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I posted this on the "Help" forum, but figured it would get a wider audience on here, so here's my problem:
I decided to get out my old Dreamcast the other day, only to discover that my controllers (and my gun) will not respond. I've tried plugging them into all 4 ports, but nothing happens. Has anyone else run into this problem? is there some kind of lock I inadvertently enabled? Any help would be much appreciated! Thanks!
This should be in the hardware forum. Moved.
Go Here. Your F1 resistor is blown, it's a common problem and easy to fix.
If you dont have a soldering iron, then just wrap some wire around the legs of the blown resistor and it'll work perfectly. If you need more help just ask.
f1 is a fuse...
True. It is a fuse, sorry :)
Thanks!
I replaced the resistor (with a 10 ohm, 1/2 watt resistor, 5% tolerance), but now only ports 1 and 4 will work, and my light gun won't work in any port lol. Any idea what the problem is now? Thanks!
yes you used a resistor in place of a fuse.
a fuse is about 0 ohms so there's no voltage drop across it
but a 10 ohms resistor would drop the 3.3V to 2.3V at a current rate of 100mA (U=RI :o)
In fact the more current your peripherals try to drain the less voltage they get and your light gun is probably too current consuming to get a proper operating voltage.
Ok, so what do I need to do? I don't understand the electric lingo. Sorry :o
you should use a fuse, problem is, nobody knows what sort of.
some just jumped f1, but it may be risky since it can blow the dremcast's psu in case of short circuit.
hm, alright. Thanks for the help.
A fuse is a resistor with a 'breaking point'. If fuses didnt have resistances then why are there mains fuses rated 3A/13A, that's the current they allow through, beyond that they 'blow'. Nearly all fuses have a resistance.Quote:
a fuse is about 0 ohms so there's no voltage drop across it
Get a multimeter and check the resistance of F1 semicolo, what?! look at that it's... it's... TEN OHMS!! omg! how could this have happened?! :p
How would that cause a short circuit? there is still a device between the +ve and ground ie. the controller. That fuse is not a diode; it would not stop a short circuit.Quote:
some just jumped f1, but it may be risky since it can blow the dremcast's psu in case of short circuit.
aluckypunk, i suggest just jumping the fuse, solder a wire between the two points where it used to be. If your DC blows up, you can blame me :p
Yes a fuse has a resistance but very low, that's why i used the words "about 0" for the fuse resistance.
I remembered checking f1 and it was 0 ohms, I'll check again just to be sure (no need to be sarcastic :-)
And I meant that a bad controller could short the psu in case of jumping f1 (sorry for my english)
Sorry, just my sense of humour :)
The F1 fuse has a resistance of 10 ohms, of that i'm sure.
Jumping the connection IMO wouldnt be dangerous at all, how likely is a faulty controller? and even if there was, there are many more resistors that would blow before the PSU, like in the main board.
Well my dear ptr check again because I checked my 2 dreamcasts and ...
OH MY GOD 0.3 ohms !!! HOW COULD THIS HAPPEN :D
I LOVE when I'm right.
(in fact my ohmmeter showed 1.2 ohms for f1 and it shows 0.9 ohms when touching the probes, why don't have I the same lab material as the university's, sigh sigh)
???
Let me check.
lol.
You are indeed right.
I deserved the obnoxious response.
I checked my 4 DC's and found all F1 fuses to be near to 0.3 ohms accounting for error (0.4 ohms).
The truth is i never bothered checking in the first place just remembered at DevCast it said it was 10 ohms, me being lazy and not checking just meant i repeated what they said in a sarcastic manner.
This has been embarressing, and so this topic will now be promptly deleted, j/k :p
errare humanum est
But really did you think of the voltage drop you would get if using a 10 ohms resistor ?
At 5 V, 100 miliamp you would only get 4V for the peripherals
and 3V at 200 miliamps ! that can't be, if you use 4 controllers with vibration packs, it certainly drains more than that, and controllers wouldn't work at 3V
I'll try to search fusing resistor datasheets, maybe some of them will make sense with the color codes we have.
Just twist the thing so the bottom prongs of the fuse touch. Easier than trying to sodder in a replacement wire or resistor.
Easier but messy, if i had the problem i would desolder it and then make a solder bridge, nice clean connection and no wire needed.
yeah but what would protect the psu or the motherboard traces if you've got a faulty controller ?
semicolo, i seriously doubt that's any danger.
How likely is it that a controller has a direct short?
Anyway, the DC is pretty resiliant, ive shorted the PSU directly a couple of times before whilst building my MF DC, perhaps i should of been more careful :p the point is the psu and mobo were fine, nothing blew. btw, i shorted the +5v line via a dodgy internal VGA circuit that i should of checked first.
well if f1 burned, there was something wrong, it's here to protect something from too high loads, if the psu is strong, that could be the pcb traces that won't like to have several amps through them.
But it can also work a long time who knows.
On the french board someone provided these colour codes :
orange white silver silver green
this page gives informations on fusing resistors : http://www.koaproducts.com/english/c...147-RF25_C.htm
those fusing resistors use a blue coating and a green color band for identification, this would give us
39 * 0.01 10% = 0,39ohms 1/4W
It can handle up to 800mA without blowing and more for short time, voltage drop at 0.8A = 0.3V so the 5V would read 4.7V for the controllers, which should be ok
If your colour codes are different then post them, it could help determining what type of fuse we could use in place of f1.
ideally you would measure the resistor's value with an ohmmeter too, just to be sure it's very low (below 1ohm)
I had that problem once with my DC. I just brought a broken DC from ebay and replaced the controller board =PQuote:
Originally Posted by aluckypunk
My two dreamcast have the same 0.39ohms resistors (orange white silver silver green).
I was wondering before i do this could it blow is a person broke his connection and plug the broke controller port in stupidly yes the person is me *puts his head down in shame*
You really can't go wrong, as long as you take your time and check what you do it will fix your DC perfectly.Quote:
Originally Posted by gavis2989
Thnks