Power Drift - monitor/board help please!

[shrunkenmaster]

Currently I have no picture or real signs of life with this, which is mildly annoying to say the least.

So far I've stripped down, cleaned and reconnected everything off the PSU board and checked all connections, and I have power, with red LEDs showing on the two PD game boards.

I've also checked the three PSU board fuses, plus the two on the monitor chassis.

I have neck glow, but no picture. As I'm pretty new to all this I have no idea if it's a board or monitor problem, or both. 

I also seem to have a spare connector, which appears to connect to the main board as pictured below.

I can't see anywhere for this to connect to - all other cables are spoken for. I also labelled each and every connector so I'm pretty sure everything is plugged in correctly.

The manual has one overall schematic which hasn't helped me. 

Could any of you lovely chaps help in any way? I have a multimeter and soldering iron but precious little else...

[mgb]

One full proof test for telling if the issue is with the monitor or game board is to take a cheap jamma board and hook it up to the monitor.
This way you can be sure which is at fault.
another test is to meter for dc voltage at the video connector on the monitor. There is a red, green, blue, video ground & sync (and sometimes another ground)
put your black lead on the video ground and red lead to each of the r, g & b and you should see maybe 1-3 volts.
that will at least be an indication of video signal coming from the game board.

another test is to turn up the screen knob on the monitor (its on the flyback) and see if you get raster retrace lines on the screen.

also one thing that should always be done: test the 5 volts hitting the game board. test for dc volts right at the gameboard main connector and make sure its at like 5.1 volts not 4.9 or lower.

Edit: from my experience lately with Sega games, I'd almost be willing to bet that the game board is at fault.

[mgb]

Also it looks like that game has a separate video board that connects to a filter board and then a connection from the filter board to the monitor.
make sure all those connections are accounted for.

[shrunkenmaster]

Thanks mgb, that gives me something to go on. Will report back when I've had a look.

[shrunkenmaster]

OK,
At the video connector R/G/B I'm getting .53V at each, at the main board 5.56V and the lower (video?) board 5.6V.

I adjusted the pot on the flyback - see image below.

I'm presuming this main board was used in other games, judging by the empty spaces designated for other components? I take it this is why I don't have any cables to connect to the sockets marked in red below?

[mgb]

5.56 Volts at the game board is high.
Is that power supply adjustable?
your boards 5 volt should be at like 5.1 volts.
also make sure this reading is always taken at the game board and not at the psu itself because the voltage at the psu will show a little higher due to drop on the wires.

[shrunkenmaster]

I thought it was high - now adjusted to a little over 5.1 at the board. Monitor is a Hantarex MTC9000 by the way.

[baritonomarchetto]

Looks like the monitor is working.

Try coining up the machine and play a "blind" game: can some sound be heard?

If not it's the board (or some cable going to the board itself).

[shrunkenmaster]

No sound at all I'm afraid, other than a little crackle on power-on.

[baritonomarchetto]

Try googling for your board and see if other working PCB's have actually your empy connectors connected.

You can also see what the connectors "names" are and check the manual for reference 

Have you ever seen your board working?

[shrunkenmaster]

Try googling for your board and see if other working PCB's have actually your empy connectors connected.
You can also see what the connectors "names" are and check the manual for reference 
Have you ever seen your board working?

Thanks my good man, I've cleared up the connectors now. The cab was in this state when I acquired it.

Over on UKVAC, it was suggested I check pin 18 on the 68000's to see if the board is resetting. I picked up a logic probe today and on the CMOS setting - Pin 18 shows:

1) Synchronized flashing LO (Green) and PULSE (Yellow), with pulsing HI (Red)

2) Steady LO (Green)

3) Steady LO (Green)

I've visually inspected both boards and they look good - no visible broken traces, badly seated chips.

Any ideas of what to do next? Any help much appreciated, as I'm new to the diagnostic side of things.

[Sky25es]

Push the test switch (open the coin door. There must be a volumen control and 2 switches. It's the second) and verify if the test menu is displayed.

Where does the "crackling" sound come from ? The monitor, PCB Assy or from the PSU ?

[shrunkenmaster]

The crackling is just in the speakers. I already tried the test buttons, nothing.

I've just got a logic probe and checked the 68000's - the board is stuck in a reset loop, so I'll be sending it to a chap who specialises in Sega boards.

[mgb]

Are you sending it to Ken Westerfield at irepairsega?

[shrunkenmaster]

It's going to Mark at http://retroclinic.com here in the UK.