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Two Issues: Screws and multiple pressses with Hi-Tek keyboard


sixsevenco
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Hi Everyone,

 

So my first problem is self-inflicted. :mad: I disassembled my TI to get a look at the keyboard and the ribbon connector. I accidentally mixed up all of the screws. I have 10 longer screws, and 5 shorter screws. I don't remember where each screw goes. Can someone give me a rundown of where the smaller screws go?

 

With my second problem, I'm not sure of next steps. I have a Hi-Tek keyboard that sometimes gives multiple presses of keys. C, M, N, and SPACE are the worst offenders, but it happens to others too. The ribbon cable seems intact to me, and the solder joints look good too, but I'm not an expert in these things. I've read through the forum on replacing the cable, and I think I have some ideas on how to proceed if that is what I need to do, but I wanted to check in with others here before I do. Is there something else I should be doing or checking? I'm pretty sure I'm the second owner of this computer, and it doesn't look like it was used at all. Pics of my ribbon cable are here.

 

Any help is appreciated.

 

-67

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There is good news on the ribbon cable front. I believe ArcadeShopper is still working on a replacement kit for the old cables that seem to be breaking. I'm currently a +2 on that list. It's a better design from what I understand. A female to female cable with a connector that will be soldered to the keyboard. That should prevent breakage and be easier for novices with an soldering iron to attach.

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So my first problem is self-inflicted. :mad: I disassembled my TI to get a look at the keyboard and the ribbon connector. I accidentally mixed up all of the screws. I have 10 longer screws, and 5 shorter screws. I don't remember where each screw goes. Can someone give me a rundown of where the smaller screws go?

 

 

So I'm trying to think through this, and I am thinking that 4 of the 5 short screws are used along the front to hold the top and bottom of the case together. The posts along the front seem too short for the longer screws. Now, to figure out where the other small screw goes...

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I've often wondered if I can just put 15 male pins on the keyboard itself, and use two 8 pin Dupont Connectors (female to female) like this: https://www.ebay.com/itm/5-PCS-Dupont-2-54mm-8-Pin-Female-to-Female-Connector-Extension-wire-L-300mm/171414252893

 

They're a little long, but wouldn't hurt. Main concern is putting the male connector on the pins and having enough space on top.

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I've often wondered if I can just put 15 male pins on the keyboard itself, and use two 8 pin Dupont Connectors (female to female) like this: https://www.ebay.com/itm/5-PCS-Dupont-2-54mm-8-Pin-Female-to-Female-Connector-Extension-wire-L-300mm/171414252893

 

They're a little long, but wouldn't hurt. Main concern is putting the male connector on the pins and having enough space on top.

 

 

Do we know the pin or through-hole spacing? I was trying to find a suitable pin header at digikey, but I don't know the spacing so it would fit properly.

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Do we know the pin or through-hole spacing? I was trying to find a suitable pin header at digikey, but I don't know the spacing so it would fit properly.

 

 

We can probably measure (I don't have a keyboard handy right now) with a digital caliper. A lot of these vintage connectors and spacing are 0.1 inch, or 2.54mm from center to center.

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yeah I'm putting together a kit with all that figured out :) new connector for the keyboard side and ribbon cable with female connectors.. I also am messing with a dual header for the keyboard side to support connecting up the usb keyboard interface as well without more soldering.

 

Greg

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Cccould be a flaky keyswitch in the keyboard itself causing your pppppproblem. ;) QD spray contact cleaner might help if it's a make/break switch rather than a membrane style.

-Edd

 

Thanks for responding! :) Would you mind explaining this a little further? What is QD spray? Is there a specific thing/switch that needs to be cleaned, or would I need to clean the switch for every single keyboard button?

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Well, that depends... TI used several keyboards, Some good, other not so much. It's pretty easy to pry up a keytop and see what's beneath. Some are separate switches, but the contacts are hidden inside. Others have a pair of fingers that make the contact when you press the key. Accessible, but for some reason harder to keep clean. I'd blame it on weak spring action on the long fingers plus more exposure to air. Another keyboard variation has a membrane inside similar to the buttons in your TV remote or the Timex TS1000 (well known for it's frail keyboard). These are crap and almost impossible to repair.

 

I'm not familiar with the Hi-Tek to guess which design route it takes. If it's not a membrane style, it may benefit from a contact cleaner. The QD brand from CRC works well and is sold at places like Ace Hardware. De-Oxit is another product some folks prefer, generally costs more and it comes in several flavors, so read up on that product first. Other people like plain ol' WD40, which is actually a pretty good answer, and who doesn't already have some?

 

Not to muddy the waters. :) Basically if you can see or guess where the contacts are, a bit of spray in there and work the switch (safest with power off, of course), wait awhile to let the volatiles have time to evaporate. Power up and test.

 

QD happens to evaporate pretty quickly and does not leave much residue. I haven't seen it harm plastics, but it might leave a liitle film evidence that can be wiped off if it bothers you.

 

If you have a radio with a scratchy-sounding control or switch, this is the answer for that trouble as well. That's kinda why I went in to such detail. All that aside, I've been spraying and tweaking the fingers of the Function and right Shift keys on my beige TI to not much avail. I'm about to swap it out for a Black & Silver to see how well it has aged. So, YMMV. (I'm suspecting a bad solder joint in the beige unit's keyboard at this point).

 

I don't personally know how the Hi-Tek kbd is made, so this is all kind of a shot in the dark. Pop a keycap up and have a look what's beneath.

 

Here's one recent thread, there must be several others to read up: http://atariage.com/forums/topic/273929-alps-keyboard/

-Ed

Edited by Ed in SoDak
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  • 2 weeks later...

So I bought some QD, but I am not seeing any improvement. It's likely that I didn't apply it right. I don't have a key puller, so using the tube that came with it, I sprayed the post of each key and then pressed it repeatedly, hoping that the QD would find its way to the contacts. I am thinking that I should probably pull each key so that I can apply the QD directly to the contact. Is this the right thing to do? Any recommendations on a key puller? Would this one work?

 

I've also done a fair amount of testing each key on the keyboard. Here are the problem keys: https://imgur.com/a/QMgyk

 

Is this helpful with troubleshooting? For example, could there be a bad solder joint with INT6?

Edited by sixsevenco
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So I bought some QD, but I am not seeing any improvement. It's likely that I didn't apply it right. I don't have a key puller, so using the tube that came with it, I sprayed the post of each key and then pressed it repeatedly, hoping that the QD would find its way to the contacts. I am thinking that I should probably pull each key so that I can apply the QD directly to the contact. Is this the right thing to do? Any recommendations on a key puller? Would this one work?

 

I've also done a fair amount of testing each key on the keyboard. Here are the problem keys: https://imgur.com/a/QMgyk

 

Is this helpful with troubleshooting? For example, could there be a bad solder joint with INT6?

 

Since there are no whole rows or columns of keys not working, it is likely that the contacts need cleaning. When you pull a key, you will notice brass fingers inside a tube with a square cross-section. At this point, you will see why spraying under the keys did not work. Somewhere on this forum, @Ksarul has posted some very good, detailed instructions for cleaning key fingers that, I think, involves running a piece of card stock, soaked in cleaner, between the fingers a few times.

 

That said, the stranded, ribbon-cable wires at the solder joints are very brittle nowadays. With time and repeated removal/installation, the wire strands begin to break off. When the last strand of a given connection finally breaks, the connection will likely become intermittent before it is permanently open. I still think that all of the keys in one row or one column would be problematic if this is your immediate problem—and that does not seem to be the case.

 

...lee

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Since there are no whole rows or columns of keys not working, it is likely that the contacts need cleaning. When you pull a key, you will notice brass fingers inside a tube with a square cross-section. At this point, you will see why spraying under the keys did not work. Somewhere on this forum, @Ksarul has posted some very good, detailed instructions for cleaning key fingers that, I think, involves running a piece of card stock, soaked in cleaner, between the fingers a few times.

 

That said, the stranded, ribbon-cable wires at the solder joints are very brittle nowadays. With time and repeated removal/installation, the wire strands begin to break off. When the last strand of a given connection finally breaks, the connection will likely become intermittent before it is permanently open. I still think that all of the keys in one row or one column would be problematic if this is your immediate problem—and that does not seem to be the case.

 

...lee

 

Thank you. Is there any special trick to pulling the keys, or do I just gently pull straight up?

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Thank you. Is there any special trick to pulling the keys, or do I just gently pull straight up?

 

You should be able to gently pull straight up. It might be easier to use a couple of flat-blade screwdrivers on opposite sides to gently pry it up—perhaps, with tape or heat-shrink tubing on the shafts to protect the pried-against keys.

 

...lee.

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SUCCESS with the QD! (Mostly...) I sprayed all of the contacts first. Then I cut a thin strip of cardboard from a Bed Bath & Beyond mailer. Soaked it with QD, and used it to scrub between the contacts. All keys appear to be behaving, with the exception of the space bar. I can't figure out how to get to the contact for the space bar. I've removed the space bar, and there is a piece of black plastic that is seemingly blocking access to the contact. I've searched the forum, youtube, and google for the answer, but I can't seem to find it. I've pulled on the black piece with some needle nose pliers, but it doesn't seem to want to budge, and I don't want to get too rough.

 

Here's a pic: https://imgur.com/a/OFD6Q

 

Any ideas on how to proceed? You guys are the best. Thank you for all of your help!

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SUCCESS with the QD! (Mostly...) I sprayed all of the contacts first. Then I cut a thin strip of cardboard from a Bed Bath & Beyond mailer. Soaked it with QD, and used it to scrub between the contacts. All keys appear to be behaving, with the exception of the space bar. I can't figure out how to get to the contact for the space bar. I've removed the space bar, and there is a piece of black plastic that is seemingly blocking access to the contact. I've searched the forum, youtube, and google for the answer, but I can't seem to find it. I've pulled on the black piece with some needle nose pliers, but it doesn't seem to want to budge, and I don't want to get too rough.

 

Here's a pic: https://imgur.com/a/OFD6Q

 

Any ideas on how to proceed? You guys are the best. Thank you for all of your help!

 

 

I figured it out. The black post does come out. I just needed to gently rock it left to right.

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