DFB1 Support thread

[foft]

There is a pattern in the errors, it looks like either two data bits have a problem (or some address thing which leads to the same).

???? ?PPX XPPP PPPP
X=fail
P=pass
?=not in screenshot

Can yarrt write to a file to capture more info?

I can check the schematic this evening to see which traces/connections this would mean.

Or send it back and I’ll sort it out, sorry!

[Badwolf]

There is a pattern in the errors, it looks like either two data bits have a problem (or some address thing which leads to the same).

???? ?PPX XPPP PPPP
X=fail
P=pass
?=not in screenshot

Can yarrt write to a file to capture more info?

I can check the schematic this evening to see which traces/connections this would mean.

Or send it back and I’ll sort it out, sorry!

@Fletch

YAARRTT will dump to serial, if that helps?

Looks like a pretty consistent pattern where bits 7 and 8 of the 32 bit bus are stuck high.

I can't see anywhere where they might obviously short to the 5V rail, but they're pulled high so it's possible the solder joints to the buffer chips buffer chips at the bottom, right of the LEDs, have dried out? IC5 and IC6.

Bit 7 is on IC6, bit 8 is on IC5.

Get a magnifying glass on it?

BW

Screenshot_2023-02-22_10-06-18.png (200.06 KiB) Viewed 2642 times

[Fletch]

Maybe I ought to mail it back to you and you can look at it. I solder a bit, but the soldering on this board is certainly more precise than I am comfortable with.

Are you okay with that? I'll certainly pay you something for your trouble and for the return postage.

Let me know.

There is a pattern in the errors, it looks like either two data bits have a problem (or some address thing which leads to the same).

???? ?PPX XPPP PPPP
X=fail
P=pass
?=not in screenshot

Can yarrt write to a file to capture more info?

I can check the schematic this evening to see which traces/connections this would mean.

Or send it back and I’ll sort it out, sorry!

[foft]

Sure of course, sent you a pm. Sorry about this!

[foft]

I can't see anywhere where they might obviously short to the 5V rail, but they're pulled high so it's possible the solder joints to the buffer chips buffer chips at the bottom, right of the LEDs, have dried out? IC5 and IC6.

Thanks @Badwolf. I think your analysis was spot on here, the board is working now.

It wasn't obviously an issue on the usb microscope, though the solder looked a bit thin on one side of these bus drivers. To be safe I re-soldered every pin on every one of the SMD chips to be sure, adding some extra solder in places. It started working after re-doing the four bus drivers, which ties in.

It's now sitting on YAART doing an extended run.

[Badwolf]

It wasn't obviously an issue on the usb microscope, though the solder looked a bit thin on one side of these bus drivers. To be safe I re-soldered every pin on every one of the SMD chips to be sure, adding some extra solder in places. It started working after re-doing the four bus drivers, which ties in.

It's now sitting on YAART doing an extended run.

Top banana. Shame you had to ship it back, but grand it's back up and firing on all cylinders.

BW

[markus0321]

I have a question only indirectly related to DFB1.
A friend sent me a faulty falcon motherboard.
To my surprise, the board came to life when I inserted one of my DFB1 cards into it. (the board itself or equipped with CT63 generates only colored stripes and patterns on the screen)
The question is what can be damaged on the falcon board, maybe someone knows right away without analyzing the diagrams what could be the reason for the damage? (I think it's CPU or Combel but maybe I'm using a mental shortcut)

[DoG]

I have a question only indirectly related to DFB1.
A friend sent me a faulty falcon motherboard.
To my surprise, the board came to life when I inserted one of my DFB1 cards into it. (the board itself or equipped with CT63 generates only colored stripes and patterns on the screen)
The question is what can be damaged on the falcon board, maybe someone knows right away without analyzing the diagrams what could be the reason for the damage? (I think it's CPU or Combel but maybe I'm using a mental shortcut)

The jumper between 20-22 on the expansion port is needed if there is not a card there. Could it be that simple?

Falcon expansion port jumper (2).png (93.62 KiB) Viewed 2063 times

[Badwolf]

Don't think it's the BG jumper as CT60 does the same. A missing BG jumper normally means white screen anyway.

Could it be the motherboard ROM? Try disabling flash on DFB1 and see if you get the same results.

BW

[markus0321]

I have a question only indirectly related to DFB1.
A friend sent me a faulty falcon motherboard.
To my surprise, the board came to life when I inserted one of my DFB1 cards into it. (the board itself or equipped with CT63 generates only colored stripes and patterns on the screen)
The question is what can be damaged on the falcon board, maybe someone knows right away without analyzing the diagrams what could be the reason for the damage? (I think it's CPU or Combel but maybe I'm using a mental shortcut)

The jumper between 20-22 on the expansion port is needed if there is not a card there. Could it be that simple?


Falcon expansion port jumper (2).png

I know that the jumper must be put on when there is no card. It must be something else on the board and the diagram is not interactive, I only have scans.