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Topic: Barco 32B Cathode and Anode sticking when changing bulbs

Justin Hamaker
Film God

Posts: 2253
From: Lakeport, CA USA
Registered: Jan 2004

posted 06-02-2019 03:22 PM

The last two times I've changed the bulb in our Barco 32B I have had some trouble getting the lamp enclosure to separate from the anode/cathode ports on the protector. This is in a drive-in where we run a 6500w bulb, so I'm wondering if the heat from the bulb might be causing the metal to slightly melt or deform, which is making the connection more difficult to separate. I'm curious if anyone else has experience this issue and how you resolved it.

I have included pictures of what the ports look like in the projector. The top one is the one that is really sticking. sticking

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Frank Cox
Film God

Posts: 2234
From: Melville Saskatchewan Canada
Registered: Apr 2011

posted 06-02-2019 04:11 PM

It's my understanding (and someone can correct me if I'm wrong) that it's important that those connections be super-clean; any dust or oil or anything else that gets on there is a problem since it insulates the connection and can cause an arc that can weld your stuff together. If it's getting slightly welded together that way, that would explain why it's hard to separate the parts.

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012

posted 06-02-2019 04:54 PM

We're not running those jumbo bulbs you're running, our screening room screen is probably humble compared to yours. [Wink]

But yes, those contacts should ideally be spot clean. If there is anything in between there, it will incur resistance and resistance equals heat and with 6500W bulbs, it's a lot of current going through there...

Especially the top contact seems to have collected some grit. You should try to get that off of there. Make sure you completely disconnected your machine from the power grid before you get in there by the way!

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Justin Hamaker
Film God

Posts: 2253
From: Lakeport, CA USA
Registered: Jan 2004

posted 06-02-2019 05:13 PM

Next time I change it I'll go over the terminals with some fine grit sandpaper.

Interestingly, after posting this I opened up the projector to visually inspect the bulb and the lamp enclosure slid right out with virtually no resistance.

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 06-02-2019 05:38 PM

Those connections look like they might be plated with silver.

If so, you will need to be careful when polishing or sanding them. If you wear the plating off it might cause even more problems in the future.

Silver plating on electrical connectors might be only a few micro-inches thick... Be careful!

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Leo Enticknap
Film God

Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000

posted 06-02-2019 09:07 PM

The nut on the anode flylead post is definitely silver-coated: replacements are super expensive. I've heard stories of people unaware of this replacing corroded ones with regular aluminum or brass nuts of the same diameter and thread count, and ending up wishing they hadn't.

I've experienced those SPG terminals getting sticky, too (at one location I service in particular) - in C series projectors as well as Bs. I took to putting a very small amount of automotive copper grease on them before reinsertion, and have never had any trouble pulling them out them since.

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 06-02-2019 11:10 PM

The place where I work does a lot of silver plating on electrical terminals. Those terminals bear resemblance to pieces I see at work.

It is a matte silver coating. Silver plating can be bright or matte depending on what additives are added to the plating bath. It’s probably only 100 micro-inches thick. Maybe even less. Silver plating is an expensive multi step process. Customers usually only ask for just enough plating to cover the surface, level out microscopic imperfections in the metal and improve surface conductivity.

There might also be a conductive anti-tarnish coating. If the terminal has been subject to abrasion or chemicals, the anti-tarnish coating might come off. Dark spots might develop where the silver tarnishes.

That’s why I say to be careful in cleaning those terminals. If you wear off the coating or, worse, wear off the silver plate you’ll have trouble down the road.

I notice black spotting on those terminals. That might be tarnish from the anti-tarnish being worn away. It might also be a symptom of improper surface preparation before the part was originally plated.

Parts are often acid treated or treated in other chemicals before plating.
If they are not properly cleaned and rinsed in the pretreatment steps before the final plating goes on black spots can develop underneath the silver plating and migrate through to the surface, causing failure.

These failures can occur days, weeks or even years after the parts leave the plating shop.

A sizable part of my job is to make sure that the bath chemistry in the plating lines is clean and up to spec so this kind of stuff doesn’t happen.

If you can say for sure that those terminals have been properly cared for and have t been subject to improper cleaning, you might be able to call the manufacturer and ask for those parts to be replaced.

You paid enough for that machine! They ought to just send you new terminals on principle.

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012

posted 06-03-2019 12:55 AM

quote: Justin Hamaker
Next time I change it I'll go over the terminals with some fine grit sandpaper.

Like Randy indicated, I won't use sandpaper, because those terminals could be plated on either sides, at least it makes sense for such types of connections. I wouldn't be using anything much more aggressive than a scouring sponge and a mild soapy solution.

You should probably check the other side of the of the connector too, although it will be a bit harder to get in there, it's likely to be dirty too.

quote: Justin Hamaker
Interestingly, after posting this I opened up the projector to visually inspect the bulb and the lamp enclosure slid right out with virtually no resistance.

It's just a theory obviously, but I guess that depending on the type of dirt that is in there, it might take a while before it starts to "cake" together.

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Marco Giustini
Film God

Posts: 2713
From: Reading, UK
Registered: Nov 2007

posted 06-03-2019 05:29 AM

as mentioned, I wouldn't sand those connectors. In fact I feel that a scourer may be dangerous too - nothing personal Marcel, this is just my guts feeling.

I'd contact Barco immediately and be very cautious with that because if those connectors get permanently stuck, your only chance is to hammer it out from the lamphouse chimney which is not what you wanna do.

Hopefully Barco has some service procedure for those connectors.

How does the connector look on the other end? The female socket.

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 06-03-2019 06:50 AM

One job we do in the plating shop involves slivering the ends of six foot long rods that are used to make electrical transformers, etc.

Those get polished after being plated using a regular, old, 3-M Scotchbrite scrubbing pad. The green ones, not the gray ones.

I’m not saying that you should clean those terminals with anything more than a clean cloth but, for reference, that’s how silver terminals are sometimes cleaned in the factory.

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Marco Giustini
Film God

Posts: 2713
From: Reading, UK
Registered: Nov 2007

posted 06-03-2019 08:15 AM

that sounds like a suitable method. I just wouldn't 'test' it on the Barco without manufacturer's guidelines as if those connectors get stuck, it's a really bad situation.

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Marcel Birgelen
Film God

Posts: 3357
From: Maastricht, Limburg, Netherlands
Registered: Feb 2012

posted 06-03-2019 08:33 AM

quote: Marco Giustini
as mentioned, I wouldn't sand those connectors. In fact I feel that a scourer may be dangerous too - nothing personal Marcel, this is just my guts feeling.

You shouldn't eat it afterwards. [Wink]

I think, the word "common sense" applies here. Those things are made from a metal or alloy, plated or not, but not from sugar. Keep in mind that they were designed to "scrub together", in order to make a good electrical connection. But also keep in mind that the lamphouse wasn't designed to be opened 10 times a day.

You don't want to rub off the potential plating, so you don't want to use anything that's abrasive to metal.

Also, you don't want to use anything with a pH too far off, to trigger an unwanted reaction with one of the metals in the alloy and/or plating.

Consulting with Barco is never a bad idea, I don't really expect them to have a procedure though, other than to entirely replace the terminals.

I've successfully removed some dirt from other but similar "high-power" terminals in the past, but depending on whether it's dirt or something that bonded with the metal, your mileage may obviously vary.

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Leo Enticknap
Film God

Posts: 7474
From: Loma Linda, CA
Registered: Jul 2000

posted 06-03-2019 05:05 PM

quote: Marco Guistini
...as if those connectors get stuck, it's a really bad situation.

Ohhhhhhh yeah. A bad situation, as in, one that can only be remedied by two hours of stripping the projector down to the chassis, a crowbar and a hammer to separate the SPG from the lamphouse, and some language that would make Reservoir Dogs look like a kids' movie. Been there and done that, which is why I'm now seriously anally retentive about applying the copper grease whenever I reinsert a lamphouse for any reason.

quote: Randy Stankey
You paid enough for that machine! They ought to just send you new terminals on principle.

If the projector is in warranty, I'm sure that they would. In my experience, Barco have always been very good about replacing parts of projectors under warranty on request. They will sometimes ask for a diagnostic package to confirm the diagnosis (especially if it's a big ticket part, e.g. an ICP or a light engine), but once the part causing the problem has been identified, they will ship a new one to you, usually overnight.

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Randy Stankey
Film God

Posts: 6539
From: Erie, Pennsylvania
Registered: Jun 99

posted 06-03-2019 05:44 PM

quote: Marcel Birgelen
Also, you don't want to use anything with a pH too far off, to trigger an unwanted reaction with one of the metals in the alloy and/or plating.

Humor... Anything that I could recommend from my work experience would involve using things like sodium cyanide. [Wink]

Seriously, though, if carefully polishing them with a Scotch Brite or a Magic Eraser doesn't fix them, replacement would be the next option, IMO.

Yes, do look into your warranty coverage. That might be your best avenue.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12814
From: Annapolis, MD
Registered: Dec 1999

posted 06-03-2019 10:04 PM

BTW, if your warranty has expired, I'd seriously look into what it would take to put it back in warranty. It would appear the Cinionic has little to no use for people that don't buy into their warranty coverage. They no longer stock parts in the USA for non-warranty and have really jacked the prices up on parts (and they weren't the cheapest to begin with). That said, they have significantly lowered the price on extended warranty and with that you get the same "standard overnight" service that a new projector gets as well as access to the parts they do have in the USA for warranty customers.

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