Leaderboard

Decided to re-base my Adders after putting it off ages.. It was well fooked, needed doing.. Should last another 40 years now... 😂😎

Yet another board nearly drove me to insanity. Maybe I'm lossing my touch with age, who knows. Usual battery rot symptoms so all the usual suspects whipped out and renewed. A bit of track patching out needed for the alpha and triac driver links but other than that pretty clean. So on power up (with diags) the triacs all test OK then the tester alpha comes up with MPU4 ALPHATEST OK so all looking good. Thinking I'm in for an early day and just waiting for the lamp tests to start it comes up with an alarm and a bit of garbage on the alpha although I can see it's trying to say 'alarm' but no idea what. The RAM solder joints were looking a bit crusty so I thought that better come out, just in case, which was good as it failed on my tester. I've had similar issues before, like the previous fault above, so it's always a good idea to check out IC16 and put it in a socket which then gives you the option to isolate the CS feeds to all the support chips. Isolating IC5 the alarm was still apparent but the alpha then stopped on a readable 6840 error. Of course changing the chip made no difference. Just a little teaser here, I'd checked the 5v previously and it was a bit low at 4.77v but we all know TTL min rating is 4.5v and it boots OK so I thought I'd come back to that later. Big mistake!! Anyway back at the ranch getting nowhere and contemplating taking out all the support chips and putting in sockets which I did. After each replacement no change to the fault so 2 days later I'm losing the will to live. By now I've made sure all the Address and Data lines are intact plus every other line from the cart to the board. I'm thinking there must be a corroded via somewhere that I've missed. Rapidly running out of ideas and it's now day 3. There's only two options left, the first one is to jump in the Thames but maybe option two first. Thought I'd go back to the low voltage supply and see what's going on there. After stripping down the regulator I thought I'd run a test on the LM323 with my bench PSU and lo and behold it stuck solidly at 5v?? Hmm, what am I missing here? Tried a spare regulator chassis and blow me the board booted and ran fine. After all that wasted work but hey ho it works so put away the swimming trunks. So what was going on with the original regulator? Putting it back with the little board again it's measuring 5v off load but if I put a 12R resistor across the output it drops to 4.77v. It was then I noticed something on the radio. I listen to Caroline on 648Khz and putting the resistor on the output more or less blocked out the radio signal! Suspicion then pointed towards the tant cap that decouples the input to the LM323. When a new one was fitted the voltage remained stable under load at 5v. As the wires to the board power socket weren't attached they probably acted like an aerial otherwise I would have noticed this before. I'm sure someone up there doesn't like me.

Worth removing the wires from the coin switch and phsically touching them together, see what happens.

They would, all the bleep means is it's changing state but if the state is wrong... could be way off the mark here but thought I'd chuck it in the mix.

I think you are right on both counts. I have just had a look on one of mine and although it has not got a hopper it has got the extended game card and that square chip near the aux 3 connector on the game card is a 68681 DUART which makes sense, so power from pl10 and information from aux3 on the game card. So that is a dead end as none of the tracks that directly go to the hopper are anywhere near the battery area. As Bob says a screwed up switch matrix can make them do funny things and something else i would look at which realy can do strange things is the RAM, although it looks quite clean in the photo it is in the battery area.

As a complete guess (but logical) and i may be completely wrong but heres my two peneth worth. Since you have mentioned that about the hopper is the alarm maybe Unexpected Pay Out.🤔

You should see pulsing outputs on pins 7-15. The ones we're interested in go to IC22 so make sure the outputs on 3,6,8 and 11 are good. Depending on what switches are operated you should then see good outputs on IC33 & 34. These two are in the firing line for the battery vapours and can do funny things. I think I've mentioned this already.

I’m on holiday at the moment, so not with a machine.. BUT hopefully this helps. with the route plug in place, it’s either top two left side, or top left, and bottom left. 90% sure it’s the former, you can link these without a plug if you wish, but a plug would be cleaner unless you have some link tabs there

Power, Power, Power. We have all done it and will no doubt continue to do so, start off and get side tracked, cant see the the wood for the trees scenario. Well done Bob, another interesting read. Didnt realise Caroline was still going, just had a look on their home page and the solar power meter for the Orford Transmitter made me chuckle.

Two pins on route plug for mars mech need to be linked to accept 10ps (two end ones)

Dont know if this helps or hinders but below is the razzle connections showing 10p never enabled but it does show the inhibit lines which maybe of some help.

Thanks for the imput guys Bob I will check those switches first today thanks Graham, it's a multi mech so electronic, but the token slot is S10 and credits as it should, thanks Nick, No I never removed the loom from big shot but did compare the pin voltages to razzle they were the same and fuse was intact, thanks

Just a thought ronnie but you did say you changed the mech cable? Did you try that cable in another machine? Also those cables do have a fuse in some cases and needs to be working and not blown obviously so assumed you checked it .

Just guessing but are are the micro switch connectors on the correct tabs ie the no and nc haven't got switched?

That output through the burnt resistor is part of the switch matrix, it that's not working right you'll get all funny things happening with the switches.