electro-music.com   Dedicated to experimental electro-acoustic
and electronic music
 
    Front Page  |  Articles  |  Radio
 |  Media  |  Forum  |  Wiki  |  Links  |  Store
Forum with support of Syndicator RSS
 FAQFAQ   CalendarCalendar   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   LinksLinks
 RegisterRegister   ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in  Chat RoomChat Room 
 Forum index » DIY Hardware and Software » The Repair Shop
Roland CR-78: Repair broken traces and pads
Post new topic   Reply to topic
Page 1 of 1 [11 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
Author Message
tonewill



Joined: Aug 21, 2009
Posts: 135
Location: England

PostPosted: Sat Mar 24, 2018 9:13 am    Post subject: Roland CR-78: Repair broken traces and pads Reply with quote  Mark this post and the followings unread

Hello,
Can anyone please advice me on how to repair broken traces and IC pads? The board is double-sided and the traces are quite thin and close together. I want to make as good a job as I can. Is there a recommended kit or something I can buy? I'm okay with a soldering iron and have patients.
Thanks for any help.
Back to top
View user's profile Send private message
wackelpeter



Joined: May 05, 2013
Posts: 454
Location: germany
Audio files: 10

PostPosted: Sat Mar 24, 2018 2:51 pm    Post subject: Reply with quote  Mark this post and the followings unread

perhaps post some pics of the PCB and the broken traces... maybe someone has a clever idea... for example when it's broken between 2 components with legs were you can solder like diodes, resistors or some caps you can easily use a wire soldering between both Points...

I'm still having mine open since months, as i need to replace some IC's there and then will perhaps go to socket most of the IC's... and eventually re-cap the whole Thing...

_________________
https://soundcloud.com/bastian-j
Back to top
View user's profile Send private message
tonewill



Joined: Aug 21, 2009
Posts: 135
Location: England

PostPosted: Mon Mar 26, 2018 5:52 am    Post subject: Reply with quote  Mark this post and the followings unread

I've attached a photo. A bodge attempt was made with wires but I want to make it better than that.
Many thanks.


DSC00142_crop.jpg
 Description:
 Filesize:  178.97 KB
 Viewed:  202 Time(s)
This image has been reduced to fit the page. Click on it to enlarge.

DSC00142_crop.jpg


Back to top
View user's profile Send private message
ringroad



Joined: Feb 28, 2012
Posts: 38
Location: Coventry, UK
Audio files: 1

PostPosted: Mon Mar 26, 2018 10:29 pm    Post subject: Reply with quote  Mark this post and the followings unread

You could try a silver conductive pen to redraw the tracks - never having used one myself I don't know how how accurate you can get with them, and looking at that you'll need to be good at it. It might just be better to attach wires.
Back to top
View user's profile Send private message
tonewill



Joined: Aug 21, 2009
Posts: 135
Location: England

PostPosted: Thu Mar 29, 2018 2:34 am    Post subject: Reply with quote  Mark this post and the followings unread

Conductive pen isn't going to be fine enough. I've watched demos of these on youtube, much too crude.

If anyone can advice on repairing the tracks and pads or where to buy such things please let me know.

Thanks a lot.
Back to top
View user's profile Send private message
DES



Joined: Feb 28, 2003
Posts: 783
Location: New Jersey
Audio files: 8

PostPosted: Mon Apr 02, 2018 11:46 am    Post subject: Reply with quote  Mark this post and the followings unread

Wow. Thats going to require some work, patience, and a steady hand. I would look for an IC socket with extended length pins...something like the old wire-wrap style sockets. The big issue hear is it seems to be a double-sided board with connections to the IC on both sides. If you find a suitable socket, insert it into the holes but make sure it is ~1/16 to 1/8" above the top of the pcb to allow you to thread/loop fine wire under the socket and around the pin (put a hook on the end of the wire feed it under the socket around a pin then squeeze/pinch it together then a dab of solder. Use fine bare wire...24-28 gauge, whatever you can get hold of. I prefer silver when possible. If you have stranded hookup wire try using the steands. Once connected to the pins, route them along the original circuit path til you get to the broken trace and attach. hold the wire in place with crazy glue or similar (note crazy glue gives off terrible fumes when heated!)

Another possibility...Get a thin flexible circuit made that has the ic pin hole layout on it. Make it just big enough to fit over the pins. If you can, design the flex circuit so there is a little extra pad at each pin so you can attach leads to it.

Good luck...thats going to be 'fun' repair!

_________________
Dave
www.davesneed.com
Back to top
View user's profile Send private message Visit poster's website
tonewill



Joined: Aug 21, 2009
Posts: 135
Location: England

PostPosted: Tue Apr 03, 2018 8:54 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks very much for all the info Dave.

Regarding the solder pads for the IC pins, can 'replacements' be had in some kind of repair kit? I just wan't to get it as good as possible. I searched for repair kits online but came up with over-the-top kits for people who do this kind of thing all the time.

Thanks again.
Back to top
View user's profile Send private message
wackelpeter



Joined: May 05, 2013
Posts: 454
Location: germany
Audio files: 10

PostPosted: Wed Apr 04, 2018 1:03 pm    Post subject: Reply with quote  Mark this post and the followings unread

Reading DES's Reply following came to my mind:

Mounted on a piece of stripboard, are hte IC's Pins long enough to fit in the socket?

If yes, i would mount the IC on the copper side of the stripboard, of Course cut or drill the traces before, and make the stripboard a bit wider than the IC is, so you have 1 or 2 solder joints on each pin left... the you can solder the Pins of the IC to the stripboard from the side and replace those traces missing with small wires from there...

But would be very cautious because perhaps you could mess up the IC.

don't know if this would work, but perhaps worth keeping a short look at it.


Edit... just looked at it closely with an normal IC... doesn't work properly because the Pins are too short... could perhaps work instead with a additional socket with longer Pins... do they exist?

found something, but don't know if the pin amount Matches...

https://www.reichelt.de/IC-Sockel/DIL-24-NG/3/index.html?ACTION=3&LA=2&ARTICLE=113266&GROUPID=7429&artnr=DIL+24+NG&trstct=pol_2

or if These are also available with longer Pins they could work too perhaps

https://www.reichelt.de/IC-Sockel/SPL-20/3/index.html?ACTION=3&LA=2&ARTICLE=19398&GROUPID=7429&artnr=SPL+20&trstct=pol_7

_________________
https://soundcloud.com/bastian-j
Back to top
View user's profile Send private message
tonewill



Joined: Aug 21, 2009
Posts: 135
Location: England

PostPosted: Thu Apr 05, 2018 7:37 am    Post subject: Reply with quote  Mark this post and the followings unread

Thanks for the extra info, very helpful. This may be the answer if repair pads aren't available in small quantities. Dave mentioned the longer pin sockets also and those are available on ebay. I was hoping to make it look as near original as possible but it's looking less likely.

Thanks again.
Back to top
View user's profile Send private message
DES



Joined: Feb 28, 2003
Posts: 783
Location: New Jersey
Audio files: 8

PostPosted: Mon Apr 09, 2018 6:17 am    Post subject: Reply with quote  Mark this post and the followings unread

There was a company that used to make a trace repair kit..can't remember the name...and while you could replace individual pads on ICs, it was a pain to keep the pads in place while soldering especially if there were traces running between pads. Also you might be able to find the flexible IC circuits as very thin pcb material instead of the kapton/brownish flexible circuit material. Maybe in proto-typing supplies?

Saw a couple suppliers of wire wrap ic sockets on Amazon...Jameco has them too. CircuitMedic has kits though pricey from them...looks like JanelOnline sells some of the CircuitMedic stuff cheaper. You could look at adhesive copper tape and a sharp xacto knife...just watch your solder temp.

_________________
Dave
www.davesneed.com
Back to top
View user's profile Send private message Visit poster's website
tonewill



Joined: Aug 21, 2009
Posts: 135
Location: England

PostPosted: Tue Apr 10, 2018 3:20 pm    Post subject: Reply with quote  Mark this post and the followings unread

Thanks for the extra info. I overlooked it on an earlier post but I'm not sure what the 'flexible IC circuits' are, are they circuits you get made to spec like normal circuits boards or are we talking about something else?
Back to top
View user's profile Send private message
Display posts from previous:   
Post new topic   Reply to topic
Page 1 of 1 [11 Posts]
View unread posts
View new posts in the last week
Mark the topic unread :: View previous topic :: View next topic
 Forum index » DIY Hardware and Software » The Repair Shop
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum
e-m mkii

Please support our site. If you click through and buy from
our affiliate partners, we earn a small commission.


Forum with support of Syndicator RSS
Powered by phpBB © 2001, 2005 phpBB Group
Copyright © 2003 through 2009 by electro-music.com - Conditions Of Use