This could apply to the AM 500A, AM 1A, AM 6A, AM 10A, AM 2.5E, and AM 5E.
Four month’s ago, when our BE AM 6A lost power to Module 2, a quick call to BE indicated the probable cause was a pair of capacitors on the modulator board. Great! They knew what was wrong. The cost for replacement... $80 each! Yikes! Well, we bit the bullet and shelled out the $160 plus shipping. Sure enough, this fixed the problem.
Last week, just 4 monthes later, Module 4 went out. So, another call to BE. This time, they informed me there is a known problem with the caps, and they have a fix. A kit to replace the capacitors. The kit costs $120 per module! Yikes again! That's $720 for the BE AM 6A. That would be $1200 if we had the 10A!
It was time to do some research. The picture of BE's kit showed a tiny pair of circuit boards you attach to the Modulator board, with 2 smaller caps. My guess is they went with a pair of 150uF instead of the larger 330uF. Either way, that seemed like a lot of money for a little board and a couple capacitors. It also looked like those caps are going to be even harder to replace when they go bad in a few years.
According to Cornell Dubilier, the original capacitors are the wide-temperature, high ripple current capacitors for power-supply outputs and UPS battery stiffening. The 3rd lead on those caps have no connection to the circuit. I suspect they are just for better strength to survive shipping abuse. I like the idea, but our transmitter is going to be here until the day it dies. We don't need that third lead anymore.
I combed the big distributors web sites looking for replacements. I wanted HIGH temperature, Long life, high ripple current capacitors, with a diameter no larger than 20mm but preferably 18mm, they must be commonly stocked and IN STOCK. I found exactly what I needed in the Panasonic EEU-ED2D331 from Mouser. Now, I wanted a fast way to replace these in the future, yet I wanted them to be held securely. I went with #1731022 Phoenix terminal blocks with top screws and side connections and 7.5mm spacing to fit the original board holes. I marked the positive with a red sharpie. I couldn't find my black sharpie.
Everything fit together beautifully. I was going to use zip tie mounts for added security, but I was not sure the zip ties and the foam tape would stand up to the high temperature for the many years of service we were expecting from the BE. I thought RTV162 was a better choice. It is made specifically for bonding electronic components to substrate. It also comes off nicely if you need it to.
So, here's the rundown:
Original caps: $160.00
BE Fix Kit: $120.00
My Caps & Blocks: $11.06
Savings doing entire transmitter: $893.64
Green lights and smiling owner: Priceless
Here are the parts needed:http://www.mouser.com/Search/ProductDetail.aspx?R=1731022virtualkey65100000virtualkey651-1731022http://www.mouser.com/Search/ProductDetail.aspx?R=EEU-ED2D331virtualkey66720000virtualkey667-EEU-ED2D331