# Lamp Matrix Diagnosis On My Back to the Future Pinball Machine

**Source:** Cary Hardy  
**Type:** video  
**Published:** 2018-09-07  
**Duration:** 10m 48s  
**Beat:** Pinball

**URL:** https://www.youtube.com/watch?v=a0uSATGyi1s

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## Analysis

Cary Hardy diagnoses and repairs a lamp matrix bleed issue on his Back to the Future pinball machine caused by a loose diode connection on the playfield. Using multimeter diagnostics and visual inspection, he identifies a weakly soldered diode socket near the upper playfield that was allowing electrical bleed, then re-solders it to fix the problem. The video demonstrates practical troubleshooting methodology for lamp matrix issues common in pinball machines.

### Key Claims

- [HIGH] Lamp matrix bleeds (lights coming on when they shouldn't) are caused by loose diode connections or bad solder joints on the playfield — _Direct demonstration and diagnosis on Back to the Future; Cary identifies the culprit as a poorly soldered diode that slides freely in its socket_
- [HIGH] Diagnostic method: watch demo mode light scan to identify where unintended lights activate, then narrow location by testing specific playfield components — _Cary's systematic approach watching demo mode, identifying Lamp Return 4 row, then narrowing to specific playfield area and testing individual lights_
- [MEDIUM] Some previous repairs on Back to the Future may have used quick fixes (loose diodes) instead of proper soldering — _Cary notes the diode 'might have been a quick fix in the past by somebody' and observes no original soldering on the connection_
- [HIGH] Back to the Future has additional issues beyond lamp matrix (non-working flashers) that require separate repair — _Cary states at end: 'I've discovered another issues that I'm gonna need to resolve on that Back to the Future machine is that I have some flashers that aren't working'_
- [MEDIUM] Ball contact with upper playfield ramps can over time cause damage to nearby components like diode sockets — _Cary speculates: 'once you hit this ramp or even this ramp up here the ball sometimes launches and makes contact with these things and who knows maybe over time maybe something's starting to...'_

### Notable Quotes

> "Some lights are coming on that don't need to be coming on. It's a huge deal. The OCD in me is just screaming and it needs to be repaired."
> — **Cary Hardy**, ~0:20
> _Sets up the motivation for the diagnostic video; emphasizes why seemingly minor lamp matrix issues matter to serious pinball enthusiasts_

> "If they were lit fully all the way like this, then I'd say we more than likely have a board issue. But since they're only vaguely lit up, then that tells me that I've got a bleed somewhere."
> — **Cary Hardy**, ~2:45
> _Demonstrates diagnostic reasoning: full illumination vs. partial indicates board vs. playfield issue_

> "so when I'm messing with this the lights go away ah you son of a bitch you are the culprit so it's this little bastard right here"
> — **Cary Hardy**, ~9:00
> _Moment of discovery when testing individual playfield components reveals the loose diode socket is the problem_

> "Look how I can slide that around. So as long as I keep it making contact, it should be all right."
> — **Cary Hardy**, ~10:15
> _Confirms the diode is not properly seated; demonstrates the loose connection that was causing the bleed_

> "lamp matrix problems can sometimes be a big hassle because you're having to go underneath the playfield and trace the wire to every single bulb to make sure that your connections are good"
> — **Cary Hardy**, ~12:30
> _Explains why lamp matrix diagnosis is challenging and time-consuming for technicians_

### Entities

| Name | Type | Context |
|------|------|---------|
| Cary Hardy | person | Content creator and pinball technician; produces detailed diagnostic and repair videos; demonstrates hands-on troubleshooting methodology |
| Back to the Future | game | Stern pinball machine; subject of the repair video; has lamp matrix bleed issue caused by loose diode socket and flasher problems |
| Stern Pinball | company | Manufacturer of Back to the Future pinball machine being serviced |

### Topics

- **Primary:** Lamp matrix diagnosis and repair, Playfield component troubleshooting, Diode sockets and solder joint quality, Back to the Future pinball maintenance
- **Secondary:** Multimeter diagnostics in pinball
- **Mentioned:** Flasher repair (mentioned for future video)

### Sentiment

**Positive** (0.85) — Cary is satisfied with the quick diagnosis and repair; frustrated by the issue but pleased it resolved easier than expected. No criticism of manufacturers or community; educational and practical tone throughout.

### Signals

- **[operational_signal]** Cary Hardy demonstrates systematic lamp matrix troubleshooting methodology suitable for content creator/technician education (confidence: high) — Uses demo mode observation, identifies specific lamp return row, narrows location, tests individual components, identifies root cause (loose diode), implements solder repair
- **[product_concern]** Back to the Future exhibits lamp matrix bleed from loose diode socket, suggesting either manufacturing defect or previous inadequate repair; may indicate quality control issue (confidence: medium) — Cary notes diode 'might have been a quick fix in the past' with 'no soldering job on this' originally, suggesting initial assembly quality issue or failed prior repair

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## Transcript

What's up guys? So I was playing my Back to the Future and I just happened to notice that there is an issue that a lot of people probably wouldn't notice. But for us pinheads, I can guarantee you, you wouldn't notice. Let me see if you notice what the issue is. Mass 0.107 Density 3.3 I know, right? Hell to the no. Now some of you might be thinking to yourselves, so what's the big deal? Some lights are coming on that don't need to be coming on. It's a huge deal. The OCD in me is just screaming and it needs to be repaired. So that's what we are going to be doing today. I'm going to be pulling out my Back to the Future and we're going to be diagnosing this Lamp Matrix issue. So let's pull this puppy out and get rocking. So this is Lamp Return 4. This is the one that looks like we're getting a bleed in our connection because they're not fully lit. If they were lit fully all the way like this, then I'd say we more than likely have a board issue. But since it's basically, they're only vaguely lit up, then that tells me that I've got a bleed somewhere. and it's probably on my play field. It's gotta be on the play field actually. Our columns. Alright so our columns are doing excellent Alright so it not a column issue it going to be a row issue Lamp return 4, that's red and yellow, Q75. And those lights consist of that one, that one, that one, that one, this one, this one and this one so one two three four five six seven where's the eighth one what am I missing one two three four five six seven and up here eight okay so So, alright, so, I'm going to check all of these lights to make sure I don't have some kind of short or a bad diode. And then we're going to see if that's what our issue is. All right, so I believe all I'm going to need is my multimeter and my handy-dandy multi-purpose screwdriver. So when I'm watching the game in demo mode, I see that basically it's, when it does a full scan down the play field, like lighting the lights up, it's they're not always on so that's telling me that there's something going down this play field that's shorting and bleeding the connection off and it doesn't seem to light up till i get around this top 25 area right here so like once it gets down to like somewhere in this vicinity is where i'm seeing my light down here come on when it's not supposed to be so it's either going to be the oh that's fairly lit right here my ultimate millions is right here or the 50k award bonus right there I think one of these is going to be my culprit I'm hoping it's not the one back here that's going be much of a pain in the butt to get to so I'm gonna get access to basically what is easiest to access to as of right now that should be much of a problem but that that a controlled one and it on a board down there i believe or is it i can remember now it been a while since i looked underneath this playfield i don't think there are any boards in there no that's just a regular uh old uh okay yeah never mind that disregard that but when it comes to easy access without having to lift any playfield parts up or anything it's going to be actually come down to just this little sucker right here and I almost want to say it wouldn't surprise me if there is some kind of issue with this because a lot of the times particularly on this game once you hit this ramp or even this ramp up here the ball sometimes launches and makes contact with these things and who knows maybe over time maybe something's starting to uh basically you know I can access everything from back here so I don't see looks like basically the diodes not detached I don't see any loose wire oh so what uh-huh so when I'm messing with this the lights go away ah you son of a bitch you are the culprit so it's this little bastard right here this thing right here and it looks like all I had to do was just twist that around oh that's that's too touchy I don't like that a ball can come up and just activate that thing again in no time I'm going to take this apart get that socket out and I'm gonna try cleaning it up I might even just replace it I've got some extra sockets and I'll just re solder a new one on there and solve this problem. I ain't gonna have that. Not today. Let's do it. We be right back and here is the issue guys it is this diode is kind of just in here it not really connected Look how I can slide that around. So as long as I keep it making contact, it should be all right. So I'm going to tighten this up. Then I'm going to do a soldering job on this because it looks like there was no soldering job on this. It might have been a quick fix in the past by somebody. In the past. all right so let's get the the soldering iron heated up and get this sucker fixed and there you go it turned out to be a lot easier fix and I thought it was going to be and I'm glad I'm an easy fix is always a good thing and it just it's what I assumed it was which is a bad bulb or a bad connection lamp matrix problems can sometimes be a big hassle because you're having to go underneath the playfield and trace the wire to every single bulb to make sure that your connections are good and sometimes the diode may end up eventually going bad. So luckily this was a playfield issue that I was able to find quickly and my guesstimation of the location of the light was almost spot-on so that actually worked out in my benefit as well. So that's one problem down but trust me I've discovered another issues that I'm gonna need to resolve on that Back to the Future machine is that I have some flashers that aren't working and I'm gonna get that going but I'm gonna save that for a different video for next time so until then thanks for watching guys peace out give this video a thumbs up and don't forget to subscribe guys and put that little ring bell down there that way you can be notified of whenever I post new material for you to check out something that you may need to know

_(Acquisition: youtube_groq_whisper, Enrichment: v3)_

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*Exported from Journalist Tool on 2026-04-13 | Item ID: 4cf5427c-893a-426a-8aad-4b6554c38e43*