RQ: Repairing a Raystorm PCB

[The Expanding Man]

It arrived working perfectly for three days. On the third day, I had it running for about 4 hours straight.

Next time I went to boot it up - I can hear the monitor clicking continuously and the blank screen refeshes at the same time as the monitor clicks.

Has to be the PCB, I think, because other boards work fine.

I bought it without any warranty, and I may have a shot of repairing it myself.

I have access to a oscilloscope, but I'm pretty ignorant of theoretical electronics.

Any ideas on how to start?

[neorichieb1971]

R-typer fixes boards.

I can't really add anything else sorry.

[IronGiant]

First thing that I would check is the large surface mount ICs on the main board - pins on those have a habit of lifting off, mainly due to board flexing.

[The Expanding Man]

First thing that I would check is the large surface mount ICs on the main board - pins on those have a habit of lifting off, mainly due to board flexing.

Thanks for that. I just had a look with a magnifying glass, and the smd components all look to be soldered securely.

I didn't have it mounted permanently in the cabinet - it is possible, though unlikely, that it may have touched some metal.

I say unlikely because it was working fine one session and suddenly failed to boot up the next session and nothing disturbed the board or cabinet in between.

The only unusual thing I can think of is that I had the cabinet powered up well over 4 hours in the last session that the board worked. This was much longer than the previous sessions I had it powered up.

I don't know much about the history of this board - it came with the manual that is all in Japanese. I'm guessing the original seller picked itup over there. I've got no idea how long it was used, or just lying on a shelf before I bought it.

[IronGiant]

Looks can be deceiving I'm afraid - the fine pins on the larger surface mount chips can look okay but when tweaked gently with a needle some might be shown to be detached.

Not saying that's the case with yours, but with those boards it's one of the first things that I check.

You say that the board hasn't been flexed, but gentle flexing of the pins due to thermal expansion and cooling can loosen an already weak solder joint on such small pins.

Of course, the board's fault might be something entirely different, but you've got to start somewhere.

[robivy64]

Step 1: re-seat the top and bottom PCBs.

[The Expanding Man]

Step 1: re-seat the top and bottom PCBs.

Thanks - I tried that yesterday. No luck.

[system11]

Ticktickticktickticktick?

Do you have a multimeter? Disconnect the PCB and measure each +5, -5, +12 against ground with a resistance or continuity check. One of the things that can cause what you describe is a short.