Author Topic: 28 pin DIP socket in 5o buck robot?? (Read 4028 times)

NOOBinDistress · « **on:** May 31, 2007, 04:23:02 PM »

Ok I fnished my board with my new parts but I still have my old parts in the board I messed up on. They are all in pretty good shape except for one and I was hoping I could make another board from the scavanged parts in the old board. The one messed up one is the 28 pin DIP socket because it is missing 1 pin. Is there any way I can fix or replace that pin? I would really like to mak another board.Please help me. Thanks.

ed1380 · « **Reply #1 on:** May 31, 2007, 05:12:06 PM »

what pin is missing? you could probably be able to make another one if the pin isn't important

NOOBinDistress · « **Reply #2 on:** May 31, 2007, 05:49:53 PM »

It is the second one down on the left in the top. I consider the top to be the end opposite of the capacitor and the voltage reg. I hope you can understand that. Thanks.

rgcustodio · « **Reply #3 on:** May 31, 2007, 06:34:28 PM »

Quote

I consider the top to be the end opposite of the capacitor and the voltage reg.

One way to determine which is top or bottom is by finding the notch on the chip or carrier. Hold the chip/carrier socket with the notch on top and the pins facing away from you (you should see the writings on the chip or the connectors on the carrier), pin 1 is the first pin on the left.

I actually got confused since you mentioned "missing pin 1", but later mentioned "second one down on the left in the top"

Vreg
Cap -------\_/---------
| |
| |
| |
| X
--------------------

OR

Vreg
Cap -------\_/---------
X |
| |
| |
| |
--------------------

<pardon the crude drawing>

If it's the first one you're still OK. If its the 2nd one then you might have problems, that pin is either connected to the ISP programmer header (if Pin 1) or connected to one of the motors (if Pin 2).

Is the whole leg missing? If there are portions of it still remaining, maybe you can still build up enough solder on it.

- Rommel

NOOBinDistress · « **Reply #4 on:** May 31, 2007, 06:35:59 PM »

It is this one
l v l
x l
l l
l l
l l -----v reg @ bottom of pins below this

it goes down to 28 pins

Is it ok? (x is missing pin)

HDL_CinC_Dragon · « **Reply #5 on:** May 31, 2007, 06:49:49 PM »

im pretty sure thats an important one. If you can find some circuits laying around that have less than 28pin DIP sockets you can desolder them and take them and get enough until they equal at least 28... thats what I did with two 14 pin sockets I found on some circuit to make another circuit without using the one I had on the robot

rgcustodio · « **Reply #6 on:** May 31, 2007, 06:52:49 PM »

I'm NOT SURE if the location of the notch in your diagram is correct (the soldering image locates the notch near the Vreg), but using the voltage regulator as a point of reference, you might be referring to Pin16 which is not connected to anything (in the current design).

(you can see the notch near the Vreg and cap side)

I don't know if you've soldered it the wrong way the first time, but if you will be soldering it properly on your next project, as HDL_CinC_Dragon said that missing leg will be connected to a very important component.

- Rommel

HDL_CinC_Dragon · « **Reply #7 on:** May 31, 2007, 06:57:14 PM »

well how you identify pins on an IC is there is a notch on the IC and that basically shows you were pin 1 is. Pin 1 is on the left of the U and it goes in the same order as you write a 'U'

1 U 6
2 5
3 4

Thats how to ID your pins

BTW that little diagram I put there could be for a 555 timer or something heh

NOOBinDistress · « **Reply #8 on:** May 31, 2007, 07:03:19 PM »

Yah well I put it on back wards probobly. But I have another Idea. Can I jost pop another unimportant pin out and pop it into place.

This diagram doesnt go by the capacitor as top it goes by what you said the little v shaped notch
l v l
1 l
l l
l l
l l
l l
l l
l l
l l
l l
2 l
l l
l l
l l

1 is the one I am currently missing 2 is the one I intend on taking out and putting in the 1s spot.

If my plan for swapping them does not work than try and tell me if you know of any house hould boards that I could take apart and find a peice like that . Thanks.

NOOBinDistress · « **Reply #9 on:** May 31, 2007, 07:04:30 PM »

sorry I didnt # it and yes I did solder it wrong so in the diagram above I just went by where the notch was. Thanks.

HDL_CinC_Dragon · « **Reply #10 on:** May 31, 2007, 07:04:44 PM »

ummmm the pin you picked to take out is important to but one above that isnt important

NOOBinDistress · « **Reply #11 on:** May 31, 2007, 07:05:28 PM »

Okay thaks so I can just pop it out and switch them?

rgcustodio · « **Reply #12 on:** May 31, 2007, 07:12:02 PM »

Focus on the chip. Match the notch on the chip with the notch on the carrier socket which is missing a pin/leg. Whichever has no color dot beside the chip is NOT USED, so you can just pop it out and put in place of the broken pin/leg.

NOOBinDistress · « **Reply #13 on:** May 31, 2007, 07:28:11 PM »

OH no.... On my good board the one I am not scavenging the notch is on the wrong side will that make a difference. Please help. Thanks.

HDL_CinC_Dragon · « **Reply #14 on:** May 31, 2007, 07:34:40 PM »

well the 28 pin DIP Socket doesnt functionally matter which direction it is in but it does very much matter which way the actual AVR is pointed. Make sure the notch on ATmega8 is point in the direction of the vreg

Admin · « **Reply #15 on:** May 31, 2007, 09:44:03 PM »

Use the pin numbers on the datasheet (also on the schematic I posted) when talking about pins.

There are only 6 pins that are very important, and those are the 6 that are required for the programming header. The rest dont matter. For example, if pin 2 is broken, use pin 4 for that servo. This requires a small change in the software and you are fine.

NOOBinDistress · « **Reply #16 on:** June 01, 2007, 05:18:22 AM »

Okay thanks but since on my good one I have the notche on the wrong side should the atmega8 notch be on the opposit side? (which is by the capacitor)

Admin · « **Reply #17 on:** June 01, 2007, 06:52:24 AM »

The notch represents the top of any IC. So yes, it should be at the top near the capacitor.

NOOBinDistress · « **Reply #18 on:** June 01, 2007, 01:13:57 PM »

I made my statement more clear. The 28 pin DIP head is put in with the notch on the wrong side. So You are saying the atmega's notch should still be on the same side as the capacitor? Thanks.

rgcustodio · « **Reply #19 on:** June 01, 2007, 01:33:10 PM »

Its a resounding YES! The notch of the ATmega8 must still be on the same side as the Vreg and Cap.

NOOBinDistress · « **Reply #20 on:** June 01, 2007, 08:35:34 PM »

Thank YOU!!! So it will work yaaaaah. My batteries should be here tommorow!!!!!

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Author Topic: 28 pin DIP socket in 5o buck robot?? (Read 4028 times)

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