Original Famicom not turning on

[s0r00t]

So I managed to get a working AC adapter for my original Famicom, along with a test game (SMB).
But before modding it to have composite output, I wanted to turn it on and see whether something would happen.

Unfortunately, nothing happened. The adapter works, but the Famicom doesn't show any sign of life (I cannot test the RF output).

Here are pics of the console : https://imgur.com/a/bnMJR
I do not see anything particular, besides the blown-up thing near the RF output.

Should I still mod the console and see what happens, or is there something I should do before?

Thanks for your help. This is what kept me going for a while, I'd really love to figure it out and have some fun.

[P]

The Famicom has no power LED or anything so I guess the only way to see if it's alive is to check if the power line is 5 V as it should. Is that what you are doing?

You can also test sound from the RF using an FM radio. Since SMB has no sound on the title screen you need to press start after powering on.

Other than that the only easy way I know is to test video and audio on a TV and for that you may need to AV mod it first.

[s0r00t]

I do not have a multimeter yet, so it was kind of a blind test. As the NES produces sound when running, I hoped the Famicom did the same...

I didn't AV mod it yet to avoid breaking it more, but if there's no way to test the console besides that, I'll do it. I do not know if the radio test would also work with a French radio.

[Frank_fjs]

Just use a test clip, aligator cable and RCA lead to test composite video output.

[P]

Yeah using crocodiles you could test both video and audio. Without an amplifier it will be a weak video signal (audio should be fine without though) but it's enough to know if it's alive.

The NES produces sound? There's no built-in speakers though. My Famicom is dead silent when on.

Are French FM radios any special? As long as it can tune into  91.25 or 97.25 MHz it will be fine.

[s0r00t]

Where should I place the crocodile? I've never heard of such a test, and my skill is too low to guess it correctly.

What I meant through "producing sound" is the faint buzzing noise you can hear when current passes through the console. But as you said, the Famicom is silent :x

I'll try testing whenever I'll be back home.

(Merry Christmas to you,  BTW!)

[s0r00t]

Alright, so the FM test failed, because there is too much interference on those frequencies. However, the components were heating nicely while running, so I guess that's a good sign?

To mod the Famicom, I've been following this guide : https://assemblergames.com/threads/guide-av-mod-your-famicom.49263/

I have these components and I've started modding it, but the RF circuitry is radically different from mine (HVC-CPU-GPM-02), and I can't figure out how to place the 120R resistor and the 200uF capacitor, nor what to desolder.

Here's my RF circuit :


What should I do?
Again, thanks for your valuable help in this adventure

[FAMICOM_87]

Do not remove,  desolder components, or cut traces,  just make this simple scheme, and you are good to go with Video for  test audio is from cartage slot pin 46 if you want to Add permanent AV mod



this is my conception of the AV mod, it is good idea to keep the original vision of the console  

BTW  did you check the FUSE and 7805 ? 

[s0r00t]

As I said, I already have the components for that mod, and went halfway through it : replaced one resistor and added one capacitor.

I'd like to finish it, if possible, to avoid ordering components and wait again....

I didn't test the fuse nor the 7805, because as I said, I do not have the equipment required yet.

[P]

You use the crocodiles instead of soldering for testing purposes. You can use the same schematic or maybe even directly on the video line from the PPU to see if you get anything at all.

I recommend to get a multimeter when doing things like this. It's very good to have in general even for just testing batteries and stuff. Instructions on how to use it can be found online.

[s0r00t]

I know how a multimeter works, and as I said I'm planning to get one ASAP.

Seems like I'll have to follow that other mod, and undo my edits to the PCB... Could someone give me the original value of the R6 resistor, please? I'll order a new one.

[FAMICOM_87]

Don't you see?
it is right on the PCB
R6 is 2.2k (2200)
R12 is 220

http://www.gnys.se/da_bear/famicom/avmod/DSC_9110.jpg

Actually you can keep this 47uF cap between pin 20 and 22
http://www.gnys.se/da_bear/famicom/avmod/DSC_9148.jpg
if you are already added it. It is for reducing vertical lines (jailbars)
also you can add one more cap anywhere on the PCB between + and -  220uF or even bigger for more reduction or, even eliminating those vertical lines  (mine is 1000uF) it is improvement not only for AV mod, but for the RF signal too keep in mind that all caps must be above 5V ! 6V, 10V, 16V,  25V or so on, because the mine PCB of the  famicom is running on 5V 



Post Merge: December 30, 2017, 10:42:31 am

Don't you see?
it is right on the PCB
R6 is 2.2k (2200)
R12 is 220

http://www.gnys.se/da_bear/famicom/avmod/DSC_9110.jpg

Well I so your PCB is different and even the resistor is in different place ,
so according to your's R6 is 150 ohm
https://i.imgur.com/GwF7qgF.jpg