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I'm not one to judge... everyone to their own

Short mops, long mops, flat mops, round mops.... quite a wardrobe you've got there Do you take any weenies with you on your nights out..... in case you get the munchies?

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Or, was it a bright shiney connection that did not appear to whet out properly? It has an appearance of the solder looking like a ball sitting on the connection. This is a cold solder joint. It happens when there was insufficient heat used for soldering and/or the flux did not flow properly, or the connection had residues of some sort preventing the flux from doing its job.

Or was the solder joint fractured, but otherwise looks OK. This could be a stress related factor that happens when there was insufficent solder used, and the connection mechanically cannot handle board flexing due to thermal stress or mechanical vibrations. These type connections can very easily break if excessive force is used to insert or remove relays.

A fractured connection can also occur if there is mechanical motion between the parts being soldered as the solder passes through the "plastic state." 60/40 solder has a 9-degree plastic state. The temperature range of the 60/40 solder's plastic state is 361 degrees F to 370 degrees F.

63/37 solder does not have a plastic state. it is either a solid or a liquid. If memory serves me correctly, the transition of 63/37 solder is 361 degrees F.

A good solder connection appears bright, and the contour of the solder is concave and free of stress lines caused by uneven heating during the soldering operation. The solder wetting should appear feathered out to all areas being soldered, with no evidence of ridges between the solder and the soldered parts.

If the solder connection is convex in appearence, it could be a cold solder connection or too much solder. It can be difficult to determine it is a cold connection on inspection, because if there was improper wetting underneath the surface of the solder, it could never be detected.

The old BGW-250 amplifiers had problems with fractured connections in their time-delay circuit. It was caused by insufficient solder and thermal stress.

It may be easier for him to send the board direct to you.... and I'll send mine as well

I'm constantly amazed at the expertise that's given so freely here... in a very materialistic world it's very unusual .

I rememeber an intermittent fault on a CP55 installed at my cinema that was eventually cured by sitting down at a bench with a hot iron and going over hundreds of connections..... an experience I hope never to have to repeat.... this could well be what'll have to happen in this case if it turns out not to be the socket.

At least the TA10 has fewer connections to consider....... it's not a job for the inexperienced.... come to think of it it's not a job the experienced want either

This book was our "Bible" when we had to work on PC boards used in Military Aviation. Hi-tech industries used the same specifications.

Unfortunatly you are exactly what's missing in the industry today, people who not only know what they are talking about but have a love for the job. I've been doing this job for some 30 yaers now... boy, man and alcoholic Guy's like yourself give much more than advice..... you pass on experience.

It's not where the information came from it's knowing how to use the knowledge and being prepared to pass it on.... thanks.

Sounds like a suck up... but it's not. I've said before on this site it's important to be able to say "I don't know", I do it all the time... when no one's around of course!! The older guys have the best tips and the younger guys would do well to listen to them.... I hope I do.

The first few pages of any Heathkit manual will also show good techniques to good soldering.

I like Kester 63/37 solder, my self. I only use 60/40 on fat connections (with fat solder).

Steve

quote:

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"One of the big problems I find with wave-soldering is that their connections are truely dependent on the how well the wave machine is maintained and is run."

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Steve, you are absolutely correct.

Here is a link that hopefully, all shoud be interested in.
http://www.hq.nasa.gov/office/codeq/solder.htm

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Fig 1 - Improper stripping of wire insulation.
Fig 2 - Birdcaged wire strands.
Fig 3 - Recessed solder.
Fig 4 - Part body (meniscus) in solder joint.
Fig 5 - Cold solder connection.
Fig 6 - Overheated solder connection.
Fig 7 - Fractured/disturbed solder connection.
Fig 8 - Poor wetting
Fig 9 - Blowhole.
Fig 10 - Rosin connection
Fig 11 - Dewetting
Fig 12 - Nonwetting.

Usually this problem is in the manual switch. The switch is wired in a different way than most manual switches. Enclosed is a schematic so you can see what I mean. Both NO and NC sides of the switch need to be healthy for the motor to work properly. The motor switch has a higher current rating than the other SPST switches used in the unit. If you swap be aware that the others are under rated for this application and will not be up to the task for very long.

I will post this reply on Film-tech also.
If this is not the cure please write.

Ken, I agree this site is invaluable in getting information that others might be tempted to selfeshly hold back. I think the greater good is served, however, in that by helping each other with solutions to various problems, we help the world to make sure that "movies (especially on film) are still your best entertainment."

P.S. Will get back to this theatre in the next day or so, and will post my results. Thanks again to all of you.

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