20 replies to this topic

[Alex Atkin UK]

I own a Donkey Kong fruit machine which developed a fault after we had a radiator leak near to it. There was no obvious water damage but its possibly damaged the MPU board.

The problem is quite a strange one as sometimes the unit works fine, but other times it will start to play the sound effects twice or three times at once which will cause the machine to slow down to a crawl. It WILL continue to function but very slowly. As each sound effect finishes it will speed up again, sometimes it will return to normal but usually at this point it will continue to play sound effects over each other and be rather laggy.

The annoying thing is that other than that it works fine. Some days I can turn it on and it will function perfectly.

The only other thing I notice is that sometimes if I leave it running it will unexpected reboot as if I had opened and closed the back door or power cycled. I have dismantled the PSU with nothing obvious wrong in it, no obvious problems with the capacitors on the MPU either. Its just very strange. I would have thought most faults would be consistant not randomly fixing themselves then occuring again.

Its really frustrating as you can guarantee that the instant you think its working fine you will end up the middle of the feature and it will lag making it unplayable unless you plan to make a cup of tea between each turn.

I have been advised its probably the MPU board at fault and quotes £50 for one, but it seems hardly worth it when the whole thing cost me only £150 when I got it. I would either like to fix it for cheaper than that or possibly sell off the working parts to anyone who needs them, as id like to replace it with another fruitie but cannot afford another £150 to get one.

Incidentally, this is an old backdoor unit with tubes rather than the newer revision with the hoppers, if that makes any difference. It must have been maintained fairly well though, its even programmed to accept £2 coins.

[lincs1]

as said in other threads for faults on maygay machines,99% of the problem lays with the psu.

it always seems to be the psu

[Alex Atkin UK]

I had noticed that opinion thrown around but figured it was worth a shot at if anyone has experienced this particular problem.

Has anyone ever sucessfully fixed a PSU?
Im thinking it might still be as simple as a capacitor fault as its common for them to cause random issues as it could be as silly as it will work well with a smooth mains input but will get erratic if the mains is a little off.

Obviously id rather fix this than get a new one as id hate to think of the delivery charges alone for one of those heavy beasts.

[lincs1]

I had noticed that opinion thrown around but figured it was worth a shot at if anyone has experienced this particular problem.

Has anyone ever sucessfully fixed a PSU?
Im thinking it might still be as simple as a capacitor fault as its common for them to cause random issues as it could be as silly as it will work well with a smooth mains input but will get erratic if the mains is a little off.

Obviously id rather fix this than get a new one as id hate to think of the delivery charges alone for one of those heavy beasts.

if u gotta multimeter check for resistance in the psu.

the postage for a beast like that would be around the £8.00 mark

[CanonMan]

I had noticed that opinion thrown around but figured it was worth a shot at if anyone has experienced this particular problem.

Has anyone ever sucessfully fixed a PSU?

I have.

You'll probably find that some of the solder joints on the connectors have cracked, making them open circuit or intermittent.

On the last Maygay PSU I looked at, there were about ten pins that needed resoldering, so I did my usual trick of removing as much of the old solder as possible and resoldering. Do this on every pin, not just those that look bad. It could save a lot of trouble later on...

You may find that some of the connectors on the main board are in the same state. Resolder those in the same way, it may solve your problem. The reel loom connector seems to suffer quite badly like this

[skabaz]

classic fault on the rear open maygay.

your fault will either be the gamecard/chips or the mpu itself.
it will have nothing to do with the power supply.

last time i had this happen was about 7-8 years ago on a super slueth machine but i have seen it a few other times as well.

ideally you want to try the mpu first(i suggest waiting until a cheap one comes up on ebay).

then if its still the same look for a gamecard on ebay.

if its still the same then you will have the hard job of trying to get replacement chips.

it could be any of the 3 as i have seen it happen with all 3.

baz

[lincs1]

classic fault on the rear open maygay.

your fault will either be the gamecard/chips or the mpu itself.
it will have nothing to do with the power supply.

last time i had this happen was about 7-8 years ago on a super slueth machine but i have seen it a few other times as well.

ideally you want to try the mpu first(i suggest waiting until a cheap one comes up on ebay).

then if its still the same look for a gamecard on ebay.

if its still the same then you will have the hard job of trying to get replacement chips.

it could be any of the 3 as i have seen it happen with all 3.

baz

most of the problems i had led to the psu as been faulty as i stated 99% of probs are down to the psu.

but like baz said try the mpu and gamecard.

if u need a mpu for the vision cabinet then i do have 1 BUT its UNTESTED so i don't know the score with it.


lincsleisure1

[Alex Atkin UK]

most of the problems i had led to the psu as been faulty as i stated 99% of probs are down to the psu.

but like baz said try the mpu and gamecard.

if u need a mpu for the vision cabinet then i do have 1 BUT its UNTESTED so i don't know the score with it.


lincsleisure1

Thanks for the suggestions everyone.

I gotta admit that considering the sheer randomness of the issue I expected it to be the PSU rather than anything else. Because if some days it will work perfectly (happened the last 2 days in fact, no glitches whatsoever) its more likely to be bad solder than a complete failure of a component. On the other hand I couldnt see a problem when I had the PSU out (though it did work properly for a while after I had done that).

Considering it went dodgy after a water leak, could it be something stupid like corrosion on the fuse terminals? I havent had those out to check their condition yet.

I will have to check the PSU, hopefully I can find my multimeter this time and check the voltages. The MPU obviously id leave as a last resort as if the PSU IS faulty it might even wreck a good MPU if undiagnosed.

[Jimbob219]

This may be absolute rubbish but could it be due to fumes from the radiator?

Jimbob

[Alex Atkin UK]

Me again. Donkey Kong finally gave out this week. I had left it turned on ready to play and heard a pop, like it had rebooted (it sometimes randomly rebooted since the glitch first started) but it never booted back up. The only LED lit on the MPU is -12V when I turn it on now.

Would you say this is a confirmation that the PSU has died or is it still possible that its the MPU board? I havent checked if its just the PSU fuses as I figure if its finally gone it proves there IS a significant fault that needs fixing first. Thing is, I dont have £50 to replace the MPU board and admittedly I havent been checking eBay for cheap MPU boards as I havent been using it during the summer because all those bulbs heat my room like a radiator.

[Guitar]

Me again. Donkey Kong finally gave out this week. I had left it turned on ready to play and heard a pop, like it had rebooted (it sometimes randomly rebooted since the glitch first started) but it never booted back up. The only LED lit on the MPU is -12V when I turn it on now.

Would you say this is a confirmation that the PSU has died or is it still possible that its the MPU board? I havent checked if its just the PSU fuses as I figure if its finally gone it proves there IS a significant fault that needs fixing first. Thing is, I dont have £50 to replace the MPU board and admittedly I havent been checking eBay for cheap MPU boards as I havent been using it during the summer because all those bulbs heat my room like a radiator.

A loud pop would suggest a capacitor so it could be on the psu or mpu.

If you are only getting 12v then I would suggest that the power supply is dead.
Thats not to say that the card / mpu isnt dead aswell. I personally would take notice of bazpeep but a loud pop and reduced power lights says psu to me.

If your worried about spending money to fix the problem I would say that machines with a theme DK, Mario, Eastenders,Dr who etc retain their value pretty well because of the particular theme.

By any chance your machine doesn't give skill nudge every spin if you hold cancel? Or if anyone reading this has any roms that do it. Obviously no machine in the wild will have these chips in but I would like to play it on the emulator to see how easy it would be to win.

Sorry about the long post.

[Alex Atkin UK]

Didnt sound like a capacitor pop and there was no smell or hint of smoke when I opened it up to check. It was just the same amplifier pop it always gave when resetting, same as when opening/closing the front or rear door.

Another reason I suspected the PSU before was sometimes when it had problems I noticed the LCD display was really dull, as if it was being underpowered. There wasnt anything obvious with the PSU when I checked though but perhaps I do need to just resolder everything and then replace the fuses. Like I said before, it happened after a leaky radiator (its a water radiator btw so no fumes) so I suspected it was some sort of corrosion in the PSU which is closest to the damp floor. Hopefully the faulty PSU hasnt blown the MPU board. I know I needed to do something when it went faulty but I was at a loss for what to do as I love my fruit machine but not as much as other things I can get for £50.

ROM is v1.1 I think, im pretty sure the emptier version must be v1.0. The emptier didnt seem to do anything.

[Guitar]

TBH I would suspect that bazpeep maybe right about the MPU. It could be a wobbly power supply that f**ked the mpu tho.

[Alex Atkin UK]

AHA!

I just powered on Donkey Kong and it booted up, but only for a short while.
I also noticed at least one capacitor on the MPU thats got a significant dome to it, so it seems even if it IS the PSU at fault its definately damaged the MPU. Or maybe its just the MPU all along like some have suggested and its just that now the bulging capacitor makes it perfectly clear. After all, capacitors can fail without any sign of failure. I only wish I had the equipment and knowledge to be able to test all likely points of failure on the MPU as I might be lucky and its only a few capacitors that have failed. Theres certainly nothing else visibly wrong, no burnt out regulators that I can see. In fact the MPU looks mint, not even dusty. However even one of the 470uF caps on the game card feels a bit domed and its curious its leading to the speaker socket when the sound was the first thing to go dodgy. Perhaps the "pop" during a reset was never meant to happen but was merely due to the fault in its early stages? Anyone confirm an audible pop during a reset?

I think I will try replacing a few of the larger capacitors (they all seem to be bog-standard 470uF, shouldnt be hard to replace) and see what happens unless anyone has any better suggestions. I certainly dont want to replace the MPU if it turns out its the PSU and it wrecks the replacement.

[Alex Atkin UK]

The following was going to be an edit of above but the silly forum rules wouldnt let me:

I just ordered some 25V 470uF caps and will try swapping those to see if it helps. I think the 100uF in the centre of the board might need replacing too though. Does anyone know what part each capacitor is responsible for? It would really help diagnosis of the symptoms if the problems are not cured by replacing the 470uF caps. Hopefully the PSU is fine but if anyone has a good idea for testing it (im going to get a new multimeter thats for sure) then it would be appreciated.

Other good news is not only is there a M1B listed on eBay but the person is even in the same city as I am, so perhaps they can help. Im going to try to get that board so if I cant fix this one or it breaks again I have a backup plan. However the E.S.P. board might be dodgy too as theres a 470uF on there too that seems domed and its connected to the speaker socket. Thats interesting seeing as the sound messing up was the first symptom of the thing failing.
Still, theres a chance nothing is permanently damaged at this point - failing caps can explain all the symptoms. People have repaired PCs with similar issues and im fairly sure PCs arent anywhere near as robust as fruit machines are, at least not this old thing anyway.

[Alex Atkin UK]

No luck. :-(

I replaced the caps and while the machine does seem to bootup more consistantly again the same problem as before remains so it seems to be as I had feared, the PSU damaged the caps so replacing them allows the machine to function but the replacements will also be damaged if the root cause is not solved. In fact it seems WORSE than before, far more obvious dimming of the bulbs while its running so it looks like a good checkup of the PSU is on the cards although I mislaid the service manual so I have no idea what the voltages are supposed to be.

If im really lucky (which so far it seems I am not) its a bad connection or bad caps in the PSU. I guess I should have figured replacing those caps too into the equasion from the start really.

Upon quick inspection the two large bridge rectifiers were rather loose on the PSU paneling. This could be interesting as if the diodes have failed it could easily have the knock-on effect I have been experiencing with the whole DC power being totally out of whack. Im still guessing here though and sadly im no expert when it comes to these things.

[Alex Atkin UK]

I know its been a while but I finally got hold of a replacement PSU board for Donkey Kong and low and behold, it works perfectly again. YAY

Its hard to believe I have had it taking up space for so long unusable. At least now if I do decide to sell it I can sell it as working towards a newer fruitie (although I wish I had space for more than one).

[aaamusements]

I know its been a while but I finally got hold of a replacement PSU board for Donkey Kong and low and behold, it works perfectly again. YAY

Its hard to believe I have had it taking up space for so long unusable. At least now if I do decide to sell it I can sell it as working towards a newer fruitie (although I wish I had space for more than one).

Great to hear that you have got it sorted at last!

Couple of points; I would say that PSU/MPU failure is about 50/50 on these machines.
MPU failure is almost always down to a leaking battery.
If the battery is blue, REMOVE IT ASAP!
Same if it is green and shoes any signs of leakage.
If it has leaked then you should clean the board with vinegar, rinse and dry thoroughly (In a warm place for hours). This neutralises the battery "acid" (actually an alkali!).
If this point has been made before in this thread then sorry, but it can't be said often enough. Backup batteries do kill good machines.

[Alex Atkin UK]

Unfortunately its died again today.  Hadn't used it in a while and powered it up to 10p fault.  Left it running to warm up and suddenly I hear a relay click, then a relay click, its powering up for a second then resetting again.

Frustratingly I hadn't been back here in the meantime so had missed the battery warning and of course it leaked.  I had cleaned that up a few years ago and everything was still fine, but who knows if its gotten worse over time as there seemed to be minor corrosion in places where I couldn't be 100% sure I had succesfully neutralised it.

To be fair, the 10p error is exactly what it did before so it could just be the PSU board again, but I really don't have the energy to look into it right now.  Kinda wish I could just stick a Rpi in this thing and run it off a ROM dump now as this old hardware is a PITA.

[Alex Atkin UK]

A followup, it was the 10p error that the PSU board fixed before, it was the random resets.  What fixed the 10p error before was re-seating the connectors, although it doesn't seem to be helping this time.

This has to be false error as it prevents the machine from working at all, I can't even get into test mode, and triggers even with the coin mech disconnected.

 

What bothers me is how ALL the stepper motors get really hot which surely is not normal when they aren't even in operation?  Is some current leaking where it shouldn't be?

Edited by Alex Atkin UK, 17 October 2017 - 02:01 PM.