XF551 Power LED

[stushug]

27 minutes ago, _The Doctor__ said:

You can't just swap heads without aligning them using a scope and alignment disk. You have now made your task next to impossible.

That being the case, I do have a scope. Where can I find and alignment disk? I would need to learn the proper procedure also. My other option, hopefully, would be that someone on here could perform the service for me. For a fee, of course.

[stushug]

22 hours ago, stushug said:

That being the case, I do have a scope. Where can I find and alignment disk? I would need to learn the proper procedure also. My other option, hopefully, would be that someone on here could perform the service for me. For a fee, of course.

Bump

[stushug]

I was able to source a new working replacement drive mech. My XF551 is now working again. I now have two salvage-able(maybe)  Mitsumi D503 drives. Does anyone here want them? All it will cost you is shipping from me to you. I don't want any money for the drives themselves.

Edited February 28, 2023 by stushug

[stushug]

Here are some pictures of the drives.

[Peri Noid]

You're too far to send these to me (Poland) ☹️ so - maybe someone else will make use of these.

[stushug]

On 2/18/2023 at 4:46 PM, Peri Noid said:

I'd look there, yes. I don't know which lead it should be right now. I'd need to measure it. But I'm on vacation right now. 

@Peri NoidI just received my 7404 chips today. I was wondering if you had a chance to check the leads for the LED yet. I'd like to do the mod you diagrammed for me, but I want to make sure I have everything correct before I attempt it. I don't want to blow up my new mech because I had some wiring incorrectly connected. I was wondering  wondering where you recommend to get the power(and ground) from to feed the new chip.

[manterola]

Notice that the diagram only works with common-cathode bi-color leds and those two rectangles in the diagram are resistors. The resistors need to be chosen depending on the LED specs and how bright do you want the LED to be, so it requires a bit of tweaking.

Typical voltage drop for leds are b/w 2 and 3V, so let's say 2.5V, and assuming the XF551 works with 5V. Then we are left with 2.5V and let's say the leds are happy with 20mA then R=V/I=2.5/20 Kohm or 0.125 Kohm or 125 ohm.

In summary, resistors around that value, like 133 , 150 ohms should work: if too bright increase the resistance, otherwise do the opposite, but getting the actual specs of the bicolor led should give you the confidence that you won't destroy the LED.

 

I want to do the same with my XF551, so I will start experimenting, but I need to eget some bi-color leds .. I was considering using a bidirectional one but I am not so sure.

 

[stushug]

4 hours ago, manterola said:

Notice that the diagram only works with common-cathode bi-color leds and those two rectangles in the diagram are resistors. The resistors need to be chosen depending on the LED specs and how bright do you want the LED to be, so it requires a bit of tweaking.

Typical voltage drop for leds are b/w 2 and 3V, so let's say 2.5V, and assuming the XF551 works with 5V. Then we are left with 2.5V and let's say the leds are happy with 20mA then R=V/I=2.5/20 Kohm or 0.125 Kohm or 125 ohm.

In summary, resistors around that value, like 133 , 150 ohms should work: if too bright increase the resistance, otherwise do the opposite, but getting the actual specs of the bicolor led should give you the confidence that you won't destroy the LED.

 

I want to do the same with my XF551, so I will start experimenting, but I need to eget some bi-color leds .. I was considering using a bidirectional one but I am not so sure.

 

I assume you received the drive I sent. Have you had a chance to check it out yet? These are the LED's that I purchased. Will they work?   https://www.mouser.com/ProductDetail/Lumex/SSL-LX2579IGW?qs=MaxZGLOdHCmjF5u1oMywoA%3D%3D

[manterola]

I just opened the datasheet. I found this:

And this:

So I guess you are okay.  What I am not sure is about the maximum current a 7404 can provide... Google mentions 8mA, so I am not sure that's enough for a LED (since the datasheet mentions 20mA) or maybe 74ls04 or other variants can provide more "juice" then 8mA. I have not experimented with LEDs to know, so you might need to try and see.

 

 

[BillC]

48 minutes ago, manterola said:

I just opened the datasheet. I found this:

And this:

So I guess you are okay.  What I am not sure is about the maximum current a 7404 can provide... Google mentions 8mA, so I am not sure that's enough for a LED (since the datasheet mentions 20mA) or maybe 74ls04 or other variants can provide more "juice" then 8mA. I have not experimented with LEDs to know, so you might need to try and see.

Multiple gates of the 7404 can be connected in parallel to provide more current.

[stushug]

50 minutes ago, BillC said:

Multiple gates of the 7404 can be connected in parallel to provide more current.

I assume that's whay @Peri Noid's original drawing has two pins jumpered and going to one side of the LED?

[BillC]

2 hours ago, stushug said:

I assume that's whay @Peri Noid's original drawing has two pins jumpered and going to one side of the LED?

This jumper isn't to connect 2 gates in parallel, it's connecting the output of the first gate to the input of the second. 

[stushug]

Well, today was the day. I decided to install the 7404 chip and my dual LED. I got everything connected and back together and my XF551 now has a Power/Busy light! Thanks to @Peri Noid for making me aware of the mod, and to everyone else that commented and made suggestions along the way. I couldn't have done it without you guys. Thank you very much to everyone!!!

[Peri Noid]

Great!