archive.worldofdragon.org

Soooo... I soldered a MPI board and it was working well, until I accidentally inserted a cartridge wrongly and the magic smoke filled the place. The MPI is no longer working and my DragonMMC isn't working either.

A Multicartridge board was affected too, but turns out that only the eeprom was fried, so I changed it and it's working again.

The symptoms are, well, dead. It doesn't do anything at all, no leds, nothing.

I was hoping it's only the voltage regulator, so let's see.

Any hints what to test?

Hi,

You should be able to test the vreg if you power the board up, one of the end legs should be 5V, the other 3.3V (centre is GND).

If there are no LEDS lit, then chances are the AVR is not getting power, as part of it's powerup routine is to check for the card, and mount it, which should blink the LEDS. Please don't insert a card, until you are sure that the vreg is only providing 3.3V, as anything greater than that will most likely fry the card.

The AVR (40 pin DIP) should be able to stand voltages up to about 5.5V, but if the regulator is delivering more than 3.3V it may also have taken out the Xilinx CPLD (big flat chip). Without that the ROM and RAM won't be selected and you won't get the normal DMMC signon message.

When plugged into a working Dragon, does the Dragon start correctly and display the normal signon message?

If all else fails, and you want to send the board back to me I can take a look for you.

Cheers.

Phill.

Hi Phil,

I get 1.2v on one leg of the vreg, which goes down with time, and 4.78 on the other one.

The leds turn on for a brief second and then the board appears to be dead.

Thanks for your kind help!