Bolex 18-5L stopped running

[Dan Winckler]

Yesterday I started up our newly acquired (eBay), working Bolex 18-5L to watch some old home movies. Everything went great for the first five reels or so then, after watching a reel and switching it off, the projector just stopped working. I've verified the power lead, probed the lamp base and gotten a reading, and examined the fuse. Based on another post I read, I suspect the capacitor; however, I haven't been able to find any comparably specced motor capacitors online. Any help or advice offered would be much appreciated!

[Steve Klare]

Hi Dave,

I'm afraid you are up against obsolete parts here. The state of the art is these parts get smaller and cheaper and the old parts start to seem ridiculous to use in new devices, so they go away.

What you have there is 4.3uF at 330 VAC maximum. I can offer you 4.0uF at 370VAC, probably in a much smaller package:

https://www.supplyhouse.com/Packard-...apacitor-4-MFD

It seems to have three "terminals", but I'm thinking it's actually two terminals and a mounting tab. (You'll need to get creative, yet still safe, in mounting it.)

This is bringing you up to about 7% low in capacitance. If you try it and it's not quite right, I have a feeling we can find you a second smaller capacitor in the range of .27 to .35uF that you can add in parallel to get well within the -5% to +10% range shown on the original part.


Hey! I realize it's a little late here, but please work safe! This is dangerous stuff! Unplug the machine and then operate the motor switch to discharge that big cap. Measure the capacitor voltage before you work.

I heard someone say recently that this kind of advice is treating people like little kids: not at all. Where I work, giving people technical instructions without laying out the hazards and preventive remedies is just plain-old negligence, no matter who they are!
(-better a kid than a corpse, I guess!)

[Dan Winckler]

Thank you so much, Steve! I can order that cap now. Do you know a source for the second, smaller one? I feel like I should go ahead and order it in case it's needed.

And yes, thank you for the safety advice – an old hacker I know reminded me to discharge the old capacitor into "a resistor or someone annoying", too. 😁

[Steve Klare]

Hi Dan,

It's pretty common, for example this .3uF Cap:

https://www.digikey.com/en/products/...F6304JL/656421

Applied between the 4uF terminals would bring you up to 4.3uF -bullseye!


You could even compare the dimensions of the existing cap to THIS 4uF cap: maybe an easier mounting and it's from the same seller:

https://www.digikey.com/en/products/...00AA0J/4833255


After I graduated from high school, I had a summer job with a power supply company. There were a number of other late-teenaged goof-offs there too. (We were cheap to hire and anxious to learn!). We left charged capacitors around for each other. (We'd get so FIRED now!)

[Dan Winckler]

Thanks again! I ordered the 4uF cap and 2x the .3uF too, just in case I need spares. The 4uF does look a lot quicker to mount, too. Hoping I can fire up the soldering iron this weekend and get it running again so we can rescan all these home movies.

Once it's working again, a question about sound: I haven't inspected all the reels to look for a copper audio strip yet, but if there is sound, what can I use? The 18-5L doesn't seem to have a speaker or audio out as far as I can tell.

[Steve Klare]

Yes, I didn't ask if you can solder: definitely a plus!

The sound stripe is actually iron oxide, basically a much nicer version of rust!

Your machine is a classic early Super-8 machine from the late-ish 1960s and Super-8 sound hadn't really hit its stride yet. The earliest sound on film cameras arrived in the early 1970s and sound projectors became much more common after that.

If you do find stripe, it would be fascinating to play sound films from a long time ago, just not with this machine!

There are still a lot of serviceable sound machines out there.

[Dan Winckler]

Cool! Apologies if there is an existing thread on this already, but can you recommend any good, inexpensive and/or easy to service Super-8 sound projectors?

[Steve Klare]

Hey Dan,

There are a number of good projectors out there, just for two examples: the Eumig 800 series and The Elmo ST-series. There are many more premium machines too: more bells and whistles.

"Inexpensive" can be a problem if it's not in good shape. A projector that has a lot of wear in the film path can damage films and in the end cost a lot and actually ruin the experience for you. It's good to think of these like tires: much better "good" than just "cheap".

With sound machines this becomes an even bigger issue because they often project longer films and more films and accumulate more wear.

It also pays to remember that these machines would be old enough to have grandkids if they were people!

I saw a Eumig sound machine once that had literally been immersed in salt-water! Good for nothing but a light-duty boat anchor, but I bet you could have it for a song!

[Dan Winckler]

Thanks! I got the new cap wired up and flipped the switch, but sadly the projector's still not running. It’s a 4 uF cap in place of the old 4.3 uF one, so either that .3 uF is making the difference or something else is broken. I can try wiring the .3 uF one in when it arrives but am otherwise stumped.

[Dan Winckler]

Two follow-up questions – can you recommend:

1) a source for professionally refurbished Super 8 projectors? I don't want to go through this again with another eBay purchase that runs for a few minutes and dies.

2) a professional scanning service that you have used personally, with good results?

Many thanks.

[Shane C. Collins]

Thanks! I got the new cap wired up and flipped the switch, but sadly the projector's still not running. It’s a 4 uF cap in place of the old 4.3 uF one, so either that .3 uF is making the difference or something else is broken. I can try wiring the .3 uF one in when it arrives but am otherwise stumped.

Are you sure the fuse is not bad? I have two Bolex 18-5's. The original standard 8 version, and the Super 8 18-5L. Both these machines needed new fuses as they were coated in green oxide. The fuse holder tube also needed cleaned out. Once new fuses were installed they both fired up with no other issues. These are well made machines, and usually only require basic maintenance to keep them running. Generally these run caps will last decades without issue.

[Dan Winckler]

Oh nuts. The fuse looked intact to me but one end is coated with green oxide. D’oh! What did you use to clean out the holder, and what kind of fuse is it? Thank you!

[Dan Winckler]

I continuity-tested the fuse and got a beep, cleaned the fuse and holder as best I could with white vinegar, and put it back in: nothing. Back to the drawing board.

[Shane C. Collins]

Then it has to be either the cap, as mentioned earlier, or a corroded wire some place in the machine. Do you have a repairman nearby that could test the electrical in this projector? It has to be something simply, since these machines themselves are quite simple in design. One more thing did you check the power cord, and where the cord plugs into. I have a Bolex 18-5 once with a loose connection at the socket. I needed to do some cleaning there and the machine fired up afterwards. I also remember needing to push the power cord harder into the socket until it clicked into place. Sometimes when there's a loose fit in the socket no power.

Also sometimes with these older machines you need to spray contact cleaner where ever there is a connection. A switch, plug, fuse, etc.

[Dan Winckler]

Thanks! Just for additional background, after it stopped working I confirmed current in the power cable with a sniffer (proximity voltage tester) when it was switched on, so I think the cable's OK. I also probed the bulb socket with a multimeter and saw voltage, but not a steady reading -- it went up and down. Would that indicate that the fuse was operating correctly?

The .3uF cap arrived today so I will add it in tonight, spray every contact I can see with DeoxIT, cross my fingers, and flip it on.

One more basic electrical question: is it alright to wire the new capacitor in parallel, e.g., by soldering its legs to the larger ones?