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AFM cabinet speaker not playing

br1Ck

br1Ck

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Joined
Jan 5, 2018
Messages
86
Location
London, UK
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.
Could it be something as simple as the ribbon cable? I haven't got a spare to test unfortunately.

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 icon_sad.gif 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
 

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My advice would be to replace the burnt connectors both socket and plug, this will not be anything to do with the sub (i assume u r referring to the sub speaker in the body) . Did you test the diodes when de-soldered as you cant reliably test them when in situ . Reg the audio, if it did intermittently work first remove the idc ribbon cable and clean all the contacts and the cable (use an isopropyl spray) and re-seat. if that doesn't work remove the audio pcb and check for dry joints around the connectors and the transistors which have heat syncs attached .

Good luck

Drew
 
J105 and J106 are both for background lighting. They won’t affect single feature lights. But replace both plugs and headers, and whilst the board is out remove all of the diodes above the connector and replace with a heavy gauge wire ( same as that in the connectors below ). The diodes are not needed and are omitted on later versions. They just get hot and cook the board.
 
I swapped the wiring for the cabinet speaker and the backbox speaker (J504 > J505 and vice versa). I got sound out of the cabinet speaker.

I swapped them back and tried new wire from the cabinet PCB connector to the speaker but no dice. I'm guessing it's something on the AV board, unlikely that its the plastic PCB connector itself!

I tried reflowing the pins and some other spots but to no avail. I've got some isopropyl alcohol arriving today so I'll give the ribbon cables and pins a good clean as suggested by @Cursaw

You can see in the attached photo (crap quality, apologies) the damage on the top left. I believe this is connectors and transistors with heat syncs attached are (?). It's all very dry and burnt looking. I tried reflowing these but it wasn't very effective. I've got some flux and stuff coming, so i'll give it another attempt tonight.

AFM cabinet speaker not playing | Tech: DMD era games | Pinside.com

| Forum Topic by br1Ck
pinside.com pinside.com
 

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Isopropyl alcohol cleanse and reflowing many many pins did not work :mad:

A little unsure of where to go to from here. Might try my hand at replacing those sockets/plugs/pins.

I found some info regarding replacing those diodes with heavy gauge wire; although I'm finding it a little confusing.


@pinballmania should I just take these diodes out completely and replace them with heavy gauge wire in their current orientation?

Cheers!
 
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.

o_O
 
br1Ck said:
Isopropyl alcohol cleanse and reflowing many many pins did not work :mad:

A little unsure of where to go to from here. Might try my hand at replacing those sockets/plugs/pins.

I found some info regarding replacing those diodes with heavy gauge wire; although I'm finding it a little confusing.


@pinballmania should I just take these diodes out completely and replace them with heavy gauge wire in their current orientation?

Cheers!
Click to expand...

Yes.
 
br1Ck said:
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.

o_O
Click to expand...

Check continuity of the capacitors on the sound section power supply. Snip off c47 and c51 if not already done. Can cure some cracklings issues.
 
Replaced the caps. (Also snipped off c47 + c51). Turned it on and it made a loud, unstable buzzing (different to previous buzzing) as though power was flowing through them(?) .

Turned off and then on again; now no sound at all. Still an instant buzzing when cab speaker is plugged in. (see
)

Did a continuity test and it made a connection.

Wondering whether I should send av board for repair or is it the power board that could be causing the problem. We measured 12v & 5v at the AV board so it seems like it's getting the right amount of power.

Is it time for a pinsound/rottendog replacement to bypass the av board? It would be a shame to send it for repair only to plug it back in and cause the same issues..
 
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Take pictures of the underside of the board for people to review.

Also, can you take a close up of what is going on here?

123.png
 
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