Hi all,

I am tackling the largest problem I have with an 'Attack From Mars' that I saved from a pub last year.

The speaker in the cabinet doesn't work. It has been replaced and you can hear that it does get signal, although it plays very quietly. The speaker HAS come on properly in the past, but only for a very short period of time (ie one ball.).

LED 100 (+12VDC Regulated) and LED 103 (+12VDC Unregulated) are both dimmer than the other LEDS on the power board.

This leads me to believe it is a power supply issue.

I've tested voltage to the AV board at connector 'L1' (?) and it reads 12V and then 5V as expected.

There is some obvious corrosion on the power board around D26 - D32 diodes. I've tested these and a lot of them read a signal both ways which would indicate they need replacing (?) This is the case for a few other diodes (?) on the power board (D7 - D20) etc

J105 wires have been hard soldered onto the board for some reason I'm guessing this is why sometimes my 'Capture 1' light dims or goes out. (It's not the bulb). I've since moved the J123 PCB connector to J121 (where it should be) since taking the attached photo.

J106 has some burnt up wires in the PCB connector. I believe this is why one of the strings of lights in the backbox is super dim.

Board diagnoses and repair is all very new to me so thank you for your patience!

If you could push me in the right direction, it would be much appreciated.

Thanks!

br1Ck

WhatsApp Image 2019-03-20 at 15.04.33 (resized).jpeg

WhatsApp Image 2019-03-20 at 15.04.34 (2) (resized).jpeg

WhatsApp Image 2019-03-20 at 15.04.34 (3) (resized).jpeg

WhatsApp Image 2019-03-20 at 15.04.34 (4) (resized).jpeg

WhatsApp Image 2019-03-20 at 15.04.34 (resized).jpeg

I just swapped the wires from J504 to J505 and vice versa and the cabinet speaker works! The backbox speakers don't work in J504 (cabinet).

So this would indicate that either the wires, the pcb connector or the output from the board is the problem. I replaced the wires from the J504 PCB connector to the cabinet speaker and no result there.

Is there a way to isolate it further and check the J504 header pins? Should they get voltage to the pin for example?

I'll take the board off and reflow the solder for these pins

Is there a way to test these ICs? Or do you know what the relevant IC's are that I should replace?

I've reflowed connections on the AV board, cleaned out the ribbon cables and pins with isopropyl alcohol - to no avail. It looks like the shotgun approach is my best bet at this point.

Thanks!

Replaced U5 and Replaced U5 and U6 (audio amplifiers TDA2030). Now when the cabinet speaker is plugged into the AV board, I get a very loud hum (60Hz) as though 12V power is being pushed to the speaker. The heatsink for the cabinet amp gets hot when it remains plugged in.

The backbox speakers are now much quieter and have a slight crackle when playing certain audio clips.