Faulty (original) Phoenix table - help!

[delzano]

I’ve owned an original Phoenix table for several years but haven’t played it for a long time. Having switched it on, the screen starts up then freezes after a couple of seconds, as you’ll see on the attached image.
Sometimes the screen shows more info, other times less, on this video it’s not showing much at all.
Has anyone suggestions as to the cause of the problem and is it something I can fix? I’m not an electrician but have followed youtube videos/web advice to fixed the odd electronic item like a faulty AV amp that needed a new component soldered on. I’ve borrowed a friend’s Ethos 5015 multi meter but not used it yet.
I loved this machine growing up and I would like to get it up and running again.
I’ve included a photo of the innards in case it helps. I’m happy to post more photos/videos if requested.
Any help would be gratefully received. I’m happy to get it fixed by a qualified if it wasn’t too expensive to do so and they’re not too distant from my location (Stamford, Lincs, about 50 miles north of Cambridge), so suggestions would be useful.
Really appreciate any help, thanks!

 

[bones]

It does sound like you may have a faulty component on the pcb but there are a few things you could try. Definitely with the machine off you could unplug the connectors where they go onto the pcb and push them back on. Same with the connectors with the grey ribbon cables linking the 2 boards,just push the 2 black levers apart and the connector will pop out a little then push the connector back in and the levers will lock back in. This may correct a dirty contacts/pin. Then really the only other thing would be to check the dc voltages where they go onto the boards. You would need to get hold of the pinouts for the edge connectors to do this. You will have a 5vdc and 12vdc but not sure if this has a -5vdc/-12vdc as well. I probably should have said first that some of these early machines had a slam tilt switch on them that can cause issues if it happens to be activated so check around the coin mech area for a leaf switch with a coin size weight on one of the 2 leafs. If the contacts made it will stop the game from running. A photo of the bottom board would be a bonus as if there are chips in sockets it's worth jacking them up a little and then pressing them back down again. Good luck and I hope it's not a pcb fault,great game and nice looking machine.

 

[delzano]

It does sound like you may have a faulty component on the pcb but there are a few things you could try. Definitely with the machine off you could unplug the connectors where they go onto the pcb and push them back on. Same with the connectors with the grey ribbon cables linking the 2 boards,just push the 2 black levers apart and the connector will pop out a little then push the connector back in and the levers will lock back in. This may correct a dirty contacts/pin. Then really the only other thing would be to check the dc voltages where they go onto the boards. You would need to get hold of the pinouts for the edge connectors to do this. You will have a 5vdc and 12vdc but not sure if this has a -5vdc/-12vdc as well. I probably should have said first that some of these early machines had a slam tilt switch on them that can cause issues if it happens to be activated so check around the coin mech area for a leaf switch with a coin size weight on one of the 2 leafs. If the contacts made it will stop the game from running. A photo of the bottom board would be a bonus as if there are chips in sockets it's worth jacking them up a little and then pressing them back down again. Good luck and I hope it's not a pcb fault,great game and nice looking machine.

Hi bones, really appreciate the reply. Followed your advice and removed the 3 connectors, & used a quick spray of WD-40 Contact Cleaner to. Tested the top connector and got 4.84V, wasn't sure where to check for the 12V. Also used the cleaner on the tilt switch, which was very dirty) & noted a thin transparent film with the contact below (not touching). Having done this the problem is the same although a couple of times there is a short looping sequence with sound rather than a static screen, I can upload the video to youtube if it helps as can only upload photos here. (I haven't separated the boards yet as wanted to check it's as simple as unscrewing the four corner screws on thee top board.) Thanks again for your help.

 

[delzano]

I've unscrewed the boards and have photographed the bottom board, which looks surprisingly clean. I've looked and all the chips look in place. I did notice this connector below the boards, assume it's meant to be 'loose' like this.

 

[bones]

Interesting, I probably wouldn't have used wd40 though. 4.84v at the edge connector could be an issue.
My thoughts are that I feel that the phoenix pcb was probably not the original because the unused connector is likely the old extra power connector for the old taito/etc 3 stack pcb arrangement. You see on the 3 stack pcbs it wasn't enough to have the power coming into the first pcb and then being transferred to the others via the ribbon cables, this caused a voltage drop. For example 5v at the edge connector may mean in reality only 4.9v at the chips on the first pcb,by the time it got to the second maybe 4.7/4.8v and the third may only have 4.6v at the chips(barely enough to work) so they had the power fed from both ends, a bit like a ring main as opposed to spur in electrical terms. Now I don't think your phoenix pcb has the second edge connector for this ' spare ' connector to plug and even if it has then I wouldn't as it's probably not compatible and could cause damage.
4.84v is low, I think the chips start struggling ti work at about 4.75v and below. I guess you could try and test the voltage at one of the 74ls chips on the second pcb and see where you are at. I don't think you have to worry about the other voltages to be honest. Pick a 74lsxxx chip and check out the pinouts online and see what you've got, it is important to take the voltage from the chip as opposed to using the edge connector for your 0v. With 74ls chips if it's a 14 pin device then pin7 is 0v and pin 14 is 5v, a 16 pin device then pin 8 is 0v and pin 16 is 5v but do look online so you are sure of the chips orientation and know which is which.
I can't remember if the power supply has the ability to turn the 5v up, if it did then do not exceed 5.25v at the edge connector. But first things first is to check the voltages as I suggested half an essay ago lol.