Bolex 18-5L stopped running

[Steve Klare]

Hi Dan,

Yes, since capacitances add in parallel, you solder one capacitor across the other and then wire each of the united connections to one of the projector's wires that connected to the old cap.

The flickering voltage on the lamp-socket probably means some internal connection isn't as solid as you need it to be. This could actually be the root of your troubles here.

[Dan Winckler]

Thank you! I sprayed every contact I could see, tried the second cap (clipped in place), nothing. Then I took the cover off the wiring loom (right word?) and probed connections between the 2 leads that go to the cap. The black one was fine, dark green was not. I tried bridging the dark green points with a bit of lamp wire, still nothing. Steve, I think you must be right that there’s a bad wire in there somehow. Have any of you completely rewired one of these?

Also, separate note: would running it with the voltage dial at 110v instead of 117V cause problems or potentially break something? Because I, er, did that….

Update: I added some photos of the wiring. The dark green wire (see IMG_7814) is the one that seems to be having trouble.

[Shane C. Collins]

Thank you! I sprayed every contact I could see, tried the second cap (clipped in place), nothing. Then I took the cover off the wiring loom (right word?) and probed connections between the 2 leads that go to the cap. The black one was fine, dark green was not. I tried bridging the dark green points with a bit of lamp wire, still nothing. Steve, I think you must be right that there’s a bad wire in there somehow. Have any of you completely rewired one of these?

Also, separate note: would running it with the voltage dial at 110v instead of 117V cause problems or potentially break something? Because I, er, did that….

Update: I added some photos of the wiring. The dark green wire (see IMG_7814) is the one that seems to be having trouble.

There's one other possibility, that could be causing the projector not to turn on, the main selector switch. Many years ago, I read on the old 8mm forum, someone had an issue with the lamp not turning on. After several back and forths it was determined to be the main selector switch. If you take the lamp housing cover off, and look behind the selector switch, you will see all the wires. Is it possible the green wire is connected to the main selector switch? The idea behind this was the wires at the selector switch have become tarnished. The problem with this selector switch is you can't gain access to it.

I once had a Bolex 18-5L Super that had this issue of no lamp. After cleaning as many switches as possible I decided to clean the selector switch. The only way I was able to do so was to spray contact cleaner behind the switch. As I sprayed the contact cleaner, I worked the switch at the same time. I sprayed a good amount of contact cleaner behind the switch as this area is very difficult to get too. I let it dry for a few minutes. I turned the projector on and the lamp worked, and still does. In your case the machine is not turning on at all, but it is connected to this switch. This might be worth a shot. I've circled the switch below. You will probably need the small clear tube that comes with contact cleaner to get behind this switch. No worries if you get a lot of cleaner back there as it will evaporate, as you know.

[Dan Winckler]

Thanks, Shane! I just sprayed some DeoxIT back there and flicked the switch a bunch -- no good.

Did you see my question about the voltage switch? I'm worried I might have burned something out by setting that to 110 instead of 117V.

Another basic question: this replacement cap is 370V. Right now it's switched on with current, but a DC voltage reading at 500V of the cap's contacts reads 0. Shouldn't there be some voltage there, if it's getting power? Again, maybe a bad connection.

Also, when I continuity-test the bottom of the fuse holder against the power contacts (coming off the inside of the jack), I get a beep, but the sheath does not. The jumper from the sheath leads to the voltage rotary switch (good beep), and I can only reach and test a few of those, so it's not clear where the fault might lie.

[Steve Klare]

Hi Dan, 110VAC vs. 117 is a pretty slender difference. Especially on rugged old stuff like this it will barely shrug! (-metaphorically!)

Your capacitor voltage should be AC, if you measure it on a DC scale, you will see very little or no voltage. Please try it again with AC Volts.

[Shane C. Collins]

Dan, any luck with the Bolex projector?

[Dan Winckler]

Hey Shane, thanks for following up! Unfortunately I had to table this project for now. I was able to find a rental projector through a great local arts organization (Mono No Aware) so I can rescan the home movies in time to share them with family this Hanukkah. Once they're all scanned I am hoping to have some downtime when I can tinker with the Bolex some more. I will probably try replacing some wiring one by one as a next step, unless you all have better advice.

[Steve Klare]

Hi Dan,

I hope you can learn a lot by unplugging the machine and poking around with an ohmmeter: look for things like the continuity of the motor and switches and wired connections.

-always better to work at zero volts if you can!

This is a simple machine: there is always the hope of a simple solution.