This is topic Troubles with Christie's rectifiers in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Giorgio Volpi (Member # 1182) on 03-18-2002, 05:13 PM:
Hi guys,
this is my first forum message.
I have worked with many projectors: Pio Pion, Fedi, Cinemeccanica, Microtecnica, Prevost, Century, Simplex and finally Christie.
I have to admit that Christie is the worst thing that could happen in my life (professionally speaking).
The Christie projectors have been showing troubles about dousers (all of them), shutter belts, lens turret and gate electric systems (P35), intermittent blocks and ball bearings.
Now I am working with 15 Christie projectors (8 P35 and 7 M35), some of which have presented a peculiar problem.
There are some projectors with 2000W console that every 800-1000 hours of operation the lamp stops to light on.
A new one substitutes the lamp and it works perfectly.
I place the old lamp in another lamphouse (Kneisley, this time) and it works perfectly.
This only happen in one theatre (less than 1 year open); 7 projectors, 3 of 3KW and 4 of 2KW, and the problem is only presented by the 2KW projectors.
Other 8 projectors in other 2 theatres: 4 of 3KW and 4 of 2KW don't present this problem.
I have revised the whole installation, components and connections: everything seems to be in order.
Can somebody help me to discover where the midget hides? ---+++---+++---+++---+++---
Have a good projection ....
Giorgio.
Posted by Steve Guttag (Member # 268) on 03-18-2002, 05:26 PM:
Giorgio,Are you using Christie lamps?
When you say they stop lighting, have you tried pressing the manual ignite button? What I am trying to determine is if it is a lamp problem, or an igniter problem or perhaps just mix of the two.
When they ignite, how long is the delay from when the contactor pulls in vs when the lamp tries to ignite. On Christie's it should be just about 1 second. If it is taking longer than you may need to adjust your igniter so it senses the boost voltage better. Not knowing your incoming mains voltage and how your rectifiers are tapped, It is a bit hard to diagnose.
Steve
------------------
"Old projectionists never die, they just changeover!"
Posted by Giorgio Volpi (Member # 1182) on 03-18-2002, 06:28 PM:
Steve,
I tried with Osrman and Christie lamps. Same result.
When the lamp stops working, it stops with manually ignition too.
The lamp doesn't have any problem. As I wrote in first message, the same "wrong" lamp installed in another lamphouse works well.
When the igniter works automatically, the delay is about 1 second. It ignites 4 or 5 times and then stops.
I tried changing the igniter; same result.
I'm checking now with an old Kneisley rectifier. It works very well.
I have to ignite manually, but lamp always starts at first time.Giorgio.
Posted by Richard Fowler (Member # 893) on 03-18-2002, 06:41 PM:
Sr. Volphi Power surges can be a problem on some of the brute force Christie rectifiers.....Kneisley are very forgiving....I had one Kneisley operating on generator power that was poorly regulated with power from 190 - 270VAC and did not burn up.....are you the technician who installed the Kneisley next to the Christie console and the Kelmar changeovers on the projectors at the El Recreo?
Richard Fowler
TVP-Theatre & Video Products Inc. www.tvpmiami.com
Posted by Gordon McLeod (Member # 33) on 03-18-2002, 06:45 PM:
Out of curiosity what is the measured no load voltage on the lamps when the don't strike
As lamps age it could be the no load is too low
Posted by Giorgio Volpi (Member # 1182) on 03-18-2002, 07:08 PM:
Mr. Fowler,
yes, I am.
I installed the Kneisley in order to test if the lamp fail again. I will check this projector vs others and I'll can determine if fault will happen for extern causes or not.
The Kelmar changeover seems to me the best way to solve the douser's annoying problems. Any suggestions about that?
I think to do that with all Christie projectors.Giorgio.
Posted by Giorgio Volpi (Member # 1182) on 03-18-2002, 07:12 PM:
Hi Gordon,when I cheked, the no load voltage was 118VDC.
And the lamp was not working, of course.
Giorgio.
Posted by Gordon McLeod (Member # 33) on 03-18-2002, 07:28 PM:
A possibility is the ignitors pulse length may be too short
On some ORC lamphouses I had to add a DIode and cap across the ignition relay coil to lengthen it
Posted by Richard Fowler (Member # 893) on 03-18-2002, 07:41 PM:
Sr.
the Kelmar changeover is the best part on the machine....the projectors should not be thought as a problem but...as a pension plan to finance your retirement. 
Richard Fowler
TVP-Theatre & Video Products Inc. www.tvpmiami.com
Posted by Steve Guttag (Member # 268) on 03-18-2002, 08:37 PM:
The Christie igniter has a bi-metal deal that will stop the igniter from burning up if it tries to strike too many times. Inside the igniter, (you will have to remove a red cover) there is a power resistor with a tap-ring on it. This ring sets the voltage at which the igniter starts to work. Moving it VERY slightly, you should be able to taylor the ignition pulse to work with your situation. I have often had to sweeten it up based on a particular bulb brand and theatre situation. FWIW, Christie recitifers normally only put out just over 100VDC on no load...they may make it up to about 120VDC after several seconds but that is about it.Another thing to check is the 4th tap on the rectifier...it sets the boost. All four taps should be in the same position. Since it is the 2KW system, they should all be set to the "high" position.
My guess though, your problem can be solved in the igniter.
Steve
------------------
"Old projectionists never die, they just changeover!"
Posted by Rick Long (Member # 213) on 03-18-2002, 09:46 PM:
Could this possibly be the fault of a heat-sensor? (not sure if there is one on those rectifiers). Perhaps a temporary by-pass of any heat-sensor would give you a clue.
Posted by Richard Fowler (Member # 893) on 03-18-2002, 11:09 PM:
Giorgio,
Steve is right about the thermostatic unit that protects the ignitor which may have to be adjusted to local conditions and the Kneisley is able to give a higher no load than the Christie rectifier on your power so the rectifier will need adjustments............
Richard Fowler
TVP-Theatre & Video Products Inc. www.tvpmiami.com
Posted by Steve Guttag (Member # 268) on 03-18-2002, 11:27 PM:
Rick,Nope, the Christie does not have a thermal switch on it's rectifier. Furthermore, the complaint was that the system would give up trying to ignite after several tries. If it was a thermal sensor, then it would drop the arc after it had heated up.
Steve
------------------
"Old projectionists never die, they just changeover!"
Posted by Giorgio Volpi (Member # 1182) on 03-19-2002, 04:21 PM:
Thanks to all of you.Steve, I worked with the resistor but the problem could been solved in only one rectifier during 2 or 3 days.
Gordon, I tried with manual (long) pulse and the lamp didn't turn on.
Richard, thanks for your philosophic help .... BTW the Kneisley is workink with a low no load voltage, about 85VDC, and starts very well.
I'd like to remember to all of you that this problem happens only at this theatre (El Recreo) and only with 2KW rectifiers.
Giorgio.
Posted by Richard Fowler (Member # 893) on 03-19-2002, 04:46 PM:
Generally Kneisley will start at 100 + no load for the 3 phase unit and varies with the tap setting...Miami Beach many years ago we had 4Kw Kneisley units in a Cinema with double throw switch on the taps since the voltage varied greatly from day to night...but was predictable. I sell mostly IREM rectifiers, so if we meet, I will trade you IREM stories for Christie stories.
Richard Fowler
TVP-Theatre & Video Products Inc. www.tvpmiami.com
Posted by Giorgio Volpi (Member # 1182) on 03-19-2002, 04:56 PM:
I think IREM is one of best rectifiers.
If my company decides to change rectifiers I'll advise them to use IREM.
I hope we can meet a day ....
Posted by Steve Guttag (Member # 268) on 03-19-2002, 08:07 PM:
I'm actually partial to Christie rectifiers and much prefer them (and most anything) to IREM. I find IREM has too much ripple. I can often get a lamp to nearly double it's normal hours when burned on a Christie rectifier.Steve
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"Old projectionists never die, they just changeover!"
Posted by German Marin (Member # 918) on 03-19-2002, 11:40 PM:
I've ever work with Christie's Projectors and I've been thinking work with Christie is a fast way to learn about "how to rapair projector's problems" and "how fast run the technician to the theatres" (I like to see the problems from a nice sight 'cause it's the best way to understand it ).
Now I feel like a son and his father by his side. (I Thank you for all the knowledge I've get from you).
Posted by Paul G. Thompson (Member # 655) on 03-20-2002, 12:36 AM:
I have to side with Steve on this one. I personally found the IREM power supplies are basically just "too dirty" with ripple to suit me.
Posted by Pete Naples (Member # 761) on 03-20-2002, 03:11 AM:
WOW! It never ceases to amaze me how things differ! I wonder if the high ripple you guys experience from IREM rectifiers has anything to do with the different voltage/frequency? In much the same we that we have loads of trouble with US made transformers/motors etc? I can't say I've ever had high ripple problems from IREM, but Christie! O yes! I repaired one last week that had blown two main diodes (gone short) and in turn took out lots of wiring and some Zeners in what I acn only surmise is the snubber network (the book that ths site has for these is not exactly what you'd call detailed). Anyway after replacing the diodes, re-wiring all the vapourized stuff and renewing the various Zeners and caps, it works once more. BTW Those Christie rectifiers are much heavier than they look! I measured the ripple and got 3.85%, which I feel is quite high for a 3 phase unit. Measured the other 11 in that building and they were all around the same. An IREM that I was servicing the following day measured 1.5%Could the single smoothing capacitor in those 12 Christies be going soft? They've been in use since the mid '80s.
Posted by Richard Fowler (Member # 893) on 03-20-2002, 07:39 AM:
IREM has many grades of rectifiers and I usually order the unit with the optional filter choke to improve ripple. Some customers also prefer if we replace the diodes to a larger value based on local requirements which we do prior to shipment. They have changed some of their manufacturing technic in recent years to where we have had some problems with crimp connections leading to the transformer wiring failing due to overheating. The factory is very responsive to maintinance issues and I had Ricardo Croce, Vice President of IREM, visit our sites regarding a problem which he found that the console manufacturer had specified the wrong grade of rectifier for the intended use....they took it upon themselves to replace the units free of charge and repremand the console manufacturer. Typical problems generally are the contactor ( which is readily available in most markets ) and diodes improperly installed by local service people ( cold solder joints on wire leads, no heat sink compound, improper torque in installing the diode ).
Other rectifier stories.....the imfamous earlier switching supply from Strong with the high failure rates....thankfully retired with a new design which the few that I am using for problem spots are working fine...many of the earlier design where taken to the trash dump. Kneisley we had some problems which was traced to improper amount of winding on the transformer which then 85 year old ( and departed ) Richard Kneisley personally took apart to solve the problem; he visited the cinema a few months later to see if the customer was happy.........
Richard Fowler
TVP-Theatre & Video Products Inc. www.tvpmiami.com
Posted by Mark Gulbrandsen (Member # 72) on 03-20-2002, 09:33 AM:
I have actually had the opportunity to measure the ripple and inrush of many different rectifiers. I use an ORC ripple/inrush meter to do this. As I have had the chance to compare this to the industry standard that Osram uses I know I can rely on accurate readings from it. I have measured 3 phase Irem rectifiers at anyplace from 8 to 12% ripple depending on size. When the relay board is working correctly inrush is always with in Osram specs. I've had many a relay board fail in these and it usually means to low of start voltage. I have seen single phase Irems measure quite a bit better than the three phase units. Typically at 6 to 8%.
Kneisley units are by far the cleanest I have measured and are typically at 4 to 5% for the three phase stuff. However the construction of them leaves alot to be desired. The rectifier stack though is about as bullet proof as they come.
Christies will typically measure as well or just slightly worse than the Kneisley's will. I always felt that Christies heatsinking was a joke though. A fan is definately necessary on these when running platter. What I really hate about Christies is the diodes they use. They are epoxy sealed instead of glass sealed and over a number of years the epoxy lets go from heat stress(yes, even with fans). You'll find that the diode has actually failed from mechanical failure as you can usually wiggle the stud itself around. Replacing these with glass sealed type diodes offers far higher reliability overall and less heat stress failure. Almost all diodes I have replaced in Christies over the years were from this sort of failure. Only a few shorted or open diodes have been observed.
As far as Strong switchers go they were alot of trouble back when they were new but after mechanical problems were straightend out in early units they proved in my locations to be no more or less reliable than iron core units. Over the last two years I'd say I've delt with an equal number of problems form iron core type and switchers. The new style smaller Strong switchers have been ultra reliable for us. We have several that get a constant beating on our rental Super Troupers. I've had one failure with the small switcher since they appeared on the market. This was about three weeks ago. The twist lock plug burnt up on one. This was due to compression set of the wires in the twist lock plug for the three phase. Checking all the twist locks in the plex revealed some others that were really loose as well. The rectifier was still ok though, just suffering a chared 3 phase connection socket. These switchers are also pretty much immune to line voltage fluctuations due to the regulation that is built in. we have had great luck in rural areas with them maintaining constant current on the lamps and they give great lamp life.
Overall I feel that rectifiers are like Jet planes. You have about the same chance with any of them but they all require proper maintainance and necessary upgrades to keep them reliable.
Mark @ GTS
www.getgts.com
Posted by Richard Fowler (Member # 893) on 03-20-2002, 10:06 AM:
Generally I use switchers is locations where power does fluctuate or if there is a shipping issue. Like jet planes and sports cars they require more followup in an industry not known ( lately ) to do such. IREM admits that their switchers have 1/3 less service life than their brute force models...but then again I have many 20 year + IREMS in the field chugging along....so 1/3 less is a very long time.
Richard Fowler
TVP-Theatre and Video Products Inc. www.tvpmiami.com www.tvpmiami.com
Posted by Gordon McLeod (Member # 33) on 03-20-2002, 09:22 PM:
Mark i always found the inrush current on the Kniesley rectifiers the hieghest of any
The best i found are the Sanrex and the Allanson ones that were made for General Sound here in Toronto
Posted by Steve Guttag (Member # 268) on 03-21-2002, 10:37 AM:
A couple of things I've noted on the IREMs when used in the states that the wiring and componentry seem to still be based on the higher voltage and lower frequency countries and as such is barely up to rating, particularly the contactors. Also, IREM insists on using spade crimps on the mains wires feeding the contactor. We have found that removing the crimps on installation (bare wire under the contactor terminal) will virtually eliminate overheating at the contactor once and for all. Since IREM insists on giving just enough wire to manufacture the rectifier, it is best to do this before any failures since you may not have enough wire to cut off the burned section.The biggest problem I have had with the Christie rectifiers are diode failures from ignition pulses. Unlike other rectifier manufacturers, there is nothing on a Christie rectifier after the diode stack to squash the noise pulse. Likewise, there is nothing on the input side to squash spikes coming in. Now they DO have capacitors and MOVs on a surge protection board (and one capacitor across the DC terminals on the old DC output terminals) but nothing right across the diode stack or the input terminals. We have found that placing a capacitor across the output stack pretty much stops the diode failures. I know Christie is working improving this.
Steve
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"Old projectionists never die, they just changeover!"
Posted by Stan Gunn (Member # 554) on 03-22-2002, 04:51 AM:
Caps in any rect will go soft with age, I have both in a place I service. The cristie has had two diodes fail, the irem had a sticky relay.
It is very important to have the relay circuit working correctly as it can cause short lamp life by applying a high surge current.------------------
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Posted by German Marin (Member # 918) on 03-22-2002, 12:39 PM:
These Rectifiers which Mr. Volpi has been talking are about 10 months old: "This only happen in one theatre (less than 1 year open)". They begun to work May 15, 2001.