CGB Wont Power On. | Game Boy | Page 1

limpid axle Aug 19, 2022, 4:15 PM

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With the power switch off I read 3.076 Volts on Pin 3 and 0 on C of the power switch. When I turn the switch on I get 1.88 Volts on both 3 and C. Power switch was cleaned and fuses pass continuity tests. Also not seeing any shorts in the power switch

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upper rain Aug 19, 2022, 4:34 PM

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looks like you have some corrosion around the board

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can you take a new photo of the power switch, thats not blured?

limpid axle Aug 19, 2022, 4:35 PM

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yeh sec

tall moon Aug 19, 2022, 4:36 PM

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How did you clean your power switch? 1.8V might be too low for the CGB to power on

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If you're getting 3V on Pin 3 when it's off and then 1.8V on C when on, there's carbon build up/dirty contacts that's causing the voltage drop.

limpid axle Aug 19, 2022, 4:50 PM

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Well I think I found the issue

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tall moon Aug 19, 2022, 4:54 PM

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Yeah, that causes voltage drop too.

limpid axle Aug 19, 2022, 4:57 PM

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Well I replace it with a switch that has both legs and it hasn't changed voltage

tall moon Aug 19, 2022, 4:59 PM

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What voltage do you get on pin 1 of the DC/DC board?

limpid axle Aug 19, 2022, 5:01 PM

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the same 1.8 and the volt rail gives me basically nothing

tall moon Aug 19, 2022, 5:03 PM

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1.8V on pin 1 of DC/DC? What do you mean by the “volt rail”?

limpid axle Aug 19, 2022, 5:04 PM

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sry meant 5 volt rail

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Pin 1 gives me 1.8 same as the power switch.

tall moon Aug 19, 2022, 5:16 PM

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Voltage of the batteries are 3V?

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Do you have a power supply?

limpid axle Aug 19, 2022, 5:21 PM

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i have a usb to dc jack, energizer AA, or LADDAs. The 1.8 is on the Energizers

tall moon Aug 19, 2022, 5:24 PM

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How are you connecting the batteries to the terminals?

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Something like this?

limpid axle Aug 19, 2022, 5:26 PM

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yes

tall moon Aug 19, 2022, 5:27 PM

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What’s the voltage on the positive battery terminal when connected?

limpid axle Aug 19, 2022, 5:28 PM

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3.076

upper rain Aug 19, 2022, 5:31 PM

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and you still have 3v when it arrives to the DC?

limpid axle Aug 19, 2022, 5:32 PM

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When it is off I have 3V on pin 3 of the switch. When turned to the on position is drops to 1.8V on the 3 pin and 1.8 on the C pin. at the input pin on the DCDC board it is also 1.8V

tall moon Aug 19, 2022, 5:35 PM

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This isn’t something you should do because it bypasses the fuse, but we’re troubleshooting. What happens when you put the leads directly on the DC/DC?

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Red on pin 1 and black on pin 3 of DC/DC

upper rain Aug 19, 2022, 5:36 PM

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I dont think you should have any voltage on the DCDC if its off?

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or am i missing something?

tall moon Aug 19, 2022, 5:39 PM

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There’s something that’s causing the voltage drop to 1.8V across the switch. In this case, we’re bypassing the switch and placing the leads directly on the dc/dc to see if it’ll power on

limpid axle Aug 19, 2022, 5:43 PM

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sec ill try

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so when jumping it I get 3V on pin 1 but it doesnt power on. My thoughts are the DCDC is jacked up

little willow Aug 19, 2022, 5:46 PM

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V across the dc jack when on?

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Pin 2 to 3

tall moon Aug 19, 2022, 5:49 PM

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limpid axle so when jumping it I get 3V on pin 1 but it doesnt power on. My thoughts are the...

No 5V on Pin 7 with the leads directly on DC/DC?

limpid axle Aug 19, 2022, 5:51 PM

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basically nothing on pin 7 of the dcdc

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with the jumper

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on pin 1

tall moon Aug 19, 2022, 5:52 PM

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Yeah, the DC/DC sounds broken

upper rain Aug 19, 2022, 5:52 PM

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Do you have the old regulator?

limpid axle Aug 19, 2022, 5:53 PM

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the dcdc in the GB is the one it came with. I have a replacement for it.

upper rain Aug 19, 2022, 5:54 PM

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it came with helders regulator on there?

limpid axle Aug 19, 2022, 5:54 PM

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is that helders in the picture? because thats what it came with

upper rain Aug 19, 2022, 5:55 PM

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Oh, sorry i mixed two issues together!

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never mind me

limpid axle Aug 19, 2022, 5:55 PM

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no worries

tall moon Aug 19, 2022, 5:55 PM

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So you have a replacement?

limpid axle Aug 19, 2022, 5:56 PM

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i do

tall moon Aug 19, 2022, 5:56 PM

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Just to verify before you desolder the old one, what voltage do you get on pin 7 of the replacement ?

limpid axle Aug 19, 2022, 5:59 PM

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I bought the DCDC solo

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so its difficult to test outside of a mainboard

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i dont have much solder wick left but ill try to get the new on it ;D

limpid axle Aug 19, 2022, 6:55 PM

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got it replaced without much hassle. No boot. went from 1.8 to 2.4 on the 3 pin and c pin on the switch when its on. still nothing on the 7 pin on the dcdc

tall moon Aug 19, 2022, 7:01 PM

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Same when bypassing the switch?

limpid axle Aug 19, 2022, 7:14 PM

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yup

tall moon Aug 19, 2022, 8:34 PM

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I'm at a loss. Can you take a picture of the install and DC/DC?

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Just to confirm, you're getting 2.4V on pin 1? Nothing on Pin 7? What about pins 5 and 6?

limpid axle Aug 19, 2022, 10:41 PM

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yup one sec

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tall moon Aug 19, 2022, 11:09 PM

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Seems like that DC/DC board is broken as well

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It's receiving the input voltage but not outputting

limpid axle Aug 19, 2022, 11:11 PM

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just my luck

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lol

tall moon Aug 19, 2022, 11:12 PM

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Do you have the legs on the old DC/DC?

limpid axle Aug 19, 2022, 11:13 PM

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yes

tall moon Aug 19, 2022, 11:13 PM

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Can you attach the power supply to Pins 1 and 3 of that DC/DC and see what's outputting from Pin 7?

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If at all

limpid axle Aug 19, 2022, 11:13 PM

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yeh sec

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In more confusion news I don't think it's the dcdc board

tall moon Aug 19, 2022, 11:17 PM

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So it's outputting correctly outside of the system.

limpid axle Aug 19, 2022, 11:17 PM

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yep

tall moon Aug 19, 2022, 11:18 PM

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Can you check if any of the power rails are shorted?

limpid axle Aug 19, 2022, 11:19 PM

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shorted to ground?

tall moon Aug 19, 2022, 11:20 PM

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Yes or with each other

limpid axle Aug 19, 2022, 11:20 PM

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yeh one sec

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so no shorts to ground and no shorts across rails

tall moon Aug 19, 2022, 11:35 PM

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I'm assuming that there's a short somewhere on the board. Unfortunately, you're just going to have to probe around the power rails. Also, like polysaurus said, you have quite a bit of corrosion across the board, so I would try to clear that out as well.

limpid axle Aug 19, 2022, 11:37 PM

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ill take a look

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thanks for all the help

upper rain Aug 20, 2022, 12:05 AM

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You said something about being able to read power on the DC DC board even when it's turned off? Is that still the case?

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Because that would probably narrow down the short

limpid axle Aug 20, 2022, 1:15 PM

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I'll verify this morning

little willow Aug 20, 2022, 3:12 PM

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Did you check the dc jack? Pin 2-3. Dirty/damages jack could xause voltage drop before the DC/DC

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The pics looked like 1.8v at pin 1 of the DC. That would suggest the problem lies before that point.

tall moon Aug 20, 2022, 4:50 PM

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little willow Did you check the dc jack? Pin 2-3. Dirty/damages jack could xause voltage drop ...

Input voltage does not go through Pins 2 and 3 of the DC jack.

upper rain Aug 20, 2022, 5:32 PM

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In the pictures he is putting the power in through the battery contacts, and they go through the dc jack

little willow Aug 20, 2022, 5:33 PM

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Looked at the pics again. I see now.

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So the problem is the trace between C and pin 1 of the DC?

tall moon Aug 20, 2022, 5:54 PM

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upper rain In the pictures he is putting the power in through the battery contacts, and the...

Only the negative battery terminal goes through the DC jack. The positive battery terminal doesn't.

upper rain Aug 20, 2022, 6:00 PM

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You're right, i missed that!

little willow Aug 20, 2022, 6:11 PM

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Or corrosion under the cart connector causing the 5v rail to short.

Not wanting to speak out of turn, just trying to understand. Being in the conversation helps me fill in my knowledge gaps. If it's not appropriate, just let me know. You guys are a lot more knowledgeable, clearly.

#CGB Wont Power On.