A Tale of three XEs - hardware mods and issues help needed

[Beeblebrox]

13 hours ago, Voxel said:

Ignorantly I gave mine away (two of them) so can't confirm, but back then the standard stereo mod churned out in the UK was the "Gumby" stereo mod.  It should be a variation of that.

@Voxel Ah, Gumby registers somewhere in the back of my mind yes. Great, thanks. 

[Beeblebrox]

Hiya. Just sourcing the Transistors, resistors and capacitors for the mod (http://ftp.atarimania.com/mags/pdf/twaug-newsletter-issue-33.pdf  page 32)

I am sourcing from UK based suppliers RS online (https://uk.rs-online.com/)

 

If I search for the first transistor on the shopping list (2N3904 NPN) I am getting various options.

 

Not being savvy with the ol transitors, which one is correct as they have additional letters after names and also have different max operating frequencies(?) :

 

https://uk.rs-online.com/web/c/semiconductors/discrete-semiconductors/bipolar-transistors/?searchTerm=2n3904 npn&redirect-relevancy-data=7365617263685F636173636164655F6F726465723D31267365617263685F696E746572666163655F6E616D653D4931384E53656172636847656E65726963267365617263685F6C616E67756167655F757365643D656E267365617263685F6D617463685F6D6F64653D6D61746368616C6C7061727469616C267365617263685F7061747465726E5F6D6174636865643D5E2E2A24267365617263685F7061747465726E5F6F726465723D313333267365617263685F73745F6E6F726D616C697365643D59267365617263685F726573706F6E73655F616374696F6E3D43617465676F72795F5265646972656374267365617263685F747970653D43415443485F414C4C5F44454641554C54267365617263685F7370656C6C5F636F72726563745F6170706C6965643D59267365617263685F77696C645F63617264696E675F6D6F64653D4E4F4E45267365617263685F6B6579776F72643D326E33393034206E706E267365617263685F6B6579776F72645F6170703D326E33393034206E706E267365617263685F636F6E6669673D3026&r=f&searchHistory={"enabled":true}

 

I'll need to buy 2 x the 2N3904 NPN transistors, (I guess I am gonna have to buy more than I need - min is a pack of 10 for one of the option.

 

Then the following which looks a lil more straight forward from the same supplier just doing quick searches:

 

Resistors:

1 x 2.2k OHM 1/4W Carbon @ 5%

2 x 220 OHM 1/4W carbon @ 5%

1 x 1M OHM 1/4W carbon @ 5%

1 x 910K OHM 1/4W carbon @ 5%

 

Capacitors:

1 x 18pf ceramic axial, NPO

1 x 10pf ceramic axial, NPO

 

thanks in advance 

 

Edited June 8, 2021 by Beeblebrox
typos

[TGB1718]

From Ebay pack of 5 offered, UK seller

https://www.ebay.co.uk/itm/160991000229?_trkparms=ispr%3D1&hash=item257bcfb6a5:g:igUAAOSwc7Ve0PWA&amdata=enc%3AAQAFAAACcBaobrjLl8XobRIiIML1V4Imu%2Fn%2BzU5L90Z278x5ickkfOCvCjTOBWK8pwriaolq5hmqc6CHLM23M0LqhR37Rn4Z%2FRgIkJK7fj1R6dIFJaew5HjnEfvBlo24cgnBvbfDWu%2FASG%2F2rKedcVwewFNgjJju2GUBXVmJ74NiUQPStUsajMA82dbN5g78EcYp3h5jLmb7CFhU76CVw76cec038NfYPlx3XBlP4XzaCiAV4aGVCMEginmZXfuuCDHbd3VH8xKNE8WrAzE0XRpGe3mm5SkMAJ5rBwlPOAsTK7n5i4yisA4zAz4%2BUVDnzN0oXiv6du9Jx1I5R8p15wkTL%2FadWVr4Y%2BNl%2Fe6Qf%2FSG2P18osqGysQTOWCObhr7DQoA%2BXHo0KG2EFebQJYOXlu4IzR4VpJlr80cqWhz0cxBnSXxfiilJzNChp%2FZDjuC%2F3CvCBMWDNiufTJu73G2dy5ciiXwvG%2Bx3gnRKRR9ZUfSuvmrKycl%2FACRajo%2BykR%2Fn1rOqNAwiHsDlQ%2FdOQRqCs%2BqxYBZn8K2TZVlCd%2B8D%2BW9TeBYhCEVfVjnQOpXGmDclVzeKdzrKFNwevbYgvniiYEgG0DXWXl%2B07V4nTOCl4d69tDRDA9otxiIJqpxxBwaGa%2BWI0f%2Bv%2F1P1%2Fl3o5IcKsrnPI9SEPm%2FLEmd64SNiCALGgGebCE8r4Uz%2BYlB%2Fhyft%2B7x%2FsdNGDh9d3AYTrZ8PGt0xdRzMmhR0N474UF6deWmGuJNMYnmcQt2nQjah%2F2d3m%2FBfPvXrw8xnzo3xI4qteGKFanQjk3JbFRecgO8xQnNXlNQKPEHLSj%2FQNU8uubwLl9P2pfRGg%3D%3D|cksum%3A160991000229cc71631815ce4ce989f641557200438b|ampid%3APL_CLK|clp%3A2334524

[Beeblebrox]

I was no longer able to edit my post so here it is again, edited with my latest - having trouble sourcing other resisitors and some major confusion re the capacitors:

 

Hiya. Just sourcing the Transistors, resistors and capacitors for the mod (http://ftp.atarimania.com/mags/pdf/twaug-newsletter-issue-33.pdf  page 32)

I am sourcing from UK based suppliers RS online (https://uk.rs-online.com/)

 

If I search for the first transistor on the shopping list (2N3904 NPN) I am getting various options.

 

Not being savvy with the ol transitors, which one is correct as they have additional letters after names and also have different max operating frequencies(?) :

 

https://uk.rs-online.com/web/c/semiconductors/discrete-semiconductors/bipolar-transistors/?searchTerm=2n3904 npn&redirect-relevancy-data=7365617263685F636173636164655F6F726465723D31267365617263685F696E746572666163655F6E616D653D4931384E53656172636847656E65726963267365617263685F6C616E67756167655F757365643D656E267365617263685F6D617463685F6D6F64653D6D61746368616C6C7061727469616C267365617263685F7061747465726E5F6D6174636865643D5E2E2A24267365617263685F7061747465726E5F6F726465723D313333267365617263685F73745F6E6F726D616C697365643D59267365617263685F726573706F6E73655F616374696F6E3D43617465676F72795F5265646972656374267365617263685F747970653D43415443485F414C4C5F44454641554C54267365617263685F7370656C6C5F636F72726563745F6170706C6965643D59267365617263685F77696C645F63617264696E675F6D6F64653D4E4F4E45267365617263685F6B6579776F72643D326E33393034206E706E267365617263685F6B6579776F72645F6170703D326E33393034206E706E267365617263685F636F6E6669673D3026&r=f&searchHistory={"enabled":true}

 

I'll need to buy 2 x the 2N3904 NPN transistors, (I guess I am gonna have to buy more than I need - min is a pack of 10 for one of the option.

 

Then the following which looks a lil more straight forward from the same supplier just doing quick searches:

EDIT/UPDATE: spoke too soon - struggling to source some of the other components in the shopping list below. (Regarding the resistors: Metal film resistors seem more commonplace, but I am looking for Carbon film resistors in each case). I've posted links next to each should it help anyone else.

 

Resistors:

1 x 2.2k OHM 1/4W Carbon @ 5% - sorted: https://uk.rs-online.com/web/p/products/1991891/

2 x 220 OHM 1/4W carbon @ 5% - sorted: https://uk.rs-online.com/web/p/products/1991801/

1 x 1M OHM 1/4W carbon @ 5%  - Sorted: Had no luck on RS online but Amazon UK have these: https://www.amazon.co.uk/Projects-250EP5141M00-Ohm-Resistors-Pack/dp/B0749S9Y5C

1 x 910K OHM 1/4W carbon @ 5% - This one is prooving very tricky to source - No luck on RS online - Amazon sells them but sourced from outside of the UK and 3-4 week delivery times: https://www.amazon.co.uk/s?k=910K+OHM+1%2F4W+carbon&ref=nb_sb_noss  Guess I'll have to go with one of these if I can't find anything else on T'internet in the UK.

 

Capacitors:

1 x 18pf ceramic axial, NPO - Not clear on RS online, Amazon or general Google search- multilayer/Single layer???

1 x 10pf ceramic axial, NPO - ditto

 

TBH the capacitors are really confusing me as, if you look at my 65XE 320k Stereo which already has the full compliment of 9 x components preinstalled, it looks like it's made up of 2 x transistors and 7 x resistors and no capcitors. But the shopping list on the TWAUG guide for the mod clearly states the above capacitors.  

 

thanks in advance for any tips ya'll might offer - I'll keep searching and seeing if I can make sense of it all 

[Beeblebrox]

41 minutes ago, TGB1718 said:

From Ebay pack of 5 offered, UK seller

https://www.ebay.co.uk/itm/160991000229?_trkparms=ispr%3D1&hash=item257bcfb6a5:g:igUAAOSwc7Ve0PWA&amdata=enc%3AAQAFAAACcBaobrjLl8XobRIiIML1V4Imu%2Fn%2BzU5L90Z278x5ickkfOCvCjTOBWK8pwriaolq5hmqc6CHLM23M0LqhR37Rn4Z%2FRgIkJK7fj1R6dIFJaew5HjnEfvBlo24cgnBvbfDWu%2FASG%2F2rKedcVwewFNgjJju2GUBXVmJ74NiUQPStUsajMA82dbN5g78EcYp3h5jLmb7CFhU76CVw76cec038NfYPlx3XBlP4XzaCiAV4aGVCMEginmZXfuuCDHbd3VH8xKNE8WrAzE0XRpGe3mm5SkMAJ5rBwlPOAsTK7n5i4yisA4zAz4%2BUVDnzN0oXiv6du9Jx1I5R8p15wkTL%2FadWVr4Y%2BNl%2Fe6Qf%2FSG2P18osqGysQTOWCObhr7DQoA%2BXHo0KG2EFebQJYOXlu4IzR4VpJlr80cqWhz0cxBnSXxfiilJzNChp%2FZDjuC%2F3CvCBMWDNiufTJu73G2dy5ciiXwvG%2Bx3gnRKRR9ZUfSuvmrKycl%2FACRajo%2BykR%2Fn1rOqNAwiHsDlQ%2FdOQRqCs%2BqxYBZn8K2TZVlCd%2B8D%2BW9TeBYhCEVfVjnQOpXGmDclVzeKdzrKFNwevbYgvniiYEgG0DXWXl%2B07V4nTOCl4d69tDRDA9otxiIJqpxxBwaGa%2BWI0f%2Bv%2F1P1%2Fl3o5IcKsrnPI9SEPm%2FLEmd64SNiCALGgGebCE8r4Uz%2BYlB%2Fhyft%2B7x%2FsdNGDh9d3AYTrZ8PGt0xdRzMmhR0N474UF6deWmGuJNMYnmcQt2nQjah%2F2d3m%2FBfPvXrw8xnzo3xI4qteGKFanQjk3JbFRecgO8xQnNXlNQKPEHLSj%2FQNU8uubwLl9P2pfRGg%3D%3D|cksum%3A160991000229cc71631815ce4ce989f641557200438b|ampid%3APL_CLK|clp%3A2334524

@TGB1718 thanks re the 2N3904 NPN transistors - I'll add them to the list of possibles. Nice and cheap.  

[Beeblebrox]

48 minutes ago, Beeblebrox said:

I was no longer able to edit my post so here it is again, edited with my latest - having trouble sourcing other resisitors and some major confusion re the capacitors:

 

Hiya. Just sourcing the Transistors, resistors and capacitors for the mod (http://ftp.atarimania.com/mags/pdf/twaug-newsletter-issue-33.pdf  page 32)

I am sourcing from UK based suppliers RS online (https://uk.rs-online.com/)

 

If I search for the first transistor on the shopping list (2N3904 NPN) I am getting various options.

 

Not being savvy with the ol transitors, which one is correct as they have additional letters after names and also have different max operating frequencies(?) :

 

https://uk.rs-online.com/web/c/semiconductors/discrete-semiconductors/bipolar-transistors/?searchTerm=2n3904 npn&redirect-relevancy-data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r=f&searchHistory={"enabled":true}

 

I'll need to buy 2 x the 2N3904 NPN transistors, (I guess I am gonna have to buy more than I need - min is a pack of 10 for one of the option.

 

Then the following which looks a lil more straight forward from the same supplier just doing quick searches:

EDIT/UPDATE: spoke too soon - struggling to source some of the other components in the shopping list below. (Regarding the resistors: Metal film resistors seem more commonplace, but I am looking for Carbon film resistors in each case). I've posted links next to each should it help anyone else.

 

Resistors:

1 x 2.2k OHM 1/4W Carbon @ 5% - sorted: https://uk.rs-online.com/web/p/products/1991891/

2 x 220 OHM 1/4W carbon @ 5% - sorted: https://uk.rs-online.com/web/p/products/1991801/

1 x 1M OHM 1/4W carbon @ 5%  - Sorted: Had no luck on RS online but Amazon UK have these: https://www.amazon.co.uk/Projects-250EP5141M00-Ohm-Resistors-Pack/dp/B0749S9Y5C

1 x 910K OHM 1/4W carbon @ 5% - This one is prooving very tricky to source - No luck on RS online - Amazon sells them but sourced from outside of the UK and 3-4 week delivery times: https://www.amazon.co.uk/s?k=910K+OHM+1%2F4W+carbon&ref=nb_sb_noss  Guess I'll have to go with one of these if I can't find anything else on T'internet in the UK.

 

Capacitors:

1 x 18pf ceramic axial, NPO - Not clear on RS online, Amazon or general Google search- multilayer/Single layer???

1 x 10pf ceramic axial, NPO - ditto

 

TBH the capacitors are really confusing me as, if you look at my 65XE 320k Stereo which already has the full compliment of 9 x components preinstalled, it looks like it's made up of 2 x transistors and 7 x resistors and no capcitors. But the shopping list on the TWAUG guide for the mod clearly states the above capacitors.  

 

thanks in advance for any tips ya'll might offer - I'll keep searching and seeing if I can make sense of it all 

okay, getting somewhere.

 

Thanks to @TGB1718 I've just bought the cheap Ebay UK 2N3904 NPN transistors.

I've also bought a bulk pack of assorted value resistors from Amazon UK (https://www.amazon.co.uk/gp/product/B07P2KCKPT/ref=ox_sc_act_title_1?smid=APNGGG8JI2BWL&psc=1) which has the following value resistors included:

2.2k OHM 1/4W Carbon @ 5% 

220 OHM 1/4W carbon @ 5%  

1M OHM 1/4W carbon @ 5%

 

So around £10 down so far - not too bad.

 

Sourcing the 910k OHM 1/4W carbon @ 5% resistor is still eluding me and seems to only be available overseas! (China mainly). I've tried Ebay UK, Amazon, RS online.   Either that or I can find every 910k APART from 1/4W and/or carbon ones. I think I am gonna have to bite the bullet and order via Amazon UK from an overseas supplier here: https://www.amazon.co.uk/s?k=910K+OHM+1%2F4W+carbon&ref=nb_sb_noss   (maybe this one which isn't too much to part with and will hopefully arrive within 4 weeks: https://www.amazon.co.uk/Aexit-Axial-Carbon-Resistors-cfa5b77dbc6478333969496540cd4296/dp/B0838KXD71/ref=sr_1_7?dchild=1&keywords=910K+OHM+1%2F4W+carbon&qid=1623168704&sr=8-7 ) - So frustrating - ah well.

 

The capacitors have totally confused me tbh as eluded to above. Aside from being confused about needing these capacitors in the first place, when I do search for them I get so many different types I really don't know which to go for.

 

So here is the board with the ref numbers: (sourced from this very helpful image post: )

 

The Capacitors are C32 and C33.

 

However they look more like resistors to my (admittedly novice) eyes:

 

 

All the capacitors I've come across in my searches for the two needed generally look like these:

 

 

 

 

Edited June 8, 2021 by Beeblebrox

[Beeblebrox]

Update: possible 18pf capacitor perhaps? https://www.mouser.co.uk/ProductDetail/KEMET/C410C180JAG5TA?qs=QTajy0ParP5UmTbf60I6cg%3D%3D

and 10pf? https://www.mouser.co.uk/ProductDetail/KEMET/C410C100JAG5TA?qs=QTajy0ParP6T4Gngn9i%2F7w%3D%3D

 

Both are multilayer, 240VDC and 5% tollerance (although these are not values stipulated in the shoping list on TWAUG mod guide).

 

No mention of the polarity (NPO) either on the product pages or datasheets.

 

Still unsure tbh. 

 

For the Mouser site at least the product filters on this website makes it easier to narrow the search down for components 

Edited June 8, 2021 by Beeblebrox
typo

[Beeblebrox]

1 hour ago, Beeblebrox said:

Update: possible 18pf capacitor perhaps? https://www.mouser.co.uk/ProductDetail/KEMET/C410C180JAG5TA?qs=QTajy0ParP5UmTbf60I6cg%3D%3D

and 10pf? https://www.mouser.co.uk/ProductDetail/KEMET/C410C100JAG5TA?qs=QTajy0ParP6T4Gngn9i%2F7w%3D%3D

 

Both are multilayer, 240VDC and 5% tollerance (although these are not values stipulated in the shoping list on TWAUG mod guide).

 

No mention of the polarity (NPO) either on the product pages or datasheets.

 

Still unsure tbh. 

 

For the Mouser site at least the product filters on this website makes it easier to narrow the search down for components 

least I now know that a capacitor can look like this too : 

[TGB1718]

With the resistor pack you are getting, put a 10K and 1K resistor in parallel, works out to be 909.09 OHMS

 

[Beeblebrox]

25 minutes ago, TGB1718 said:

With the resistor pack you are getting, put a 10K and 1K resistor in parallel, works out to be 909.09 OHMS

 

@TGB1718 Thanks for the tip.  I've already resigned myself to the fact that the 4 week waiting time for the Amazon UK (via China) sourced 910k was my best bet so that's on order. But good to know I have another option. 

 

I still need clarity on the capacitors as per the mouser.co.uk site possible options. I am hoping they'll suffice. (Holding fire on ordering them).

[TGB1718]

These will do the job :- pack of 10 £1.45, they sell both values

https://www.ebay.co.uk/itm/303358627684?_trkparms=ispr%3D1&hash=item46a1954f64:g:SbQAAOSws-xdyX6K&amdata=enc%3AAQAFAAACgBaobrjLl8XobRIiIML1V4Imu%2Fn%2BzU5L90Z278x5ickkpFtSR0CGv%2Bh98r8Yb9quSzaZGkI6110C6twTVyq40P7%2FCFKVRxWpugOA0Mc5dagD%2F35t%2B3PLUNo0dNyEY4GLIQAA%2BWxtbwIsR3jxVphdi93iyawHXGNJYQPJZELP7E%2BfuriYQTL7bfttFP7u84j26I5c2aQCF6Dmqai5ANr3YT4lLi73l5JGx%2BoUntMCUrB5ojy8t%2FxwTVJRfG3Q%2Ff2XpKNjMXURDJFko3G15wx5q8Ut0cF5wGnDobffYaQCyjQjF046kdQmID8CcyO%2Fk4pDFYbMjbz8JeTaxwm59txFAgBEBDld1sZGeztApg4bBu6Gl0I%2BdXmDKqmClEOkB3HkW44PfSyuEvkiqvfWi87SPL7bHfVE3aPYvZjnmwxJnmz9W9g3HjUMECPBFHGraChiJ3euVTQWuEgIyYvtCsj8RbCnON8DsKol2L13dFDhCnL0sqpnN3FDFg5nmyGZJL0PcFOu931k0MczwidhvI%2Fljq1EkN3Rw%2FMmfe5N3GYKdkoza57QR%2Fmcatgd10F5lR%2FudHqP9td66UAubaKQsVZXkK8%2FsXaxjtzU8Fyj1WErAugI%2FNk2IxGnWAz3edapaJBgbdy%2FxIqJgF0hHCUGmlsv8%2FxgHSLCoO0nSazq%2BUIyLzyXbct%2FPLQsARMkJ0Ei3BhP%2BIFmwYJfCqdXXCJC6NXyCJXEAx0XjGZPWj46uwZNeIUAVNStPrmGaXXW6Fbxc3Ku3ODYiucyu1%2BCcI6Dhg4HQsDO2zJq8jCq39NAKSwHHeFWv4FfbcBnNDpM3Scbk%2BwFK8bQS0NsAww6%2BXZDh87gyXw%3D|cksum%3A303358627684fc761edac15e4811b0757fc65e3d684c|ampid%3APL_CLK|clp%3A2334524

[Beeblebrox]

20 minutes ago, TGB1718 said:

These will do the job :- pack of 10 £1.45, they sell both values

https://www.ebay.co.uk/itm/303358627684?_trkparms=ispr%3D1&hash=item46a1954f64:g:SbQAAOSws-xdyX6K&amdata=enc%3AAQAFAAACgBaobrjLl8XobRIiIML1V4Imu%2Fn%2BzU5L90Z278x5ickkpFtSR0CGv%2Bh98r8Yb9quSzaZGkI6110C6twTVyq40P7%2FCFKVRxWpugOA0Mc5dagD%2F35t%2B3PLUNo0dNyEY4GLIQAA%2BWxtbwIsR3jxVphdi93iyawHXGNJYQPJZELP7E%2BfuriYQTL7bfttFP7u84j26I5c2aQCF6Dmqai5ANr3YT4lLi73l5JGx%2BoUntMCUrB5ojy8t%2FxwTVJRfG3Q%2Ff2XpKNjMXURDJFko3G15wx5q8Ut0cF5wGnDobffYaQCyjQjF046kdQmID8CcyO%2Fk4pDFYbMjbz8JeTaxwm59txFAgBEBDld1sZGeztApg4bBu6Gl0I%2BdXmDKqmClEOkB3HkW44PfSyuEvkiqvfWi87SPL7bHfVE3aPYvZjnmwxJnmz9W9g3HjUMECPBFHGraChiJ3euVTQWuEgIyYvtCsj8RbCnON8DsKol2L13dFDhCnL0sqpnN3FDFg5nmyGZJL0PcFOu931k0MczwidhvI%2Fljq1EkN3Rw%2FMmfe5N3GYKdkoza57QR%2Fmcatgd10F5lR%2FudHqP9td66UAubaKQsVZXkK8%2FsXaxjtzU8Fyj1WErAugI%2FNk2IxGnWAz3edapaJBgbdy%2FxIqJgF0hHCUGmlsv8%2FxgHSLCoO0nSazq%2BUIyLzyXbct%2FPLQsARMkJ0Ei3BhP%2BIFmwYJfCqdXXCJC6NXyCJXEAx0XjGZPWj46uwZNeIUAVNStPrmGaXXW6Fbxc3Ku3ODYiucyu1%2BCcI6Dhg4HQsDO2zJq8jCq39NAKSwHHeFWv4FfbcBnNDpM3Scbk%2BwFK8bQS0NsAww6%2BXZDh87gyXw%3D|cksum%3A303358627684fc761edac15e4811b0757fc65e3d684c|ampid%3APL_CLK|clp%3A2334524

@TGB1718 wow thanks - I would have never know these would be ok to use for this mod. (For start they look completely different to generally what I've been looking for). So to double check they are both 50V and this will be fine to use as per the TWAUG shoping list which stipulates Ceramic axial NPO capacitors with those pf ratings?

You have been incredibly helpful - many thanks. 

Edited June 8, 2021 by Beeblebrox

[+Nezgar]

On 6/7/2021 at 12:40 PM, Beeblebrox said:

65XE

 

On the face of it I thought it was working. Sound and visuals appear ok. It boots to the READY prompt and the keyboard is working. Self test is showing RAM/ROM spears ok. I soon realised something was amiss when I tried my Rescue on Fractalus cart. It boots but the top buttons ((HELP/START/SELECT/OPTION/RESET) don't work.

I was able to revive an XE with non-functional START/SELECT/OPTION by adding some resistors to increase the input voltage to those keys to help the GTIA detect them. (The others are read by POKEY) - not requring replacing the entire mylar. Similar tweaking may help with HELP and RESET. A variable POT will help you determine the thresholds for ON and OFF to help choose appropriate resistors.

 

Here I show the completed mod:

 

[Beeblebrox]

14 hours ago, Nezgar said:

I was able to revive an XE with non-functional START/SELECT/OPTION by adding some resistors to increase the input voltage to those keys to help the GTIA detect them. (The others are read by POKEY) - not requring replacing the entire mylar. Similar tweaking may help with HELP and RESET. A variable POT will help you determine the thresholds for ON and OFF to help choose appropriate resistors.

 

Here I show the completed mod:

 

@Nezgar thanks, yeah I was put onto that topic earlier and plan to do this mod at the same time as adding the components for the video enhancement. Thanks for the tips 

[Beeblebrox]

On 6/8/2021 at 8:33 PM, Beeblebrox said:

@TGB1718 wow thanks - I would have never know these would be ok to use for this mod. (For start they look completely different to generally what I've been looking for). So to double check they are both 50V and this will be fine to use as per the TWAUG shoping list which stipulates Ceramic axial NPO capacitors with those pf ratings?

You have been incredibly helpful - many thanks. 

Well I bite the bullet and sat down this afternoon with the old soldering iron to undertake the XE video mod. This involves adding the missing components to the bottom right of my 130XE modded A8. (The one with Ultramon/RS232 installed).

(Check out the TWAUG guide page 32)

 

Not a natural at this by any means. Using my working 65XE (320K Stereo) A8's motherboard (which has the components) as a visual reference, and following the TWAUG instructions -  I soldered the components on.

 

Couple of hours later, once happy my attempts at soldering would suffice, I booted her up. Nothing! Doh! No display.

 

Pretty stuck at the mo. I can see there is power but no image signal. So I've gone from a working A8 with washed out display to one without a display signal at all! 

 

I installed the components as follows:

 

Visual ref to indicate the board number points:

2 x 2N3904 NPN transistors installed in Q4 and A5. I double checked and they are installed the correct way around.

 

The resistors:

1 x 2.2k OHM 1/4W Carbon @ 5% installed in R26

2 x 220 OHM 1/4W carbon @ 5% installed in R18 and R20

1 x 1M OHM 1/4W carbon @ 5% installed in R29

 

All were installed the same way as they are in my other A8, (although I understand from reading up that resistors work whichever way you install them).

 

Next I installed the ceramic disc capacitors. As I couldn't source the ones installed in my other 65XE 320K A8, with a little help from @TGB1718 I bought these ceramic disc capacitors (values 10pf and 18pf), instead of the

18pf ceramic axial, NPO and 1 x 10pf ceramic axial, NPO detailed in the TWAUG guide.

 

Being new to this I read that ceramic disc capacitors do not have a polarity, (certainly all the Googling I did backed this up - all these had were the two values printed on the front with a black mark top dead centre, 18pf and 10pf.

I soldered 18pf to C32 and 10pf to C33, each with the capacitor's marked number facing forward.

 

Final component, the final resistor. I wasn't able to source the 910k OHM 1/4W carbon @ 5% resistor easily and again TGB1718 kindly suggested I run a 10k and 1k resistors in parallel which would give me 909.09 OHMS.

I did this after Googling up on how to run resistors in parallell in this way. These were soldered in place on R28.

 

I double checked the soldering. Not great but thought it would be ok:

 

 

 

. I checked on the underside of the board too. Looked ok:

 

 

 I was using a narrow tip soldering iron at around 230c.

 

I did notice here I'd bridged the right hand solder points for R18 C33 and R27:

 

 

 However looking at another board from a broken XE where these components are missing you can clearly see these points are connected so I think this is ok:

 

 

So I am at a bit of a loss. It could be a number of things as follows or a combo:

 

Maybe the above bridged points I mentioned aren't supposed to bridge.

There could be another unintentional bridging I am not aware of. I can't find one.

Maybe the capacitors are soldered the incorrect way around (even though I understand these types of disc ceramic capacitors don't have a polarity)

Maybe the parallel resistor 910 ohm (10k + 1K) alternative doesn't work for some reason.

 

Any ideas would be most welcome because at present the A8 is now out of action.

 

thanks in advance

 

 

 

 

 

 

 

 

[Beeblebrox]

@Voxel and @Sugarland  just wondered if anything was standing out or obvious which may be causing this total fail? 

(Aside the fact I probably shouldn't quit my day job and take up soldering professionally!!

[Sugarland]

I don't know man. That's a lot to read and go through and the photos are at different angles and directions so it's hard to know what I'm looking at. How about removing all of the stuff you added and return it to the way it was and start over?  Carefully triple check your work. Alternatively just remove it all and get a UAV-D which is easier and will look better.  Trying to help, I did warn you in advance to not mess with it. 

[Beeblebrox]

@Sugarland  Sure, appreciate that. I can indeed remove it all and see if I can revert it back, however I might leave it a while to see if I have any other feedback/suggestion.

You posts earlier (post 2) were regarding messing with other memory upgrades rather than this smaller graphics correction addition, (effectively adding back missing components), and others in this topic had said it's worth going for. I know there is a risk to everything when ya take on these things which of course I fully accept.  I just thought this relatively simple adding back of missing components would be a good place to start since this tried and tested technique has been around for decades. Thanks for taking the time to respond - appreciated 

[Beeblebrox]

Woke up this morning and after checking my soldering etc and trying a few more times to get it to work I decided to remove all the installed components to make sure I'd not done any irreparable damage. Within 3 mins I've removed them all then thankfully it booted up fine.  (Never been so happy to see the Blue screen ready prompt heh heh!) So I've absolutely no idea what the issue was. PCB contacts look ok. Might attempt it later on when the 910 Ohm resistor arrives in July. 

[TGB1718]

14 hours ago, Beeblebrox said:

All were installed the same way as they are in my other A8, (although I understand from reading up that resistors work whichever way you install them).

No polarity on resistors or these types of capacitors, only electrolytic/tantalum cap's are polarity sensitive.

 

Glad to see removal reverted it back ok, the only thing that could possibly have caused a failure is if you put

the transistors in the wrong way (I'm sure you checked first, but they are the only active components in the upgrade.)

 

Edit: I've just looked at the circuit diagram, if you didn't have this circuit, then Freddie was getting it's clock signal from 'A' in the picture below

Not sure what/where 'B' is in your XE, but if it's still there then you would need to disconnect it for this to work.

Otherwise, your trying to provide 2 different circuits to produce the clock.

 

 

 

Edited June 19, 2021 by TGB1718
Update

[TGB1718]

Ok, further look at the diagram, I think the square 'crystal' is that circuit and you would have to remove it and put a smaller crystal

like the ones in your pictures with one fitted (14.187576)

you have :-

you need:-

 

Make sense I think

 

Forget what I said earlier about the transistors, I think this is what's wrong

Edited June 19, 2021 by TGB1718

[Beeblebrox]

45 minutes ago, TGB1718 said:

No polarity on resistors or these types of capacitors, only electrolytic/tantalum cap's are polarity sensitive.

 

Glad to see removal reverted it back ok, the only thing that could possibly have caused a failure is if you put

the transistors in the wrong way (I'm sure you checked first, but they are the only active components in the upgrade.)

 

Edit: I've just looked at the circuit diagram, if you didn't have this circuit, then Freddie was getting it's clock signal from 'A' in the picture below

Not sure what/where 'B' is in your XE, but if it's still there then you would need to disconnect it for this to work.

Otherwise, your trying to provide 2 different circuits to produce the clock.

 

 

 

@TGB1718 Thanks. I definitely soldered the transistors the correct way (flat side facing left as you look at the board - I copied exactly what is in place in my 65XE 320K stereo A8 which has all these components.

 

I following the TWAUG newsletter instructions:

 

 

It doesn't mention anywhere the need to disable/do anything else. TBH I wouldn't have a clue  Very relieved I got it reversed and working again but will try again once figured out. Thanks

Edited June 19, 2021 by Beeblebrox
typos

[Beeblebrox]

8 minutes ago, TGB1718 said:

Ok, further look at the diagram, I think the square 'crystal' is that circuit and you would have to remove it and put a smaller crystal

like the ones in your pictures with one fitted (14.187576)

you have :-

you need:-

 

Make sense I think

 

Forget what I said earlier about the transistors, I think this is what's wrong

@TGB1718  Just seen your latest reply - ahh interesting. The TWAUG instructions don't mention replacing this crystal. Wonder if anyone else has had to do this? thanks

[Beeblebrox]

@TGB1718  ok just looking at my working 65XE 320K A8 with the components already installed it has this: 14.187678 C070034-001

TEW 7F

 

 

Not sure I am gonna be able to source one of these crystals TBH. My broken XE boards I have laying around all have the other crystal so not an option to salvage it from them unfortunately. 

 

May have to abandone this mod and leave this 130XE as is, or opt for one of the video mods (UAV/Sophia2), at some stage.  Thanks for all your help - it's all a learning curve/experience and at least it's got me soldering again. 

 

 

Edited June 19, 2021 by Beeblebrox
typos

[Voxel]

The crystal is fine and does not need replacing.  You'll notice there are relevant pads present for both types of crystals.