It is just 61-69 that aren't functioning properly. The problem with 60 was an erroneous soft patch at the board. Also, our copy of the drawings for the
system only show a fan behind the MultiLink, no other controller, and none are listed on the Bill of Materials.
Clifford, I found the schematics yesterday at the
theatre.
Just a little prelim info, that you probably already know. There are two
circuit boards in the multilink. One controls dimmers 1-60 and the other controls dimmers 61-120. The boards are identical and the only difference is the setting of the
address with dip switches. The top board usually controls the dimmers 1-60 and the lower board dims 61-120, but it is possible to be reversed if some one working on them connected the wrong cables.
The critical thing about working on a multilink, is to document every cable you
disconnect, as there are many that have the same connectors.
If your multilink is assembled correctly, the most likely problem is an integrated
circuit on the lower board. The data coming to each board is multiplexed. In order for the data to be demultiplexed and control individual dimmers. There are eight data switches that each
break out eight channels. The integrated
circuit that is labelled "U33" controls the first eight dimmers on each board. Therefore on the lower board it controls Dims 61-69. This is the only component in the multilink that is common to those eight channels. U33 is a 4051 logic chip or IC. It might have other numbers or letters with the 4051 depending on manafacture, and age of fabrication. The fact that the first number is a "4" indicates that it is CMOS. CMOS ICs require carefull handling during installation, as they can be damaged with static electricity. There are newer versions of the Chip that are TTL and aren't as sensetive to damage. I would still replace it with one of the true CMOS cips and keep yourself or whoever does the repair grounded. You can google and find out how tha is done.
The ICs are soldered into the board, and the board is a multilayer board. This means that it is very easy to damage the board during desoldering. I would
purchase spare chips, and remove the old one by snipping the leads of the IC as close to the chip as possible, with really small cutters. Then I clamp a hemostat (devices used by paramedics) to each lead at a time tip the board over and then touch the pad where the lead is soldered with a soldering
iron, while jiggling the board very gently. The weight of the hemostat should pull the lead from the solder pad. If it doesn't fall immediately, pull the soldering
iron away, let it cool and then try it again. The trick is not to apply more heat than necessary. Once all of the leads are free from the board, use a solder sucker or solder wick to remove all of the solder from the through holes that the leads were in. Then I would put a 16 pin DIP
socket where the IC came out. This will facilitate putting the new IC in with less heat involved. The
socket will have a slight indentation on one end, and the
Circuit board will have a silked screened
image of the IC with the same indentation, or a dot at pin 1 or the number 1 at pin 1. The indentation indicates the end that pin 1 is located. When inserting the IC into the
socket, make sure that you have placed pin one at the end with the indentation. Pin one on the IC will either have the indentation, or a dot at pin 1. Most
circuit boards are laid out so that ICs of the same model are laid out in the same direction.
The components that you need are available from many sources, but I did look up the part on Mouser.com for you. The IC is Mouser part number 595-CD4051BEE4 and is $0.54. The integrated
socket is 649-DILB16P-223TLF and is $0.20. That is for a pressed pin
socket. If you want a Machined pin
socket, then it is 855-D2816-42 and is $1.18. I personally would go with a machined pin
socket considering the high speed switching and importance of having it work during a show. The shipping is going to cost you about $6.00 for approximately a five day delivery. Considering the cost of the shipping in comparison to the products, I would
Purchase several of each part. Also, If you are in need of
XLR connectors for either audio or
DMX, you might want to consider purchasing some at the same time.
Neutrik connectors can be found with a search for audio connectorsl There are some XLRs that at are considerably less expensive than the Neutriks, that are very close in quality, that I use all of the time. The catch is that they are manufactured by Pomona, a long time test
connector manufacture, and therefore they don't show up under audio
connector search. They can be found under test connectors, or Pomona.
I hope that this helps, and if you need to contact me direct with any more questions.
[email protected]
Tom Johnson