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Right in the Middle of my FB2+ mod - quest about onboard/cart switch


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#1 wongojack OFFLINE  

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Posted Sun Oct 30, 2011 7:50 PM

Summary
1) How should I remove the jumper across J9?
2) Do J9 open AND J3 shorted both have to be true to use cart?
3) Can I wire the onboard/cart switch using GRD from J9 OR J3?


I've got the cartridge slot all wired up and I'm getting ready to attach to the actual FB2+ board.

Whats the best way to remove the resistor thats across J9? I'm not really experienced with this and I don't want to damage the pads underneath.

Also the silkscreen says
J3 Short = Game Cartridge
J9 Open = Game Cartridge

From the descriptions on this board about the various switches that people have built, I'm guessing that this is an AND condition, meaning both of these have to be true to get the game cart mode?

Also, I pulled my cart slot off of a broken 4 switcher that had a broken power switch and would not display correctly, I proceeded to desolder the difficulty switches off of it and wanted to use one for the Onboard/Cart switch on the FB. These switches only have 3 "connectors" hanging down. Can I still use one of them? I think I should be able just to connect the ground of one of either J9 OR J3, or do they have to use their own ground? I would of course connect the other side of each to the switched position of the switch, something like this:


FB2Switch.png


Device is switched to J3 (cart) in the above example. Will that work?

Edited by wongojack, Sun Oct 30, 2011 8:04 PM.


#2 wongojack OFFLINE  

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Posted Mon Oct 31, 2011 10:32 AM

I found some other posts on this. BAtari had trouble desoldering the resistor and offered this (in a different post):

BTW, J9 is on the right near the yellow wires I soldered in. When I tried to desolder the 0 Ohm resistor at J9 I screwed up its solder pads so I followed the traces to R10 and C7 and soldered wires there instead. Indeed, shorting these connections does enable the FB2 ROM and it works properly so I know my screwup wasn't fatal. But carts don't work when shorting J3 and opening J9

I'm thinking I might just try to clip the little wire on the resistor and then use either R10 or C7, whichever is the actual switch. If I can use GRD for J3 this will mean not having to desolder the resistor and potentially f'ing it up.

If anyone has advice for me that would be helpful :)

#3 wongojack OFFLINE  

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Posted Mon Oct 31, 2011 3:39 PM

As far as my question about how to remove the resistor at J9, I found this video which seems to demonstrate the technique:



The example is NOT on a Flashback.

Edited by wongojack, Mon Oct 31, 2011 3:41 PM.


#4 wongojack OFFLINE  

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Posted Mon Oct 31, 2011 4:15 PM

I've got pictures of what I've done so far here:

https://skydrive.live.com/redir.aspx?cid=ec7bd1a81d3e9f22&page=play&resid=EC7BD1A81D3E9F22!127

I'll update that as I make more progress.

#5 wongojack OFFLINE  

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Posted Mon Oct 31, 2011 8:15 PM

I got the resistor off just fine using the technique in the video, but then I immediately pulled the pad off when trying to solder a wire to the top pad of J9 - 5h!+

I guess I can hope that BAtari's work around works for me too, or maybe I'll just never play the flashback games on this one, or something else entirely.

My mistake on this one was that I don't have a magnifying glass that I can strap to my head - the switch pads are smaller than the others and it really takes precision.

#6 wongojack OFFLINE  

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Posted Sat Nov 5, 2011 9:06 PM

I was able to repair the 'lifted' pad by carefully sanding off the coating on the traces that lead to the pad area and then soldering my switch wire across them. It was a delicate repair, but when I was done, I tested and the Flashback rom worked again.

At some point, the A/V wires came disconnected from the sub board - I didn't realize this was happening and got some unusual results while testing. I eventually had to strip and re-solder the A, Grd, and V. Continuity tests fine with the points on the top side of the board now so I think that is repaired.

I proceeded with my mod and got the cart wires soldered on fairly easily, tinning both the wires and the pads was critical.

Since the diagram shows lower J9 and upper J3 connected to the bottom lead of the switch, I assumed that it would NOT matter if I connected the corresponding wires manually - so I connected the lower pad of J9 to the lower pad of J3. When I did that, I tested the cart slot and got garbage. Then I connected to top and bottom of J3 - no change just garbage.

It all seemed to be going great, but something isn't right. I switch back to the Flashback rom and it also looks just messy.

Flashback_Garbage.jpg

Because I have a FB 2+ I used gnash's alternate pin 20 workaround that he identified here:
http://www.atariage....ort-workaround/

Aside from just unknown stuff killing me, I think there could be 2 main places where I've screwed up.

1) Connecting the lower pad of J9 to the lower pad of J3. I'm actually using the upper pad of C7 as a work around - maybe this caused something to blow, but that seems unlikely. Perhaps someone else will comment on that.
2) Using the alternate pin 20. This is a pin directly connected to the ROM, so maybe my flashback doesn't like that. I checked for shorts around it and didn't find any. I'll pull that wire off tomorrow and see if there is any change.

A possible 3rd place is my work around J9 - its a mess, but continuity checks out and I did test that the FB worked after I repaired it. Right now I actually have one wire connected to the top of J9 and the other connected to the top of C7. They connect and the FB did work connected like this. Thanks to BAtari for this work around.

I guess another problem could be the A/V wires that came loose.

My cart edge connector could also be flaky since I wasn't able to properly test it.

If anyone wants to chime in and stop me from talking to myself, I will gladly welcome your advice.

#7 pimpmaul69 OFFLINE  

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Posted Tue Nov 29, 2011 1:02 AM

i had wires 16 and 17 backwards which caused this to happen

#8 wongojack OFFLINE  

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Posted Tue Nov 29, 2011 1:51 AM

I'm not sure what I did. I disconnected 13-24 and still had the display problem. When I disconnected everything the Flashback worked again.

I went through tonight and reconnected everything, checking for continuity to the edge connector and testing video output every 4 wires or so. I finally got it to work.

I used gnash's work around for pad 20 (wire to the 5th lead on the ROM area directly above pad 20). I had to solder it 2x as the first time I only got the 2k carts working. I reset the joint further "down" away from the chip and then carts above 2k worked as expected. Was pleased to see Asteroids with no flicker!

AsteroidsFlashback.JPG

Now I just have to start cutting on the case to place my switch and cart port . . .

#9 wongojack OFFLINE  

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Posted Tue Nov 29, 2011 1:58 AM

As far as the switch is concerned, the lower pad of J9 is ground and the upper pad of J3 is also ground. Actually, every ground on the board I tested was connected, so there are lots of options on how to wire your switch.

To test this just set your multimeter to test for continuity and touch the leads to the various grounds on the board:

lower J9
upper J3
pad 12
pad 24

Basically, my diagram is correct, you can take the ground from either J9 OR J3 to complete the switch.

#10 wongojack OFFLINE  

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Posted Tue Nov 29, 2011 2:45 PM

Pictures (and captions) updated here:

https://skydrive.live.com/redir.aspx?cid=ec7bd1a81d3e9f22&resid=EC7BD1A81D3E9F22!127&parid=root

#11 pimpmaul69 OFFLINE  

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Posted Tue Nov 29, 2011 5:02 PM

I'm not sure what I did. I disconnected 13-24 and still had the display problem. When I disconnected everything the Flashback worked again.

I went through tonight and reconnected everything, checking for continuity to the edge connector and testing video output every 4 wires or so. I finally got it to work.

I used gnash's work around for pad 20 (wire to the 5th lead on the ROM area directly above pad 20). I had to solder it 2x as the first time I only got the 2k carts working. I reset the joint further "down" away from the chip and then carts above 2k worked as expected. Was pleased to see Asteroids with no flicker!

AsteroidsFlashback.JPG

Now I just have to start cutting on the case to place my switch and cart port . . .

just thought i would show you a few pics. if you want clean on the outside you can see where top and bottom cuts are. you have to be very careful to trim tabs off of the sides of the slot plastic. the side cuts go to inside of reinforcment tabs on inside, then trim down enough to remove reinforcement area completely on both sides.

Attached Thumbnails

  • 2 010.jpg
  • 2 011.jpg

Edited by pimpmaul69, Tue Nov 29, 2011 5:25 PM.


#12 pimpmaul69 OFFLINE  

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Posted Tue Nov 29, 2011 5:14 PM

also if you have a harmony cart, not all the incompatible games on compatability list are actually incompatible. most of them work for me.. even the 2 that have a fixed version work for me without the fixed version.(decathlon and robot tank)

Edited by pimpmaul69, Tue Nov 29, 2011 5:15 PM.


#13 wongojack OFFLINE  

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Posted Tue Nov 29, 2011 5:19 PM

I think I understand what you are saying, but the term "slot plastic" isn't completely clear.

So your cart guide sits on top of the FB? What did you use to secure it?

#14 pimpmaul69 OFFLINE  

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Posted Tue Nov 29, 2011 5:23 PM

I think I understand what you are saying, but the term "slot plastic" isn't completely clear.

So your cart guide sits on top of the FB? What did you use to secure it?

commercial strength hot glue. slot plastic= cart guide

#15 pimpmaul69 OFFLINE  

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Posted Tue Nov 29, 2011 5:31 PM

2.jpg
as you can see it sticks out a little, but does not look like a hack job. like all the others i have seen. no offense to anyone who put guide internally, i just dont like seeing my cuts even as clean as the may be.

Edited by pimpmaul69, Tue Nov 29, 2011 5:39 PM.


#16 wongojack OFFLINE  

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Posted Tue Nov 29, 2011 5:42 PM

What did you use to do the actual cutting? I don't really have a lot of tools, and I'm not really interested in buying something just for this.

I guess if I'm going to cover up the cuts with the guide then I don't need to be very precise . . .

#17 pimpmaul69 OFFLINE  

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Posted Tue Nov 29, 2011 5:49 PM

What did you use to do the actual cutting? I don't really have a lot of tools, and I'm not really interested in buying something just for this.

I guess if I'm going to cover up the cuts with the guide then I don't need to be very precise . . .

i used a drill with very small drill bit to make a ton of holes to perferate. top and bottom drilled from top first then drill sides from bottom inside reinforcement tabs. then used razor blade to cut out and then clean up. then you have to widen the sides, so use razor to trim down more til the reinforcement tabs are gone. and like i said, very very carefully cut tabs off the sides of the cart guide. cut the long length first, then cut off right under the lip. otherwise you can break part of the lip off

#18 wongojack OFFLINE  

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Posted Sun Sep 9, 2012 4:25 PM

Another update to my post here - I had some trouble putting the Flashback board back into the case. In trying to smoosh everything back in, I pulled up pad 8 and shorted wires 1 and 2 together. This caused me to basically shelve this project for the last 6 to 8 months.

This weekend I got 'er back out and carefully exposed wire leading to pad 8 by sanding away the coating with a piece of sandpaper attached to a very small flathead eyeglass screwdriver. Then I had to connect a single wire across both exposed leads. This worked and I was able to set the wire in such a way that it did not pull when I put it back in the case.

I was using an IDE cable and I left wires 1-8 basically together, only separating them at their edges. This was fine for wires 1-7 but 8 ended up stretching a bit due to the orientation of the plastic fasteners on the case and the reset button which happens to be near where these wires need to run. If I had to do it again, I would have separated more of my wires at least the last 5 or 6 inches closest to the board. In the end, I separated wire 8 completely from its friends on the IDE cable.

I've mounted the cart port from above just like the pics in pimpmaul69's photos. His instructions made sense once I got into it. Drilled a bunch of holes and then used exacto and a file to remove a section of the case. I then had to remove some of the ridges on the lower half of the cart port which I could shave off with an exacto. It fits snugly but will pull out when trying to remove a cart. I'll have to epoxy it into place.

All in all, its working and is back in the case, but it really feels kinda fragile. Fitting it back into the case was a bit nerve wracking even after I'd made a few adjustments to make it easier. I choose not to put all the screws back in. I expect it to break if its dropped or just gets handled roughly, so this will be more of a trophy for me than a serious game system. I will say that if I do a 2nd Flashback mod it will be much easier and the end result will likely be much better just because of experienced gained by doing it once.

Please reply to this thread or send me a PM if you have questions about my mod. I do have 2 more Flashbacks that I could mod, so if anyone has a broken VCS or a loose cart port, I'll pay you to ship them to me (for me to keep not send back).

#19 pimpmaul69 OFFLINE  

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Posted Sat Sep 15, 2012 12:23 AM

Another update to my post here - I had some trouble putting the Flashback board back into the case. In trying to smoosh everything back in, I pulled up pad 8 and shorted wires 1 and 2 together. This caused me to basically shelve this project for the last 6 to 8 months.

This weekend I got 'er back out and carefully exposed wire leading to pad 8 by sanding away the coating with a piece of sandpaper attached to a very small flathead eyeglass screwdriver. Then I had to connect a single wire across both exposed leads. This worked and I was able to set the wire in such a way that it did not pull when I put it back in the case.

I was using an IDE cable and I left wires 1-8 basically together, only separating them at their edges. This was fine for wires 1-7 but 8 ended up stretching a bit due to the orientation of the plastic fasteners on the case and the reset button which happens to be near where these wires need to run. If I had to do it again, I would have separated more of my wires at least the last 5 or 6 inches closest to the board. In the end, I separated wire 8 completely from its friends on the IDE cable.

I've mounted the cart port from above just like the pics in pimpmaul69's photos. His instructions made sense once I got into it. Drilled a bunch of holes and then used exacto and a file to remove a section of the case. I then had to remove some of the ridges on the lower half of the cart port which I could shave off with an exacto. It fits snugly but will pull out when trying to remove a cart. I'll have to epoxy it into place.

All in all, its working and is back in the case, but it really feels kinda fragile. Fitting it back into the case was a bit nerve wracking even after I'd made a few adjustments to make it easier. I choose not to put all the screws back in. I expect it to break if its dropped or just gets handled roughly, so this will be more of a trophy for me than a serious game system. I will say that if I do a 2nd Flashback mod it will be much easier and the end result will likely be much better just because of experienced gained by doing it once.

Please reply to this thread or send me a PM if you have questions about my mod. I do have 2 more Flashbacks that I could mod, so if anyone has a broken VCS or a loose cart port, I'll pay you to ship them to me (for me to keep not send back).

Any pics of your final product. I would like to see how it came out

#20 wongojack OFFLINE  

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Posted Mon Feb 11, 2013 3:38 PM

Well, I finally posted more pics of the finished product on my skydrive. You can see it here: http://sdrv.ms/128dCMH

I also pulled the stupidest move of all time and right after I took that picture, I removed the cart with the machine on. It still works, but I have big color problems - :(

#21 wongojack OFFLINE  

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Posted Tue Feb 12, 2013 10:26 AM

Update today is that it is back to working just fine. I also got some better pics here:

http://sdrv.ms/UatOJF

#22 mmervine OFFLINE  

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Posted Thu Feb 14, 2013 7:20 AM

Congrats...glad you got it working again!




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