Manchester
Can anyone help me out here please?
https://pinside.com/pinball/forum/topic/seawitch-j1-as-2518-18
(Topic ID: 61134)
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Seawitch
Stern Electronics, 1980
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Quoted from Chalkey:Use the Steve Kulpa guide linked, cross reference the schematics if necessary. I'll get you a photo when I get home if you need it.
Looked there but it looks back to front, if you could do a photo that would be great - cheers!
So i've re-pinned the connectors on the TA-100 all showing correct voltages. I can't seem to get the 5v on the SDU-100 Rev C.
- Re-pinned connectors J3 and J4
- Rebuilt 5v section (apart from 2.2 Cap)
- New Voltage Regulator (tested on bench)
- Ground mods done and 5v TP1 -> Tp3
Now i can give the board 12v on the bench and all is well, but as soon as i plug it into the backbox no 5v, i've checked pin 12 on J3 and its giving out 12v unreg.
Its got me scratching my head some what..
Any ideas?
Quoted from j_m_:silly question, but have you checked continuity on the wire(s) that should be providing the 5v to the SDU board from the rectifier board?
Cheers, I am getting the 12v unregulated, 5v is regulated from this on the SDU board.
Right i've sorted the SDU board out and the game now boots and i can start a game. All switches are registering in test, only problem i have now is the Solenoids don't seem to be working correctly, i.e If the Right slingshot is hit the knocker sounds and the right bumper will trigger the ball trough.
Any help would be appreciated 
2 weeks later
Do these roms get bitrot or something, i've not had a battery in there (was waiting on a memory cap) and the ram won't clear now. All the displays show 22, it was working before. I'm sure i remember reading something about it corrupting the code if there is no battery?
2 months later
8 months later
Its a stock MPU 200.
Instead of being 0's its random numbers, i seem to remember reading that if you ran it without a battery for a bit it corrupts the ROM - which i find very hard to believe.
I'll check the voltages in a bit.
Cheers
Quoted from Quench:Sounds like you have an Alltek MPU board.
Failure to get the 7th LED flash means that the MPU board is not getting it's 43 volt input. It comes in at pin 15 of MPU board connector J4.
Get your multimeter out and measure it:
Factory Stern MPU board you should measure 21 volts at test point TP1
Alltek MPU board revision L you should measure 43 volts at test point TP2
Alltek MPU board revision J and K you should measure 43 volts at test point TP7
any other revision Alltek, you need to look in their manual for it.Sorry, if you get a '2' where there should be a '0', a '3' where there should be a '1', a '6' where there should be a '4' etc, then it's the same issue at pin 26 of connector J1.
Anyway it sounds like you may have a few MPU board connector issues that need to be dealt with.
Just tried now and it booted into a game, turned off and it wouldn't do the 7th flash.
Voltages:
TP3 = 21/22v
TP2 = 14v
TP5 = 5.1v
Pin 15 of J4 = 45v
So all within range, i think i will repin that J4 and see if that makes any difference.
3 months later
Quoted from Quench:Disconnect all but one of the displays. If it still happens, swap that last display for another. If it still happens, you have an open circuit on the display BCD data 1 signal from the MPU board at pin 26 of J1 to all the displays at pin 18. This is a Blue-White wire that gets daisy chained from one display to another on pin 18. More likely you have a bad crimp terminal connection at the source MPU board pin 26 of connector J1.
Many thanks for that I owe you a beer. It was pin 26 on the connector after all.
Next question is there any modifications to be done to make the loop shot more accessible?
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