Phoenix MB7052 programming help

S

Skeet

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15CR
Hi,
This is my first post on here. Thanks for admitting me to the community. I'm trying to restore a phoenix cocktail arcade game, but I've run into a major problem. The two MB7052 PROMs are dead. This has been discussed on here before and I believe that they require a specialist vintage programmer to burn new ones. I have an XGecu T48 and obviously that won't do it. I can get hold of NOS MB7052s or 82S129s, which I believe are compatible and easier to burn, but still require a specific vintage specialist programmer.
The PCB and the Pleiades pcb that came in the he cabinet was sold as "was working, but then stopped working", but on inspection there are a lot of faulty ROMs and other ICs, probably due to the fact that the CPU and ROM boards were connected to each other the wrong way around (connector 1 to connector 2 and visa versa) and the power supply board Voltage regulators were fried.
I'm making good progress finding all the faulty ICs, etc and would really like to get this PCB working.
Is there anyone that has the ability to burn MB7052s or 82S129 tristate PROMs and is willing to burn them for me. I am happy to pay for your time.
I'm in Leeds, UK.
I would be most grateful for any help
 
philmurr

philmurr

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How do you know the PROMs are faulty? It's unusal (though not impossible) for one, let alone both of them to fail. They're used as the output for the video stage so there's a lot that could be faulty before them and make them seem dead.

I can programme them for postage cost if you provide the blanks, but I'm just trying to avoid you incurring unnecessary expense
 
S

Skeet

Newbie
Credits
15CR
philmurr said:
How do you know the PROMs are faulty? It's unusal (though not impossible) for one, let alone both of them to fail. They're used as the output for the video stage so there's a lot that could be faulty before them and make them seem dead.

I can programme them for postage cost if you provide the blanks, but I'm just trying to avoid you incurring unnecessary expense
Click to expand...
Hi Phil, thanks for your reply, that is very kind of you.
Well, yes there is a lot wrong with the board and as I said the original DC linear power supply regulators are all dead also it has been powered up with the two board interconnectors plugged in the wrong way round!
I'm using a Suzo Happ power supply adjust d to 5V at IC Vccs with a Jamma loom and a PCB junkie Phoenix to Jamma adapter.
When I power it up I get what sounds like the phoenix whirring sound, but no video. The sound stops after a few seconds and it just turns in a buzzing noise. There is no excess current drain on DIM bulb and if I turn it off and on sometimes I briefly get coloued garbage on the screen (with some characters) which can come back very briefly before disappearing again. Twice I have seen the motherhip very briefly appear which gave me great hope!
As for the MB7052s they get quite hot as does the adjacent IC4 and the CPU Several of both MB7052 pins were broken which I have repaired.
IMG_20250502_132940_1.jpg
When are poke around the board with the scope, so many data lines are absent, erratic, low voltage, floating.
Also a quick read/verify of the 12 EPROMS shows 5 of them read as mostly filled with 00s and won't even verify themselves!
As the board is in such a mess, my plan was to replace the obviously knackered two MB7052s, IC4 (if tests bad), CPU and burn all new EPROMs and then see where I'm at then. Hopefully it will be easier to fault find and pin down where the rest of the damage is.
Below are photos of my dual board Phoenix. I think it's a bootleg.
I am new to arcade pcb repair (not electronics repair) and this a steep learning curve. Am I going about this in a sensible manner.
Do you have any more advice?

IMG_20250502_132817_1.jpgIMG_20250502_132803_1.jpg
Edit: just checked the hot IC 4 (SN7407N) and all 6 inverters are dead, so socketed it and will replace with a new one when it arrives.
 
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