Question

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opac
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Question

Post by opac » Mon Jan 03, 2005 10:51 am

hope this is a place where i can ask questions like this.
i have a problem,
i bought a used gameboy to give to someone, started playing with it. the bateries ran out so i tried connecting an ac/dc adapter that can change voltage to it. the pin was too big to plug into the normal spot on the gameboy so i used wires and connected the adapter to the place where batries would be put in. i set it to 3V but didnt seem to work. the next slot was 4.5V, switched it to that.... obviously i have burnt something(can smell it). i tried putting new bateries and didnt work.
a while back i kinda did the same thing to my graphing calculator.<p>are they repairable? i havent been able to open either because of the screw types so need to go and screwdrivers from some store. if this is repairable could you instruct me on how or where i could find this type of information please? the gameboy was for a poor kid back in my home land srilanka. please help me or give me some advice.<p>Thanx
Ryan

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Chris Smith
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Re: Question

Post by Chris Smith » Mon Jan 03, 2005 11:48 am

It can be fixed most likely, but I don’t think you have the skills necessary to even look. What is burnt out is most likely a Zener diode, and the fact that your not even set up to pull the unit apart I think says "your not prepared” and you don’t have the tools or skills necessary? <p>I could be wrong? <p>I would not proceed any further, as You could destroy the unit all together. Find a hobbyist that has done these sorts of things before?

opac
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Re: Question

Post by opac » Mon Jan 03, 2005 12:27 pm

i have fixed an answering machine and vcr before but they didnt involve diodes... im interested in opening it out and fixing it myself. im in first year computer engineerig and will eventuall start learning about circuits and stuff. could u tell me how it can be fixed or where to find information on this type of thing? and how difficult it might be? i like to fix things...

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philba
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Re: Question

Post by philba » Mon Jan 03, 2005 12:45 pm

I think it might be worse than just a diode. IIRC, in at least 2 of the models, there is nothing preventing reverse polarity at the battery connectors (other than the difficulty of inserting batteries backwards). So, it could be bad news for the processor. <p>At this point, how much money do you have in it? It may just be the price of a learning exercise.<p>By the way, these devices are kind of cool to hack. Lots of development tools for them and the older ones are dirt cheap. Here's an interesting site though it doesn't cover the latest 2 models.<p>http://www.semis.demon.co.uk/Gameboy/Gbmain.htm<p>ed: here's another, even better link but no GB Advance. http://www.rawer.de/marc/Gameboy/Docs/GBProject.pdf<p>[ January 03, 2005: Message edited by: philba ]</p>

opac
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Re: Question

Post by opac » Mon Jan 03, 2005 1:03 pm

paid $30 canadian for gameboy color +2games.
i checked out the sites, i have learned about the different types of gates and stuff but those diagrams seem a little complicated for me. would u be able to explain how it could be fixed or what needs to be replaced(and how it looks like)?

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philba
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Re: Question

Post by philba » Mon Jan 03, 2005 1:33 pm

sorry, can't help you there.<p>Phil

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Chris Smith
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Re: Question

Post by Chris Smith » Mon Jan 03, 2005 1:50 pm

Start after getting it open, at the point where the wires meet the board. Look for the first componment, and see if its fried, and you may need to undsolder it to find out if its blown.<p> The diode, or Zener, is usuall a very small device looking like a resistor, but black [usually] with no color bands. <p>Then if this fails, trace it to the next component, and so on? <p>Look for smoked parts, bad caps [poof], etc.<p> Its more of a visual and common sense approach to it than Me telling you what is bad. <p>At least it will be a lesson for you that we all have been to. <p>Smoked em, been there, done that....

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Re: Question

Post by Deal » Mon Jan 03, 2005 4:03 pm

Hi Opac, I played it back to where you got stupid with your 'batries' and started wishing that the 4.5 volt setting got sent into 'you' brainwaves, and you emerged a voltaged brainiac not capable of proper insertion to where the gods of stupidity were notified and electrons visited your ability to procreate or further pollute intelligent life-streams.

opac
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Re: Question

Post by opac » Mon Jan 03, 2005 4:15 pm

lol, ur a funny guy!

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Re: Question

Post by terri » Mon Jan 03, 2005 10:00 pm

In the back of my storage locker I have a smoke pump and injection chamber which might help. You put the fried device in the chamber and start up the smoke pump and force the smoke back into the component. This usually fixes it.<p>(Yeah, yeah, I know, all you old-timers have heard that one before.)<p>Opac, I feel for you. We've all screwed up like that. I'll screw up again, and so will you. Empathy and sympathy to you.
terri wd0edw

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Re: Question

Post by paulrevelcet » Tue Jan 04, 2005 12:20 pm

First have a look at this gameboy<p>Then this gameboy<p>Maybe this will help you in finding your trouble, if you cant read the schematics then this would be a great time to learn how.

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MrAl
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Re: Question

Post by MrAl » Tue Jan 04, 2005 1:48 pm

Hi there,<p>opac:<p>You may have gotten lucky. By the looks of
that schematic, and if it's the same one you
have in your Gameboy then the only problem could
be that 100uf capacitor. Most likely you connected
the power supply up backwards and blew that cap.
Replacing it alone could solve the problem,
but i would only use batteries after this.<p>Now, do you know how to solder? If not you're
going to have to find someone who can solder a
new cap in there for you to try this out.<p>You're lucky because even with reverse polarity
on the input connector the transformer in there
isolates the main circuitry from the input voltage,
so most likely everything aside from the input
part is still working just fine.<p>Hope this helps!<p>Take care,
Al
LEDs vs Bulbs, LEDs are winning.

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Chris Smith
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Re: Question

Post by Chris Smith » Tue Jan 04, 2005 6:11 pm

I also see a power Reset?

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Edd
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Re: Question

Post by Edd » Wed Jan 05, 2005 12:06 am

A few observations:
This is the problem area associated with the power supply unit:
http://www.devrs.com/gb/files/gameboy3.gif
If this is indeed your units circuitry, the main operational circuitry is truly isolated by virtue of the utilization of a DC/DC power supply board in its design , if it doesn’t work, power is not even created for the isolated game circuitry..Therefore ,there is a high probability of damage being restricted to just the isolated power supply components.
Since you applied power through the battery holder you averted the units built in reverse polarity protection afforded by the 2S100 series steering diode. With the other protective item being the battery /or/ AC power switch mechanically activated by the adapter plug being inserted. Also, those wall warts with their slide switch adjustment between 5 or so levels are notorious for providing an appppppreciably higher voltage than they are set for until the instant that the unit is loaded down by the circuit that they get connected to. However, the main NPN darlington switching transistor, (2SD164) has a hefty rating of 60VDC breakdown with a 1 amp current carrying spec.
Looking at the supplied 6VDC power input, it makes two routes, up to the good/weak battery circuit and its LED indicator. This circuit being of no consequence due to its high resistive isolation.
The reverse application of your voltage to the 100 ufd electrolytic (as per Sir Al) is of different degrees of severity in accordance the type of electrolytic that it is, with the tantalum family failing first with the common dry foil electrolytic type being more tolerant, it probably has a rating of 10Vdc working voltage.
So in the end, check out four things first:
• Ohm out that 6VDC power buss to ground and if low res/or/shorted, lift the 100ufd and test again, if still bad :
• Check for the possibility of break down from C-E of the 2SD164 power transistor, lift it out and test out of circuit.
• That 1 uh series power line choke filter is made with fine wire and it possibly vaporized open if the '164 crashed.
• Check throughout the power line bus foil path for a vaporized open path. <p>As per others suggestions you probably need accomplished assistance in your quest, specifically,tools,tech/test equipment and micro soldering expertise. The soldering itself will typically need a round toothhpick sized tapered tip for soldering rework and if the board gets fried/delaminated , that is BADDD.<p>I knew I had that that G.B. schematic in my archives, but was delayed in finding it, due to the fact that I had it under fish locator, as a Gameboy was altered to be the display for same. Also the same drawing is floating around at different sites, just being copied. Examining the circuit design,I notice that there is one error that is carried forward on all. This being the fact that there should be a wiring junction/union just to the right of D3. A 5VDC sample of the developed secondary voltage is fed back on a partial base biasing of the '164 and simultaneously a filtered sample is presented to the V threshold zener (D25) for overvoltage shunt regulation of the '164 base drive by the degree of conduction of 2SD1326's C-E path to ground. <p>73's de Edd
[email protected] .........(Interstellar~~~~Warp~~~Speed)
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;) ;)<p>[ April 26, 2005: Message edited by: Edd Whatley ]</p>

opac
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Re: Question

Post by opac » Sat Jan 22, 2005 11:53 am

i finally was able to open up the gameboy. the screwes were tri-something(dont kno what they are called) but used one of the small philips screwdriver and pliers to turn it(tight). any ways, something appears to be burnt/exploded and says D2 next to it. dont kno what else could be wrong. i scaned the circuit board and sent it to a gmail account i just created.
is it possible for someone to take a quick look at it please?<p>gmail.com
username:gbhelp
password:helphelp

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