Author Topic: GT/Express replacement volume wheel  (Read 147 times)

Astral

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GT/Express replacement volume wheel
« on: March 25, 2022, 09:31:02 PM »
The volume wheel on my GT was cactus. Based on what I read in a few places a GameBoy Colour wheel would do the job. I replaced it (brand new). The volume goes all the way up but doesn't completely cancel when turning down. This says to me the resistance is too low. Apparentely the GBC wheel is 10k.

In comparing resistances across matching pins between the unit I repaired and another unit I have, the readings don't match. This is with all kinds of pin testing combos.

I have searched and tested and googled and getting over it trying to work out what wheel to try next.

Does anyone know the specs of the volume wheel needed?

(Interestingly - based on findings a very small audio section schematic it looks like the GT/Express only has mono out to the speaker and headphones - and therefore likely only 3 of the 5 pins on the volume wheel are used (in, out, & GND).

Is there a known source for a replacement GT/Express volume wheel that is known to work fine (and without modification - eg apparentely a Game Gear wheel works but no way this'd work without enlarging the shell opening)?
« Last Edit: March 25, 2022, 09:47:27 PM by Astral »

Keith Courage

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Re: GT/Express replacement volume wheel
« Reply #1 on: March 26, 2022, 10:33:55 PM »
I don't have the exact specs but a game gear dial works for it as well. There are also some sony Discmans I have used volume dials from as replacements.

For either option, game gear or discman, you have to slightly file out the opening on the express to make things fit nicely. Maybe you can look up the specs for a game gear dial and then find one that's smaller to fit an express?

tawy

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Re: GT/Express replacement volume wheel
« Reply #2 on: March 27, 2022, 03:57:40 AM »
Donít file your gt.
10k pot will work fine.
https://a.aliexpress.com/_uuo25Q

Astral

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Re: GT/Express replacement volume wheel
« Reply #3 on: March 28, 2022, 04:23:53 AM »
Yes I would rather not file my GT.

Tawy have you actually used one of those and it worked fine?

I ask because that's exactly what I have already replaced the faulty one with - a brand new 10k GameBoy Colour wheel.

tawy

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Re: GT/Express replacement volume wheel
« Reply #4 on: March 31, 2022, 03:19:27 AM »
try to add a 10k resistor on a end of the pot to check if 20k totally mute the sound.
when you removed the old one it said 203 or 103 inside?

Astral

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Re: GT/Express replacement volume wheel
« Reply #5 on: April 11, 2022, 05:41:07 PM »
The dial was too far gone to see any markings.

Have you actually fitted what you recommend and had it working fine? I appreciate people offering advice but so wary of people offering advice that they have read or theorised on and so on and not actually confimed to be true. Such as the Game Gear wheel recommendation.

I have considered adding enough resistance to be able to lower the volume to "off" but consider that this will also limit the top end volume. Ultimately the solution needs to have the range of no resistance<->full resistance.

Keith Courage

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Re: GT/Express replacement volume wheel
« Reply #6 on: April 11, 2022, 09:44:11 PM »
The gamegear dial does work as I have used one before. So I can confirm it. Volume dials from Sony discmans also work. Specifically the ones that have lenses that are compatible with Turbo/pce CD drives. I just don't know the specs of either option in order to help you find a different dial solution that doesn't require some filing of the case to make the dial fit nicely.

DUO headphone dials do Not work as the pin order is different even though they both use 5 pins.
« Last Edit: April 11, 2022, 09:50:11 PM by Keith Courage »

tawy

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Re: GT/Express replacement volume wheel
« Reply #7 on: April 12, 2022, 03:52:32 PM »
that kind of wheel potentiometer always works the same.
you can find 3 pins or 5 pins wheel potentiometer, on 5pin, it is a dual potentiometer.
https://aliexpress.com/item/1005001483428067.html
the Game Gear pot is actually a 10k 5pin pot
https://console5.com/wiki/File:Game_Gear_VA0_Schematic_-_Sound.png
the one from the gbc is the same
https://console5.com/wiki/File:Nintendo_GBC_Schematic.png see VR on the audio part.

« Last Edit: April 15, 2022, 08:38:16 AM by tawy »