Where to measure resistence?
Posted: Sun Feb 07, 2016 5:47 pm
My dreamcast laser is taking increasingly multiple attempts to read discs, so I opened it up for the first time to adjust the pot, but I haven't actually done it yet. At most I just took some compressed air and sprayed out the years of dust.
I didn't really know much about the insides of the dreamcast so I've read a bunch of tutorials and watched a bunch of videos on how to adjust the pot to increase the laser strength, so I know where to do the actual adjusting.
The trouble I have is I don't know where to measure the resistance. It's something that gets recommended a lot, but all the tutorials I've seen never show it being done and skip straight to adjusting.
From looking at this video, I understand that there are three points for a pot.
https://www.youtube.com/watch?v=9Bsg6ITWHk8
Though when I look at mine, I don't see nice prongs that I can clip on to like that video.
I only have a passing knowledge of electronics so I guess this is something that should be obvious to anyone who knows anything about electronics, because otherwise I probably would have already found how to do this by now.
From the screw, I see it attached to a small ribbon which leads to three points. I'm guessing these are the probe points.
https://imgur.com/a/OvPgX
(There's also my model info label if that helps)
From what the video says, I tried sticking the leads on the outer studs just to get a max resistance, but I'm having a hard time keeping a steady hand and getting a consistent measurement. The things are the size of pinheads and there's nothing on which to rest the leads without touching something else. If can't reliably measure the outer two, I don't think I'll be able to get to the middle one.
Also when I switch the order of the probes, the measurement changes. I get either 0.8 MOhms or 0.5 MOhms (I forget now if it was K or M). That doesn't sound right when I've seen this post saying the measurements can go up to 1.6 KOhms.
http://segahub.org/index.php?topic=547.0
It doesn't help that it the studs are unlabeled (unless it doesn't matter and all I need is to measure the middle and either of the outers, regardless of polarity)
So I have the following questions:
1) Where do I measure the resistance? Even more specifically, where exactly do I put the positive and negative probes? (drawing on the pictures I provided would be helpful)
2) If the probe points are what I think they are, any tips on how to easily get a consistent and steady measurement?
3) Out of curiosity, what tends to be the starting resistance on most DCs? This could help me know if I'm probing the correct spots.
I didn't really know much about the insides of the dreamcast so I've read a bunch of tutorials and watched a bunch of videos on how to adjust the pot to increase the laser strength, so I know where to do the actual adjusting.
The trouble I have is I don't know where to measure the resistance. It's something that gets recommended a lot, but all the tutorials I've seen never show it being done and skip straight to adjusting.
From looking at this video, I understand that there are three points for a pot.
https://www.youtube.com/watch?v=9Bsg6ITWHk8
Though when I look at mine, I don't see nice prongs that I can clip on to like that video.
I only have a passing knowledge of electronics so I guess this is something that should be obvious to anyone who knows anything about electronics, because otherwise I probably would have already found how to do this by now.
From the screw, I see it attached to a small ribbon which leads to three points. I'm guessing these are the probe points.
https://imgur.com/a/OvPgX
(There's also my model info label if that helps)
From what the video says, I tried sticking the leads on the outer studs just to get a max resistance, but I'm having a hard time keeping a steady hand and getting a consistent measurement. The things are the size of pinheads and there's nothing on which to rest the leads without touching something else. If can't reliably measure the outer two, I don't think I'll be able to get to the middle one.
Also when I switch the order of the probes, the measurement changes. I get either 0.8 MOhms or 0.5 MOhms (I forget now if it was K or M). That doesn't sound right when I've seen this post saying the measurements can go up to 1.6 KOhms.
http://segahub.org/index.php?topic=547.0
It doesn't help that it the studs are unlabeled (unless it doesn't matter and all I need is to measure the middle and either of the outers, regardless of polarity)
So I have the following questions:
1) Where do I measure the resistance? Even more specifically, where exactly do I put the positive and negative probes? (drawing on the pictures I provided would be helpful)
2) If the probe points are what I think they are, any tips on how to easily get a consistent and steady measurement?
3) Out of curiosity, what tends to be the starting resistance on most DCs? This could help me know if I'm probing the correct spots.