whats the best way to reflow an snes motherboard?

just what the title says. I have a 1-chip snes that plays some games but not others depending on which pins the game uses. all of the pins in the cart slot seem to be making good contact and when i push my finger down on the motherboard, i can get some of these games to play for a second.

it seems that one or more chips have a loose solder connection.

i was thinking of putting some flux around the chips and heating each row of pins up with my heat gun till the solder melts.

I have heard of using a toaster oven to do the whole board at once.

Im concerned if i did that that the small surface mount stuff on the bottom would fall off though.

My advice is to not take the "shotgun" approach. Find out which chip is causing the issue by individually assessing and pressing down.

If you have a rework station, use that. If not, see if you can find a butane torch with an element attachment like this one:


I've fixed SMD chips a few times with my Weller Portasol now (my Super Everdrive was one of them). Just keep movement steady, don't apply heat longer than necessary, be wary of nearby components and use a low temperature (mine is STUPID hot even at its lowest setting).

I'd be really careful onechips are rare. Before doing anything I'd use a probe to check connectivity between each pin in the cartridge slot and the solder point of that pin on the underside of the pcb.

Drakon wrote:

I'd be really careful onechips are rare.

Yes. Don't wreck it.

In this case I think I would reflow it by hand.

Apply flux to the pins then brush a fine tip soldering iron each pin at a time.
Last week I reflowed a SNES CPU this way while trying to troubleshoot a console with weird problems.
It did not solve my problem but It did not make it worse either.
You just need to make sure to not create bridges between pins.

Edit: Also, if you want to make continuity tests around the board, the guys over at NESDeV made a redrawn schematic of the console. If you did not know already.
Much easier to read than those originals that are available around!

MaxWar wrote:

In this case I think I would reflow it by hand.

Apply flux to the pins then brush a fine tip soldering iron each pin at a time.
Last week I reflowed a SNES CPU this way while trying to troubleshoot a console with weird problems.
It did not solve my problem but It did not make it worse either.
You just need to make sure to not create bridges between pins.

Edit: Also, if you want to make continuity tests around the board, the guys over at NESDeV made a redrawn schematic of the console. If you did not know already.
Much easier to read than those originals that are available around!

I like this method too; Especially when there are nearby components. Make sure your iron is squeaky clean, it's easy to accidentally bridge pins.

God...I just don't like the idea of reflowing a onechip. Maxwar is the redrawn schematic a onechip schematic? There's multiple pcb revisions of the snes.

I think the Schematic is based on the original SNES but It can still help figuring where connections from cart slot go. Granted I have never worked on a 1chip so do not know how Alien they are inside. But the schematics helped me greatly when working on a GPM-02.


Get them here, In any case its a great thing to have on your hard drive !
http://forums.nesdev.com/viewtopic.php?f=12&t=10470

The onechip should be completely different since they consolidated the two ppu chips into one.

I reflowed this whole board and it didnt make a difference.

it still does the same thing. Power light comes on - no video except for a flash when i flip the power switch. some games i can get the first screen that would come up and then they lock up.

btw i have tons of dead snes here so if it was a ram error or something i could use those if they are the same. the only thing i dont have is a spare 1chip.

but how would you find something like that?

I recently revived a DOA sharp twin famicom if you read here:

https://16bitgamer.canadian-forum.com/t335-twin-famicom-repair

After inspecting the pcb for broken traces I socketed all the major chips.  How the system came turning the power button I got a screen of garble that did nothing.  I socketed all the major chips (cpu, ppu, two main ram chips) and tested the chips in a working toaster with everything socketed until I found the chip that wouldn't go (ram chip).  Replaced the ram chip and all was revived.

The onechip snes you can't inspect many of the pcb traces, other thing would be to look for a part that's fallen off like a tiny surface mount part on the solder side maybe. If you can't find any pcb damage or missing parts and you really think one of the chips is dead then you could swap the chips but that's surface mount desoldering / soldering which takes practice.

Drakon wrote:

I recently revived a DOA sharp twin famicom if you read here:

https://16bitgamer.canadian-forum.com/t335-twin-famicom-repair

After inspecting the pcb for broken traces I socketed all the major chips.  How the system came turning the power button I got a screen of garble that did nothing.  I socketed all the major chips (cpu, ppu, two main ram chips) and tested the chips in a working toaster with everything socketed until I found the chip that wouldn't go (ram chip).  Replaced the ram chip and all was revived.

The onechip snes you can't inspect many of the pcb traces, other thing would be to look for a part that's fallen off like a tiny surface mount part on the solder side maybe. If you can't find any pcb damage or missing parts and you really think one of the chips is dead then you could swap the chips but that's surface mount desoldering / soldering which takes practice.

thats a great idea for the nes to have a testbed with everything socketed.

mvsfan wrote:

Drakon wrote:

I recently revived a DOA sharp twin famicom if you read here:

https://16bitgamer.canadian-forum.com/t335-twin-famicom-repair

After inspecting the pcb for broken traces I socketed all the major chips.  How the system came turning the power button I got a screen of garble that did nothing.  I socketed all the major chips (cpu, ppu, two main ram chips) and tested the chips in a working toaster with everything socketed until I found the chip that wouldn't go (ram chip).  Replaced the ram chip and all was revived.

The onechip snes you can't inspect many of the pcb traces, other thing would be to look for a part that's fallen off like a tiny surface mount part on the solder side maybe.  If you can't find any pcb damage or missing parts and you really think one of the chips is dead then you could swap the chips but that's surface mount desoldering / soldering which takes practice.

thats a great idea for the nes to have a testbed with everything socketed.

I also have a borked SNES. It works, but controllers inputs will not work and it crashes at specific spots in most games. ( It was troubleshooted a lot and everything points to the CPU)
If everything was not SMD in the SNES I would try the socket and chip swap approach to be sure.

If I had more borked SNES I would try it any way but it is the only one I have. When you think about it, Out of 10 borked SNES you would be likely to obtain 8 working consoles just by swapping the bad parts.

MaxWar wrote:

mvsfan wrote:

Drakon wrote:

I recently revived a DOA sharp twin famicom if you read here:

https://16bitgamer.canadian-forum.com/t335-twin-famicom-repair

After inspecting the pcb for broken traces I socketed all the major chips.  How the system came turning the power button I got a screen of garble that did nothing.  I socketed all the major chips (cpu, ppu, two main ram chips) and tested the chips in a working toaster with everything socketed until I found the chip that wouldn't go (ram chip).  Replaced the ram chip and all was revived.

The onechip snes you can't inspect many of the pcb traces, other thing would be to look for a part that's fallen off like a tiny surface mount part on the solder side maybe.  If you can't find any pcb damage or missing parts and you really think one of the chips is dead then you could swap the chips but that's surface mount desoldering / soldering which takes practice.

thats a great idea for the nes to have a testbed with everything socketed.

I also have a borked SNES. It works, but controllers inputs will not work and it crashes at specific spots in most games. ( It was troubleshooted a lot and everything points to the CPU)
If everything was not SMD in the SNES I would try the socket and chip swap approach to be sure.

If I had more borked SNES I would try it any way but it is the only one I have. When you think about it, Out of 10 borked SNES you would be likely to obtain 8 working consoles just by swapping the bad parts.

Ive been borrowing the power input connectors off of my glitchy snes' up till now.

this is my second 1-chip ive had that was messed up though and it would be great to fix one instead of putting it on the pile.

So far here's what I do to fix broken power Input.
Those now use the Genesis Model 1 adapter, or equivalent.

MaxWar wrote:

So far here's what I do to fix broken power Input.
Those now use the Genesis Model 1 adapter, or equivalent.

For my onechip american snes systems I just bought some cheap super famicoms and swapped the cases / backplates to convert them into onechip super famicoms.  The snes pcb is the same as the super famicom you just need to swap the back plate which is just held in with the power jack.  Once you swap the back plate you get a super famicom power jack so it'll use a model 1 genesis power brick / standard sfc brick (same thing).  Plus the super famicom case looks way better than a snes.

And then you put the Super famicom boards in the SNES case?

Edit: The real question I guess was: Do you actually sacrifice a console in the operation?

MaxWar wrote:

And then you put the Super famicom boards in the SNES case?

Edit: The real question I guess was: Do you actually sacrifice a console in the operation?

No sacrifice like you guessed just a straight swap.  You take a onechip snes and a non-one chip super famicom.  You take them out, swap the back plates and swap the cases.  Now your onechip is in a nice super famicom case and your two ppu snes is in a fugly american snes case.  The backplates are straight swappable no rewiring is needed, you just desolder one and solder in the other.  Since the backplate contains the power jack once you swap it you also swap the type of power jack your system takes.  Whatever system winds up in the super famicom case can take more common power supplies, it's only systems in snes cases that need the less common snes power brick.