Hey, everyone. New to the hobby. Bought my first machine at an auction with unknown provenance. I am an engineer, so I somehow passed Electrical Circuits in college, but I had zero interest in Electrical Engineering so I forgot most of what I once learned.

Everything on my machine seems to work except the (non-flipper) solenoids, which blow the 1A slo blo fuse underneath the playfield. This includes thumper bumpers, outholes, and drop targets.

I checked each solenoid for resistance and got 3-8 ohms or so across the leads, which I think is OK. The switches all test OK in test mode, so I don't think one is stuck closed. I had a fast-blow 1A fuse (slo blo's in the mail) for a quick test, and it blew immediately upon turning the machine on. Nothing even made a noise like it was trying to fire. I then checked the circuit to ground and the yellow wire to every solenoid shows about 163 ohms to the cabinet (ground), which to me sounds like a short. The other color wire from the solenoid gives me a slightly higher resistance measurement to ground. None of the other switches or lights show continuity to the cabinet (ground)

A few questions from here
1. Am I on the right track?
2. What do I do next, just start replacing wires or is there another diagnostic method to narrow it further?
3. If I start replacing wires, is it better to start from the last solenoid in the chain and keep testing for a short or the first in the chain and test for operation?

Thanks everyone in advance. Once I get everything cleaned up, I will post pictures like a proud father.

Will try those. Busy day today, so won't get to it until at least tomorrow.

I used a more accurate multimeter today. Resistance across leads on all solenoids except flippers:
Drops "E"- 14.8 ohms
"I": 14.2
"G": 14.4
"H": 14.4
"T" 14.3
Knocker - 14.7
Saucer (ejector hole at top of field): 11.2
Outhole kicker: 11.5
Thumper bumper L: 11.4
R: 10.7*
Sling shot "L": 11.3
"R" 11.3
* The only solenoid that looks like it is not original equipment is the Right Thumper Bumper.

Everything articulates manually. I still show a short, albeit with some resistance (175 ohms-ish), to the ground on the case of the machine on all solenoids except flippers and the knocker, which is the only solenoid above that worked in self test mode. I suspect the knocker is on another circuit.

Now, I have made my first mistake that might be costly. I accidentally hit the contact on the third flipper with the support rod and now all that works are lights - most of the time. It has booted up with sound and flippers a couple of times since the incident, but I probably fried something. I tested all fuses and all are OK except for the one on the field solenoids (which I received slow blow 1A fuses today)

OK, did more work today trying to find the problem. I don't think that my brief short on flipper 3 the other night did any good, but I also didn't break anything from what I can tell.

Sometimes, when I turn on the machine, it lights up but no sound and it doesn't display any numbers. If I tap the (non energized) end of the big capacitor in the power module, sometimes everything gets energized and starts to work (kinda like the 1980s version of TV repair-give it a bump on the side). I can then get into diagnostic mode for at least a couple of minutes and it will eventually lock up again with no sound and no numeric display. In test mode, all switches are open (all but one test good when manually closed) and still only solenoid #12 (knocker) fires in the solenoid test. I now have no fuse in the 1A slo blo circuit until I find something that I can fix to keep from wasting money on fuses. When the machine tries to start up but doesn't, I feel like it is starving for power. Instead of a "squawk" and displays showing numbers, I get a quick "thup" from the speaker and the displays are blank.

I am starting to think that I need to fix the Power Module by replacing or refurbishing it as the first step. Like I said earlier, I have a bit of tech savvy, but I don't even know how to test a capacitor, so I don't know where to go from here. I have the tools to test and solder resistors and diodes (I might even have replacements in stock with my Arduino kit) but I have maintained a "don't touch" policy with the "business end" of capacitors. If I could buy a new power module for ~$150 and find it fixed me up, I would be a pig in slop. If I could buy $50 in parts and fix it myself, I would be hooked on this hobby for life.

Oh, and Go Chiefs! I knew I needed a decent (albeit probably temporary) avitar.

I re-seated the playfield connector on the power module and the flippers, sound, and lights work again. The temporary short I discussed earlier apparently did not fry anything.

The playfield solenoid fuse (1A slo blo) still burns up before I can detect any solenoid movement in the field when I turn on the machine.

I think that I might start from the playfield fuse and cut the yellow wire and start to move through the 11 non-working solenoids one at a time unless someone can help me with some advice. I might have a power supply problem that I will have to deal with later, but I don't think a lack of power would trip a slo-blo fuse unless there was something else wrong as well. I have convinced myself that one of my field solenoids (or the wires connecting them) are shorted to the case of the machine. I can't seem to ferret out the problem with my multimeter, but I certainly welcome any advice to help me narrow down the problem. I measure ~170 ohm on the leads from every solenoid on the field to ground with the machine off and all switches open. At 43V DC, it blows a 1A fuse. V=IR means I should not be surprised at the result.

I could also work backward from the Right Thumper Bumper that is the only non-OEM solenoid on a hunch that perhaps it was a problem that the former owner diagnosed but failed to repair properly...

At this point, without more advice from you, I will probably cut the wire to the "replacement" thumper bumper and work up and down the circuit and measure the short to ground as I go.

Thank you, Frunch. Now we are getting somewhere.
TP1 5.22V OK
TP2 185V OK
TP3 250V OK
TP4 44.7V OK
TP5 (Didn't test, oops)
TP6 (-)0.5V NOT OK
TP7 (-)0.3V NOT OK
TP8 0V NOT OK
TP9 0V NOT OK.

Fuses all test OK and look like they are the right rating. The board doesn't tell me if any are slo blo, but neither do the fuses. FU1 and FU8 look pretty exotic so I guess they are SB.

After the results above, I removed the board and in the process, the "Controller" connector detached from the board. I was careful to put it back into place but it needs to be soldered for sure. I attached pics of my power supply.
Here are the results for resistors and diodes:
R1: 600 ohms
R2 is strange*
R3: 2.6 ohms
R4: 100.6 ohms
R5: 22,000 ohms
R6: 93,000 ohms
R7: 390 ohms
R8: 1200 ohms
R9: 81,000 ohms
R10: 8,200 ohms

*When I use the diode setting on my multimeter, R2 shows 1200 one way and infinite when I switch the leads. When I use the 200K ohm setting, it starts low and increases. If I flip the leads, it starts negative and rises indefinitely. It doesn't look like the other resistors and looks like it was probably replaced.

D1 525 ohms one way
D2 518 ohms one way
D3 512 ohms one way
D4 471 ohms one way
D5 610 ohms one way
D6 530 ohms one way
D7 514 ohms one way
D8 510 ohms one way
D9 520 ohms one way, 1450 backwards
D10 660 ohms one way

All of the parts labeled JW test for continuity, but some seem to have very high resistance. I don't know what they are or how to test them. I don't know how to test capacitors and frankly the two big caps on the board scare the crap out of me. You said I should replace them anyway, so I won't even try to test.

20181231_113940 (resized).jpg20181231_114000 (resized).jpg20181231_114004 (resized).jpg

I have the manual. I am slowly digesting and understanding as much of the 115 pages that I can.

I missed the fact that 6-7 and 8-9 are AC. As soon as I get the board soldered up, I will reinstall and check again. My brain was stuck in DC mode. I was obviously thinking that I was in a pickle with this board having 6-7-8-9 at zero volts DC.

I am still working on getting the jargon straight, so thanks for your patience. When you say re-flow, you mean to re-melt the existing solder joints for the connectors, right? Should I add a little bit of flux to the connectors that I know are bad? Should I avoid adding any more solder? Also, the caps you recommend replacing are just the two big ones, correct? And, when you say re-flowing the connectors, I assume you mean every one on the board and not just the joints that I know are crap.

I have no idea what is going on underneath the heat sinks, and I am nervous because it looks like someone has removed them. Any advice?

Also, R2 and D9 have me a little bit nervous. R2 definitely looks like it is not OEM, which could be OK but also could be very bad. I see in the manual that it is "100K ohm 1/4 watt FC1A, FC3B, FC8A Fuse Clips". It looks like the resistor is 100K ohm. The weirdness with the multimeter could be nothing.

Like I said earlier, I am glad that there is a $180 solution (buying a new board), but I think I might be able to do this with the equipment I have with and bit of help. I very much appreciate your advice.

Last question: I have a few soldering irons, but I am curious what you recommend for PCB repair. I have a couple of gun-type irons that are good for bulky wires and one cheap pen-style iron that I never seem to have much success with. Should I get a good pen-style iron for this hobby? I love to have a good excuse to buy a decent tool. My soldering guns are great for soldering connectors to 12 ga stranded wire, but seem to be a bit much for PCBs.

Bit of good news. I soldered up the connector that was clearly not connected and re-assembled the machine (I have ordered a better soldering iron before I re-do the whole board). The intermittent issues are gone and I was able to test TP5-9 on the power module.
TP5 16.8VAC
TP6 10.2VAC
TP7 10.3VAC
TP8 6.1 VAC
TP9 6.1 VAC

All looks food except that TP5 might be a bit high.

I still have a short in the playfield solenoids. I get 168 ohms to the cabinet on the yellow wires on all of the solenoids except for the flippers and thumper. The other color wire for each shows 168 ohms plus about 11 ohms.

Do I start removing solenoids until I get rid of the short, or do I need to start testing the control board? I read the pinwiki quoted above for solenoid problems on the 6803 and it was a little bit above my pay grade at this point. I see TP1-7 on the control board, but I can't find a ground and I don't know what/how to test the points.

The yellow wire is common to all of the solenoids and appears to connect them all in series (two yellow wires to most solenoids). That makes me think that is the ground, yes?

Also, if you were to have a situation like this, would you cut out the second solenoid in the circuit and then go down the chain adding one at a time, or start from the last one in the series and cut until the short is gone? I am thinking that I should start from the last in the series and cut until the short is gone. The biggest risk with this method is that the short is not in the solenoids/wiring but in the control board and I have then cut 11 solenoid connections that need to be reconnected before I consider control board repair/replacement. Maybe I will find the first solenoid in the series, cut it out to verify the short is somewhere in the playfield and then reconnect the whole series and work backwards, cutting solenoids until the short is gone.

Thank you, again. You helped me tremendously.

Here was my journey today:
1. Removed the connector from J6 and the short is gone. 1A SB fuses on the playfield held, some of the the previously dead solenoids now fire. Sweet. Still can't play since J6 has the flipper coils on it.

2. Tried to figure out the exact culprit. I test wires CJ-6 #1,2,3 and no short to ground (8 and 9 strangely have ~600 ohms to ground but I just figured the flipper coils may be constantly energized with a low current). I then tested pin #1 on J6 on the control board and that is where I think my trouble is. 215 oms to ground while the other pins test open. Probably bad news, but it eventually helped me take a guess on what to remove from the circuit.

3. Messed around a bit, blew a couple more fuses, decided that I might have a short on the "G" drop target between the solenoid and the nearby bulb so I inserted some electrical tape to make sure they were not touching (tip from pinwiki). Blew another fuse and decided to take a break and have a cold beverage.

4. Tested and re-tested everything in J6, which by the way the manual is not correct. There are only five drop targets and there is a wire in J6-4 and there is not a wire in J8-4. I could not figure out the numbering conventions and what the heck Drop Tar 1/2 and Drop Tar 4/5 might mean, so I figured it out on my own:
J6-1: "I" drop target
J6-2: "G"
J6-3 "H"
J6-4: "E"
J8-7: "T"

Since the J6-1 pin was cool kid that was acting like nobody else in the group, I decided to desolder the "I" drop target solenoid and try another fuse. Voila! I am now rolling. There are about 6-8 bulbs out and it could use a good cleaning, but otherwise the game does great other than the "I". Not quite eligible for high score until the "I" drop works, as it seems the machine recognises the fault and lets me play but does not score the "I" target behind the drop target. Before I desoldered the solenoid, the drop and the target behind worked good in test mode.

Now, what to do? I strongly suspect the problem is on the control board and a quick search suggests that maybe nobody sells or services 6803 control boards. I took the control board out and looked for any obvious problems. The circuit board connects CJ-6 to CJ-8 (unused perhaps?) on the bottom trace and then goes into Q11 on the top of the control board before I can't tell which end is up. Nothing looks awry. I could not detect any repair attempts to the control board, but the battery is new-ish (not OEM but also not the pinside-recommended replacement strategy). My machine seems to remember high scores and program settings.

I read the pinwiki article for the 6803 solenoid troubleshooting and it mentioned that R1 and VA1 are suspect. I will try to check those out but I am quickly getting out of my league as far as repair goes.

Whatever happens from here, I am going to get a rubber kit, replace the bulbs, clean and wax the playing surface. I see no reason to not try to replace the "I" solenoid as well, but I won't hold my breath (and I will make sure I have spare 1A SBs on hand). The previous owner seemed to not like the Tilt sensors, so I might refurb those as well. The plumb-bob seems to be just cut out (although pinwiki suggested cutting out the cap, so maybe it still works and I am just seeing the recommended mod) and the "lift-tilt" is just smashed together so that the ball doesn't move. Again, sorry if I am not using the correct terms.

So long story short (too late!), I think I am hooked. I have wanted to do this hobby for quite some time and never took the plunge. When I had a chance to buy Eight Ball Champ for a song, I finally jumped in and I am excited that it gave me a chance to work and learn and even more excited that I might not have a money pit. I don't know if I will parlay this into a fancier machine that needs repair, rinse and repeat, or keep it since it is my first.

I pulled this from Pinball Rehab. From the manual, I think Q11 is SE9302 transistor (and the one I should look at closely):

I assume I am testing with my DMM on diode setting...
------------------------------------------------------
NPN transistors, left lead is base (i.e. - TIP102, TIP120, TIP121, TIP122, 2N6045 and SE9302 )*

Put the DMM's red lead on the left leg of the transistor*.
Test to the middle leg and the right leg with the black lead.
You should get a reading between .3 - .9 volts on each (the two reading should be about the same).
Put the black lead on the left leg of the transistor.
Test to the middle leg and the right leg with the red lead.
Your DMM should read open on each.
Test across the middle and right legs, you should get an open reading.
Reverse leads on the middle and right legs, you should get an open reading.
* Orient the transistor with the metal tab facing away from you and the leads pointing down.
--------------------------------------------------------

I will check adjacent transistors as well and compare.

I de-soldered the wire that attaches to J6-1 on the control board from the "I" drop target solenoid to fix the problem (I think that is the + wire -edit we already covered that it is ground.). All the switches still test fine; the machine knows when the "I" target is dropped and when the target behind it gets hit. It just seems to not score the hit if the game starts with the "I" dropped or if the game tries to pop the drop targets and the "I" doesn't go up. Whatever voodoo is involved with that I will probably never know. I am just glad for now that it doesn't throw up some sort of error and not let me play.

I am banking on the transistor for now, but probably won't have time to mess with it today. I am going to check out my local Pinball Supply store. I will probably use them to source my refurb parts and ask what they would charge to solder my board if I tell them what needs to be done. I assume that would be less expensive than asking them to figure it out and fix it. I don't trust my soldering skills on the control board. There is too much going on in a small space for me to replace a transistor and not expect to screw something up.

The family and I played a few games today and it seems that I was wrong about the "I" not scoring. So the game is definitely playable, you just get a free drop. Certainly not the end of the world...

We played until it was obvious from the debris that I need to replace all the rubbers. I figured as such. There are some other minor things like bulbs and plastic acorn nuts and switches that you have to hit hard to register and one switch that locked closed while playing (that I adjusted before tango-ing on). This machine will be getting some love soon. There is now enough chunky old rubber on the playfield that I am going to wait to play until I replace all of it.

Back to the board. I tried the test method above and it didn't quite go as I expected but I did notice a difference. I might be spatially challenged and/or not understanding the wiki, but the transistor in Q11 is different than adjacent transistors in that in diode test the left (black) to center (red) gives me a reading of ~590 while the similar adjacent transistors show open. The wiki said that the left/right should be open as well but all of the transistors I tested read about 600 in diode mode. I don't really know what this means, but it is something. I think the transistor is probably bad like you suggested, but it might be impossible to reliably test it without removing it from the circuit board. The solder joints are small and very close to each other, so I will employ a professional to replace it if that is where I end up.

I contacted the two "pinball houses" in town that seem to specialize in parts and service and not (necessarily) sales. One was closed due to business hours and the other should have been open to answer the phone but did not. I sent similar e-mails to each house and will decide who to work with based on how it goes from here. I really want to support the local guys if they really want to support me. Kinda like my mechanic. He doesn't get much work from me because I DIY everything I can, but he gets 100% of the stuff I can't do on my own and he is honest and fair on price.

Thanks for the advice on the diode. I ordered a new coil/diode today as well as a new transistor, new set of rubber, etc. I figure I am covered either way for the repair and the price to ship is about the same price of the coil/diode.

I called both the local pinball houses twice, left vm messages, and e-mailed both without a response. Not what I was looking for, so I ordered online from Marco Specialties.

For the caps (and perhaps a better battery solution), I plan on checking out Great Plains like you suggested. This first order of stuff is mostly bulbs, rubber, plastic acorns, thumper bumper plastic, Wildcat 125, etc. which it doesn't seem like those are what Great Plains does. Since 99% of the machine works and I am dying to play it, I want to get the playfield in good shape before I start tinkering any more.

BTW, I was cruising Craigslist and found the saddest ad for a pinball machine ever: kansascity.craigslist.org link

I feel like I should buy it to set it free.

I (finally) did more research on the squawk and talk board and watched a video of people playing a fully restored Eight Ball Champ game. My machine squawks but does not talk. I think I can figure it out, but not until I finish the other restoration. The voice function doesn't seem to do much other than during start-up and the playfield game sounds work OK, so I am not in a hurry to fix the voice. I see there is plenty of discussion on the S&T board, so I will probably take that offline. I am adding to my list of caps/battery mods that I need to get from Great Plains.

IT WORKS!!!!!

I finally got the courage to buy the Hakko soldering station (as recommended) watch some tutorial videos, take a practice run on a PCB that is not quite so precious as the 6803 control board and swapped out the transistor, re-connected the solenoid and viola! Everything now works. Here is a running list of repairs so far:

Re-flowed power control board
Removed capacitor from R Rollover switch
Replaced transistor for "I" drop target
Cleaned pot on Squawk and Talk
Adjusted about 6-8 switches
Replaced all rubber
Cleaned and polished playfield
Replaced plastic thumper bumper tops
Cleaned/adjusted flippers

So, all-in I figure I have maybe $300-$400 in equity on a pretty fun game in decent shape that plays perfectly (except for one insert that is concave and frustrates the heck out of me because it changes the angle of the ball right in front of the flippers).

Thanks, again, for everyone's advice. I am totally geeked right now. I am going to go play.

New problem with two bulbs that won't light.

I am trying to troubleshoot this all on my lonesome this time, but want to check in with you vets to see if I have it right because I don't understand what my DMM is telling me. I apparently have too many new topics for a newbie and too few posts in other topics. I will work on that once my laser focus on my own machine subsides.

-10,000 left rollover and 10,000 right rollover lamps do not light even though they have fresh bulbs and test for continuity across the leads with bulbs installed (first check - are they plugged in?). No voltage is being applied, I am sure. The other 98 bulbs and all of the switches and solenoids (and Squawk and Talk) on the machine work fine.
-Manual calls out only "Rollover lanes 10,000". Sweet. Both bulbs are on the same circuit and we are now down to one problem that is affecting both lamps
-Lamp assemblies each have a diode. Both check 700 one way and open other. Seems the same as sister lamp assemblies. I did not test to make sure the diodes match polarity (could be an issue with two bulb assemblies in parallel I suppose).
-Connections on both "10,000" lamp assemblies have continuity to ground. That is different...
-Checked pin CJ12-4 with the wire assembly disconnected and compared to J13-2, J13-8, etc (other rollover lane lamps) The problem pin acts like it is connected to ground through a diode (one way reads ~700, other way reads open). Other pins are open both ways.

Now, I feel like I am getting somewhere. The transistor connected to CJ12-4 is suspect. (I now have some confidence in changing out transistors, BTW) I have a hard time ciphering wire schematics, so I will trace the suspect transistor by inspecting the wire traces on the 6803 control board to find out which one might be goofy.

I then for kicks and grins tested the disconnected wire through the wiring harness to CJ12-4, and it tests the same as the pin (diode reading ~700 to ground one way, open other). Now I am unsure of my diagnosis. The sister lamp assemblies are open to ground when I test them through the J13 connector.

The wires are good from the harness on the control board to the lamp assemblies. Very low resistance when I test from the harness to the lamp assembly.

When you say check DC voltage, I am not quite sure what you mean. I am nervous to turn on the machine and start hooking my DMM to stuff without knowing what I am looking for. You are suggesting the DMM set to low DC volts with the black lead on the red/white wire on the lamp assembly and the red lead on the other wire on the lamp assembly?

Sorry for the remedial electrical circuits questions.

I concur on the Q65 location and MCR-106-1 transistor spec. Your digital manual copy seems to have better resolution than my paper copy.

I see what you are saying. The + lead should have voltage to ground, but it doesn't light because the board is not completing the ground side of the circuit. I will probably try the continuity method, as stuff is pretty tight underneath the playfield and I am uninterested in having an accident.

Let's say I continue to suspect the transistor and I swap it out. Do you have any tricks for taking it out and leaving clean holes in the PCB? Last time, I tried re-flowing the leads on the transistor and adding a dab of fresh solder. I then tried to use a solder sucker without full success. It looked clean, but never freed up the transistor. I ended up cutting two of the legs, pulling the center out under heat and pushing the remainder of the other two pins out with a small round soldering iron tip. This left solder in the holes that I couldn't seem to suck out. I had more success in my trial runs taking out components, but those were newer PCBs. Perhaps the age of this solder keeps the viscosity super high...

Diodes test OK. I haven't taken out the board to see if I can learn anything about the transistor. I probably won't until this weekend at the earliest. It is such a minor thing that I just want to work on my high score for a while.

I have 6116 NVRAM module coming soon, so I will get to learn about customizing game settings. I haven't tried to do that yet, because I don't think it would remember any changes I made.

(I know that there is some topic drift in this thread. I am trying to find out why I can't post a new topic with the mods - it could be a problem with cookies on my machine or that I have made too many new threads or I am just an idiot. All three are distinct possibilities.)

I installed my 6116 NVRAM today and it has to be the best $16 plus shipping I have spent so far. Someone had apparently replaced the original NiCd on the 6803 control board with a lithium rechargeable and the game settings seemed to stay stable, but it was probably a matter of time before I developed problems. The high score seemed to not work as intended, but it maintained game options otherwise. I cut off the battery, got everything programmed, and we are dancing along. This machine has in the last three months, traveled back in time to 1985.

The Pinitech installation instructions for the 6116 board weren't much help; I think when they wrote the instructions "enter operator mode and hit A until "Feature Options" is displayed", they were talking about a more modern 6803 machine. I did have to take the control board out of the machine because the 6116 required FIRM pressure to install into the socket. All being said, I would classify the conversion as "plug and play" beyond what we may have imagined 30+ years ago. I took the chance with the control board removed to check out the Q65 transistor that helps control the light(s) that are dead.

In diode mode, I tested all of the permutations and compared results to similar circuits Q34. Q51, Q66 and Q35. They all tested the same. I understand that testing transistors on a circuit board might not always show that something is bad. So I then tested the wire in the harness J12-4 and determined it is continuous to the positive lead on the light circuit. Even far away from the lamp, I get low voltage drop after the diodes for both lamp assemblies and ~700 (one way, open other) when I bring the diodes into the equation. The "+" side of the circuit is acting perfectly from my estimation. I just need to figure out how to get the control board to close the "-" side of the circuit when appropriate.

Then, I test pin J12-4 on the board in diode mode and it also gives me continuity (with some resistance) to ground. Similar pins J13-1, J13-8 etc. show open. I am thinking for sure something is awry on the board, but I am less sure what component might be dead at this point.

I notice that in the schematic you attached, J12-4 is phase B and J11-1 is phase A on the Q65 circuit. J11-1 is "Bonus 9", which I think is the lamp for the 9 ball in the center of the field, which works as intended (and not coincidentally has the same wire code). Does this mean anything? I checked the "Bonus 9" for operation and also the diode, both check out good.

I have read about multiplexed circuits and it seems like that is what I have here. Does this mean the transistor is now 99.9% suspect? I don't yet understand multiplexing (and my eyes get glazed over once I read NAND).

The "9" is off when it should be and constantly on when it should be.

I tested for resistance across the metal leads on the back of the lamp sockets with the bulbs in and I show low resistance. Take the bulbs out, open circuit. I tested the diodes on the lamp assemblies and they both read about 700 one way and open when hooked up in reverse. A 9v battery hooked across the leads in the sockets lights the bulbs. If I hook the 9V battery up backward and include the diode the lamps do not light. If I connect + and - correctly with the diode included, they light. I have positive DC voltage (it jumps around quite a bit but there are lots of flashy lights on the playfield) at the sockets with the machine turned on. It think I have eliminated the light sockets and bulbs.

So, is it possible that only the "B" phase on the transistor is bad? I still don't understand transistors very well.

With my 9v tester, I compared the two non-working lamps with others like it and they acted the same. Hooked up +/- correctly = light; backward polarity = no light.

Going back to my original observation, the J12-4 pin on the board is the only one that gets a reading on my DMM in diode mode. I think something has to be wrong on the board. Do you think I run a risk of damaging something by testing J12-4 pin for DCV with the machine running? Adjacent pins are flashy lamps as well so I don't think if I accidentally short two adjacent pins it will be a big deal. If I do, where should I pick up +DCV? I see TP1-4 on the control board, but don't know which TP does what.