Making Waves Commentary: The Shotgun Approach

A little over two years ago, Fox 6 photojournalists were showing up at our service shop with odd, seemingly unrelated problems with their camcorders. The symptoms involved anything from servos to color encoding to erratic controls. We learned that the solutions, however, were almost always the same–change out a group of surface-mounted electrolytic capacitors or replace the entire circuit board. The DVCPRO camera or studio deck always went away working again until another, unrelated, failure occurred. Repair veterans like Greg Capalbo of GRC Electronics were warning us that the failed capacitor scenario was an epidemic, especially with Panasonic gear, but also to a lesser extent with Sony and other brands. And Panasonic was not supporting out-of-warranty fixes with either parts or labor.

As we saw more electronics come in with bad capacitors, it became increasingly clear that the future duties of our ENG specialist Ladd Prier might involve an endless, daunting series of tracing erratic component behavior to a circuit, then buying new caps, awaiting their arrival, then swapping them out and hoping the bad behavior would disappear. We visualized the coming stack of broken equipment and unhappy users. There had to be a better way.

Ladd and I come from a time when a technician took pride in tracing an obvious equipment failure to one or more components directly responsible. When an RCA TR-3 2″ videotape player headwheel wouldn’t spin up, I would get the four-inch thick manual, an extender, and Tektronix 545 oscilloscope and through a series of calculated guesses, eventually find the open or shorted germanium transistor or diode, then replace it and check a couple of waveforms before pronouncing the monster ready for duty.

Fast forward 25 years. Today’s equipment contains little undocumented black boxes. When the servo fails, you change out the servo board. But what if all boards fail on all news equipment? We were looking at a potential of essentially having to replace part-by-part all of our five-year-old Panasonic equipment.

A Better Way

On a whim, I called our temporary agency, TLC Staffing, and asked if they had any registered rework specialists. In manufacturing, these are the people who take circuit boards with errors on them, either by design or by manufacturing defect, and change out components as ordered to resurrect those boards. {mosimage}They are skilled at performing Lilliputian surface-mount technology soldering, and with incredibly tedious repetition.

TLC sent us Vu Le, who appeared businesslike, cheerful, and ready for action. Over the next ten weeks, he replaced nearly every surface-mounted capacitor in every Panasonic DVCPRO deck, both from the field and from inside the plant. He changed up to 400 caps a day for a total of nearly 20,000. Total cost: nearly $16,000 including parts. Every VTR and camcorder finished worked like new, especially when heads were changed at the same time. There were no more mysterious misbehaviors, a fraction of the downtime, and Ladd was now free to take care of the more normal maladies of ENG.

Months after Vu went on to other work, we noticed more equipment failures that seemed as though they could be capacitor related. Modules in our Wheatstone TV-80 mixer started having problems with bandpass and open circuits. Our digital Hitachi studio cameras had assorted color problems.

This time we didn’t hesitate. We hired temp Daniel Yanez to swap out all the electrolytics in those devices, though less careful to estimate the extent of the project. Now some 10 weeks later, Daniel is still slaving away, module after module. He began filling a three-gallon plastic jar with the tiny devices, and now it’s nearly a third full.

Obviously, if we knew the more about the exact nature of the failures, we could be more selective about the replacement. Were some of the caps higher grade? Which values really fail? If temperature is a factor, couldn’t we perform an IR scan to find the hotspots? Since we didn’t have a good composite history of the mixer and cameras across their user base, we didn’t have the knowledge to pick and choose what devices to replace, so we replaced them all. The basis for doing so was 100% empirical and 0% scientific.

Epilogue

Industry experts continue studying the science behind the SMT chip capacitor failures. It surprises me to learn that they blame not just chip chemistry, but physical conditions during manufacturing and board assembly. It appears as though bad things are happening to good companies with respect to their products not living as long as expected.

We bought replacement capacitors that were labeled as having a long expected life, but there’s no assurance that we’ll even double their life. In fact, we’ve replaced the camcorders in a surprise blast of capital funding. I expect the 7-year-old standard definition cameras and analog audio mixer can’t be far behind.

Daniel is looking for his next gig. Got bad stuff?


Comments

Courtesy CGC Communicator

The capacitor saga dates back to about 1998 and the wide use of surface mounted electrolytics. Those parts have a time and temperature rating. The ones supplied in most gear do not have the most generous ratings. While we deal with Sony, Panasonic, JVC, etc., their original board assembly may all be
done at one outside vendor. Thus, plenty of gear was built with marginal capacitors.  I first ran into this with Panasonic DVC-Pro recorders.  One audio card that was troublesome had 50 of the beasts on it.

The best way to test for bad capacitors is with a Capacitor Wizard that uses a high frequency to measure reactance. It works fine testing caps with no need to unsolder.

Roy Trumbull, roy547 (at) msn.com

 


 

The Panasonic DVC-Pros are the first and worst detected.

We tried Panasonic replacement kits and they didn’t fix all symptoms. I decided not to test the capacitors, figuring that we would have too many iterations of failure/remove/disassemble/test/replace/reassemble/return. Our rework guy could replace 400 caps per day, so I just said to heck with testing –replace them all!

It’s been my experience that measuring in-circuit reveals the problems in only one point in time and doesn’t address future cap failures. In our case, we haven’t had any symptoms in our DVCPRO decks since the mass replacement of capacitors.

Gary Stigall


URLs FOR ELECTROLYTIC PROBLEMS

Scroll down to the Great Capacitor Scare:
http://catless.ncl.ac.uk/Risks/22.73.html#subj9

This article discusses acidic leakage damaging circuit boards in mobile radios:
http://www.repeater-builder.com/motorola/spectra/spectra-caps.html

While this article is oriented towards PC board mounted caps, the cause is the same – bad electrolyte:
http://en.wikipedia.org/wiki/Capacitor_plague

And more links yet:
http://www.ttiinc.com/object/ME_Zogbi_20050919.html
http://www.badcaps.net/
http://www.theinquirer.net/default.aspx?article=24596 (re Dell)

All in all, it looks like bad electrolyte is the root cause.
In some cases it causes a reduction in capacitance value (which
changes circuit performance), in others it blows the tops off the
caps, in others the electrolyte eats its way out of the cap and
eats up the board.

Mike Morris, WA6ILQ

KSDS Gets FCC OK to Raise Power

(Disclosure: The author is employed by Bay City Television, San Diego-based programming, advertising, and marketing arm of XETV Tijuana)

The FCC issued on October 31 a construction permit for KSDS (FM), 88.3 MHz, to increase power from their current 3 kW vertical to 22 kW ERP vertical, upgrading the facility from class A to class B1. The station, operated from the campus of City College downtown, but transmitting from a tower at Mesa College in Linda Vista, has been operating since 2002 with 3 kW ERP vertical polarization after a compromise worked out with Fox Television affiliate XETV, channel 6 in Tijuana.

The latest CP approval comes as a surprise to XETV, which has fought the increase in power since 1995 on grounds that it creates a substantial interference zone since the stations are only separated by a minimum of 200 kHz between allotments, or 550 kHz between carrier centers. The stations represent a unique situation in the U.S., where a border non-commercial FM had protected a channel 6 TV signal broadcasting in English-language from Mexico. The new construction permit appears to change the crossborder relationship by declaring previous protections null and void.

The new FCC ruling says that previous international broadcast treaties do not specifically deal with the TV-FM interference issue, so the XETV signal has no rights to protection from U.S. non-commerical FM stations after all. At the same time, the order gave recognition to XETV public service efforts and ordered that KSDS broadcast its increased power in vertical polarization only. KSDS must provide a shallow null to the southeast, and they must remediate any known interference and report unsolved cases to local FCC inspectors.

KSDS intends to have its facilities ready for increased power by spring 2007.

Yuma Market First in Nation to Adopt New 12 MHz BAS Plan

The Yuma-El Centro TV market underwent a changeover to the new BAS 12 MHz per channel ENG microwave spectrum plan Friday, September 22, according to Robbie DeCorse, Chief Engineer at KYMA (NBC) in Yuma. He says that they “haven’t had any issues since the switch; it’s business as usual.

Meanwhile in San Diego, Nextel is working to get the necessary 75%
of the market under contract. Pat Hughes of Sprint-Nextel says that
they believe it will be next summer sometime before the switch takes
place here. He forsees Santa Barbara switching soon, then Palm Springs
and San Diego. Los Angeles will be last due simply to the sheer number
of people involved in the project.

Once the market has contracted for the changeover, there has to be a “caucus” to decide the exact swapover date.

Hughes encourages those who want to learn more to get updated information from their special website at www.2ghzrelocation.com.

FCC Fines 106.9 Pirate in Encanto

The FCC issued September 27 an order asking Joni K. Craig to pay $500 for operating an illegal FM transmitter on 106.9 MHz in the San Diego neighborhood of Encanto. The commission had issued in May two Notices of Unlicensed Operation (NOUO) for the pirate station, located a few blocks south of the KOGO towers. That notice addressed Alan M. Conrad and Maria A. Conrad, who are listed as owners of the property and addressed the assumed name of the station, “Radio Active Radio.

In the latest FCC order, the original $10,000 fine was reduced to
$500 when Craig provided tax documents that proved to the commission’s
satisfaction that she was unable to pay the full fine. She was also
able to convince them that she played only a passive role in the
station and “took steps to shut down the station.” San Diego inspectors
had monitored the station several times between October 2004 and August
2005.

Joni K. Craig is a spokeswoman for the San Diego Foundation for Change.

October 2006 Meeting – Studer

In a presentation of interest to both TV and Radio engineers, Jamie
Dunn, Studer’s Western Regional Sales Manager will introduce two of
Studer latest technologies with the opportunity to see Studer’s
complete digital console product range installed in their 53 foot
mobile demonstration truck.

Studer is one of the oldest and best known worldwide audio companies. Formed in 1948 by Dr. Willi Studer in Zurich Switzerland, Studer Professional Audio became famous throughout the world for its high quality and robust tape machines. Even today, a Studer tape machine can still be found in practically every studio or broadcast facility. Studer, however, was also a major manufacturer of mixing consoles for both production and on-air applications. For the past 15 years, Studer has been at the forefront of digital technology and now has a product portfolio dedicated primarily to digital mixing consoles focussed towards Radio and TV applications.

Vistonics is Studer’s patented technology of mounting rotary encoders and switches onto a TFT Screen. It forms the basis of the revolutionary and award winning user interface of both the Studer Vista 8 and new Vista 5 Live Broadcast consoles. The presentation will give a brief insight into the philosophies that make Vistonics the Return of the Human Interface.

The OnAir 3000 is Studer’s 3rd generation of digital on-air console and is based on a modern router based architecture and flexible hardware concept. Jamie will introduce the underlying concepts and philosophies behind the product.

Jamie relocated to Los Angeles in July of 2005 with his wife and 2 year old daughter to take on his present role of Studer’s Western US Regional Sales Manager. Previously living and working in Zurich, Switzerland at the Studer Headquarters, he had been working for Studer for 6 years as Product Specialist and Sales Director for North and South America. Originally from the UK, Jamie is a “Tonmeister” (Sound Master) graduate and prior to working for Studer, worked as a classical recording engineer and editor for an independent production company based in London.

Members and guests, please join us Monday, October 23, at 6 PM for snacks and a social hour, and 7 PM for the demonstration. It all takes place at TV Magic, 8112 Engineer Road in Kearny Mesa, San Diego.

Society of Broadcast Engineers, San Diego