Space invaders won't boot up

Paulf

Site Supporter
Aug 3, 2018
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Lincoln
Hi all,
Hopefully someone will have a clue what's wrong. Firstly, I've got basic DIY electronics insight so any answers please as an idiots guide.
Playing si when flippers just packed in, lights, music continued to work but nothing else. Checked fuses and solenoid driver fuse blown. Replaced this but still nothing. Green light on mpu flashes 6 times (forums say should be 7), and now speaker hums ( think it's playing si background sound) but can't really hear.
I have multimeter so can check voltages but beyond checking blown fuses I'm lost.
Cheers

Paul
 

Moonraker

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Aug 18, 2011
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Start again, with power off, by pulling out the fuses and testing with the meter on both the driver pcb and regulator pcb.

It is possible that the solenoid drive fuse has blown again, given that the 7th flash is solenoid voltage. If that is the case then it is possible that one of the solenoids has shorted so you will need to lift up the playfield and test each coil using the ohms setting on the meter. Also check for a wire that might have come off and shorted on something.
 
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Paulf

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Aug 3, 2018
22
7
3
Lincoln
Thanks Alan, I'll start looking at this tonight. Daft question, but once the fuses have been pulled I then put the power back on to test across where the fuses where on the pcbs?
 

Moonraker

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Once the fuses have been pulled you test each fuse with the meter putting a probe on each end and test with continuity or ohm setting. Leave the machine switched off when removing the fuses. Once tested, good fuses can be returned to the machine bad fuses should be replaced. If you do'n have any bad fuses then look underneath the playfield for a wire off a solenoid and test each solenoid using a probe on each lug and the ohm setting on the meter. Leave the power on the machine switched off.
 
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Paulf

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Aug 3, 2018
22
7
3
Lincoln
Right, so I've checked all the fuses and they are fine. Also resistance through all coils with ohm meter. The solenoid in the door was disconnected so reconnected and in test this, the knocker and what I think is the relay (on solenoid driver) worked.
There is one wire on top right flipper solenoid that isn't connected see pic.
I've tested this while on and there's 40v going through it (no power to other dead solonoids). However the left flipper (see pic). Only has 2 wires going to same connector. Main bottom flippers have 3 to same connection point.
Tested rectifier and all voltage slightly lower than expected tp5 at 41v, tp2 at 198. Did the same to mpu and solenoid boards, again slightly lower but within 10%
The sound module tps fine but still get background hum that gets louder when turn volume up.
So question is do I connect up random wire or am I looking at something else?
Cheers
Paul
 

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Solar Sailer

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Jun 22, 2018
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Basingstoke
Heres mine. You need to get the brown back on.
Common issue when the playfield has been left to rest on the lockdown bar.

Its 7 flashes on the MPU. The first one being a flicker not a flash then 6 flashes.

Have you done a solenoid test from the test menu to see if any or all fire through the test sequence?

Door solenoid is quite late in the test sequence, 10 I think, then relay, then back to 1 which is knocker I think.
There is a fuse on the driver board as well but if that's gone you would not get anything.
 

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Paulf

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Aug 3, 2018
22
7
3
Lincoln
Thanks both, I'll solder it back on tomorrow and see whether it fixes it or sets it on fire! I think by the sounds of it I've also been expecting a 7th flash as it flashes once in test, pauses and then flashes 6 times.
 

Moonraker

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I've tested this while on and there's 40v going through it (no power to other dead solonoids).
The 7th flash is to indicate there is 40v to the solenoids which you have confirmed. The feed chain for solenoids is broken with that wire off (when it came off it blew the solenoid fuse), hence the need to re-connect (solder it back on) it before doing anything else. Remember to give it a good tug to check that the soldering is good and that it won't come off again in a hurry.
 
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Paulf

Site Supporter
Aug 3, 2018
22
7
3
Lincoln
Hi again, nearly but not quite there. Resoldered wire onto solenoid. Turned on and fine. Tried a couple of times and noticed right top flipper flips but didn't stay up as other 3 did when buttons pressed. Lifted playfield and looked at solenoids. When pressing flippers could see sparks going between eos contacts on those 3 but not 4th. Then it blew the 5a fuse f4 on rectifier board. Any thoughts?