CD80 Rack
General CD80 rack info CD80 ramp and power supply cards
CD80AE power supplies CD80SV fuses Non-Strand upgrades
Strand Lighting CD80 dimmers are the industry standard. Tough, reliable, virtually indestructible — heck, you can even stand on the modules (except for the Supervisor or SV modules); they are the work horse of many Hollywood studios.
The Strand Lighting CD80 dimmer rack has gone through three generations.
- First there was the ramp card AMX based unit released in the early 80’s.
- Then came the Advance Electronics (CD80AE) version in the early 90’s that allowed for rack patching and DMX input. In my opinion, this unit was a sort of kludge add on, but it worked surprisingly well.
- Finally, we have the Supervisor rack (CD80SV). This rack was thoroughly redesigned from the ground up. Unfortunately, none of these dimmer modules are compatible with the earlier models. The CD80SV rack is fully microprocessor based and is quite powerful and expandable. I think this rack is quite ideally suited for architecture applications with its built in SWC, analog, and Outlook capabilities.
The CD80 dimmer modules can often be easily repaired as most of the parts are commonly available. The most common failure is a bad SSR (SCR in some early 12kW modules). Ignoring the SSR, the CD80 modules are usually free from major problems and often run over ten years without fail.
The two most common reasons CD80 electronics fails are because of lighting and ground loops. Fortunately, Emlight offers complete repairs on the electronics except for the CD80SV processor. The CD80SV processor is entirely surface mount based and is not easily repaired. But, from what I have seen, this processor seems to be very reliable. I believe I have seen only one failed SV processor in the field since the product came out. (2003 - correction, I have now seen two. Lighting hit though.)
Even though the Strand Lighting CD80 dimmer rack is tough, a regular once a year maintenance program will prevent the more annoying and time-consuming failures like 12kW dimmers welding themselves to the rack because of a loose power or load pin. Things to check are for loose connections and large amounts of dust and debris. On the SV racks don’t forget to clean the air filter.
CD80 ramp and power supply cards
Tip 1: Question: Can I “hot plug” the cards?
Answer: No. Absolutely not. Do not, under any circumstances, plug in a ramp card or power supply card while power is being supplied to the card cage. You will either:
a) immediately damage the card,
b) damage the card in such a way that it will fail within 1-3 weeks, or
c) be lucky and have nothing bad happen this time
TIp 2: If your ramp cards have just been calibrated you should not have to adjust them again for quite a while. The only thing you may have to adjust are the power supply cards. The reason for this is that their output voltage is dependent on your input voltage, i.e. AC line voltage. The power supply card is calibrated by measuring between the green and black test terminals. You should measure 9.8Vdc with all the ramp cards at full. For ramp cards, I recommend you send them to a qualified service center to be tested, like emlight (hint, hint), since more test equipment than is normally available to the average user is needed.
Tip 3: Question: What card controls what dimmer?
Answer: This is the ultimate head scratcher. You know you have a bad ramp card but which one is it so you can send it be repaired or swapped out. Here's a handy chart that may help you out (I made this ugly GIF graphic back when I was a partner with Lytemare):
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Basically, the rack is divided in columns and rows. Ramp means ramp card and PSU means power supply card or unit. The two number separated by the “/” are the dimmer output numbers that are in that slot for that column and row. 2.4kW dimmers are dual modules so there are actually two dimmer outputs in each slot. 6kW and 12kW dimmers you will only count the odd numbers of the number pair.
CD80AE power supplies
Tip 1: After spending years with Lytemare, my partner and I found that a certain resistor would always burn up over 3-7 years because of excessive current. And once this resistor goes it’s bye, bye power supply. It completely fries. So we came up with a simple preventative measure. Now, this is not a cure. We both felt that either the power supply was mis-designed by the power supply manufacturer or that the power supply was being used in the wrong application as the CD80AE power supply. We never figured that one out but on every every rack we saw the resistor was turning dark brown in color. Now this is hard to see as the PCB’s are very dark in color, black in most cases.
Well, all we did is change R31 to a 1 or 2 watt resistor (metal film). Now I am not going to give out the value of the resistor because I only want qualified techs attempting this mod and any tech should still remember the resistor color code. Oh, and if you make a mistake ... that’s your problem and I assume no liability for this. If in doubt, send the power supply in to get modded by a qualified tech.
CD80SV fuses
Tip 1: Fuses and I mean big ones. SV racks ship with a manual, keys, a security torx wrench and a bag with green stufff and other things. The green stuff is your spare air filter. The other things are what you are interested in. Among them should be these rather large gold colored fuse jobbies. There are three in a 3 phase rack mounted directly behind the fan assembly. To get to them you have to remove the fan assembly tray. Don’t yank it out because the fans are still attached to the rack via their power cables. Slide it out carefully and you’ll see three big old fuses mounted on the rear sheetmetal of the rack. If you lose a phase on your processor then this is where you should look when you can’t seem to find anything else wrong..
Incidently, this is where an emergency transfer cabinet lands its mains sense wires to determine if the rack has lost power. It’s a small thing and most people will never run into this but, when you do, it can be a stumper, just like it was for me on my first SV system turn on.
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