DC Digital - No HDMI Signal after Installation

dominion

New member
Dreamcast Revision: VA1 - PAL
Dreamcast Motherboard Revision: "IC BD KATANA MAIN VA1 MADE IN JAPAN 837-13778, SEGA 1999 171-7965E SEGA"
DC Digital Revision: 1.3a
Vendor: A distributor in the United Kingdom

Hi,

I have just purchased 3 DC Digital units from a distributor in the United Kingdom and have been tasked with installing the DC Digital on 3 Dreamcasts all VA1s - All PAL Versions.

I have attempted to install the DC Digital mod and I have failed to get a video signal from the DC Digital.

I am 99.9% certain that the soldering I have done on the flat flex cable on the top side of the Dreamcast motherboard is not at fault.

I have confirmed the soldering joints from the Video Framebuffer IC (315-6258) are good by checking under the microscope as well as checking for continuity from each of the used pins on the Video IC to the resistor array packages on the ribbon cable. (N.B. The termination resistors for the video signal are packaged in RN2, RN3 and RN4). For good measure I have verified the resistance values on each of the resistors in arrays RN2, RN3 and RN4. I have also measured the continuity from the other side of the array packages back to the copper on the other end of the flat flex connector. (Jump 8 is good as I have tested the resistance from the joint to the other side of the SMD resistor)

A similar rigorous check has also been applied to the Audio IC (315-6232), with Jumps 5, 6 4 and the jump to the capacitor being good.

I have very carefully and patiently inserted the ribbon cable into the flax flex connector onto the DC Digital Board mounted onto the bottom side of the chassis mounted above the lower shield (provided sticker has been applied to the underside of the DC Digital board).

In some instances the ribbon cable makes a very mild but noticeable "click" with the connector lock open, I then have closed the ribbon cable lock. This is the only connection that I am uncertain about being good.

I have soldered the two wires for the Maple bus sniffing and an additional wire for the reset. Again, continuity confirmed with inspection under microscope and with a multimeter.

Upon powering up the Dreamcast there is no HDMI Signal Detected by my TV.

The Dreamcast console is outputting a composite signal and the Dreamcast operates as it should using the composite cable.

The DC Digital is creating a WiFi access point, so can I reasonably assume that the flat flex cable is properly seated within the connector? (And that the board at least is connected to 3.3V rail and GND ..?)

It it worth noting that I am somewhat experienced in this modification as I have done one console before which worked perfectly so we can rule out the TV being at fault, I just followed the instructions and checked through the soldering meticulously to make sure the solder joints were good and there were no shorts.

The only conclusion I can draw is that there is an issue with the board (potentially the FPGA needs to be "re-flashed"), with the WiFi working the indications are that the ESP Chip is operating as it should.

I will await any advice before proceeding.


Thanks in advance!
 

dominion

New member
Looks like we are all in different timezones :)

For completeness's sake, I had a few questions.

1.) Is it possible to apply 3.3V and GND from my bench power supply to power up the DCDigital board and then connect this to my TV? I just want to see if a test image can be generated to rule out an underlying issue with the board.

2.) Purchased from Kaico in the United Kingdom. I was not aware the board I had purchased was a clone and not an original.
 

chriz2600

Administrator
Staff member
1) Please try to add some more solder to the video dac pins. They look almost not soldered at all on the first image.

2) If the LED on DCDigital lights up, connection to 3.3V and GND is good. Also check the LED blink pattern for further trouble shooting:

https://github.com/chriz2600/DreamcastHDMI/blob/develop/DCHDMI-LED.md

3) Video output requires a working video clock connection, so you won't get any image from DCDigital, if not properly connected to the console.

4) The ESP8266 takes care of the FPGA firmware, if the FPGA fails to start, it re-flashes it's firmware part and restarts.

5) The board Kaico sells is technically not a clone, as DCDigital is opens source. These forums are for black dog tech customers only. It’s not fair to ask us for support from other producers on an open source project. You should contact them for support.
 

dominion

New member
Hi Chris,

Thanks very much for your reply.

1.) I will add further solder as requested to the Video DAC pins and get back to you.

2.) It is hard to witness if the LED on the DCDigital has lit up, I certainly can't see anything albeit with the console partially assembled, however the DCDigital is definitely creating an access point.

3.) I have contacted Kaico and have yet to receive a reply, I completely understand that yourself/citrus are not at all responsible for the quality of the product I have received, however any pointers or guidance you give, or any other members of the board may give, would be greatly appreciated.

Thanks again for your assistance, I will add more solder to the pins and get back to you.
 

dominion

New member
Just to close this thread, I went over the soldering with my iron and the issue seems to have been down to a poor connection on the flat flex cable. Drowning the board in even more flux and holding the iron on each pin for about 2 seconds seems to have resolved the problem ;-)

As a cautionary tale, my initial soldering was done by simply tacking down the flat flex cable, this has the negative effect of "wicking" away the solder on the pins under the pads of the ICs.

Thanks for your help in any case.

A related technical question, you say that the FPGA needs the video clock to generate an HDMI out signal, is this to synchronize the HDMI out video to what the console is actually outputting? It would be a nice to have to have a switch that you could flick on the board that would output a test signal, or would that put up the cost as you'd need a crystal on the board?

Thanks all for their help and I think the DC Digital is a great product, the image quality on my HDMI Television is great and it has breathed a new lease of life into a 20 year old console!
 
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