I see some spider chips on the board.

Full sized schematic of the board is here:

https://www.pinwiki.com/wiki/images/8/85/LasVegas_schematic.pdf

Service manual is here:

https://www.pinwiki.com/wiki/images/7/7e/LasVegas_Service_Manual.pdf

Maybe try Steve Kulpa?

The display driver spider chip is probably the same as used in Gottlieb System 1 games, but the PPS4 CPU chip is mask programmed and unique to this game.

Most probably, and least costly, the electrolytic capacitors on board have failed. If replacing those does not help, the switch matrix driver chips are cheap to replace. But more detailed description of the problems would be nice.

There are a few resistors that look cooked as well.

Maybe reach out to the guy in the video you posted from Pinball Mayhem. It sounded like he was going to be working on fixing the board on the one he purchased.

Ed

Jeremy from Pinball Mayhem here

It may be a month or more before I really dig into mine but I have made some good progress with some basic testing. Turns out the board won't fully boot when a switch is stuck (makes sense). I disconnected the playfield switch harness connector and shazam - it booted. So my board appears to be properly working but I have not fully tested it with the playfield switches plugged in.

I will shoot you an email
Jeremy - Pinball Mayhem

Here's some information for board repair people:

It appears the transistors which are "house marked" as 224N1 are actually 2N3904 and the ones marked 223P1 are actually 2N3906.

Thank you

Unless there is something wrong with the spider chips, this board should be a fairly straightforward one to repair.

That's what I'll be counting on

is steve still around? I know he used to live near me

There are some forum members here that do board repairs.

Here's some pics from the board repairs. Main failure point appears to be that high voltage (30V) got into the switch low voltage (15 volt) and blew a chip. Still working through some bugs but making progress.

Comparison of my board and the board to be repaired. My board is an older version but it appears to only have a few relocated components (minor changes).

DSC05765 (resized).JPG

Blown chip

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here's the underside

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left skid marks on the board

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new chip sitting in a nice socket

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Other repairs and upgrades done to the board (My board will get these also)

This board had high heat marks left by the old zener diode and resistor - new ones installed up off the board for better cooling (small transistor also replaced)

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New small electrolytic caps installed

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New resistors installed up off the header boards for better cooling (old ones left burn marks)

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before shot of old diode bridges

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upgraded to 8 amp bridges

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That's more like it.

It's good that you are mounting the heat generating parts higher off the board for better air flow. Also good that you use sockets for the integrated circuits.

Good job spotting that blown chip.

Thank you

Much appreciated

I forgot the most important pic of the board repair - the underside! Where my work really shows - as in it doesn't stick out like a sore thumb where I replaced the chip with a socket.

DSC05783 (resized).JPG

UPDATE - the bugs have been fixed - apart from some further play testing to verify the repairs stick and nothing else craps out - I am calling this repair done!

So - what were the bugs? Well after the initial component replacement (blown chip, and other components that showed overheating) a game could only be started if a pop pumper or sling was activated first (very odd). On this game the solenoids are active all the time (there is no relay for these). Also during a game the pops/slings would not score any points.

There was more than one reason as is the case with most things that are 42 years old. ONE: a simple resistance test of the start button circuit path led me to the header pins on the board. Not only were they lightly corroded but when I went to resolder them the solder actually went away from the pins! After cleaning and resoldering the resistance test passed. TWO: As to the pops/slings: This circuit ties the activation switches to a signal amplifier - this signal goes to a transistor and that signal then goes along a similar path as the start signal. I believe this transistor was flaky and locked on causing the start signal to be ignored. After a pop was fired the transistor would relax. I tested this by removing the transistor - the game would start normally. Lucky for me this was the same part number transistor that I replaced in the high voltage circuit and I ordered extras (always order extras if they are cheap).

In the pic below my son is enjoying testing out the repairs

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Had a problem happen on my board with the sound - thought it might have been the speaker or volume switch BUT it was something different.

Thank goodness the schematic calls out the real part numbers instead of "house" numbers. A nice upgrade to the sound would be to replace that silly volume switch and it's associated three 1.8k resistors with a normal 5K potentiometer to control the volume.

Thank you. I'm building XP with each repair

I am working on one of these machines for a co-worker. I have repaired several things but it would not start the scoring. It would start the game but wouldn’t start registering points.
I was testing the circuit from the rollover switch to start the scoring to pin 31 of IC1 and didn’t seem to make contact. I was inspecting the legs on IC1 and it looks like someone tried to re-seat the chip and bent some legs. I pulled it and was trying to straighten the legs. Two broke off
I’m going to try and tack some back on.
Is there anywhere to get these chips?

Hmm that is a major setback for sure. A used board is my best guess for a replacement chip. But this chip may be salvageable. If you carefully remove part of the plastic over the broken pin you should be able to solder a thin wire onto what's left of the broken pin.

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I guess I’m in the market for a board now. I’m hoping I can tack some legs back on, but not sure.
Someone really made my life harder folding these legs. I didn’t want to pull it out, but it had to be done. If I can find another board I will just desolder the whole chip and socket together.

I haven’t worked on this exact chip but I’ve done this before on other ones. I was able to tack a new leg on a few chips by extracting a leg from a spare twin leaf socket. I just cut off the leaf portion and cut down the socket leg to size, tinned it, was able to tack it on the chip leg.

If you have trouble lining things up, you may be able to put the chip back into the socket with the broken legs, carefully insert the new legs into the appropriate positions, and the socket should hold things together while you tack it. Just be careful not to melt the socket lol.