The Aussie Pinball Arcade
Aussie Pinball Forums => Technical Matters => Circuit Board Repair Guides => Topic started by: deep six on July 15, 2011, 10:39:07 AM
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Hi All
I thought I would start a new thread on this board rebuild of mine, it started out as a solonoid question but kind of migrated to this.
I figured the old thread was 3 pages long and getting a bit hard to follow.
So to recap, I have the rectifier board out of my Stern Galaxy, although it looked extremely ugly it was still working, for how long I can't say though.
Following excellent tips from members of this board, and from gleaning info from other places on the web, and even though I was advised to possibly look at just buying a new board I have pushed on with rebuilding my old board.
Partly through stubborness and partly because I am too cheap to buy a new one and partly because I figured the experience gained would be a huge help with other issues I will no doubt encounter with the rest of the machine.
Here is the board as found in situ.
(http://www.atcheaven.com/Images/rect.jpg)
Here is the board as it now stands
(http://www.atcheaven.com/Images/nakedboard.jpg)
The board is now stripped and sanded, most of the solder removed, it has taken what seems like forever to get all the old solder off. I wore out two tips on my solder sucker, plus half a roll of solder braid, of course this is all new to me so someone with more experience would have most probably found it easier.
At first I was very careful not to sand off the screen printed locations for the transformer inputs, but then I figured it was more important to get a good connection so I went back and sanded madly around all the points. I did take the step of photographing both sides of the board (twice) so I should be able to find where everything goes.
I also made a set of decals, one for the top of the rec board mount plate that shows specs of fuses etc, and also made some to fix to each wire in respect to its location on J1, J2 and J3. plus a set for E1 to E12.
if anybody would like a set of these please pm me with your address and I will post them out, its my small contribution to this board, I figured there was not much info I could share but wanted to give back something since everyone has been so helpful to me.
The parts for the board turned up from Big Daddy yesterday so I am about to go into the re-assemble stage.
One thing I'm not sure on though is should I be re-tinning the board where I have rubbed through to the copper, I know some of this will be covered when I re-solder components back on but some will still be bare??
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Looks to me like you're off to a pretty good start ^^^ You should have it finished in no time! Glad to see you decided to keep going on the original board rather than replace it, Its really not that hard to rebuild one of these as you will find out. If you follow all of the instructions in the repair guides you should have no trouble getting it going ^^^
With regards to buying replacement boards, i'm the same, i'll ALWAYS try to repair an original board first (unless someone has totally ruined it), and buy a new one as a last resort.
looking forward to seeing how it turns out... Cheers.. Mitch
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Great work so at it's far more rewarding to repair instead of replace and a really food board to start with just about right to start building your confidence. Well done
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One word of advice - I would run a thin piece of wire through each hole when re-assembling to 'stitch' the two sides together as the through hole plating was poor to start with and may have been damaged over time and with all of your EXCELLENT efforts.
I strip off a piece of multistranded hookup wire and use one strand of that. Stops any nonsense & eliminates problems when things heat up and become intermittant.
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Almost there.
I had a bit of trouble understanding where the jumper wires were meant to go, had trouble making out their orientation on nino's post and couldn't find another pic elsewhere so in the end I just reasoned that the top and bottom boards had to be connected at some points so armed with my multi meter and a bit of wire to poke through each hole I figured it out.
Using a combination of nino's jumper wires and mikes stitching suggestion I made sure they had continuity.
I did this one a little differently though, I found where two tracks overlapped each other and simply drilled a hole straight through the board, ran a piece of solid copper wire through and soldered both ends, this worked for three out of four jumpers and for the last one where there was no overlap I was lucky to find a corresponding holes so I used another piece of solid wire with some insulation borrowed from a piece of 8amp automotive cable to make the connection.
I had a problem on the back side of J1 at pin 8 where the copper track was missing altogether so I used another piece of solid copper wire to rebuild this, one end soldered to the bottom of the pin and the other through the adjacent hole soldered top and bottom. Hope it works, multi meter says I have continuity so should be good.
All I have to do now is solder the transformer wires back in and its almost go time.
(http://www.atcheaven.com/Images/Board-soldered.jpg)
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Very nice work ^^^
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Getting real close now. I think I have to buy a new crimping tool, my old one does a pretty bad job of crimping the terminals, but then it was probably never meant for this job.
Just got a question, I have a couple of small white (nylon?) washers left over. Can't remember where these went, they do have a kind of star impression left in them which would suggest they maybe go under the earth lead terminals (Earth lead from trans to rec board mount plate) But that would seem to insulate the earth lead which doesn't sound right.
Washers in question are shown in pic sitting on top of transformer.
(http://www.atcheaven.com/Images/Plank.jpg)
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They go on the screws that go through the bridges to stop the screws shorting the tracks together.
You can see them in your before photo.
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Oh Yeah, thanks Ken, guess I won't be needing those anymore.
Cheers Mate
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Looking good so far.
Did you sand down and lacquer the transformer base board? It looks pretty spiffy ^^^
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Looking good so far.
Did you sand down and lacquer the transformer base board? It looks pretty spiffy ^^^
+1 on the lacquer
You don,t want all that shiny copper tarnishing.
make sure you use the solder through type lacquer.
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Yep, I sanded down the plank and at the same time I was lacquering a piece of wood so I thought hmmm, that might look OK on the plank,
Thanks Beaky on the circuit board lacquer. I bought a tin of this stuff from Jaycar a while back but then I got to thinking, if I lacquer the circuit board, and then I find I have stuffed up somewhere it would make it hard to re-solder any components.
When you mentioned solder through lacquer I grabbed the tin and read the description and sure enough it is rated as solder through.
I never knew there was such a thing.
Cheers
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Yep, I sanded down the plank and at the same time I was lacquering a piece of wood so I thought hmmm, that might look OK on the plank,
Thanks Beaky on the circuit board lacquer. I bought a tin of this stuff from Jaycar a while back but then I got to thinking, if I lacquer the circuit board, and then I find I have stuffed up somewhere it would make it hard to re-solder any components.
When you mentioned solder through lacquer I grabbed the tin and read the de******ion and sure enough it is rated as solder through.
I never knew there was such a thing.
Cheers
no probs, glad i could help.
the board is looking great by the way.
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That's some very nice work indeed !
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Thanks nino, but really, you inspired me, when I read your post on how to rebuild the rec board I wanted to get mine looking as nice as yours,
I only hope the damn thing works now after all this effort.
A big thanks to everyone on this board as well who have followed my project and offered helpful comments on the way. I probably wouldn't have tackled this otherwise
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Well, the board is all but complete now, I still have to borrow a set of correct crimpers to hook up the J1, J2 and J3 looms. Will get on to that a bit later.
here is the finished article, not a lot different to the last pic but just with the transformer wires soldered in and board in place.
(http://www.atcheaven.com/Images/Board-done.jpg)
Here are my observations.
I wasn't sure whether to fit the heat sinks before or after soldering in the bridges, I went for before as I wasn't sure if I could hold the nuts tightly enough that secure the heat sinks in place.
The down side to this is the heat sink grease is messy stuff and if you are not careful it would be quite easy to contaminate the board where you are about to solder the legs in place.
I would suggest probably leaving the heat sinks til last.
The bridges are hard to hold in place while you wrestle the legs into position. I first tried to use a G clamp to hold them together but this was quite cumbersome so in the end I found a couple of rubber bands did a fair job. You can see these in the pic above where I have left them in place for reference.
I unsoldered all the transformer wires which in the end probably wasn't neccesary but it did make the board a lot easier to handle and saved me from dragging the transformer around everywhere.
I went a bit crazy sanding back the board in order to have a good surface to solder to. While this is good practice I ended up sanding off the screened on locations for the transformer wires.
It was possible to refer back to the before pics and find the E1 to E12 locations but it would have been a lot easier if they were left intact.
I did make a point of writing these in permanent marker but every time I cleaned the board down with contact cleaner in order to remove the flux the markings washed away and I had to do them again.
One of the transformer wires lives right underneath the resistor at R1, if you have removed the transformer wires it would be a good idea to solder this wire (I think it was E1) back in place before fitting the resistor.
The diodes are polarised so you need to make sure you orient them the right way, the board will guide you with this as it has a band symbol printed which shows you where the diodes should fit.
I wasn't sure if the resistor next to the diodes was polarised so a quick search on google told me they were not, but just to be sure I soldered mine in the same way as shown in ninos post (which turned out to be opposite the way I was planning)
Last of all I gave the exposed copper parts of the board a coat of specialised clear circuit board lacquer. You need to be careful when spraying this stuff as it takes a fair while to dry, it can run a bit and you don't want to coat the fuse holders or the J1-J3 pins with it.
Anyway, fingers crossed it all works!!
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Great stuff - looks good.You have discovered correctly - resistors are NOT polarised.
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That's a fantastic result - well done ^^^