The Synchronar Solar powered LED watch was the brainchild of American electronics inventor Roger Riehl. What wasn't there to like: No batteries to change; user adjustable accuracy within 4 seconds per year, programmed to change the date and time accordingly for leap years and Daylight Saving, shock, temperature and pressure resistant, and 23 Display functions? Easy to read in any light, with a stylish and unique shape? In theory it was the perfect timepiece,"The most indestructible watch"(Synchronar2100 ad). Unfortunately, two of it's strengths turned out to be its "Achilles Heel" - the batteries that were intended to never be changed leaked or quit taking a charge, and then the "indestructible"[almost] Lexan plastic housing stood between any repairperson and the delicate insides. Insides that had been flooded/filled with a transparent, sticky "potting gel", which protected the internals for extremes of temperature, pressure and force. It's been 36 years since the first Synchronars were offered to the public. Roger Riehl improved the circuits thru 4 major changes, designated Mark I thru IV, until his passing in 2005. Few working ones remain, as the leaking batteries destroyed many of the circuits, and opening the Lexan case without ruining the insides holds much lower odds than cracking eggs without breaking the yolk. I can personally attest to this having opened more than 30 of these. [edit] Howard Riehl believes the potting gel has been saving the circuits from leaking battery damage, a contention I don't personally agree with, as every Synchronar I have opened has had a lot of damage from the batteries leaking, and the leakage seems quite able to follow any voids in the potting gel. This has been the case in SYnchronars where the potting gel cured hard(properly) or soft(improperly). I also have wondered about the reasonableness of vacuum sealing the cases, as the batteries may actually have been induced to leak by a low or negative atmospheric pressure. Batteries are never sealed tight, those seals are meant to give if pressure gets outside a certain range, either internally or externally. Not sure if those batteries are designed for negative atmospheric pressure.[end of edit] Fast Forward ----->2007
Howard Riehl, Roger's youngest son is now assembling Synchronars from parts that were never completely assembled. Howard now knows where some of the more common failure points are. These Synchronars have new, heavier wires from the solar cell to the circuit. The batteries are new Ni-MH [edit], the Synchronar "build-your-own" kits aren't sealed, but Howard tells me he seals the RWR10LE cases as tight as ever, and fills the cases with a quality, modern potting gel. Howard claims that most people still want the gel in there. [end of edit] I don't know how many of these Howard will be able to put out, but I think they are an excellent opportunity to have a working Synchronar, one that will really go for years. Contact Howard here riehl_synchronar_2100@yahoo.com I've purchased two of Howard's "build your own" modules - one clear case, one standard red case. Now, curious collectors can take a look under the hood, of one of the most controversial digital watches ever, minus the infamous "potting gel". [edit] I personally opted for small dabs of silicon to stop parts from moving or shorting out, and clear silicon for the seal. By always storing upright in it's display box when not wearing it, I will hopefully notice any battery leakage and it will have accumulated in the lower part of the case, away from the circuit board. Note, the "build-your-own" kits have circuits that failed one test - the stopwatch doesn't work.[end of edit]
The module case is one of just a few clear ones Roger Riehl, Sr. had made. | Installed in Case | Module with case off.
Springbars & magnets turned over on right. |  |  |
| Solar cell and Reed switches. | Quartz oscillator,Reed switches. Yellow square covers the IC chip. |  |  |
Detail of display wirebonds. | 
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