Keyboard Problems

[manterola]

Just to confirm... What was the result of interchanging the 4051 chips? if still the same behavior, then the problem is "upstream".  So it might be the connector itself (the small metallic contacts) or some point in the mylar.

If metallic contacts, you can try the experiment of a very gently push of the metallic contact involved (check the schematics, again assuming you have a consistent row of characters not working associated to an specific pin) against the mylar, and try typing. If the experiment works, then you might try cutting 1cm or half centimeter, and then , last resort, new keyboard connector.

If you DON'T have a whole row or column of characters not working then you have to explore what's going on with that particular key which is failing, like maybe the little spring missing, or cleaning the contact with a pen eraser or something similar.

[StickJock]

When I disassembled my 320XE (power switch had stuck & RAM died during 30 years in storage), the keyboard mylar had bonded to the connector.  When I unplugged it, it pulled off the conductive material off of several of the traces.  I tried several times to fix it with some conductive paint, but eventually ended up buying a new membrane (and power switch) from Brad at Best.

 

On an 800, also in storage for 30+ years, the Mitsumi keyboard membrane had stuck to the PCB so it wasn't flexing enough to make contact (none of the keys worked).  Carefully peeling it off of the PCB (used a heat gun on low to help loosen it up) and laying it back down rejuvenated it (although a couple of keys did need some banging on to get back to 100%).  Of course, I only did this repair after ordering new 4051s and finding out that they didn't fix it, and then swapping keyboard with a perfectly working, virgin 800 with a stackpole kb to isolate the issue to the kb itself....

 

So yeah, there can be many reasons a keyboard isn't working properly.  If it is a single key, then it is probably an issue with the keyboard itself.  If it is an entire row or column (on the scanning matrix, not necessarily on the keyboard itself), then it is either a bad 4051, or a bad connection between the 4051 and the key matrix (like in the connector or the mylar trace going to the connector).  If the entire keyboard is dead, it could be the Pokey, the 4051s, or the keyboard itself.

 

Good luck!

[JagChris]

It is the 7 --> delete key that isn't working identified earlier with pin #1. Kjmann switched the 4051s around when I was over there to no effect.

 

I think my best shot might be the trimmings suggestion.

[_The Doctor__]

deoxit the physical keyboard connector and let thoroughly dry, do the trim. press keys a lot.. see what develops

[JagChris]

Will do

[manterola]

One quick check you can do, to test the connectivity of pin1 of both the mylar and connector is to put your multitester in continuity test mode, and than pin 1 should go to pin 14 of U23 if I am reading the correct schematics. 

So you put one multitester lead in the pin14 of the 4051 (U23) and the other in a point of the trace of mylar that goes to pin 1. Do it carefully because yiu don't want to cut the mylar trace by removing the conductive paint with the multitester lead. 

If the multitester beeps, you know that the connection mylar/connector/pcb if working correctly and you can narrow down the source of the problem. 

 

 

[JagChris]

13 hours ago, mimo said:

Not sure if Bruce at myatari has any, but he's selling a keyboard for not much more https://www.ebay.com/itm/Keyboard-for-Atari-800XL-Computer-MYLAR-Condition-A-/133144481008

 

Although I would try and avoid a mylar keyboard if you can, other than that buy the one from retronics, great quality

Ok there are keyboards for the XLs that aren't Mylar? I put this on watch. This little 600XL is costing me but I hate waste.

 

@Stephen where was Brad gonna ban you from? His website? 

[mimo]

5 hours ago, JagChris said:

Ok there are keyboards for the XLs that aren't Mylar? I put this on watch. This little 600XL is costing me but I hate waste.

 

 

https://atariage.com/forums/topic/105170-600800xl-keyboard-variants/

[+Stephen]

8 hours ago, JagChris said:

@Stephen where was Brad gonna ban you from? His website? 

Yeah - I might still have the email, but was basically told "### already contacted me about this and I said no.  Don't order for someone else or you'll not be allowed to order anything".  Childish as hell.

[manterola]

11 hours ago, JagChris said:

Ok there are keyboards for the XLs that aren't Mylar? I put this on watch. This little 600XL is costing me but I hate waste.

 

@Stephen

I actually prefer the type 4 keyboard you most likely have, I really like the feeling, I can type quickly in those keys. Type 2 keyboards with switches are also great. 

Anyway, I think you are very close to get this problem nailed down and you might not need a new mylar. maybe is the keyboard connector, or even the 4051 socket pin 14.

 

[JagChris]

I'm going to buy a new Mylar from sell my retro just to have it.

 

I'm a little worried about shipping delicate unfoldable Mylar all the way from Europe. 

 

It's odd that Brad(or was it Bruce, I get those two confused) went through all that trouble to get those Mylars manufactured and spends paragraphs bragging about them, then won't sell them. 

[StickJock]

7 minutes ago, JagChris said:

I'm a little worried about shipping delicate unfoldable Mylar all the way from Europe. 

I don't know about other vendors, but the mylar that I got from Brad was rolled up & put in a little plastic tube.  I was also worried about it getting folded/creased, so was pleasantly surprised by the packaging method.

 

[manterola]

23 minutes ago, JagChris said:

I'm going to buy a new Mylar from sell my retro just to have it.

 

I'm a little worried about shipping delicate unfoldable Mylar all the way from Europe. 

 

It's odd that Brad(or was it Bruce, I get those two confused) went through all that trouble to get those Mylars manufactured and spends paragraphs bragging about them, then won't sell them. 

But sellmyretro.com is located in UK right?

 

[mimo]

49 minutes ago, manterola said:

But sellmyretro.com is located in UK right?

 

No, it's an international selling site like eBay 

[JagChris]

My understanding is that particular seller is from the UK

[mimo]

Close, Warsaw, Poland

[Sinjinhawke]

I bought one of the Retronics mylars for my 600xl last year.  It oddly will not work when attached to the keyboard.  When I plug just the mylar into the keyboard connector and press the connections together with my fingers they all respond appropriately in the keyboard test but when attached to the keyboard it's like the springs are not pressing it enough. 

 

I reattached my old mylar just to see if I was doing things wrong but that one works (mostly, it's got a broken trace somewhere).  The best I got was the OPTION and SELECT would function with the new mylar.  What is described at the 18:00 minute mark of this video is what I'm experiencing with the new mylar.  Maybe my Atari springs are like my knees now.  Old and weak.

 

I would order a mylar from BEST but I had to delay an order he priced out for me because my car broke down suddenly using up a lot of $$$$.  I want to save my attempt to order from him to a larger order than a mylar so I don't annoy him again.

 

 

[Rob Mitchell]

I had a bad keyboard situation on my 800.  I ruled out the keyboard, then POKEY by swapping with another good working 800.  Next I looked here and learned about the two CD4051BE multiplexers.  Ordered five off eBay for $10 shipped.   I just replaced both on my 800 and now it is working well again!   I'm glad I did not have to take apart the keyboard unnecessarily.