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Modification to Trinity switcher to provide dry contacts from an open collector system.

The customer came to me complaining that he had two switchers in his control room and he needed his tally lights on his cameras to be able to work with either switcher by throwing a simple switch. The customer would throw the switch when he moved to the other video switcher.

The customer suggested we use a serial port switch, a box that had a front panel switch with an A/B action, which he had and was not being used for anything. On the rear side were three DB9 connectors, two in and one out. I took the switch apart and found it to be perfect. Next I had to determine what each of the three main pieces of equipment used/needed to make the tally light function. The customer did NOT ask to have both switchers active at the same time for tally which could get messy.

I opened this switcher box and installed a terminal block to allow me to rewired/change the Trinity DB9 connector. The Sony DB9 was perfect and I used it as the standard. The terminal block consists of two side by side sets of screws. One side is the switch and the other side comes from the DB9. In this way, I could move the wires around to make the Trinity work with the correct tally wires coming from the CCU.

Sony switcher: The switcher provided dry contacts and each contact had a corresponding ground. This is a professional tally method.

DB 25 pins:

• Tally – 1 is pin 1
• Tally – Gnd is pin 2
• Tally – 2 is pin 3
• Tally – Gnd is pin 4
• Tally – 3 is pin 5
• Tally – Gnd is pin 6

I made up a DB25 to a DB9 cable about 6 feet long to connect the switcher to the A/B tally switch.

Trinity switcher: Documentation showed two IC’s, ULN2064 that had open collector outputs. I found this quite disturbing. I needed to provide 12 volts to each tally output in series with the tally light. The current rating is 250 mA maximum. It would be so simple if this switcher had dry contacts.

DB9 pins:

• Output 1 is pin 1
• Output 2 is pin 6
• Output 3 is pin 2
• Ground is pin 5

I made up a DB9 pin to a DB9 pin extension cable to hook up the Trinity solution adapter to the A/B switch box.

Ikegami CCU: The CCU provided its own power supply and wanted to see dry contacts as one of its hook up methods. The documentation showed two other methods where we could supply power of 5 to 24 volts. We tried using the Ikegami power supply but it would not supply the 12 volts to the Trinity. The voltage was too low. I felt real uneasy supplying an outboard power source to the CCU. The CCU tally pins were DC so I had to observe polarity if I did anything other than dry contacts.

Solution: I immediately decided upon some requirements. I was going with the Sony solution and provide dry contacts at the Trinity. I did not want the Ikegami CCU to provide the voltage to the Trinity collectors even though the documentation showed this might work. I did not want one equipment power supply to see any other equipment voltage. The Ikegami would only “see” dry (no voltage) contacts.

I looked for components and wanted to find some solid state relays as they are my personal favorite. Our local part supplier did not have these so I had to settle on reed relays. I chose NTE R56-7D .5-12VDC. I liked the extra set of contacts. But I only wired one set, pins 14 and 8.

The reed relay coil resistance is 500 ohms so I could expect a draw of .024 Amps from each relay. If a special effect were to be set up where all three cameras were hot, tally on, the draw would be 3 times .024 which would equal .072 Amps. A one Amp power supply would do the trick.

The supplier did not have the protection diode so I purchased some diodes that I did not use and the reason why will be explained later. The reason you should put the protection diodes in is when you remove the voltage from any coil the energy stored in the expanded magnetic field of the coil will collapse and thus create a back electro motive force, EMF, or a spike voltage. This might cause component failure so you really do need some EMF protection. But I got lucky on the bread board (explained later).

I decided to put the power supply in the box as I can not stand the power supplies inside the wall type plug in units. I have taken some of these apart and they use cheap components, cheap design and they get too hot and fail too quickly.

Parts List:
3 reed relays, NTE R56-7D .5-12VDC (A better relay would be the NTE R56-7D .5-12D which has the protection diode).
1 Full wave rectifier rated at 1 amp.
3 LED’s
1 pair PC board fuse connector.
1 Fuse, 1/2 Amp
1 Plug in the wall 12 VAC transformer with a 1×5.5mm plug
1 Chassis mount female 1×5.5mm power connector, chassis mount.
1 PC board with existing traces for bread boarding. I cut what I needed with a Dremel tool.
3 IC sockets for the reed relays.
1 12 Volt IC regulator (I recommend a variable voltage regulator)
1 Electrolytic capacitor 47 uf at 25 volt. ( no particular value except that it is rated above 18 volts DC).
1 22K resistor (bleed resistor for the electrolytic capacitor)
Multi colored hook up wire.
1 DB9 male chassis mount connector. (Be sure you know which pin is #1. I can not tell you the frustration of wiring these backwards by not taking extreme notice of the pin count).
1 DB9 female chassis mount connector.
1 Case, plastic, with internal PC board mounting capability.
1 wall AC to AC adapter, model AC-1283A with 850mA max output.

I put the relay components on to a Heathkit Digital Design ET3200 to test the concept and ring out any problems. It was on this bread board that I stuck an LED in series with the reed relay coil and was ecstatic to see both work perfectly together. I had calculated that the 500 ohm coil would act as a sufficient IR limiter for the LED. The coil had reduced the voltage down to between 10 and 11 volts so the current through the LED was close to .020 amps. I had picked the LED’s up from a parts bin with no documentation so I am guessing that I am at the limit of the LED current so that might not be too good. The IR loss through the collector to emitter might bring down the fear factor a bit. I sat back an thought about what just happened. I had a perfect visual continuity checker for the reed relay coil. I also had a back EMF protector. The LED might also work as a fuse but I bet the coil would open first, just in case some catastrophic event took place like the power supply going to 30 volts. . It does not take much for me to get real happy and I sat back and reveled in this stroke of good luck.

The power supply output was 18 Volts DC so I had to add a 12 volt regulator. I wish I had wired in a variable DC regulator so I could dial in the final output to 12 volts after the IR drop from the reed relay. If you do go with a variable regulator be sure you measure the voltage at the DB9 connector not from the output of the regulator.

In the above schematic (image part Eagle Layout Editor and Snagit text overlay) you can see a very simple concept. The positive power supply voltage enters through the LED and then into the coil and to the contact at the Trinity awaiting that switcher to complete the connection by allowing the collector to conduct thus completing the circuit. We only use one set of dry contacts. If we thought we needed more current handling we would wire both contacts in parallel.

The image above shows the case with the completed circuit fully wired. The IO connectors are
to the left and the power connector is on the right side of the box. Note the fuse at the bottom
right. Also note the three LED’s associated with each reed relay. The power supply is constructed
in the right lower quadrant. The regulator is at the top right. The lower DB9 are the inputs to the unit from the Trinity.

Wire colors:
Black = ground
Red = power supply output prior to the regulator.
Orange = 12 volt regulated output.
Blue = K1 dry contact out.
Gray = K2 dry contact out.
White = K3 dry contact out.

I did make one mistake. I forgot to factor in the IR loss of the LED and relay coil in series with the Trinity. I found the voltage out from the modification box was not 12 volts but 10 to 11 volts. I recommend anyone that make one of these modifications insert a variable DC regulator so you can dial up the voltage to meet the printed specifications of the Trinity. In theory, the 12 volts will appear at the collector until the collector conducts. So would the unit work if the collector is turned on and then the adapter is then connected to the Trinity? In either case there would be a momentary 12 volts for the collector to “see” but that voltage would tank down to 10.5. I took note that if anything went wrong I would have to replace the regulator with a variable one and dial in a higher voltage.

I hooked the unit up to the Trinity and found it worked perfectly. The more perfect test is time. If the customer does not come back with a complaint then it truly works.

The information here is for educational and reference use only. Decide on your own how to proceed in performing any repair you face. We do not accept any responsibility for this information being entirely accurate. We hope it is accurate. Most of the information posed here has been noted to be significant, used in the repair process, and to some extent tested for accuracy through the actual discovery and recording of performing a repair. If you decide to use any of the information here, try to keep in mind that a number of factors may change when you attempt the “same” repair. Models do change from apparently being same units. Their are definitely different methods of making a repair. The steps that you should use to achieve a successful and expedient repair might be different. The problem you face with a piece of equipment might be similar but not an exact match to what we faced. Just use common sense and always be a bit skeptical of following our methodology until you feel that you and we share the same viewpoint and tactics.

Lens Repair: Schneider – Kreuznach, Arriflex-Cine-Xenon 1:2/50

Problem #1: The lens came to me with a major problem. It was in two pieces. I soon discovered that the lens had two problems. The second problem was that the lens was loose. If you held the very front of the lens firmly in one hand the rear of the lens could move or pivot a bit up or down or side to side.

Solution: I removed the rear element by unscrewing it. There was a series of screws that were quite loose inside. I tightened the screws and this made the lens tight. I then proceeded to go to the second problem.

In the image above the rear lens assembly has been removed revealing the rear optical element. Unscrew the element by rotating in a counter clockwise direction. Upon removal of the rear element, you will see inside the front part of the lens a number of screws. Tighten the screws. Reassemble the rear optical element back into the lens.

Problem #2: The lens came to me in two pieces. This lens is a puzzle that is somewhat difficult to figure out. The major thing going for me was that the focus ring was not loose and I felt I could depend upon its setting to help me get back a lens that would achieve critical focus. The puzzle depended upon getting the rear element part to marry with the front part of the lens using the correct dihedral threads. To complicate matters a bit are two rear lens tabs that must chase along a channel. By trial and error I went through quite a number of possible threads until the lens matched the focus markings. When doing this, you should understand that there is a single screw that acts as a pin into a 180 degree cut out. I placed a pencil mark on the lens where one end of the 180 was. The other end of the 180 channel was at the infinity mark. When screwing the lens together, visualize where that pin goes into the lens but without the pin. I used a magnification lamp with a circular florescent bulb to look into the hole and determine when I had screwed the lens in too far. You will not be able to screw the lens in but will meet some resistance. This is because the two small tabs must locate into the front lens piece. Slowly rotate the back of the lens element until you feel the tab move into the slot. .When you think you have found the correct threads, screw in the screw pin and test the lens.

Note the image above has a tab labeled. It is this tab that rides into the channel seen in the picture below.

The channel cutout above is where a set screw will be used to ride in the channel and determine how far the focus ring will turn.

The above image shows the special set screw that is used to unlock and lock the focus ring and allow the lens back end to be removed.

When you think you are finished putting the lens back together, do a focus check, using a camera, to ensure that the lens repair is a success.

I had to depend upon ground glass focus for the eye and measuring the lens at infinity tape out to a test star chart with the iris wide open. I firmly recommend that any lens repair be done by a good optical repair shop. When I did this repair, I was working for a state university that had a very limited budget.

The information here is for educational and reference use only. Decide on your own how to proceed in performing any repair you face. We do not accept any responsibility for this information being entirely accurate. We hope it is accurate. Most of the information posed here has been noted to be significant, used in the repair process, and to some extent tested for accuracy through the actual discovery and recording of performing a repair. If you decide to use any of the information here, try to keep in mind that a number of factors may change when you attempt the “same” repair. Models do change from apparently being same units. Their are definitely different methods of making a repair. The steps that you should use to achieve a successful and expedient repair might be different. The problem you face with a piece of equipment might be similar but not an exact match to what we faced. Just use common sense and always be a bit skeptical of following our methodology until you feel that you and we share the same viewpoint and tactics.

Macintosh: Final Cut Pro 4.5 fails to load with M-Box connected.

Problem: Pro Tools and Quick Time failed to load when the M-Box was connected.

Symptoms: When Final Cut Pro was launched you could see the items that it was loading but then the items would stop and the small spinning color wheel would never stop. The application was locked up.

Machine configuration:

• iMac G5
• 1.5 gig memory
• System OS 10.3.9
• Final Cut Pro ver. 4.5
• Pro Tools LE ver. 6.4
• Quick Time 6.5.2 Player 6.5.2

This was a test machine. I had newer versions of software but I wanted to know what versions worked together step by step, like going up a ladder. In this way, I could go backward/downward to a setup that would function properly.

Solution: There is a couple of solutions posted on the web but none that worked for me. It took quite some time but I discovered what I think is an elegant solution. Well it worked for me and I do hope it works for you if you have this problem.

Go to the “Applications” folder inside the boot hard drive.

Inside the “Applications” folder is the “Digi Design” folder. Open it up.

Inside you will find an icon called “Digidesign CoreAudio Setup” as shown in image above. Click on this icon to open this application.

Next you will see the screen shown below.

Click on the button “Supported Applications…”.

You are given a list of applications that Digi Design thinks you want to use as part of its Core Audio. Highlight “Final Cut Pro HD”.

And now click on the button that reads “Remove Selected Application”. This is really neat as you can go right back and put “Final Cut Pro HD” right back in if this does not work for you. I love it when I can easily retreat.

A splash screen appears that asks you to confirm this removal. Just click on the button that reads “OK” and you are done.

Try out Final Cut Pro and you might find that it will now load and so will Pro Tools and even Quick Time.

The information here is for educational and reference use only. Decide on your own how to proceed in performing any repair you face. We do not accept any responsibility for this information being entirely accurate. We hope it is accurate. Most of the information posed here has been noted to be significant, used in the repair process, and to some extent tested for accuracy through the actual discovery and recording of performing a repair. If you decide to use any of the information here, try to keep in mind that a number of factors may change when you attempt the “same” repair. Models do change from apparently being same units. Their are definitely different methods of making a repair. The steps that you should use to achieve a successful and expedient repair might be different. The problem you face with a piece of equipment might be similar but not an exact match to what we faced. Just use common sense and always be a bit skeptical of following our methodology until you feel that you and we share the same viewpoint and tactics.

Sony VO5850 would squeal when threading tape.

This is a very old VTR deck but I still include it here because a LOT of cable companies and education schools might still use this video tape recorder.

Upon examination of the deck it was determined that the thread ring was rotating too close to the capstan base plate. It was determined that the thread ring rollers were worn and they were replaced.

Then the gear block assembly that moves the thread ring in a circle needed to be positoned to force the thread ring away from the capstan.

After these parts replacements and adjustments were made the unit worked smoothly with no sqealing noise.

The information here is for educational and reference use only. Decide on your own how to proceed in performing any repair you face. We do not accept any responsibility for this information being entirely accurate. We hope it is accurate. Most of the information posed here has been noted to be significant, used in the repair process, and to some extent tested for accuracy through the actual discovery and recording of performing a repair. If you decide to use any of the information here, try to keep in mind that a number of factors may change when you attempt the “same” repair. Models do change from apparently being same units. Their are definitely different methods of making a repair. The steps that you should use to achieve a successful and expedient repair might be different. The problem you face with a piece of equipment might be similar but not an exact match to what we faced. Just use common sense and always be a bit skeptical of following our methodology until you feel that you and we share the same viewpoint and tactics.  

Bad video out from Sony SLV-N51 VHS

Customer complaint: Bad video. The customer thought one head was dirty. The customer used a head cleaning tape. The customer said one tape came back out of the machine wrinkled.

Evaluation: I opened the unit and cleaned very guide and the head. I then noticed that one guide was not firmly attached near the capstan. It was quite loose. It was held barely on the left side but seemed to rise up a bit on the left hand side where the base goes into the base plate.

Repair: The image above shows the bad part. I had to see what was expected to hold that piece in place. I had to remove the mechanical drive unit which sits on top of the electronic circuit board. . There are two ribbon cables and one cable for the load motor that has to be detached. There are a number of phillips screws that need to be removed. Two phillip screws can not be removed until you move the front panel out and away along the top. There are four tabs on the front top that must be released to rock the front panel away. I kept the bottom of the face plate attached. There are two phillip screws that hold a horizontal plate over the tape cartridge cavity. Be careful when lifting and removing the drive unit as there is a finger behind the video tape entrance door. You must get that finger out from behind the door. The whole mechanical drive unit can be lifted carefully up out from the circuit board.

Remove the drive belt from under the mechanical drive unit. I had to remove a “C” clip on the motor shaft shown in the image above. This dropped out the capstan shaft and part of the motor rotor. I removed three screws (two shown in photo above) around the capstan that then released the stator part of the motor. I then could see the back side of this tape guide. I noticed that the only device holding this guide in place were two very thin tabs of plastic. This design “in my opinion” was too easily set up to fail. To my delight, I noticed a hole into the back side of the part shown in the photo below. It quickly dawned on me to use that hole and put a screw into it to fix it back in place. The head of the screw would also be held in place by the motor mounting plate. This made me very comfortable about the possibility that the screw falling out and shorting the stator windings. The motor stator plate covered the screw completely.

In the image above, it is the white plastic part that has one tab broken. The capstan motor had to be removed to get to the back side of this part. The large hole is where the capstan motor resided before I removed it. Three smaller holes are used to mount the motor. Note the white plastic part has a hole down its center.

A plastic tab had broken off one side of the tape guide. I decided upon a quick fix. I reasoned that the motor stator plate rested above the chassis plate by about the thickness of a screw head. I was going to use a screw to fix the piece in place. I cut back the protruding plastic with a Dremel Tool because the white plastic protruded too high above the chassis plate. I found a screw with a thin elevated head. I applied a locking type of fluid on the screw threads to secure the screw once I had it tight into the part. I tightened the screw into the white tape guide.

Assembly: Do the reverse of taking the unit apart. Just be careful of the finger mechanism that must be placed in front of the video tape front door. It seemed quite tricky to get back in place. I applied some gentle pressure to the top of this guide to make sure it was solid. I tried to rotate the piece and it did not rotate as the base of the plastic rested against a thin metal plate on the top side of the deck.

Checkout: I put the unit back together and it worked fine. I expected to find bad tracking but my test tape showed no tracking errors. With such a flimsy design, I felt fortunate that I was able to achieve a successful repair.

The information here is for educational and reference use only. Decide on your own how to proceed in performing any repair you face. We do not accept any responsibility for this information being entirely accurate. We hope it is accurate. Most of the information posed here has been noted to be significant, used in the repair process, and to some extent tested for accuracy through the actual discovery and recording of performing a repair. If you decide to use any of the information here, try to keep in mind that a number of factors may change when you attempt the “same” repair. Models do change from apparently being same units. Their are definitely different methods of making a repair. The steps that you should use to achieve a successful and expedient repair might be different. The problem you face with a piece of equipment might be similar but not an exact match to what we faced. Just use common sense and always be a bit skeptical of following our methodology until you feel that you and we share the same viewpoint and tactics.