RF + Mod SNES = A loving couple?

[Neo]

Hiya

I�ve got a modded SNES (Hz and region), but by some reason I can�t get a working RF-signal out of it. This is the case in both 50 and 60 Hz, with or without region mod.

At first I thought the RF port was broken, so I tried an RF-modulator with the AV port instead. Nope, still no good. I�ve tried it on both old and brand new TVs, but the result is still the same. Now, isn�t THIS weird?

Suggestions anyone? Have I discovered something impossible? ^_^;

/Neo

[NFG]

That's really odd.  In theory you should be able to make it function by switching the mod back to the original mode.  If that doesn't work you might have fried something, but I'm at a loss when I try to guess what.  

[Guest]

If that doesn't work you might have fried something, but I'm at a loss when I try to guess what.

I don�t think that�s the case, since the modulator should be able to convert the AV signal what-so-ever. Obviously a fried component should only lead to a direct loss of a function, not making an external add-on malfunction.. or? ^_^;

[Chuplayer]

Is your TV set to channel 3 or 4 as appropriate? Is the RF switch set to channel 3 or 4 as appropriate? Does your TV channel and RF switch channel setting match?

I recently accidentally switched my VCR's output from channel 3 to 4 by unknowngly hitting it with my knuckle while screwing the cable in the back, and it took me a few hours to figure out what was wrong  ^_^  

[Neo]

Um, I may be slow, but how do I change these settings?
(Yay! we may have a solution! ^_^)

/Neo

[Chuplayer]

Look for a little switch on the back of the console. It should say "CH3/CH4" or something like that. (Or it might have different channels where you live, seemingly in the UK since you have the 50/60hz mod.)

Next, make sure you're using the normal antenna setting on your TV. Do not use other settings for inputs like composite in or RGB in or whatever. Just set it to the right channel. (usually 3 or 4) Turn on the system and it should work.

If not, there's another method of getting it to work that I remember reading about. Something about a video switch or something. I'll dig up some information for you if this information doesn't work. Good luck!

[Tom61]

I don�t think that�s the case, since the modulator should be able to convert the AV signal what-so-ever.

That's not a modulator, that's an automatic switch box. The SNES outputs RF directly, that little box just switches over to SNES whenever it's turned on. (unlike the older switch boxes where you had to slide the selector between TV and Game)

Try the switchbox on a NES (they use the same RF switcher) to see if it still works.

[Guest]

I don�t think that�s the case, since the modulator should be able to convert the AV signal what-so-ever.

That's not a modulator, that's an automatic switch box. The SNES outputs RF directly, that little box just switches over to SNES whenever it's turned on. (unlike the older switch boxes where you had to slide the selector between TV and Game)

Try the switchbox on a NES (they use the same RF switcher) to see if it still works.

No, he's talking about the modulator from the N64 RF switch set. (He didn't state it specifically, but I have one myself, so I know.) Since the N64 doesn't have a direct RF out, it has a little piece that goes between the AV multi-out and the switchbox cable that converts the signal from the multi-out into RF. It was a nifty little way for Nintendo to cut costs on the RF when it came to the N64. And annoying, because back then I used RF, and I had to buy a whole new set just to get the little modulator piece. I couldn't just use the SNES switchbox alone  :angry: BTW, I'm pretty sure that little modulator piece has its own "CH3/CH4" switch.

I got a good TV that had composite inputs a couple years after I got my N64. It was such an improvement! Everything looked and sounded better! It's nowhere close to RGB or component, but back in 1999, it didn't matter. I was rocking it out with my N64 and SEGA Saturn with enhanced visual quality and kickass stereo sound!

[Chuplayer]

Whoops, that was me up there talking about N64 modulators and stuff. I wasn't logged in  ^_^  

[Tom61]

OK, I see now. Neo probably fried the video chip (or more) then if switching the Station/RF switch to the right place doesn't work.

RF is dead + the A/V is dead (since that's what the modulator takes) = fried video, since both the A/V port and RF take input from the video chip.

[Guest]

No no, the interesting part in this drama is that the AV works just fine, with good picture and sound, just like it should be. The creepy problem is that neither the RF port nor the modulator is able to give me a RF signal, meaning the following: the modulator won�t translate a very well working AV signal! Also, both the existing plain RF signal and the modulated RF signal look VERY similar. Hm..

[Chuplayer]

Okay, I've got one more suggestion before we turn to the video switch or whatever it's called. Does your TV have an "AUX 3/4 IN" and, if so, are you screwing your RF switch into it? If you are, you need to switch your TV to its "AUX 3/4 IN" mode or whatever it may be called on your TV. Switching it to its "AUX 3/4 IN" mode should be just like switching it into the composite video in setting except it's not composite.

Ideally, you should remove the Cable TV or Antenna cable from the back of the TV, screw it into the Nintendo RF Switchbox, and then screw the switchbox's cable into the TV. When you turn your system on, it should override the Cable TV or Antenna signal and display the game's signal (that is, if everything's on the right channel). That way you won't need to worry about the "AUX 3/4 IN" and have the problem you're having. I never use the "AUX 3/4 IN" so I can't tell you exactly how much of a problem it can cause.

Since you can get good video and sound from composite cables out of the A/V multi-out, you should be able to get good RF from it when you use the modulator that plugs into the multi-out. I've never tried it on an SNES, but I see no reason why it shouldn't work. I doubt that you have a bad modulator, too. You've just got to make sure everything's set to the correct channel. Even if the RF out in the system itself is fried, the external modulator independently mimics the hardware that is in the internal RF out inside the system itself, so there should be no problem using the external modulator because it acts on its own.

When in doubt, set everything that goes to your TV to channel 3 (or the appropriate channel in your area). That way you can test each device separately.

[Neo]

Hey, it works!




Nah, just kidding ^_^. I actually use one of those RF switchboxes, and I know it�s not broken �cause it works perfectly wiht my NES. Also, I got none of that mentioned switch on the back of the machine (is it on the inside?), but as stated before, a modulator in the AV port should do the trick what-so-ever.

Um, I guess it�s time to give up on this thing sometime soon.. HOW in the world do the machine put out an untranslatable AV signal that the modulator won�t make any sense out of? And WHY do the original RF signal behave in the exact same way? Oh well, guess I got my hands on a very special little machine with lots of personality ^_^;.

Any more solutions to try out Chu? I thank thee for your help anyway =).

[Chuplayer]

Well, since the very same RF switch works on the NES, trying a "video switch" or whatever it was called would be useless because it wouldn't be getting any signal anyway.

Still, it doesn't seem like you found the switch I'm talking about. As for the switch on the SNES itself, it's on the back of the system, and it's located just between the power input and the RF out. That's where it is on my American version 1 SNES from 1993. For the modulator, well, the switch should be somewhere on it. I can't tell you exactly because I can't find it right now to look at it, but if you find the switch on the SNES, you should be able find a similar one on the modulator yourself because then you'll know what to look for.

Don't give up until you find the switch and play around with it to see what works.

[Tom61]

HOW in the world do the machine put out an untranslatable AV signal that the modulator won�t make any sense out of?

More likely it isn't outputing the +5V the RF modulator needs, the modulator uses power from the console to convert the A/V to RF. Maybe something is wrong with the +5v, and the internal RF modulator uses 5 Volts too. Put an voltmeter to pin 10 (should be +5V) and pin 5 or 6 (ground) and see what it says.

The 5 Volts output may be low, as I think you'd notice other problems if it was gone completely.

[Neo]

First to Chu:

Heh, I really don�t have the switches you want me to have ^_^;. I know there�s a switch on my old NES, but in the place where I should find one on the SNES is only the mod swith. Maybe the modifier used the old hole, but when I opened the machine a couple of weeks ago I didn�t see any spare switch laying inside anywhere (as far as my memory go anyway).

The modultor may be a little different from yours then, �cause there�s only the A/V plug and nothing else on it (nothing on the inside either). However, it IS an original Nintendo modulator, just not with a switchbox. It looks like a small "convertor" box.

Um, the video switch thing you mentioned above, what�s it about?


Second to Tom:

Well, I guess it�s worth checking out (when I get hold of a voltmeter). If the power should indeed be too low, what should I do next to fix it?


Thanks guys for still trying to help me out =)

[Chuplayer]

Well, if you don't have it, you don't have it. No need to get a video switch. It won't do you any good. Get the +5v tested. See if that's the problem.

[Tom61]

Well, I guess it�s worth checking out (when I get hold of a voltmeter). If the power should indeed be too low, what should I do next to fix it?

Check out the power supply sub board, get a schematic for it and fix away, if the voltage is low there. Otherwise trace down 5 volts until you find where it drops suddenly, and fix that part.

Personally I probably would've bought another SNES by now and just dedicated the other to A/V use.

[Guest]

I don't know if this relates to the topic, but.. I noticed that in my 50/60 Hz and lang. -modded Megadrive the RF modulator can't handle 60Hz output. If the 60Hz setting is used, the RF output is black and white. My machine is euro -pal. And besides, why you wan't to use RF? - It's bad.

[dum dum]

no its not related to the topic
its well published that a megadrive 50/60hz mod will produce a broken AV signal when switched to its un original frame rate, this is why sites telling you how to do this say you need an rgb cable to play in colour.

there is a work around to get colour for a megadrive 1, and some models of megadrive 2 that use the standard sony rgb to cvid chip... all the pal megadrive2s i have opened use a clone chip and it doesnt seem to work??

[gaz]

first of all let me clear this first bit up -  there is no i repeat NO chan 3/4 switch on a PAL SNES, modified or not modified. as far as i am aware it only appears on the US NTSC SNES.

i have to say i agree with tom61 avout voltage checking the pins on either the voltage regulator ( that little sticky-uppy chip that's screwed onto the heat sheilding of the SNES) or on the graphics processor. these are the bits that are by-passed to each other to make the 50/60hz mod work, so u can identify them easily because wires will be connecting them...

hope this works 4 u  

[Neo]

Hmm, I�ve finally gotten my butt out of the sofa to try and fix this little machine. Err, I haven�t got much routine with hardware mending, so let�s straight some things out, ok?


"Put an voltmeter to pin 10 (should be +5V) and pin 5 or 6 (ground) and see what it says"

Since I haven�t yet opened the machine more than removed the top, are these perhaps pins on the voltage regulator?

"on the graphics processor. these are the bits that are by-passed to each other to make the 50/60hz mod work, so u can identify them easily because wires will be connecting them..."

Meaning I should put a volt meter between pin 24 and ground, and pin 30 and ground (according to the rough schematic in the 50/60hz mod page on Gamesx.com), right?


Last, anyone got a good SNES schematic?

/Jon

[Neo]

Uh, one more thing ^_^;..

"Some of the latest releases may not be happy running this way, you may want to install a switch to route this pin to either +5 or Ground"

(Us/Eur Snes Mod page on Gamesx.com)


Could this have to do with anything? I suppose +5 means +5 volts and according to the statement one should do something about either that point or ground.

[gaz]

yeh,your best bet is to take a look at that snes 50/60 hz mod page, take your console apart and use the diagrams to identify the bits - your graphics processors (there are two of them) and your voltage regulator. now if this mod has already been done on your machine then there will be 4 wires coming from your switch - two form the middle connector, and one from each of the other connectors. the two from the middle wires will go to pin 30 on one graphics processor (s-ppu2 b on a pal snes) and the other one to pin24 of the other (s-ppu1). there may be lots of tape all over the place left by the person that modded it so i don't recommend fiddling with it as you may break the connection. the other two wires from your switch should go to ground via a resistor on the output of the voltage regulator. the output part sends 5v to the two graphics processors in 50hz mode, where the ground outputs 0v (it simply grounds them), to them to give an ntsc signal in 60hz mode. now what i would do first if i were you is first check the wires are firmly connected to the switch and the voltage regulator, and that the voltage regulator is firmly connected to the pcb - it could be that something has come loose as the mods can be delicate, this would either give you a scrambled picture or no picture. the other possibility is that the a/v ouput itself is knackered. get a voltmeter and poke around with it a bit, or take it to a tv repair shop and see if they'll do it... if u want to give me your email i can send u a txt file  and some jpegs explaining the mod quite comprehensively...

[Neo]

Mm, most of it makes sense I guess..

If I�m about to fiddle with a voltmeter by myself, is there any risk I�ll break anything by connecting something wrong? I guess I could take the machine to a TV repairer, but if not needed I�d rather do the fiddling myself.

E-mail: drejgon@hotmail.com

[gaz]

as i don't want to assume any responsibility if you fry your console - the short answer is yes, you can damage your system. however if the negative end of your voltmeter (normally the black end) is properly earthed (i.e. connected to a part on the pcb such as where the heat sheilding screws on, or the metal ring around the hole where the screws that bolt the console together go through the pcb) then you're free to podge around on any other bits you want to test with the positive (red) end...remember don't blame me if the console turns into a mini-firework...

[gaz]

a couple of things - first of all try what tom61 said: your voltmeter on pins 10,5 and 6 on the r/f output (underside of the console, under where the a/v box is) and see if u get 5v and 0v respectively.
or- you could just try an rgb scart cable and see if that works. if u can't get a snes one get a gamecube or n64 one and remove the capacitors in the scart end, as these give a fading picture. i wouldn't recommend getting an official nintendo one as they're really expensive - a third party one should be about half the price if not less.

[Neo]

Well, as stated in previous posts, a scart cable from the A/V port works just fine, but I need to use the machine on a TV that doesn�t have a scart connection..

[Neo]

These are the results:

Pin 10: ~ 10V
Pin 5 and 6 = 0V


One of the pins on the regulator (IGO) also gave me 25V, but is this really correct?

One more thing, when trying pin 11 and 12, the voltaged decreased until almost hitting 0V. Then it wouldn�t rise, but it�s not like anything�s broken, since the voltage drop only decreased while testing and not between the seances.. Condensator perhaps?

I was supposed to test 10 + ground, 5 + ground and 6 + ground, right? Or was it 10 + 5 and 10 + 6? Does it matter? Um, is the heat shielding good for ground?

Uh, hehe, guess I got a lot of questions there... maybe I got none of the test rounds right, but that�s why YOU guys are here to help me, so.. ^_^;;

[Neo]

Eh, guess the previous post was kinda messy. I�ve fiddled around a little more and come to discover this:

Pin 10, Pin O (on the regulator) and one of the four pins right under the RF box all give me an exact value of 10,1V. I guess this is not a coincident and that they�re somehow in contact with each other or at least work with the same source of volts.

Could this be the voltage problem then? If so, then I got way too much volt instead of the opposite. I checked the resistor and it said 2,2kOhm (like it should), so the problem can�t be there..

[gaz]

to be honest i'm out of ideas - i think i got the wrong end of the stick: i thought you were getting no picture at all... the only thing i can think of is that as you're not getting a signal to the composite pin (9) on your a/v out or a signal to your r/f box then whatever's supposed to be outputting the signal isn't doing it's job, the r/f box is more than likely o/k (this may have crossed your mind!!). and i'm not sure which component supplies the signal as the circuitry on the board is largely laquered over. just give all the components a damn good visual check and see if any pins have worked their way loose, then give everything a prodding with the volt meter. also, have a look at the 'n64 a/v pinouts' section on the gamesx home page - this may give u an idea...keep us informed on any results, i'll try to help!