Compare the voltage/behavior on the gate leg of another SCR in lamp test mode. If the result is the same, Q47 is being told to switch on.

With the confusion on where the gate leg was on the SCR, please redo the jumper test from test point TP3 on the lamp board to the gate leg of Q47. Does the Tilt lamp illuminate?

Are you using LEDs or incandescent lamps?

Quench continues to be my hero.

Anyone have a red paint match for Viking cabinet?

Molotow Signal Red

Thank you. One more thing that I can't seem to find are the Bally stamped lane guides. Anybody have a source?

I looked forever and couldn’t find them, so I ended up restoring my old ones with retrobright. Beware ebay, I tried one with the title “Bally” and they came with just the lightning bolt.

Good tip and thanks. I've looked everywhere I could think and everybody is out seems like there is some real money to be spent on making some more. Seems odd that no one is producing them.

I'm pretty sure Rick/Planetary would have the rights to make them, right? Anyway, they are increasingly rare to see.

Jsa ,

Quench is a legend!

Helped with my flight 2000 ta-100 board

So when I test the right leg on TP3, it doesnt light. When I test it on the center leg, it lights dimly. I am using LEDs, but I have incandescents that I can use to test also.

When doing the voltage test on other SCRs, I get a much larger difference in reading in lamp test mode. It goes from 0ish to 150ish (one hundred fifty) mV. The SCR in question only goes from 0ish to 15ish mV.

Ok, maybe doing these tests in lamp test mode wasn't a good idea since it doesn't help your multi-meter to give steady readings.

Please open up a support thread for this in the "Tech: Early solid State" subforum so this thread can return to normal discussion about the games.

Try the following and answer in your new thread.

Install normal incandescents in the Tilt lamp socket and also the Ball In Play lamp sockets.
Start a game and put it in Tilt mode.
Measure the voltages on the lamp driver board at the following locations (black multi-meter lead connected to TP1 GND on the lamp driver board and leave it there).

Measure these locations for the Tilt lamp:
U4 Pin 14
U8 Pin 14
U8 Pin 15
Q47 gate leg

Measure these locations for the Ball in Play lamps:
U1 Pin 14
U6 Pin 11
U6 Pin 12
Q16 gate leg

.
Both these lamps should be lit so we're comparing voltages for their selection and drive circuits.

The following images are to clarify IC pin leg numbering anti-clockwise:

Pin_Numbering6a.jpg
Pin_Numbering2.jpg

Thanks Quench
https://pinside.com/pinball/forum/topic/tilt-lamp-for-stern-stars

Anyone have any bally cabinet hardware? I need the cabinet bracket to hold a centaur Era playfield. Left and right

20190330_194928 (resized).jpg

I have a meteor where the ball feed is sometimes too weak to get the ball out of the trough. Sometimes it works fine, sometimes it won't feed a ball and will continually kick it gently, roll back down, and repeat. I've verified that the mech is buttery smooth and isn't hanging on anything. I took it apart and reassembled just in case. I ran out of time troubleshooting and need to go back later. Other than repinning connectors and reflowing joints are there any likely suspects? Would a failing transistor, chip, or bridge potentially cause this? It's got a fairly new weebly rectifier board.

The little plastic piece by the left arrow on my Eight Ball Deluxe was worn loose after years of use. The looseness would cause the kicker arm to sometimes hit the ball off center, not giving it enough velocity to make it through the trough, describing exactly what you're talking about it. This would happen once out of maybe 8 to 10 times. I could not find a new plastic piece to replace it, so my rigged resolution was to pull off the plastic piece, wrap some tape around the post, then put the plastic piece back on so it's nice and tight. So far it's worked well for the last 2 months.

Kicker.jpg

Question for the AS-2518 enthusiasts here, as I have not played many of these games due to not many being sited / available to play, what games of the Stern Category and then the Bally Category have the best rules? If possible don't worry about the art and layout as I am more focusing on the games features (drops etc) and mainly RULES.

Stern -

Bally -

To each their own...
For me:
1) Star Gazer; spinner points or drop target points.
2) Harlem Globe Trotters; over all good game.

B - Paragon, centaur
Stern - Flight 2k, quiksilver

True, true,true. Very good games.

I got all 4 of these

Thanks guys, and interesting, will have to check them out...

I honestly thought fathom may have got a mention, but maybe the art is one of the bonuses there as I did ask based on rules

Anyone have a left and right set of these?

s-l1600 (resized).jpg

I had the right side flippers go out on Space Invaders the other day. I found a wire that had broken free from the EOS, so soldered it back in place. And the flippers on the right still aren't working. I'm getting voltage to the coil lugs, but not getting 43V to the cabinet button. I forgot to do a continuity check, but will do it tomorrow when I'm at my location. It's probably something simple, but I've never had a dangling wire not bring a flipper back to life after it was soldered back on. The left side works, and there is only one circuit sending power in, plus all 3 coil lugs on the right have voltage, so the windings are in one piece.

Am I missing something obvious?

Did you check the back traces on the SDB.?

The S33 switch on my mpu doesn't work and I want to change some sound settings on my medusa. According to the schematic there are only 2 points for the switch on the mpu but looking at back side of the board there are 4. Does anyone know what 2(?) points I would bridge to bypass the switch?

Screenshot_20190404-003617 (resized).png

????? Bally Medusa sounds are controlled by test function #18; the button is on the coin door.
Setting are "00", "01" chimes no background snd.
Setting "02" scoring noise effect no background snd.
Setting "03" scoring effects with background snd
You control the input by pressing the start button on the coin door...
Note: the input cycles from 00...03 and back around again.
read pg.7 of the Medusa game manual
Part #F0 713

I didn’t but will certainly check the path tonight.

One side of S33 goes to the NMI pin of the CPU the other to ground (0v). R13 is a pullup resistor on the CPU side which keeps the NMI pin HIGH (5v) when the switch is open. When the switch is closed it the path ground over rides the pullup resistor and the NMI pin or CPU (p6) would read 0v.

With the switch open CPU P6 should be high, 5v. While the switch is closed CPU P6 should be low (0v).

You can measure continuity through the switch too. When switch is closed you will ready continuity through it.

BUT i don't think any of this matters. The sound settings cannot be cleared by the NMI audit clear button. You must use the start button to scroll the audit. Safe bet is to set all audits past 15 to '03' for most advanced sound effects on all games.

Hello Pin-Gurus

I'm new to the forum.
My name is Andreas. I'm 49 years old and from Stuttgart / Germany.
After reading a while and learning many things about pins and their electronics I decided to subscribe to the forum.
Thanks for your valuable input!

A few weeks ago I startet my first pinball project.
I'm trying to bring a Power Play (MPU 2518-17) back to life. After it's many years of hibernation I'm trying to restore the pin. The MPU board had the expected problems with oxidation so i changed all headers and sockets with new ICs (U8, U9, U10, U11) after cleaning the board carefully.

It boots fine but there seems to be a bigger problem with the switch matrix. After I got several wrong (and differend) results on switch testing, I isolated the MPU from the playfield and connected only J4. Then I measured the Strobes and Inputs on J2 with a scope from PIA up to the header pins.

I got readings of very nice and crisp signals up to the anode of the Diodes. In case of ST0 the diode CR43. On the kathode side of the diodes the signals goes bad. I looks like the signal can't "discharge" fast enough. Or some other signal or potential is crosstalking and keeps the strobes on "High". Sometimes after powering up the signals on the strobes are good. But only for a few minutes the they stay high again.

I'm staring at the schematics for hours and disconect caps and resistors along the trace. But no difference.

Any ideas what can cause the signals to stay high?

ST0_error (resized).jpg

Hi sinus and welcome to Pinside

There are many different conversations happening in this thread so may I suggest you create your own new thread in the early solid state tech support sub-forum and post your question there:

https://pinside.com/pinball/forum/forum/tech-early-80s-solid-state

In your new thread please give us some more details about the actual switch problems you're having.

Cheers.

Does anyone know of a decent 4" speaker replacement option?

Over the years, I've purchased a number of 4" Kicker 4 ohm speakers and I've been quite happy with them. They may be a bit overkill for the source but at least I know I'm not making it worse.

I know the stock speakers are 8ohm. Would going down to 4 ohms over/underpower the speaker? I'm not super certain on how all that works

You're correct that in most cases, Bally was really cheap and used crappy 8 ohm speakers. However, at least on Future Spa and similar generation, the amps in the sound board were actually specified to work with 4 ohm. I've been running 4 ohm with no problems.

The only 8 ohm 4" speakers you can get are basically designed to beep in a microwave.

[Edit: To answer your question, they do not under or over power your speaker. You do have greater latitude to adjust the pot, as designed, instead of blowing on it and it being too loud or soft.]

The SDB in an early Bally SS shows 2.2v for 5v test points.....

I picked up a non-working 1978 Bally Black Jack project a few weeks ago and I'm finally getting around to it this weekend. Power on and GI comes on but MPU won't boot (solid LED). Disconnected all boards and started with the power supply. Fuses are intact and at the correct values, and all test points on the rectifier board show proper DC and AC voltages.

I now have J3 on the rectifier board and J3 on the SDB connected. TP1 and TP3 on the SDB show only 2.2v instead of 5v. All other test points on the SDB show their correct values. Figure this will be the starting point of the repair journey. I've re-pinned all of the connectors on the SDB and rectifier, but no help.

I'm looking for guidance on what to check next, hopefully something specific to do to hone in on the low 5v SDB circuit (vs. shotgunning and replacing a bunch of parts...I'm not very handy yet with a soldering iron on a PCB). Note: The SDB in this machine is a Stern SDU-100 Revision A (blue masking). I don't have another spare SDB at the moment to stick in there and see if it progresses any further.

Thanx in advance for any guidance...

Question, I bought a space invaders backbox with glass etc. But there is no board to drive the front bulbs. I can buy the board to do that. Wonder how this is going to be attached and will work if I just power the board? How are these bulbs attached to the board, I see some huge connectors in the manual.

Are you trying to just light up the head for display or asking how to reconnect it to the cabinet and hook it up?

Anyone have a spare transformer/rectifier laying around? Bought a frontier without a head key and was surprised to find mine missing once I drilled the lock at home...

79AB03CC-B9E1-4F63-B3B9-4C485BD746A5 (resized).jpeg

Ouch!

Just try to lit up the backbox for decoration. I do not have the rest of the machine

Keep your eyes open, these are getting harder to find. E122-125 is what you are looking for in regards to the transformer, harness and rectifier are easily purchased.

You can get a new rectifier board from:
https://nvram.weebly.com/new-pcbs.html

A DIY kit is only $35 shipped or $55 shipped assembled.

The transformer might be a bit more tricky to source.

ok thanks everyone. Looks like I can grab the transformer for $200 which stings but what can you do

It won't work just by powering the board. You need something to control the lamps, which is the MPU. And to power the MPU you'll need regulated +5V and unregulated +43V. The lamps are normally +6V unregulated, but you could use regulated +5V if you want.

I would just use a computer AT power supply for the 5V, but you will also need a transformer to "fake" the zero crossing circuit on the MPU, something in the 21-24V range. Might be difficult to find.

What I would suggest, and what I did since I also have a SI head with no body, is to buy a E122-125 transformer and rectifier. Take an AC power cord and wire a connector to supply power to the transformer (I'd have to check the schematics to see which pins are the AC supply). Then you can power everything in the head including the sound board and displays. I made a switch matrix board so I could actually coin up, start a game and score points. It makes a very cool wall hanger.

Hmm, that sound like a lot of work, I was hoping a 2 channel running light board would be available I see some 4 channel ones on Amazon. But not sure I can add 32x 6v lamps to that.
https://www.amazon.com/Channel-Lights-Controller-Chaser-HK9984/dp/B01NC1XZLZ

It says 5A max and those look like some beefy drive transistors so I have to assume that's 5A per channel. You'd have no problem running incandescents with it - 8 per channel as you need.

Note to self: The Alltek SDB and the Bally SDB are not exactly the same electrically.

When I picked up a non-working project Mata Hari months ago, I re-pinned all the connectors and got it up and running with Alltek boards. Been working for months. Got the original Bally boards back from being repaired and put them all in - boots fine but no solenoids. Go back to the Alltek SDB, works fine. Put the newly repaired Bally SDB in, boots all the way and can even start a game but no solenoids.

Probed the Bally SDB with a DMM - all TP's fine with voltage except TP3 (showed 0V, should be 5V). I tied the 5V from TP1 to TP3 with alligator clips, and the Bally SDB then worked fine.

I then took a closer look at the J3 connector (specifically the jumper wire connecting pins 13 and 25). No continuity. I pulled the jumper wire out, and sure enough one of the pins that I had re-pinned months earlier was mangled. I re-pinned the jumper wire, put it back in, removed the TP1 to TP3 alligator clips, and everything works again with the Bally SDB.

The Alltek board apparently does not need that jumper wire present in the J3 connector. I screwed up the crimp months ago and never knew it because the Alltek board just worked. When the Bally SDB didn't work, I never suspected there to be a wire issue given that the Alltek worked fine!

SDB J3 Jumper Wire - Damaged Pin.jpg

There is an upgrade you should do to the AS-2518-22 board.
Look here on the www.pinwiki.com:
http://www.pinwiki.com/wiki/index.php?title=Bally/Stern#Solenoid_Driver_Upgrades

Peter