opt2not
Well-known member
Alright, I'm stumped.
Been working with Ken on this one, but I think now it's time to get some more eyes on this thing.
My Robotron Cabaret was playing awesome till it froze while I was having a nice 5 million run ....grrrrr!
It froze then went straight to the rug-pattern and gave me the initial "Factory reset" error regarding the cmos.
So, I figured it was a battery thing...turned the cab off, went into the back, noticed two things:
1. original battery holder and the AA batteries was all crusted up and fuzzy looking. I ended up pulling the main board out, and installing a new lithium battery holder I got from bob roberts. While I was on that board, I re-flowed the solder on all the power headers...and did the Ram upgrade to 4164's with power adapter plug, again purchased from bob.
2. the power supply had a few caps swollen. Now I just recapped this thing a year ago, caps should last longer than that! So I was concerned that perhaps the caps I got from bob had a couple defective ones that were on their last legs...so I recapped the Power Supply with new ones. Also swapped out the bridge-rectifier at BR1, heat-sink transistors with new ones, AND replaced all the power headers and re-crimped new IDC connectors to and from the Power supply.
Practically a full shotgun.
Now, when I power up the machine, I get RAM error 1-2-L and the rug pattern persists and doesn't progress past that. It just keeps repeating the rug pattern.
I swapped around RAMS at that location, but am still getting the same error at that spot. I thought perhaps the socket is gone, so I pulled the board again, and replaced the socket.
Still the same error.
Another thing I noticed is that the F2 fuse on the power supply keeps blowing. I believe for compact games, this line is used for coin lights/switches and general illumination. Don't know if this line is used anywhere else for operation...
I checked voltages at the 1J1 header: the 5v line is coming in at 4.8v, and the 12v line is sitting at 11.9v.
Ken suggested that I re-crimp the ribbon cable from the Rom to the CPU board. I did so, and made sure to checked the continuity of all pins, first on the ribbon cable to the ROM board, then from the ROM connection header pins to the CPU board's headers. Re-crimping was successful, but I still get the same 1-2-L RAM error.
So I went back and metered the Test Points (from the schematics) on the Power Supply Board just to make sure I'm not going crazy.
With 4J2 plugged-in I get:
TP1 = 4.8
TP3 = 11.5
TP4 = -4.8
TP5 = 11.2
TP6 = -15.7
With 4J2 unplugged I get:
TP1 = 4.8
TP3 = 13.6
TP4 = -4.8
TP5 = 14.6
TP6 = -15.0
What's interesting is the voltage drop under-load on TP3 and TP5...is this normal? I just want to eliminate the possibility that my PS board is at fault here. I've pulled out that board so many times now and have practically checked every component and pin on it.
Ken also suggested I re-flow the fuse holders and squeeze the clamps together so they make good contact with the fuse. Did that, no change. Fuses are new and clean, they're fitted snugly into the clips and are making good contact.
I really don't know what else to try now. I have a logic probe and multi-meter, and am handy with the soldering iron.
Anyone have any suggestions?
Been working with Ken on this one, but I think now it's time to get some more eyes on this thing.
My Robotron Cabaret was playing awesome till it froze while I was having a nice 5 million run ....grrrrr!
It froze then went straight to the rug-pattern and gave me the initial "Factory reset" error regarding the cmos.
So, I figured it was a battery thing...turned the cab off, went into the back, noticed two things:
1. original battery holder and the AA batteries was all crusted up and fuzzy looking. I ended up pulling the main board out, and installing a new lithium battery holder I got from bob roberts. While I was on that board, I re-flowed the solder on all the power headers...and did the Ram upgrade to 4164's with power adapter plug, again purchased from bob.
2. the power supply had a few caps swollen. Now I just recapped this thing a year ago, caps should last longer than that! So I was concerned that perhaps the caps I got from bob had a couple defective ones that were on their last legs...so I recapped the Power Supply with new ones. Also swapped out the bridge-rectifier at BR1, heat-sink transistors with new ones, AND replaced all the power headers and re-crimped new IDC connectors to and from the Power supply.
Practically a full shotgun.
Now, when I power up the machine, I get RAM error 1-2-L and the rug pattern persists and doesn't progress past that. It just keeps repeating the rug pattern.
I swapped around RAMS at that location, but am still getting the same error at that spot. I thought perhaps the socket is gone, so I pulled the board again, and replaced the socket.
Still the same error.
Another thing I noticed is that the F2 fuse on the power supply keeps blowing. I believe for compact games, this line is used for coin lights/switches and general illumination. Don't know if this line is used anywhere else for operation...
I checked voltages at the 1J1 header: the 5v line is coming in at 4.8v, and the 12v line is sitting at 11.9v.
Ken suggested that I re-crimp the ribbon cable from the Rom to the CPU board. I did so, and made sure to checked the continuity of all pins, first on the ribbon cable to the ROM board, then from the ROM connection header pins to the CPU board's headers. Re-crimping was successful, but I still get the same 1-2-L RAM error.
So I went back and metered the Test Points (from the schematics) on the Power Supply Board just to make sure I'm not going crazy.
With 4J2 plugged-in I get:
TP1 = 4.8
TP3 = 11.5
TP4 = -4.8
TP5 = 11.2
TP6 = -15.7
With 4J2 unplugged I get:
TP1 = 4.8
TP3 = 13.6
TP4 = -4.8
TP5 = 14.6
TP6 = -15.0
What's interesting is the voltage drop under-load on TP3 and TP5...is this normal? I just want to eliminate the possibility that my PS board is at fault here. I've pulled out that board so many times now and have practically checked every component and pin on it.
Ken also suggested I re-flow the fuse holders and squeeze the clamps together so they make good contact with the fuse. Did that, no change. Fuses are new and clean, they're fitted snugly into the clips and are making good contact.
I really don't know what else to try now. I have a logic probe and multi-meter, and am handy with the soldering iron.
Anyone have any suggestions?

