130XE Repair: Bad RAM, motherboard variations

[deffroe]

Sugarland You are the man!

 

Never in a million years would I have thought, "No power light, it must be the keyboard!".

 

I connected it to the TV and low and behold up pops the READY prompt

 

Still the same, No response to any key press including RESET.

 

If there is anyone on here from the UK can you recommend anywhere where I can get a replacement keyboard mylar?

 

Thanks again to everyone who has responded, I'm feeling happier just knowing my 130XE is not dead.

 

I'm off to scour Ebay for a while in search of keyboards.

 

Phil

[+tf_hh]

- Failed post - Deleted -

Edited February 28, 2017 by tf_hh

[deffroe]

Afternoon/morning!

 

Slowly but Shirley!!

 

Made enquiries to Best Electronics about a 130XE Mylar but to get one shipped over to

the UK is a bit pricey so decided to try the cheaper option first.

 

I bought some conducting silver and have been inspecting the mylar and touching up where

it looks like there is a break.

 

I've gone from ZERO keys working to a working RESET and LED!!!

Got a few keys working too but oddly some keys display other characters.

2 & 3 work but the 3 displays a 2, 0(zero) display <. (full stop ...) displays /

 

Guessing that some of the silver is jumping over another track of the maylar.

 

Another couple of tries and touch ups and hopefully I'll have a fully working keyboard again.

 

Phil

[tjlazer]

also the ribbon cable connector can get flaky where it inserts into the motherboard. You can usually pull it out a little to get a better connection.

[1050]

Can't possibly find it these days, but I once saved to a text

file a diatribe from an old school BBS style forum where the

email replies were stacked one over the other with headers

in between. At any rate, the subject was the 'new' fix for

bad mylars in the recent XE line and the fix was to let it

oxidize as much as it was going to and then use a resistor

bridge to determine the value of a parallel resistor for that

mylar trace that would make it work on all keys for that trace.

Then solder that value resistor onto the stock one, paralleling

it to an oxidized value.

 

In essence it was to make the resistor pack of such a value

as to now work with the mylar that you have. I've never

tried this simplistic approach but the replies he got to that

post indicated that he was a life saver and this was the

greatest post of all time and he would certainly be rich

and famous.

 

Despite the misplace accolades, it could still work?

I do have the bridge for this, but I'm still not set up to

find a bad mylar and give it decent test myself. eBay was

selling a modern day bridge using 1% precision chip resistors

as a school project went viral as they say. $40 IIRC.

Bridge isn't the proper term, it's a resistor substitution

box where you dial in the resistance you want by operating

several rotary switches.

[_The Doctor__]

Ah one of my old posts and fixes...the original box was a decade resistance box....and in fact I give the technical tidbits in another post somewhere on here....

 

http://atariage.com/forums/topic/190500-130-xe-keyboard-membrains/?p=2494328

 

ah such ramblings, the post could use a clean up and some more detail I guess... I wouldn't mind at all if someone follows the procedure across the key range just select the lowest value of your findings and put that across the lot and look at simius fix as well. Pictures and process posted as you go.

I've posted a number of other places and times depending on my memory and thoughts as well as last time I did this the values usually settled within a range as time marched on... I am sure a couple people will clue us in.... I like to keep some resistance in the mix no dead shorting....

 

_T D__ proud member or the former ABE's ACE's and LVAUG

Contributer to the Atari Computer Users Technical Exchange BBS / Sysop of Starship a support BBS, and Co-sys of same as well as Parallel Dimension a both fun & technical Atari BBS.

 

p.s. I searched out a decade project kit for you.... however these can be had even more cheaply, it will get the job done....I couldn't imagine being without one back in the day....

https://www.sparkfun.com/products/13006

Edited April 14, 2017 by _The Doctor__

[_The Doctor__]

memory lane,

 

http://www.atarimagazines.com/atariclassics/v2n5/thanks.php

http://www.atariarchives.org/cfn/05/10/0008.php

some other stuff just searching about

 

and John's post about rtime8 battery... he forgot to give the item number for the holder..

A worn-out battery in the R-time can cause some problems with certain programs. Several months ago, we tracked down a problem to a weak battery, even though the R-time still kept perfect time. We found that replacement solder type batteries were impossible to find. The solution?? Replace your worn out battery with a socket and buy replacement batteries at the local Radio Shack. I have tried several different battery holders and the best one found was from Bogen Communications, Inc. It is a 24mm diameter Coin Cell Holder and is available from Digi- Key Corporation. A good replacement battery is available at Radio Shack. It is a Lithium Battery, part number CR2430 at a cost of $1.99, the total cost of replacement is less than $3.50. The replacement socket adds just a little too much height to close the cart fully. The solution to this is easy with the Bogen socket, just file a little plastic from each of the three stand-offs on the socket and it fits perfectly!! I have installed three of them so far with no problems. P.S. Some sockets which will fit the replacement cells, will not fit the R-Times properly. They could require much more modifications than the one listed.

Edited April 14, 2017 by _The Doctor__

[deffroe]

Been a few weeks since I've really been able to spend any more time with my 130XE,

but just wanted to say thanks for comments of help and to just make a note of my progress really.

 

Did another sweep of the maylar, cleaning up where I'd been previously and adding more silver

where I thought there was a break.

 

So when it came to powering up, some of the repeating keys, 2 worked and 3 gave a 2 etc...same on a few other.

This time some of those repeaters had gone as had some previously working keys BUT more importantly I got

a full set of option keys working..woohooo! Which means I was able to do a Self Test.

 

Looks like it is and only is a dodgy mylar. RAM Test passed with flying colours, sound test worked as expected.

 

So looks like when I've run out of silver and keyboards still not working i'm gonna have to buy a new mylar.

 

Phil