Anyone got a used system 7 MPU for sale? Not working is OK.

Mof, it seems to me that problems with drops falling or not usually have to do with the metal leaf "spring" on the back of each drop target which holds each drop target up. If you remove the two screws holding that on you will be able to take it off and bend it slightly. You need to bend it in towards the target for your problem and out away from the target if your drops are not dropping when hit by the ball. If you get that adjustment right you can tighten the bracket again. I think loosening the bracket is usually a quick fix for the drops not dropping but if you get the leaf springs right you shouldn't need to have it loose.

Looking for help with an Alien Poker. Everything is working but the right flippers. They were working as of Sunday evening. Went to play after getting home Monday from work and they do nothing. I've tried reseating all the connectors. I repinned a few connectors. Reflowed solder on all connectors. Had the 40 pin and a few others completely replaced. I've cleaned the switch at the flipper. I know supposedly that the flipper system on this system 6 is supposed to be easy to figure out but I'm at a loss at this point. I'm by no means a pin repair expert though and any help that could be provided for a dummy would be great.

I recently fixed my first flipper issue on HMM, so I will offer my expert advice . Check the wires connected to the flipper coils; I had couple broken solder connections which was causing one issue. Also check that the switch is making contact when the button is pressed. Good luck.

-Do you have 28V or so at the right side coils ? Check pinwiki for best test procedure.
-If not is there a broken wire between one of the coils or EOS switches or bad fuse (I don't have a system 6 right now so don't remember the fuses)
-When you push the right cabinet switch do you get continuity from any right flipper coil lug to the plug at 2J2-1 or 2J2-2 (flipper ground returns)
-If not figure out where the wire is broken. Test flipper to cabinet switch and cabinet switch to 2J2-1 or 2J2-2 (one is for left, one is for right don't remember).

Pretty simple circuit from memory.
-Turn game on and the flipper coil should have power. Check that.
-Start game and the relay engages to connect 2J2-1 and 2J2-2 to solenoid ground on the driver board. So if left flipper works, this should work.
-Press flipper button and flipper ground lug on the coil should connect to 2J2-1 or 2J2-2 and therefore solenoid ground. causing the flipper to fire

Note that the EOS switch is involved so check that is working correctly.

Just repaired a system 6 CPU and thought I'd share the info. This is the same board I repaired about 3 yrs ago for running too fast, see https://pinside.com/pinball/forum/topic/williams-sys-6-cpu-runs-too-fast

This time the game quit running while in attract mode and only G.I. was working on the machine. The diag LEDs indicated it was booting, and pressing the test button locked on the bottom LED reporting bad ram. Of course the ram was not the issue. The board was able to run Andre's test chip and everything passed, but would not run any game ROMs. I compared address line activity with a logic probe on several chips with a working board and found no activity at IC15 pins 10, 11, & 12.
Replacing IC15 - 74LS139 solved the problem.

I read about the controlled lamp upgrade for 3-7 boards, and that there are two options. One is replacing the transistor with a MOSFET and using 2 resistors per line to cut the draw down - the other is easier - replacing the transistor with a TIP-125(or 127) and adding in a 10k 1/4w resistor for the usually burned 27 ohm ones.

I've done it on Sys 6 boards without an issue, but can the same be done to a system 9 board since they're similar design/parts/etc? I see the mosfet option on Pinwiki, but like the TIP-125/127 solution better and would rather give that a go on the board.

I have a Laser Ball that I recently purchased. Has been worked on already but I need to rebuild the flippers. Not having any luck finding the double stacked eos switch on the right flipper. Contacts look ugly. Not finding one so far. Anyone have any suggestions for who might have one? Pin Life is a no go.

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I've got a (mostly complete) laserball playfield sitting around. If you can't find anything new and you dont mind used, PM me and I'll take a look for that switch. Chances are I have it..

Id recommend buying the switch blades and contacts from Pinball Resource and either remaking it yourself, or take a regular EOS, transfer it to the larger existing switch body, and add in the new low current pieces. I did this on my Firepower and its worked like a charm

The extra switch on this stack is not a lane change switch, it is to activate the third flipper like on Flash, so these are both high current switches.

Either way - PBR sells both low voltage and high voltage contacts and light/medium/heavy thickness blades. I fix a lot of EM/hugh current ones by taking a switch apart, replacing the contacts, and putting it back together.

Pinball Resource has what I need and is shipping out. Part of the problem is I was looking at the switch wrong. I thought both were closed at rest but one is actually open. Need to see if I can verify adjustments. Saw on Vid's thread that flipper switch should be set to 1/8" open when flipper is held in up position. Does this mean that the open switch in the stack should be open 1/8" at rest?

Nah, so long as the open one makes solid contact, you'll be fine. Id keep the gap minimal, at least 1/8" but can be a bit more. The smaller the gap, the closer the flippers will flip together. 1/8th is recommended so the switches don't arc across.

Also, its important the closed switch doesn't open till near the end of the flipper stroke, or you'll lose power to soon in the shot.

https://pinside.com/pinball/market/classifieds/ad/104552
Selling untested boards

I stumbled on a badly labeled auction lot for an Algar apron if anyone is looking.

https://dotysauctionservice.hibid.com/lot/82947162/metal-advertisement/

Time for a thread bump. I rearranged my games room to get all my Sys7s together.

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