chance pi build

[baum7154]

I'll use your picture to add the ground in. Should work OK just look a little ugly. I'm getting excited to
have a good working PI machine when the weather finally turns good again![/QUOTE]


You might want to ohm out the various ground islands on the solder side of your Silverdog board. You may need to put those 3 wire jumpers (from your 3.jpeg) in to get all the grounds to work, and it will save you a lot of soldering.

Dan

[Waikiki_Sweep]

I see the A733 on ebay but they also call it 2SA733 which is a different animal (much lower HFE).
I ordered most parts from Mouser but they didn't have the transistors. I bought a 2N7000 before
I checked out the mods so too late!

Check this one.
http://www.ebay.com/itm/121193562746
Guy sent me 10 pieces of 2sc945 from Illinois for $2.25 with free shipping. And I have received it in regular postal envelop in 5 days here in Hawaii.

[Waikiki_Sweep]

I'll use your picture to add the ground in. Should work OK just look a little ugly. I'm getting excited to
have a good working PI machine when the weather finally turns good again!

[/QUOTE]
You have a perfect ground layer covering all your PCB instead of my defective one. So may be you do not need to add extra jumpers. But jumpers over passes of high current: near coil, dumping resistor, tank capacitor, MOSFETS may let it work a little better I think.

[baum7154]

You might want to ohm out the Silverdog board after installing the three wire jumpers indicated in your 3.jpg pix. If they ohm out ok then you will save a lot of soldering for yourself. I think Wakiki Sweep has a board not from Silverdog.

Dan

[Silver Dollar]

The jumper wires are there in the top layer. The grounds are not there so I'll have to jump them all in.

I just had a look in my junk box and didn't find anything. Then I took a look at an old CB radio I had
started dismantling and found 3 C945's! (I just wish there was one more).

Thanks for the link

"Check this one.
http://www.ebay.com/itm/121193562746
Guy sent me 10 pieces of 2sc945 from Illinois for $2.25 with free shipping.

I'll use those to make sure there's no problems!

[Waikiki_Sweep]

You might want to ohm out the Silverdog board after installing the three wire jumpers indicated in your 3.jpg pix. If they ohm out ok then you will save a lot of soldering for yourself. I think Wakiki Sweep has a board not from Silverdog.

Dan

Silver Dollar has posted a picture of his board.
Looks like three jumpers are here:
http://www.geotech1.com/forums/attac...1&d=1394368646

That board looks exactly like my. I bet both of them are from same source.

[Waikiki_Sweep]

and found 3 C945's! (I just wish there was one more).

Two more, because of upgrade. My 2N7000 went to trash can too.

[Silver Dollar]

Opps I forgot about that one already.I guess I'll have to buy some...

[baum7154]

Thanks for your help! The mods for the new software aren't a problem. I was refering to #35 in this thread (page 2) where
someone said

"I have started to solder parts on Chance PCB and have noticed on that PCB just missed whole ground layer on the top.
So I will have to make several wire jumpers to ground all components properly. Probably it was one of that epic failure
PCB's from the first Chance with mistakes."

The PDF from Silverdog shows 3 layers;

[ATTACH]28723[/ATTACH]

[ATTACH]28724[/ATTACH]

[ATTACH]28725[/ATTACH]

I just checked and sure enough I have one of the original boards with the ground plane (2.jpg) missing.
It would have been nice to have a corrected one but I can do something like this to fix it;

[ATTACH]28726[/ATTACH]

I can see where the screen is written to and places where he talks to the external A/D but
to find the disc code will take a bit of study.

As I study your 2.jpg pix it is the ground plane with the non ground connections isolated from the plane. It is connected to battery negative and to the ground side of the coil and to other ground points in many other places. Perhaps in some production runs this layer is missing. I did not know of this problem with Silverdog boards.

Dan

[Silver Dollar]

Yes the first boards from Silverdog had that plane missing. They were replaced but some are still floating around.

One other question. Around version 0.84 there was a software change to support a different AD, the schematics have never
been updated. Does the latest software version work with MCP 3201 or ADS7816? I bought the 3201 so I'm hoping it works!

"You can try new update 0.83 for MCP 3201 and 0.84 for ADS7816."

[Waikiki_Sweep]

Yes the first boards from Silverdog had that plane missing. They were replaced but some are still floating around.

One other question. Around version 0.84 there was a software change to support a different AD, the schematics have never
been updated. Does the latest software version work with MCP 3201 or ADS7816? I bought the 3201 so I'm hoping it works!

"You can try new update 0.83 for MCP 3201 and 0.84 for ADS7816."

Yes. All versions of code work with MCP3201 and someone told that with MCP3201 Chance works better than with ADS7816.
Probably that compatibility with ADS7816 was made because MCP3201 was rare in Russia few years ago.

[baum7154]

Yes I too am using MCP3201 with V1.2.1 firmware.

Dan

[Silver Dollar]

Great! As soon as my parts get here I should be able to get this puppy working!

I found a thread that said the Chance software was written in C that is why it
jumps around so much and will make it harder to disassemble...

I built a parallel port programmer but it doesn't work yet. Lucky we use them at
work so I can try it there! (and use theirs if I don't get mine going).

We had to buy special parallel port cards to get them to work as the Kanda
software wouldn't see the first card (if anyone is having problems).

[Waikiki_Sweep]

I built a parallel port programmer but it doesn't work yet. Lucky we use them at
work so I can try it there! (and use theirs if I don't get mine going).

We had to buy special parallel port cards to get them to work as the Kanda
software wouldn't see the first card (if anyone is having problems).

I have used USB programmer for AVR. You can find it on eBay starting $3. Name is USBASP. http://www.ebay.com/sch/i.html?_nkw=USBASP
Also there is a very simple software to use with it - Khazma AVR programmer. http://khazama.com/project/programmer/

But please pay attention for fuses because for Khazma checked bits = 1 but on Chance website with Ponyprog screenshot it has checked bits = 0

So INVERT ALL FUSE BITS or Ooooopppssss.... Atmega8 Bricked.....

Also write codes first than fuses so if you mess up with fuses you will have at least codes ready to go.

[Silver Dollar]

Wow $3! How can they do that? It costs more than that for a USB connector here!

My homemade one is working! I made it from junkbox parts so it didn't cost me anything.
I'm having trouble with a similar one at work, it doesn't work with 3v parts so I hope to
mess with this one and come up with a fix for that one. It is the original Kanda one. Here's
a picture;



The other HC244 was blown I think. They both were sitting in my junkbox for 15 years...