BT Vision box

[DarkNeo]

We've hit a little snag, everything is wired up right, but we're getting 0xFF bytes for the CPUID. We've checked the connections, made sure we weren't getting them mixed up, and they're fine.

One thing we have noticed is that pin 5 of the JTAG doesn't seem to be connected to anything on the board, as the resistor packs to either side of the JTAG are missing, and there's no resistor in the area circled on the attached image. We can't find a decent image of that area anywhere else to compare what is supposed to be there though. (btw this picture was before modding, we have bridged the JTAG enable)

[is0-mick]

The resistors are present on my board.
If you want an image.. there should be one in the hardware section in my "how - to" pdf

Mick

[DarkNeo]

The resistor in your image is covered by the cables coming from the JTAG port. Do you have a 'before' shot?

[warrmr]

If we were to bridge the resistor on J5 would this make the jtag work or would we need to bridge the 2 lots of resistor packs each side of it.

once again thanks for your guidance and for putting up with all the noobish questions.

[is0-mick]

The resistor pack at 3332 is 10k (marked 103). (probably for pullup to 3v3 for each pin) same for pack 3331.

I would think both packs would be needed to get a correct signal.

The small resistor from pin 5 just seems to be a link. it measures < 1ohm on my meter....

Mick

[DarkNeo]

The resistor packs definitely seem to be pullups. I've bridged that missing resistor, and I've now started getting zeroes instead of Fs. I've put a breadboard between the mainboard and the modchip with some 10k resistors pulling up to the 3.3V, and I'm still getting zeros for the CPUID. Any idea what could be wrong?

What I've tried:
I've checked the wires about a million times, using the vias near the JTAG points as test points (so I know the solder joints are alright - they're about 0.2ohm). I've checked the JTAG lines aren't shorting against each other (or to anything else). I've checked the reset line (using pin 4 of the header near the JTAG, serial output shows resets are being detected correctly when booting and soft-rebooting), and the 3.3V (coming straight from the power header), and the ground (coming from the 3 pin header next to the fan header). I've followed the chip schematic properly and tested my modchip board...all seems to be in order.

[is0-mick]

Maybe some of the other lines where the missing resistor packs go are needed to be pulled up too?
try finding an old scrap pcb? or such and removing them, and fitting them to the pcb?

Mick