Jump to content
hloberg

harware keyboard problem, this ones strange

Recommended Posts

Just got a new beige, I don't think it's a QI as I don't see it on the motherboard, anyway only the 1, lowercase t and 0 work? I opened it up and it's not a bad keyboard. I disconnected the keyboard from the motherboard tested shorting across the pins on the board that connect the keyboard ribbon cable. only certain pins work. I cleaned the pins very well. tested again, still only certain pins work. I even tested shorting across the resistors that lead to the pins to make sure it wasn't a dirty pin issue. same thing. I looked the motherboard over for bad traces and don't seem to see any, of course some really small one could be getting past me. Note; the box had sever water damage but the machine turns on just fine, takes a cartridge (of course can't do anything except console BASIC since can't press 2).

Any ideas? 

 

Share this post


Link to post
Share on other sites
Just got a new beige, I don't think it's a QI as I don't see it on the motherboard, anyway only the 1, lowercase t and 0 work? I opened it up and it's not a bad keyboard. I disconnected the keyboard from the motherboard tested shorting across the pins on the board that connect the keyboard ribbon cable. only certain pins work. I cleaned the pins very well. tested again, still only certain pins work. I even tested shorting across the resistors that lead to the pins to make sure it wasn't a dirty pin issue. same thing. I looked the motherboard over for bad traces and don't seem to see any, of course some really small one could be getting past me. Note; the box had sever water damage but the machine turns on just fine, takes a cartridge (of course can't do anything except console BASIC since can't press 2).

Any ideas? 

 

9901 bad?

 

Sent from my LM-G820 using Tapatalk

 

 

 

  • Like 1

Share this post


Link to post
Share on other sites
6 minutes ago, FarmerPotato said:

I think you described that you disconnected the keyboard, and touched pins together to mimic keys pressed?

 

In that case most likely the 9901 chip is bad.

 

ugh, what I thought but not what I wanted to hear. I think I'll bring it to Austin with me.

Explains why the guy sold it to me for just a little above the cost of shipping. The @@#&(# probably knew it was bad but didn't list it for parts or repair.

oh well, it'll make a good electronics project to see if I can get it working again.

Share this post


Link to post
Share on other sites
13 minutes ago, arcadeshopper said:

9902 bad?

Sent from my LM-G820 using Tapatalk
 

you sell them?

Share this post


Link to post
Share on other sites

We can get one out of a scrap 4A for you.

Otherwise it's about $3-$5 from China, $30 domestic.

I forget whether it's soldered or socketed, but no problem, we can desolder at the Hackerspace. 

 

Share this post


Link to post
Share on other sites
We can get one out of a scrap 4A for you.
Otherwise it's about $3-$5 from China, $30 domestic.
I forget whether it's soldered or socketed, but no problem, we can desolder at the Hackerspace. 
 
Soldered

Sent from my LM-G820 using Tapatalk

Share this post


Link to post
Share on other sites
2 minutes ago, arcadeshopper said:

Soldered

Sent from my LM-G820 using Tapatalk
 

not one of my favorite things to do but I have desoldered and soldered in sockets on boards before. I be sure to bring some sockets.

Share this post


Link to post
Share on other sites
5 minutes ago, FarmerPotato said:

We can get one out of a scrap 4A for you.

Otherwise it's about $3-$5 from China, $30 domestic.

I forget whether it's soldered or socketed, but no problem, we can desolder at the Hackerspace. 

 

sounds like a plan. thanks.

Share this post


Link to post
Share on other sites
3 minutes ago, hloberg said:

sounds like a plan. thanks.

OK. We have a really nice Hakko desoldering vacuum gun and ChipQuik. Makes it a breeze. Bring a 40 pin socket.

 

 

 

  • Like 1

Share this post


Link to post
Share on other sites
15 minutes ago, FarmerPotato said:

OK. We have a really nice Hakko desoldering vacuum gun and ChipQuik. Makes it a breeze. Bring a 40 pin socket.

 

 

 

40 pin, will do.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...