Modding Famicom GPM [solved]

[Pikkon]

Like 80sFREAK said,get some flux dude and I would also get some desoldering braid.

[Finfami]

OK, I'll have to try your suggestions later, I'm not currently where the Famicom is.

However, I still think that there is small change that I damaged the PPU when soldering, look this photo which I took with earlier mod attempt:

http://imgset.net/zNezhP

The black stuff is definetely from the PPU. There is not bits missing but clearly the soldering iron touched the PPU for some time. The reason there is wire going under the motherboard is because I was having lots of troubles soldering into pin 22. But later I started from scratch and the mod is currently more like it's supposed to be in terms of component placing etc.


And is it possible that some solder got under the PPU, possible causing troubles? Transistor was mentioned as one cause and I did maybe use too much force when removing it.

[chowder]

I don't want to be a dick, but that soldering is terrible.  Are those pins on the transistor connected together?  It's hard to see what's going on with those huge blobs of solder everywhere, I'd get some de-soldering braid/a solder sucker to remove everything and start again.  Try the suggestion from hvc01 to see if you can at least get sound so you know whether the board's actually working.  I found it useful to practice removing components and soldering connections on an old computer motherboard, and watched some Youtube tutorials when I was learning.  You should not need any force to remove the transistor from the board if you do it properly

[Finfami]

I'm not offended, I know my soldering is not good. I redid the mod so the pic which I posted last is not the current situation.

I don't have alligator clips and to be honest I don't know what ems shield is.

However, here is audio recording about this Famicom:

https://clyp.it/qj0uqwsk

RCA connector soldered to pin 46.

1) Famicom hooked to TV without power supply
2) Power supply hooked to Famicom but not to the wall
3) Power supply hooked to wall
4) Famicom powered on

and then everything in reverse.

EDIT: Okay now I get it. I left the RCA plugged to TV, switched on Famicom, then got another RCA cable, touched the metal part on the back of Famicom with one end and other end to the another RCA cable's outer ring, I get sound!

https://clyp.it/du3r5jpd

[80sFREAK]

Ummm... did you connected shield of the cable(outer part of RCA) to the pcb's ground?

[chowder]

EDIT: Okay now I get it. I left the RCA plugged to TV, switched on Famicom, then got another RCA cable, touched the metal part on the back of Famicom with one end and other end to the another RCA cable's outer ring, I get sound!

https://clyp.it/du3r5jpd

OK, that's good

You can do a similar thing with the video, ground the outer ring and touch it to pin 21 on the PPU (the one you've been soldering on to), you should get some kind of video output.  It won't look great, but if that works then you know the PPU isn't toast.

[Finfami]

Goddamn, did the same thing for video and there it is....

The guide did mention that I need shielded cable for video, I however assumed that I can get audio the same way as with that another mod, soldering simple cable to pin 46.
Because I had difficulties with the mod, I was trying to test if I get even sound from the Famicom, after I heard only buzzing I was almost certain the Famicom was dead, until after measuring etc. started to have some hope.

As for jailbars, I think the image quality is very good, I'm using 40" TVT and they are very very faint. There is however some sort of horizontal interference going on:

https://www.youtube.com/watch?v=BuBZzCisvYo

I am using very long RCA cable which I assume could contribute something, in addition of this "trick" I'm using to even get video at the moment?

[hvc01]

So the whole problem was an open circuit with no ground. He shoots he scores! Good work. At least you have fixed it. 😃

[Finfami]

Yeah... I assume that was very basic thing, I probably should research some basics....

But now the mod is finished and the Famicom works fine. I see many people opt to put rca jacks on the side of the console, for shorter wires I assume.. I had only one rca jack so I did the same thing as with first Famicom I modded, used the existing one and added one for audio. Ports on back. Even though this Famicom is newer than the first one the plastic has yellowed and it overall feels like cheaper quality, it is much weaker which I noticed when modifying the case for rca jack.