- 3M calls their 2123 insulating resin "reenterable" so the stuff can certainly be removed and the boards can look quite... intimidating when they first come out of the box but with a little patience and a little work they clean up well enough to allow repairs and/or changes. So, all P5 boards built since 2004 are potential candidates for conversion to digital ZDL switchers and/or ZDL simple flowmeters. The list of potential candidates would normally include boards built back in the 90s, unfortunately however, the potting compound used up to the end of 2003 does not allow those boards to be reworkable. So "See you later, alligator" for those so-called PDLs...
- Close reexamination of multiple old boards revealed the ultimate truth in the end: The "crazy greek", and "crazy" wasn't the usual adjective but that's another story, who wanted to put expensive electronics in a $30 plastic box, ha ha that's so funny, and have the entire assembly sit at the bottom of lake Erie for decades, wasn't all that crazy after all. But you know Jack, after three years of no switching failures, I couldn't help but notice, nobody is laughing anymore...
- Close reexamination of multiple old boards also revealed something unexpected, something completely forgotten: Because I designed these boards I know that from the hardware point of view a P5 was a P4 with a faster crystal. The recent switching success with the P5 switchers was accomplished with the same boards the dismal failure known as the "trustco fiasco" was done with back in 1998. It didn't have to happen, the hardware was already perfected in '98! History v2.0, 1998-1999.
- Further, the switching circuitry in the PDL3 (1997), PDL4 (1998), CDi99/PDL5 (1999), CDi3/P7 (2011), and the upcoming CDi4, the switching circuitry on all five boards is identical, these boards were designed to drive two latching solenoids since at least the PDL3 in '97!
The NTRM, "Nothing To Repair Man", November 18th, 2017
- It is very likely the lithium battery encapsulated in the DS1386 RTC, RTC=Real Time Clock, actually lasts for at least 15 years at lake-bottom temperatures, instead of the 10 years stated in the Dallas Semiconductor RTC Datasheet, patience please, as this list grows to an anticipated number of at least 30 or so rows, over 40 of these at the "PDL Cemetery".
- The 3V board memory backup battery lasts for at least 9 years, it has been moved outside of the board compartment since the ZDL switcher in June 2017, and should be changed out every 7 or so years when the main battery is replaced. Although this battery will keep the storage memory alive with a terminal voltage as low as 2.5V, experience demands replacement when the voltage falls below 2.9V.
- In order for board assemblies to make it into this list they need to be perfect electrically, and the RTCs need to not have missed a beat since the first time they were plugged in up to 15 years earlier. The second time around, when any of these are redeployed, their RTCs will look like this, and their backup batteries will be outside the potted board assembly like this, and they'll be called ZDL5 boards!
- Obviously, the boards listed here are a little past "their warranty period", prospective future clients should keep this in mind!
- A quick note about semiconductor date codes: See the "RTC Date Code" column below, 0335 means the chip was manufactured during week 35 in 2003. 0414 = week 14, 2004 and so on.
- Thank you TLM, I mean thank you for the education!!! * Long live the PDL Cemetery!!! * To the stars, through adversity!!! * Στ' αστέρια, μέσω αντιξοότητας!!! * AD ASTRA PER ARDUA