Atari 400 keyboard troubles

[jokker]

Hey all,

 

Hoping I can find some help with this odd keyboard issue on an Atari 400. It's a brand new keyboard to replace an older one that's basically rotted and fallen apart. I remember it still working with the non-destroyed keys until I put it away for a bit until I got a better keyboard. So I pulled it apart and plugged in the new keyboard and well no keys work except for Reset, Option, Select, Start and break. No other keys seem to respond at all. I plugged in the old keyboard and it exhibits the same issue.

 

I put in some disks and checked that the 400 itself seems to be ok. I loaded up SpartaDos, Jumpman from disk and Basic and Assembler cartridges. I didn't encounter any problems at all except for the lack of keyboard functionality.

 

Could this be a sign of the POKEY giving up the ghost or is there another something else I can look at. I'm pretty new to the 8bit Atari line as I'm more of an ST guy. Still it's always nice to play around with another platform.

 

Thanks very much in advance for any help!

[UNIXcoffee928]

Hey all,

 

Hoping I can find some help with this odd keyboard issue on an Atari 400. It's a brand new keyboard to replace an older one that's basically rotted and fallen apart. I remember it still working with the non-destroyed keys until I put it away for a bit until I got a better keyboard. So I pulled it apart and plugged in the new keyboard and well no keys work except for Reset, Option, Select, Start and break. No other keys seem to respond at all. I plugged in the old keyboard and it exhibits the same issue.

 

I put in some disks and checked that the 400 itself seems to be ok. I loaded up SpartaDos, Jumpman from disk and Basic and Assembler cartridges. I didn't encounter any problems at all except for the lack of keyboard functionality.

 

Could this be a sign of the POKEY giving up the ghost or is there another something else I can look at. I'm pretty new to the 8bit Atari line as I'm more of an ST guy. Still it's always nice to play around with another platform.

 

Thanks very much in advance for any help!

Have you cleaned both the male & female keyboard connectors with rubbing alcohol? Have you re-seated the POKEY?

 

As a side note, if you Armor-All the old broken 400 Keyboard, and put it in a black frame, behind glass, it makes a really cool office decoration.

 

 

 

[jokker]

Hey thanks for the reply,

 

So I re-seated the POKEY - no change

Tried another known working POKEY from an 800XL - no change

Checked the POKEY socket - socket is fine

Checked the keyboard connector - connector is fine

Tried 400 POKEY in the 800XL - works just fine

 

 

So I guess the POKEY is a ok it seems. Perhaps something else has shorted somewhere on the board. Visual inspection hasn't provided me any clues as of yet sadly. I gave all the socketed chips on the board a firm push to make sure there was a good fitting.

 

Any other thoughts?

 

Thank you again!

 

Have you cleaned both the male & female keyboard connectors with rubbing alcohol? Have you re-seated the POKEY?

 

As a side note, if you Armor-All the old broken 400 Keyboard, and put it in a black frame, behind glass, it makes a really cool office decoration.

[CThiesUGP]

I had the same problem with my 400 that I got from ebay. I changed both 4051 ICs now the keyboard works fine. the 4051 IC chips are located next to the pokey chip. just swap those out for new ones and It should work.I believe the 4051s are still in production.

[russg]

I had the same problem with my 400 that I got from ebay. I changed both 4051 ICs now the keyboard works fine. the 4051 IC chips are located next to the pokey chip. just swap those out for new ones and It should work.I believe the 4051s are still in production.

 

http://www.jameco.com/1/1/32333-hef4051bp-652-hef4051b-hef4051bp-6528-channel-mux-demux-analog-linear.html