Opened A Xbox To Find A Hitachi-lg Dvdrom, **MERGED TOPICS** Options

[LenteSubigo]

Here is what I sent to my brother-in-law, correct me if I am wrong, because he will get this in 6-8 hours when he gets to work.

Point #1 – Outputs 0 volts when it should output 5 volts. Outputs 3.3 (3.20-3.25 actual) volts when it should output 0 volts.

Point #2 – Outputs 3.3 (3.20-3.25 actual) volts when it should output 5 volts. Outputs 0 volts when it should output 0 volts (no prob here.)

5 Volt sources are available

Ground is available.



This circuit requires almost no current. The 0 volt values can be anything less than 1.5 volts, and the 5 volt values can be anything greater than 4.2 volts and still work correctly. The circuits must be very small, and very simple. The most precise circuit isn’t the most important thing, the simplest, cheapest, and smallest circuit that can output the voltage within the tolerances is the most important thing. It is also very important that all the components used are available at radio shack, as a lot of people are going to be using the circuit.

[hippo]

You should just code a 12c508 for this.

[wenid]

That's fine if you already have a PIC programmer, although still a little expensive. We can certanly do it with a quad op-amp chip, which would be cheaper and (for most people) simpler.

[ferrari_rulz_02]

well why dont we get all of the people who can do this in different ways, and come up a 'database' with different ways of doing this. i am sure there would be more then one way to do it, so why not tell the pople the different ways?

[LenteSubigo]

well why dont we get all of the people who can do this in different ways, and come up a 'database' with different ways of doing this. i am sure there would be more then one way to do it, so why not tell the pople the different ways?

I myself, think that having multiple choices will just confuse people. I think that we should find a very simple circuit that is also cheap and available at radioshack. This will make it so that we can put out 1 really nice tutorial.

[ferrari_rulz_02]

I myself, think that having multiple choices will just confuse people.  I think that we should find a very simple circuit that is also cheap and available at radioshack.  This will make it so that we can put out 1 really nice tutorial.

ok, fair enough. its just that i would like to be able to see all of the options, so that i can choose the one that suits me teh most.
but your right, many options will confuse the less technically minded of us.

[LenteSubigo]

ok, fair enough. its just that i would like to be able to see all of the options, so that i can choose the one that suits me teh most.
but your right, many options will confuse the less technically minded of us.

I don't see a problem giving out all the options, but when it comes time to putting out a tutorial we should decide on one, and not release multiple tutorials. I can just see someone mixing up 2 different circuits. So, 1 tutorial, and all the options posted on a webpage or a forum thread is prob the best idea.

[maximilian0017]

Max joining the fight

Please take a look at the following data sheets

Hef general specifications
http://www.standardproducts.philips.com/pr...df/hef4049b.pdf

Quadruple true/complementing buffer
http://www.standardproducts.philips.com/pr...df/hef4041b.pdf

This is a long time ago for me too but this should be the way to go
Just hook up and go, (if i'm not forgetting something ofcourse)
A few current limiting resistors would be all that's needed (To make sure nothing happens)


A reed relais is a simple device and the current needed isn't that high, but if that 3.3v output can't handle it it's byebye dvd drive.
And it's a logic problem so lets use digital logic to solve it


Wenid: thanks for getting the firm. image for us, great work!!

(Does someone have any experience with decompiling firmwares?, isn't that 8051 compatible?!?)

Going to the sore to get a lg drive

[wenid]

Hef general specifications
http://www.standardproducts.philips.com/pr...df/hef4049b.pdf

I don't know why this ended up actually being a link to a hex inverting buffer, but if you really did read the "Family Specifications" (which can be found at http://www.standardproducts.philips.com/su...pdf/hefspec.pdf), then you may have noticed the minimum "Input voltage HIGH" (with a 5V supply) is specified as 3.5V. This is the same problem we started with, in a sense.

Quadruple true/complementing buffer
http://www.standardproducts.philips.com/pr...df/hef4041b.pdf

Not sure why you mentioned this chip -- a hex inverter would do the trick if we had the right levels, but if we had the right levels we'd only need to invert one signal. The only problem with the other signal is the low voltage.

A few current limiting resistors would be all that's needed (To make sure nothing happens)

I still think that a 7405 (or similar -- 74L05 etc) would probably do the trick. It should see the 3.3V as a high level signal and it can provide 5V output highs. The drawback is that the high voltage outputs are made possible by open collector outputs so they ALL need to be tied high, even the ones not being used. It may be OK to tie more than one thru a single resistor, but even so it's quite a bit of extra fiddle.

A reed relais is a simple device and the current needed isn't that high, but if that 3.3v output can't handle it it's byebye dvd drive.

Indeed. I don't know what it's like in other parts of the world, but reed relays with 3.3V pickup voltage are not easy to come by in my neck of the woods.

And it's a logic problem so lets use digital logic to solve it

Trouble is that it's not really a logic problem. Only the inverting is a logic problem, and that's a no-brainer. The difficult problem is turning the 3.3V signals into 5V signals (or whatever).

Wenid: thanks for getting the firm. image for us, great work!!

You're most welcome. It was a right pain, so I hope it turns out to have been worth it in the end.

(Does someone have any experience with decompiling firmwares?, isn't that 8051 compatible?!?)

Not me. As I understand it this firmware is at least partly encrypted. What I DO know about disassembling microcontroller code for these kinds of devices is enough to let me know I don't want to get into it any further.

[HunTerror]

I lashed together a quick "protoype" op-amp circuit this morning. Once again the LDIN/TRAYOUT is fine (but not quite what I expected -- see below) but the LDOUT/TRAYIN is not working as expected. Clearly I'm even more hopeless at this than I thought. In case anyone else can shed any light, here's a schematic of what I did.

As I said, the LDIN/TRAYOUT op-amp is working as expected, except that when LDIN is high TRAYOUT is 1.25V, not 0V. With my limited understanding of this stuff I'm not sure why this is happening, but I don't think it matters since 1.25V is low enough anyway. Also, when LDIN is low TRAYOUT only shows 3.9V, not 5V. When I was playing with the transistor inverter circuit I measured the TRAYOUT voltage both with and without it hooked up to the Xbox. It showed well over 4V when disconnected but only 3.9V when connected, so I'm guessing it's somehow due to the load on TRAYOUT from the Xbox.
With the LDOUT/TRAYIN op-amp I'm reading 3.9V at TRAYIN all the time, no matter what the state of the LDOUT signal.

I think you're on the right track with using a simple opamp as an inverter / level shifter. However, the TL072 wasn't really intended as a single-supply opamp and you are likely getting issues because of that. I'd try the same circuit with an LM324 (4 opamps per package, available at Rat Shack too)

From an EE standpoint, using an LM339 comparator would be even better, but since you'd require some pullup resistors on the output, it may be more difficult for some. The circuit could be the same as what you've showed.

[maximilian0017]

I don't know why this ended up actually being a link to a hex inverting buffer

Sorry, typing first and looking later doesn't work (must have been inverted )
And i thought of an earlyer project of mine that involved a 4041, but lets get back to the problem.

I've been looking at some datasheets(and reading too this time ), and why not use a 74hc04 (L1,35V -H3,15V) or a 74hct04 (L0,8V-H2V) (with VCC at 4,5v)
The output is almost VCC so that would be almost 5V
http://www.semiconductors.philips.com/acro...4HC_HCT04_3.pdf
(The 74HCU04 Isn't very well suited, don't buy that one!!)

Invert tray in, buffer the rest

Not me. As I understand it this firmware is at least partly encrypted. What I DO know about disassembling microcontroller code for these kinds of devices is enough to let me know I don't want to get into it any further.

They aren't using masks etc, maby if we compare both versions there would be an obvious reason why it doesn't work, as long as they didn't cut it out for those extra commands....well lets get it working first

[wenid]

I think you're on the right track with using a simple opamp as an inverter / level shifter.  However, the TL072 wasn't really intended as a single-supply opamp and you are likely getting issues because of that.  I'd try the same circuit with an LM324 (4 opamps per package, available at Rat Shack too)

Snap! I just got back from buying a couple of these very devices (as well as some 74LS05s). They are cheaper than the quad version of the TL072, too, but not as cheap as a 74LS05. The only reason I tried it with the TL072 in the first place was because I had some lying around.

From an EE standpoint, using an LM339 comparator would be even better

Probably. I don't know much about comparators myself.

but since you'd require some pullup resistors on the output, it may be more difficult for some.

That was the attraction of the op-amps that got me sidetracked from the 7405 idea (that and the fact that I had some op-amps on hand but no 7405s -- I now have both, however).

The circuit could be the same as what you've showed.

Except with pullups added, presumably

[wenid]

I've been looking at some datasheets(and reading too this time ),  and why not use a 74hc04 (L1,35V -H3,15V) or a 74hct04 (L0,8V-H2V) (with VCC at 4,5v)

I don't know what you're looking at, but to me it looks like the minimum voltage input HIGH on this is 3.15V at Vcc of 4.5V. That's cutting it a little close for my liking since the actual high is only measuring as 3.22V here and the Vcc will be 5V.
However it may still work and avoids the need for the pullup resistors that I'll have to use with a 74x05.
Anyway, I'll try one of these 74LS05s shortly and let y'all know...

[wenid]

OK. Here's the latest, but this one actually works. It's not as clean and simple as I was hoping for, however.

[maximilian0017]

That's cutting it a little close for my liking since the actual high is only measuring as 3.22V here and the Vcc will be 5V.

Thought we were talking about 3,3V, well ok, Lets use a 74HCT04 then, its high at 2v and its low on 0,8 at vcc 4,5-5,5V is perfect, no way near 3,22V

In the hc/hct design guides it says that all unused imputs should be tied to VCC through an 1,2KOhms resistor, and if we use two of the ports to buffer another one of the signals it should be easy to connect, no mention of output termination or so...probably not needed.

Isn't the pinout of the 04 and the 05 the same?, then why are you driving output pin 4,6,8 high and tieing it to output pin 2?(inverted ldout)
(probably a stupid question)

Have to go to the store next week, we don't have electronics stores everywhere here.

p.s. the scematic looks alot easyer than the other ones, this is defenately the way to go