Twin famicom destroyed graphics repeated problem.

The place for all discussion on gaming hardware
Post Reply
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

Hello

kindly check the problem here: https://imgur.com/a/W9GrGFY

I checked NESRGB and power supply plus cables and everything is perfect. it was working yesterday and found this issue now.

this issue keeps getting repeated! I mean when I open the console and do reflow the solder joints of capacitors in main board it returns to being perfect... then all by itself after couple of days starts showing this issue! this cycle keeps getting repeated. I am not even sure the caps reflowing is the solution but what is the problem?

most of those caps were replaced by a kit so there is no problem in them being old and leaky.

this twin famicom caused me more trouble than i can describe due to this issue.


for your kind help
fernan1234
Posts: 2175
Joined: Mon Aug 14, 2017 8:34 pm

Re: Twin famicom destroyed graphics repeated problem.

Post by fernan1234 »

My guess: PPU got damaged during the NESRGB installation. Only fix may be to harvest another PPU.
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

fernan1234 wrote:My guess: PPU got damaged during the NESRGB installation. Only fix may be to harvest another PPU.
well, i though it was like that before since i ruined my nesrgb board itself. so i sent it to oldskool admin for repair (i sent the entire main board + nesrgb + ppu) and he verified that ppu works.

after i posted this thread, i resoldered some caps mainly the one after reset switch and it worked perfectly fine. i swapped the 2 caps which are 10uf as an extra. it returned to working fine and i played a lot on it.

i hope this is the last of it.
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

Hello

I tried using it just now and the problem returned all by itself!!

what is wrong with it??

it is really the most weird problem I have ever faced in electronics!

just open it, solder some joints back and it returns to work! then returns to be broken again by itself.
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

This time I didn't resolder anything but rather pressed the nesrgb assembly more + pressed the ppu more (didn't do it previously). I guess maybe the nesrgb assembly becoming loose or so despite the pins are tight.

we'll see what happens.
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

and just now it returned to the exact same problem!!

I just literally unscrewed the case screws.. then when I saw the internals did another test and it worked! just like that.

so now i really wonder what the hell is happening!
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

The problem keeps getting repeated.

I notice when I somehow push the NESRGB assembly board it gets fixed. However, I don't think it was loose.
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

unfortunately this keeps getting repeated.

I open the system, retighten everything despite being good to begin with... then it starts working again. after some days it returns to glitch.

what is really going on???
DejahThoris
Posts: 719
Joined: Sat Oct 19, 2013 10:26 pm
Location: Riverside, CA

Re: Twin famicom destroyed graphics repeated problem.

Post by DejahThoris »

VEGETA wrote:The problem keeps getting repeated.

I notice when I somehow push the NESRGB assembly board it gets fixed. However, I don't think it was loose.
Cold/cracked/bad solder joints, a trace got nicked, something of that sort given you being able to press on it and it gets better.

Time to crack out the magnifying glass and the multimeter.
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

DejahThoris wrote:
VEGETA wrote:The problem keeps getting repeated.

I notice when I somehow push the NESRGB assembly board it gets fixed. However, I don't think it was loose.
Cold/cracked/bad solder joints, a trace got nicked, something of that sort given you being able to press on it and it gets better.

Time to crack out the magnifying glass and the multimeter.

well, i just had it glitched, then simply gently pressed down the cart connector itself without disassembling anything then it worked again.

i don't mind soldering stuff but tracing would be kinda hard since even the disc system itself is glitched when it happens. so the cart connector traces should not be the problem here?

what joints and traces should i invest my time on?
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

DejahThoris wrote:
VEGETA wrote:The problem keeps getting repeated.

I notice when I somehow push the NESRGB assembly board it gets fixed. However, I don't think it was loose.
Cold/cracked/bad solder joints, a trace got nicked, something of that sort given you being able to press on it and it gets better.

Time to crack out the magnifying glass and the multimeter.
the problem returned, now could not solve it by pushing anything.

I will be taking it apart and investigate but for such a problem where do you suggest I look? like the usual culprit area or ICs?

I am not familiar with how famicom board (twin famicom here) generates graphics besides that it has a PPU as graphics chip. so could it be that investigating all traces related to PPU (NESRGB assembly now) is the one needed here?

I verify that I was extra harsh to the motherboard when I desoldered the original PPU. Then I did the recap in the same session and when reinstalled everything back it started happening. Personally I don't think recapping did anything bad since it was very easy but I admit PPU desoldering was harsh.
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

I have done all repairs i could, cleaned everything, resoldered everything... etc.

but still the problem returned!

what the hell is going on??!


EDIT: before i was going to re-open it to try and see, i pressed the SCART cable more into the switcher and then it worked normally without touching the console. now I am confused since the scart rgb cable should not affect it like this. i know loose connection can cause bad sync but broken graphics??
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

The problem happened again! checked cables and so on, everything perfect.

this is after doing some cleaning and re-soldering...etc.

what else can be done??!
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

Now I re-opened it then tried warping it both sides (bending it) and the system worked and didn't work... according to bending. thus concluded there are some broken traces which gets connected and disconnected according to bending and physical pressure.

my previous fix to this was to connected such problematic traces using solder. looks like solder with these very fine traces also gets broken\disconnected with tension.

thus I tried connecting all problematic traces using external wires from the points directly, which i should have done in the first place. then tried bending it all sides while power on... and the device kept working perfectly fine!

I conclude this is a solution at least for now xD. although this time very confident it is going to work for sure.
User avatar
Syntax
Posts: 1774
Joined: Wed Aug 09, 2017 12:10 am
Location: Australia

Re: Twin famicom destroyed graphics repeated problem.

Post by Syntax »

Nice job finding the faults and fix.
Traces repaired with just solder cracking again with PCB flex sounds like a nightmare,
ill be adding a bit of wire on anything that seems like it can flex at the break point from now on TY.
User avatar
bobrocks95
Posts: 3460
Joined: Mon Apr 30, 2012 2:27 am
Location: Kentucky

Re: Twin famicom destroyed graphics repeated problem.

Post by bobrocks95 »

Broken traces are so hard to diagnose even with a set of schematics, glad to hear you got such a longstanding problem fixed. I have a similar problem with a Neo Geo MVS with some trace corrosion that is broken pretty much every time I turn it on.
PS1 Disc-Based Game ID BIOS patch for MemCard Pro and SD2PSX automatic VMC switching.
User avatar
VEGETA
Posts: 425
Joined: Mon May 31, 2021 10:40 am

Re: Twin famicom destroyed graphics repeated problem.

Post by VEGETA »

after this very painful experience, here are my top recommendations:

1- clean the entire board with alcohol first, this is to find corrosion and stuff. if you find any, fix it by putting fresh solder on top of it after cleaning.
2- always use external wires... fast fixes are bad fixes! this is very important. your wires should be soldered firmly with short distances as possible.
3- replace electrolytic caps if you can, especially big ones since they tend to store energy a lot for supply.
4- do not use excessive heat since this destroys boards if done for a long time.
5- use the best tools available, invest money in them. why? because desoldering without automatic pump desoldering tool is painful and will force you to use lots of heat and pressure for very long time in order to get the chips out. probably this was what destroyed the traces for my case. I recommend buying a proper desoldering station with automatic pump. I still don't have one but plan to. if you don't have money and only very few desoldering jobs needed then get a good manual pump and use it with your soldering iron but with low heat. use flux and pre-tin the joints with fresh solder before you start.
6- be careful with fragile stuff in retro systems such as tiny wiring harness, plastic plugs, ribbon cables..etc. since it has been 20-30 years for them and they can break with slightest of pressure.

I am searching for 220v version of ZD-915 desoldering tool or any good 220v used tool like that if someone can offer.
Post Reply