Possible 250 JTAG points

Its ALIVE ALIVE I Tell you ;)


Im still not convinced .
A great big ditry hole right through the PCB and not cutting any tracks .
You see all them wee hols around where he has cut through thats where the track jump from one layer to the next , I have also found that the ambit 200 has a 5 layer board . so I recon the 250 may be the same .


Hope I am wrong .

Still . Many thansk for posting ,. Its still good to see people trying to recover the trusty 250 modems



Cheers

Icon
 
Last edited:
you can see the via's and tracks on the board ....most of them wee holes are not linked to via's so cutting in the board wont do any harm
 
Are you sure you need any resistor as with the surfboards you can just use any chipless/resistorless jtag lead.

Yes I know theyres warnings but Ive never had any problems.
 
I think the resistors was origionally needed with the Blackcat as it was going through a chip.

Dunno if this 330 one is needed though. If the other's aren't then maybe this isn't.....?

Will have a stab at it when I get some free time.

:)
 
i tried the jtag without the 330r it detected the bcm but it didnt detect the flash
 
Right, sorry for reviving an old thread but I have finally got some spare time so want to have a stab at this.

What can be used for the 330 resistor, Maplins part please?

What did you use brianmullen8 m8?

:)
 
theres usually a 330 in the A120, next to the BCM chip.... i dont know whether its worth risking but the Pace4000 has lots of 470's which are only slightly higher rated and did work with the A120/A200 JTAG, but its your risk not mine.

get your magnifying glass out lol and if you dont know how to remove/replace an SMD, read the A200 JTAG guide by me & Heji.

[33] multiplied by [0] would be 33omhs.



ImH.
 
iamhim said:
get your magnifying glass out lol and if you dont know how to remove/replace an SMD, read the A200 JTAG guide by me & Heji.

[33] multiplied by [0] would be 33omhs.



ImH.
Click to expand...

Just had a look for the guide. Checked the stickies, downloads, guides, and files and tools.....

Have you got a link to it?

Also are you casically saying that a 33ohms resistor will do the job? Electronics aren't one of my best cards ;)

lord-icon said:
Wish you good luck Monkey

Please post your findings if it works


Cheers

Icon
Click to expand...

Will do m8 ;)

:)
 
Found these posted on another forum.

5x--100K Res----M100K
1x--74LS244N---QQ56L
 
im no electronics engineer, i just play with whatever is availible, most of the parts i use have been salvaged from something else.

i havent tried the A250 JTAG yet, im too busy with a project ;) but apparently if R251 is missing between the FLASH and the BCM you can only detect the BCM??? can anyone confirm if R251 is required and if so, the rating thats needed??? im guessing it would be 000, 330 or 102???

if you setup the rest of it in the meantime MONKey and try it out, then maybe you can confirm this?



for the parts between the wires.... in the attatched photo you can see that surface mount parts have been used so its most likely ok to do the same, otherwise the colour coded resistors should give you the same result.


attatched is the A200 JTAG guide..... here are the videos to go with it ;)

http://www.digitalworldz.co.uk/forums/attachment.php?attachmentid=18670&d=1158537997
http://www.digitalworldz.co.uk/forums/attachment.php?attachmentid=18671&d=1158538064
http://www.digitalworldz.co.uk/forums/attachment.php?attachmentid=18672&d=1158538126



ImH.











ps: for anyone wanting to JTAG the A120 or A200 *without* soldering the pin header onto the back of the board...... theres info about how to do this in the guide below, its simple and you only need 2 x 10pin headers, a soldering iron, solder, tape and a short JTAG cable with sockets on both ends (or HDD cable) to use as an extension. (pictures included)

: ambit120 , ambit200 , ambit250, ntl120 , ntl200 , ntl250 , soldering a pin header , blackcat , enable jtag :
 
Thanks for the info ImH, I'll take a look at those files you posted later on ;)

I'll make one up as soon as I can without the resistors to see if I have the same effect as brianmullen8 did in post #47

I'll report as soon as I have done it, prolly be Monday now.

:)
 
ianhim....

what are you using to clear the jtag port solder m8...i always struggle with that on a 200!
you make it look easy.....ive burnt out a 200 port or two trying to clear the solder.

thanks
 
hi NoOne, i thought the other cleanup methods were too time consuming and wasteful, so here's how i do it;

i use a solid metal safety pin (the old chunky ones, not the flimsy ones) with the end point bent in slightly (lock the safety pin and hold the lock, then push up in the middle with your thumb to make it bend slightly but make sure you dont bend it so much that it pops out of the lock!), this way i can slant the pin and then press down when the solder is bubbling, in the video you can see im switching between the soldering iron and the pin to test the solidity of the solder.... when it shines and the pin starts to move i quickly take away the soldering iron and push the pin through until i feel it getting too tough to push anymore, at this point it must be rotated so that the solder doesn't stick to the pin but rather sets around the pin... finally its eased out of the hole with some more rotations so nothing lifts up.

on the other side of the board you end up with a mountain of solder which should have enough space to house a pin, if any pins wont go through then just take the header off and re-do the points that are not accepting a pin. the nice thing about these mountains is that they act like an assistant for the soldering part... they hold the pin header in place so all you have to do is touch the pin with your soldering iron and the old solder instantly flows, the second this happens apply a small amout of fresh solder for the final joint and its all done in quick time!


[warning - risk of damaging parts]
i used another method a few days ago, this is tricky though.... basically you get a pocket knife (or anything that wont absorb the heat so fast) and hold it on the top of the pin header, now while holding the board sideways use a heat blower (or in my case a blow torch hrhr) on the underside of the holes and wait for the pin header to start sinking, we want it to go through enough so its held in place but not enough that the plastic on the other side has melted (too much heat for too long!) after letting the board cool down for a little bit have the board face down on a steady surface BUT have the pin header resting on the knife, then apply heat to the underside of the board where the holes are and push the board down so that the all pins on the pin header are being pushed up by the knife... if its done correctly it looks like barely any solder has been used to install the pins (factory style) and it takes a lot less time to do... you're just risking damaging things but if you're fast enough its np.
[/warning - risk of damaging parts]



ImH.
 
Well I had a try today and I failed miserably!

First attempt drilled straight through the modem! LOL

Second attempt drilled too far and damaged the BC chip.....

Final attempt I don't know what happened but there was no points there!

I am now throwing the towel in with this. I found it MUCH easier to lift the chip and reflow it back to the board.....

:)
 
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