Question about main LED and F1 resistor

semicolo · Post by **semicolo** » Thu Aug 18, 2005 12:05 pm

maybe I should give it a try on documenting this thing, I remember someone on the french boards saying the color codes could apply to fuses.

LyingWake · Post by **LyingWake** » Thu Aug 18, 2005 4:02 pm

So I'm kinda confused? What should I grab then, something like 4.7 ohms? Obvously you are more experianced about them than I am, so some recommendation would be great.

mikozero · Post by **mikozero** » Thu Aug 18, 2005 5:57 pm

another problem with using a resistor is that in one way it's exactly the same using a piece of wire in that it won't blow again, so if the same controller fault happens again (fishing controllers and steering wheels are the big culprits) the circuitry of your DC 'further in' won't be protected from damage as they would be (and are supposed to be) with a normal 'blowable' F1.

semicolo wrote:maybe I should give it a try on documenting this thing, I remember someone on the french boards saying the color codes could apply to fuses.

seeing as it's the single most common fault with Dreamcasts, you'd be doing us all a very large favor if you could nail it.

i'm going to try e-mailing SEGA i think (you never know)
i just have to formulate the letter in my head first...

LyingWake · Post by **LyingWake** » Thu Aug 18, 2005 6:47 pm

Just incase you got side tracked; before I messed with the resisitor, the LED I tried to replace wasn't shining very bright. After testing the LED on the power supply, it was bright. So I figured the problem was the resistor (since I did a cheap fix by twisting the F1 resistor) because I had read in some other old post that this person would get higher voltage once this person replaced a bad resisitor (I'm not positive which one it was, but it was a resistor by all means).

After trying to replace the resistor with a known working resistor from a different controller board, I started having problems with my video and audio output being MIA. I bought some new resistors (10k ohms [didn't pay much attention to the k when I bought them even though I understand k is short for "thousand"]), which obviously wouldn't work. Still video and audio problems.

This seems a little much just for a simple LED replacement, but I guess that's my fault for not buying the right resistors in the first place. Really, I just need to know what resistor I need to buy so that my auido and video will work like it should again.

mikozero wrote:another problem with using a resistor is that in one way it's exactly the same using a piece of wire in that it won't blow again, so if the same controller fault happens again (fishing controllers and steering wheels are the big culprits) the circuitry of your DC 'further in' won't be protected from damage as they would be (and are supposed to be) with a normal 'blowable' F1.

Are you suggesting that I should just use wire to connect the two points for the F1 resistor? If yes, what are the consequences that I might run into, and what are the chances I would run into them.

mikozero · Post by **mikozero** » Thu Aug 18, 2005 7:16 pm

no, that would be . . . . . . . bad

if you twisted the resistor before like you said you may have damaged your DC 'further in' like i mentioned.

if you've had a controller fault (do you have a fishing controllers or steering wheel ? third party controllers ?) there would be nothing to blow because you twisted the wires together effectively removing the component from the current path so any overcurrent/surge would be able to pass straight down the line and into the DCs motherboard or whatever.

twisting not a good idea (for the same reason a bit wire isn't), i know some people on the forums suggest it but that component is ment to blow for a protective reason. what you do when you twist it is like using a nail for a fuse in a household appliance it'll work but its not safe or a good idea.

if i understand what you say you've done you might have permanently damaged your Dreamcast.

LyingWake · Post by **LyingWake** » Thu Aug 18, 2005 7:25 pm

I've had the resistor like that for at least a year with absolutely no problems until I removed it. I do have a keyboard and a mouse, which I used once in awhile. I do not have any third party peripherals.

All I'm looking for is what type of resistor I need to purchase that would act like the original one.

mikozero · Post by **mikozero** » Thu Aug 18, 2005 7:42 pm

well thats the thing, no one seems to actually know

like i said before i don't think it is a resistor, resistors don't normally burn out like a fuse (F for fuse ?) there's a component called a fuse-resistor which is a cross between both (but i'm like a lone preacher trying to tell people that) the component markings don't generally help because they don't fit the norms and i'm sure from what i've red that the component is different in NTSC and PAL machines. i'm really sorry i can't help you more, i'd love to know the answer myself because i currently have a DC that has the same fault (i have a spare though) and would like very much to get it fixed properly.
sorry

LyingWake · Post by **LyingWake** » Thu Aug 18, 2005 8:08 pm

If you get any information from SEGA let me know. I may even end up e-mailing them as well.

semicolo · Post by **semicolo** » Fri Aug 19, 2005 11:53 am

if it is a fuse resistor, designed to blow if overpowered it value should 50 times its original when blown, could someone measure the resistance of a blown f1 ?

semicolo · Post by **semicolo** » Fri Aug 19, 2005 11:56 am

trouble is the marking of those fusing resistors seems to differ from a constructors to another.

Alexvrb · Post by **Alexvrb** » Sat Aug 20, 2005 11:57 pm

Yeah. If you can't find a perfect replacement, I'd think a simple fuse would be better than a resistor or nothing at all, yes? But what amperage?

dcmodder · Post by **dcmodder** » Sun Aug 21, 2005 12:00 am

well the whole nothing at all was the problem. if you did somthing that would normally just blow the f1, on a dreamcast that didnt have an f1 installed the whole dreamcast would be screwed rather than just that f1 resistor. i'll admit it's a pain in the butt when it blows but replacing one component when you blow it is much better than replacing the entire dreamcast.

LyingWake · Post by **LyingWake** » Sun Aug 21, 2005 1:05 am

dcmodder wrote:if you did somthing that would normally just blow the f1, on a dreamcast that didnt have an f1 installed the whole dreamcast would be screwed rather than just that f1 resistor.

I'm not sure if I'm following what you're saying.

Alexvrb, I remember hearing something about "1 amp" but this was before I knew much about anything. I thought it was something to do with a "1 amp resistor", but from my limited knowledge of resistors now, I don't think there's a such thing. So maybe that's for the "fuse"?

mikozero · Post by **mikozero** » Sun Aug 21, 2005 1:35 am

replacing the f1 with a normal resistor (which won't 'blow' under fault conditions) is (imo) just as bad...

if we could identify the component correctly there is a chance we could replace it with a miniature circuit breaker which could be reset if a controller fault occured rather than having to be replaced, it would be an outstanding mod for the console because as i said this is one of, if not the, most common fault that occurs in DCs.

Alexvrb · Post by **Alexvrb** » Thu Aug 25, 2005 1:13 am

dcmodder wrote:well the whole nothing at all was the problem. if you did somthing that would normally just blow the f1, on a dreamcast that didnt have an f1 installed the whole dreamcast would be screwed rather than just that f1 resistor. i'll admit it's a pain in the butt when it blows but replacing one component when you blow it is much better than replacing the entire dreamcast.

A fuse would be better than using EITHER a resistor OR nothing at all, because the fuse will blow.

LyingWake wrote:Alexvrb, I remember hearing something about "1 amp" but this was before I knew much about anything. I thought it was something to do with a "1 amp resistor", but from my limited knowledge of resistors now, I don't think there's a such thing. So maybe that's for the "fuse"?

Fuses are designed to blow at a specific amperage, yes. But 1 amp seems a bit high for this application, which is why I was asking for a good amperage replacement, what current would the F1 blow at? If it was really 1 amp, I could pretty easily put in an automotive fuse and an in-line fuseholder. SFE or AGC design.

mikozero wrote:if we could identify the component correctly there is a chance we could replace it with a miniature circuit breaker which could be reset if a controller fault occured rather than having to be replaced, it would be an outstanding mod for the console because as i said this is one of, if not the, most common fault that occurs in DCs.

Most breakers I see are higher amperage. Do they make them as low as say, .5 amp?

mikozero · Post by **mikozero** » Thu Aug 25, 2005 2:07 am

kind of thing i mean -

http://www.allelectronics.com/cgi-bin/c ... type=store

semicolo · Post by **semicolo** » Thu Aug 25, 2005 11:11 am

Seems good to me, and it's cheap too.

LyingWake · Post by **LyingWake** » Fri Aug 26, 2005 5:34 pm

Well, after replacing it with a new controller board that hasn't been touch modding-wise, the DC still doesn't want to give me audio or video. So I tried replacing the power supply, still nothing. Then the GD-ROM drive, again, nothing.

So I figured I was done. I tried using a different mother board, and there it went. I worked. Apparently the mother board went bad, but how, I'm not sure. It happened after I removed the original F1 resistor and tried replacing it with a new one (trying to get more voltage for my main LED mod).

Anyways, it's fixed now but I don't think it's worth trying to replace the main LED again.

LyingWake · Post by **LyingWake** » Sat Aug 27, 2005 5:34 pm

Actually, now it makes me think. The fixed DC wasn't working when I just tried to turned it on. I started to get the the same feeling as when the other DC wouldn't show any audio or video, and it's not a good one.

I took my modem out with the modem LED mod done and it works. When I plug it in, it doesn't. Weird, it was just working fine before with it in, now it doesn't wanna work. The wires are probably touching each other or one wire touching two pins. I'll take a look at it later and see what the problem really is.

I can bet that was the same problem as before, I just didn't think of taking the modem out.

Alexvrb · Post by **Alexvrb** » Sun Aug 28, 2005 3:50 pm

Yeah, you're gonna have to tear the modem apart.

miko: 2 seconds after following that link I found this: "Since this is a thermal device relying on heat generated by an overload condition, response time is inverse to the degree of overload." So to me it has diminished usefulness. Most breakers probably work like this, in hindsight. I never really had a reason to think about it. Either way, I think I'd rather have a fast blow fuse.