper (another list member) carries the batteries as do I. https://youtu.be/IGTdNMx1V1w Jeff Birt (Hey Birt!) From: M100 On Behalf Of Kevin Becker Sent: Tuesday, March 3, 2020 8:59 AM To:m...@bitchin100.com Subject: [M100] LCD Lines I've had a Model 102 for years that I enjoy tinkering with and I've often thought I should pick up a Model 100 as well but never had a real need. Now with new forthcoming REXCPM on the horizon I figured I might start watching eBay looking for a deal. I ended up picking up a nice clean (on the outside anyway) m100 that has some screen issues. There isna large horizontal band of missing pixels all the way across the screen as well as some vertical lines missing for about half the screen. https://imgur.com/JHnyrUB I've seen the repair video linked below fixing similar issues. Squeezing the bezel fixes part of the widest section of missing vertical lines near the middle of the screen but leaves every other line missing still. No amount of pressure anywhere around the bezel seemed to affect the missing horizontal lines, nor the alternating section of missing lines. My question is, is there anything else I should check before removing the LCD bezel and examining the elastomer strips? The NiCad has just begun leaking but has not reached the board. All but one of the smaller black electrolytic caps have leaked quite a bit though. Is there any way that damaged traces on the main PCB would produce the issues on the LCD? https://imgur.com/JHnyrUB https://www.youtube.com/watch?v=bYa-zT75N9s
Re: [M100] LCD Lines
Yes, all the small black ones had leaked on the ones I have done. The others looked fine but there was no sense in not changing them all wile I was in there. Jeff Birt (Hey Birt!) From: M100 On Behalf Of Kevin Becker Sent: Tuesday, March 3, 2020 9:24 AM To: m...@bitchin100.com Subject: Re: [M100] LCD Lines I've seen your part 1 of this repair and I believe you also saw leaking from all the smaller black electrolytic caps, didn't you? I haven't seen the part 2 but I'll check it out. The capacitor list is great, I was going to go through the service manual and assemble a list today at work if I had the chance but this saves me the effort. I also used a NiMh in my T102 and was planning to do the same for this guy. -- Original Message -- From: "Jeffrey Birt" mailto:bir...@soigeneris.com> > To: m...@bitchin100.com <mailto:m...@bitchin100.com> Sent: 3/3/2020 10:15:07 AM Subject: Re: [M100] LCD Lines It ‘could’ also be a driver issue, i.e. the driver for one row is flakey or not being enabled. You would have to try and match the missing row up to the matching driver(s) and check for the proper signals. Looking at the schematic there are several signals marked ‘CS’, i.e. PA0-PA7, PB0-PB1. These are the enable signals for each driver so you could check at the LCD connector to see if they are all being twiddled. This is a classic issue with the ‘zebra strip’ on the LCD though. You may be able to fix it by releasing the bezel and cleaning the LCD, PCB and elastomer strip well. I did a video on recapping a M100 and made up a color-coded capacitor list with part numbers. There is a link in the video description to download the list. I used a super-cap instead of a new battery on this machine as an experiment. On subsequent M100s I have used NiMh cells though as they have a much longer back up time. Arcadeshopper (another list member) carries the batteries as do I. https://youtu.be/IGTdNMx1V1w Jeff Birt (Hey Birt!) From: M100 mailto:m100-boun...@lists.bitchin100.com> > On Behalf Of Kevin Becker Sent: Tuesday, March 3, 2020 8:59 AM To: m...@bitchin100.com <mailto:m...@bitchin100.com> Subject: [M100] LCD Lines I've had a Model 102 for years that I enjoy tinkering with and I've often thought I should pick up a Model 100 as well but never had a real need. Now with new forthcoming REXCPM on the horizon I figured I might start watching eBay looking for a deal. I ended up picking up a nice clean (on the outside anyway) m100 that has some screen issues. There isna large horizontal band of missing pixels all the way across the screen as well as some vertical lines missing for about half the screen. https://imgur.com/JHnyrUB I've seen the repair video linked below fixing similar issues. Squeezing the bezel fixes part of the widest section of missing vertical lines near the middle of the screen but leaves every other line missing still. No amount of pressure anywhere around the bezel seemed to affect the missing horizontal lines, nor the alternating section of missing lines. My question is, is there anything else I should check before removing the LCD bezel and examining the elastomer strips? The NiCad has just begun leaking but has not reached the board. All but one of the smaller black electrolytic caps have leaked quite a bit though. Is there any way that damaged traces on the main PCB would produce the issues on the LCD? https://imgur.com/JHnyrUB https://www.youtube.com/watch?v=bYa-zT75N9s
Re: [M100] LCD Lines
On Tue, Mar 3, 2020 at 10:10 AM Stephen Adolph wrote: > I recently had very good luck fixing an LCD. > > With careful inspection with a microscope I found corrosion on the traces > that drive the LCD from a particular driver. > The corrosion was right under the rubber conducting gasket. I > disassembled the LCD, removed the gasket, carefully repaired the traces, > reassembled and voila all good. > I have had very poor luck re-assembling M100 LCDs into a workable state. My experience has been that the zebra strips never make good contact again once they've been removed from the PCB; they deform over the years to take the imprint of the copper pads such that they are not smooth anymore. I periodically fantasize about finding a company that can manufacture new zebras for the M100 (similar to how new PC1/PC3 LCDs were recently manufactured by Robert B.) Am I in the minority? -Josh
Re: [M100] LCD Lines
Did he do PC3 screens too? I've got a PC3 that could use a new screen... -- Original Message -- From: "Josh Malone" To: m...@bitchin100.com Sent: 3/3/2020 4:25:58 PM Subject: Re: [M100] LCD Lines On Tue, Mar 3, 2020 at 10:10 AM Stephen Adolph wrote: I recently had very good luck fixing an LCD. With careful inspection with a microscope I found corrosion on the traces that drive the LCD from a particular driver. The corrosion was right under the rubber conducting gasket. I disassembled the LCD, removed the gasket, carefully repaired the traces, reassembled and voila all good. I have had very poor luck re-assembling M100 LCDs into a workable state. My experience has been that the zebra strips never make good contact again once they've been removed from the PCB; they deform over the years to take the imprint of the copper pads such that they are not smooth anymore. I periodically fantasize about finding a company that can manufacture new zebras for the M100 (similar to how new PC1/PC3 LCDs were recently manufactured by Robert B.) Am I in the minority? -Josh
Re: [M100] LCD Lines
On Tue, Mar 3, 2020 at 4:28 PM Kevin Becker wrote: > Did he do PC3 screens too? I've got a PC3 that could use a new screen... > Yes: https://www.tindie.com/products/halfbakedmaker/lcd-replacement-for-trs-80-pc-3-sharp-pc-125x/ >
Re: [M100] LCD Lines
That's awesome news. I followed his quest to do the PC1 screens but then lost track of his progress I guess. I'll have to order one to add to the projects list. As far as new M100 elastomeric strips, a brief search on alibaba shows plenty of manufacturers offering to make them. Probably wouldn't be too hard to send off some measurements and get a batch made. -- Original Message -- From: "Josh Malone" To: m...@bitchin100.com Sent: 3/3/2020 4:32:20 PM Subject: Re: [M100] LCD Lines On Tue, Mar 3, 2020 at 4:28 PM Kevin Becker wrote: Did he do PC3 screens too? I've got a PC3 that could use a new screen... Yes: https://www.tindie.com/products/halfbakedmaker/lcd-replacement-for-trs-80-pc-3-sharp-pc-125x/
Re: [M100] LCD Lines
I have not had any success removing the LCD bezel so would not recommend that approach. It was hard for me to get the elastomer strip to re-conform on the PCB making things worse in the end. I tried it on two different LCDs so perhaps I need more practice :) One trick that works for me is to put some de-oxit (or similar) on the elastomer and the use a thin piece of plastic or card to very gently massage the elastomer via the gap between the bezel and PCB. The screen can be powered to make it easier to see which lines are being impacted. Looking at the image I would say it looks like oxidation issues. Driver issues usually result in faint lines that vary in intensity with the contrast. At least in my experience. From: M100 on behalf of Kevin Becker Reply-To: Date: Tuesday, March 3, 2020 at 6:58 AM To: "m...@bitchin100.com" Subject: [M100] LCD Lines > I've had a Model 102 for years that I enjoy tinkering with and I've often > thought I should pick up a Model 100 as well but never had a real need. Now > with new forthcoming REXCPM on the horizon I figured I might start watching > eBay looking for a deal. I ended up picking up a nice clean (on the outside > anyway) m100 that has some screen issues. There isna large horizontal band of > missing pixels all the way across the screen as well as some vertical lines > missing for about half the screen. > > https://imgur.com/JHnyrUB > <https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fimgur.com%2 > FJHnyrUB&data=02%7C01%7C%7C11f720b67c2245a08b6f08d7bf836522%7C84df9e7fe9f640af > b435%7C1%7C0%7C637188443363400945&sdata=fGJwDWec%2BdE%2BPiQcyZPrpx > kG83%2BxmG%2B57GOHpJto1gU%3D&reserved=0> > > I've seen the repair video linked below fixing similar issues. Squeezing the > bezel fixes part of the widest section of missing vertical lines near the > middle of the screen but leaves every other line missing still. No amount of > pressure anywhere around the bezel seemed to affect the missing horizontal > lines, nor the alternating section of missing lines. My question is, is there > anything else I should check before removing the LCD bezel and examining the > elastomer strips? The NiCad has just begun leaking but has not reached the > board. All but one of the smaller black electrolytic caps have leaked quite a > bit though. Is there any way that damaged traces on the main PCB would > produce the issues on the LCD? > > https://imgur.com/JHnyrUB > <https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fimgur.com%2 > FJHnyrUB&data=02%7C01%7C%7C11f720b67c2245a08b6f08d7bf836522%7C84df9e7fe9f640af > b435%7C1%7C0%7C637188443363410949&sdata=zhTvH8SfeTH9Jgu2FFZFougRul > AffDcHxO6%2BFn%2B7V2Q%3D&reserved=0> > https://www.youtube.com/watch?v=bYa-zT75N9s > <https://eur04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.youtube > .com%2Fwatch%3Fv%3DbYa-zT75N9s&data=02%7C01%7C%7C11f720b67c2245a08b6f08d7bf836 > 522%7C84df9e7fe9f640afb435%7C1%7C0%7C637188443363410949&sdata=ZGNJ > %2BckPwnPSbkxjksD7JyFfdQbHmr5IX654qjCxqCU%3D&reserved=0>
Re: [M100] LCD Lines
That is an interesting approach. I've taken several PC-3 pocket
computers apart and reassembled them which is my only experience with
elastomeric strips. I've been successful in that regard on the smaller
PC-3 scale. I have to admit, I'm not eager to disassemble the LCD on
this M100 so I may give that a try first.
On a side note, I ordered replacement electrolytic caps, a new NiMh
battery, and an 8kb RAM module to bring it up to 32kb so I hope I
actually can get the screen working to make it all worthwhile.
On Tue, 2020-03-03 at 19:40 -0800, B4 Me100 wrote:
> I have not had any success removing the LCD bezel so would not
> recommend that approach. It was hard for me to get the elastomer
> strip to re-conform on the PCB making things worse in the end. I
> tried it on two different LCDs so perhaps I need more practice :)
> One trick that works for me is to put some de-oxit (or similar) on
> the elastomer and the use a thin piece of plastic or card to very
> gently massage the elastomer via the gap between the bezel and PCB.
> The screen can be powered to make it easier to see which lines are
> being impacted. Looking at the image I would say it looks like
> oxidation issues. Driver issues usually result in faint lines that
> vary in intensity with the contrast. At least in my experience.
> From: M100 on behalf of Kevin
> Becker
> Reply-To:
> Date: Tuesday, March 3, 2020 at 6:58 AM
> To: "m...@bitchin100.com"
> Subject: [M100] LCD Lines
>
> >
> > blockquote.cite { margin-left: 5px; margin-right: 0px; padding-
> > left: 10px; padding-right:0px; border-left: 1px solid #cc }
> > blockquote.cite2 {margin-left: 5px; margin-right: 0px; padding-
> > left: 10px; padding-right:0px; border-left: 1px solid #cc;
> > margin-top: 3px; padding-top: 0px; }
> > a img { border: 0px; }
> > li[style='text-align: center;'], li[style='text-align: right;']
> > { list-style-position: inside;}
> > body { font-family: Segoe UI; font-size: 12pt; }
> > I've had a Model 102 for years that I enjoy tinkering with and
> > I've often thought I should pick up a Model 100 as well but never
> > had a real need. Now with new forthcoming REXCPM on the horizon I
> > figured I might start watching eBay looking for a deal. I ended up
> > picking up a nice clean (on the outside anyway) m100 that has some
> > screen issues. There isna large horizontal band of missing pixels
> > all the way across the screen as well as some vertical lines
> > missing for about half the screen.
> > https://imgur.com/JHnyrUB
> >
> > I've seen the repair video linked below fixing similar issues.
> > Squeezing the bezel fixes part of the widest section of missing
> > vertical lines near the middle of the screen but leaves every other
> > line missing still. No amount of pressure anywhere around the
> > bezel seemed to affect the missing horizontal lines, nor the
> > alternating section of missing lines. My question is, is there
> > anything else I should check before removing the LCD bezel and
> > examining the elastomer strips? The NiCad has just begun leaking
> > but has not reached the board. All but one of the smaller black
> > electrolytic caps have leaked quite a bit though. Is there any way
> > that damaged traces on the main PCB would produce the issues on the
> > LCD?
> >
> > https://imgur.com/JHnyrUB
> > https://www.youtube.com/watch?v=bYa-zT75N9s
Re: [M100] LCD Lines
Thanx for the info on this. I have a Model 100 that sometime recently developed a single missing horizontal row of pixels. I was thinking about opening it and possibly heating the strip a bit to try to fix it, which is a common known fix for similar issues with the original Gameboy and I have done that. (Admittedly, that was years ago, and I'd have to refresh my memory on what I actually did, but it worked. There are videos on youtube for that.) But when I went googling, the information I could find on trying anything to fix it didn't look promising. Still not sure I will try it (just the one missing row), but knowing it is that same type of elastomeric type of connector give me some hope... Although, the thought of maybe going in on a group order of new strips from Alibaba or wherever is something to consider too if someone could set that up. Sent: Tuesday, March 03, 2020 at 7:53 PM From: "Kevin Becker" To: m100@lists.bitchin100.com Subject: Re: [M100] LCD Lines That is an interesting approach. I've taken several PC-3 pocket computers apart and reassembled them which is my only experience with elastomeric strips. I've been successful in that regard on the smaller PC-3 scale. I have to admit, I'm not eager to disassemble the LCD on this M100 so I may give that a try first. On a side note, I ordered replacement electrolytic caps, a new NiMh battery, and an 8kb RAM module to bring it up to 32kb so I hope I actually can get the screen working to make it all worthwhile. On Tue, 2020-03-03 at 19:40 -0800, B4 Me100 wrote: I have not had any success removing the LCD bezel so would not recommend that approach. It was hard for me to get the elastomer strip to re-conform on the PCB making things worse in the end. I tried it on two different LCDs so perhaps I need more practice :) One trick that works for me is to put some de-oxit (or similar) on the elastomer and the use a thin piece of plastic or card to very gently massage the elastomer via the gap between the bezel and PCB. The screen can be powered to make it easier to see which lines are being impacted. Looking at the image I would say it looks like oxidation issues. Driver issues usually result in faint lines that vary in intensity with the contrast. At least in my experience. From: M100 <m100-boun...@lists.bitchin100.com> on behalf of Kevin Becker <ke...@kevinbecker.org> Reply-To: <m...@bitchin100.com> Date: Tuesday, March 3, 2020 at 6:58 AM To: "m...@bitchin100.com" <m...@bitchin100.com> Subject: [M100] LCD Lines I've had a Model 102 for years that I enjoy tinkering with and I've often thought I should pick up a Model 100 as well but never had a real need. Now with new forthcoming REXCPM on the horizon I figured I might start watching eBay looking for a deal. I ended up picking up a nice clean (on the outside anyway) m100 that has some screen issues. There isna large horizontal band of missing pixels all the way across the screen as well as some vertical lines missing for about half the screen. https://imgur.com/JHnyrUB I've seen the repair video linked below fixing similar issues. Squeezing the bezel fixes part of the widest section of missing vertical lines near the middle of the screen but leaves every other line missing still. No amount of pressure anywhere around the bezel seemed to affect the missing horizontal lines, nor the alternating section of missing lines. My question is, is there anything else I should check before removing the LCD bezel and examining the elastomer strips? The NiCad has just begun leaking but has not reached the board. All but one of the smaller black electrolytic caps have leaked quite a bit though. Is there any way that damaged traces on the main PCB would produce the issues on the LCD? https://imgur.com/JHnyrUB https://www.youtube.com/watch?v=bYa-zT75N9s
