Differences between MkIII/IV modules.

[Sully008]

Okay, post whore here.

Does anybody know the differences between a MkIII and a MkIV module in terms of features? I have a set of instructions for setting a Mk IV module (April '82), but I don't know if those will work with what I have. Actually, is there a way to tell by looking at the board if this is a MkIII or IV? This was an already open module so there was no serial #.

[dot matrix]

Here's a partial list I put together based on my own experience, I don't know how correct it is. The IV was a massive upgrade adding daylight savings time, improved accuracy, a second timezone, a stopwatch, and an inaudible, visible-only alarm. However, the IV did not have the AM/PM indicator of the III. The IV also used what it called a "jog" (like a doubleclick) for accessing or setting some of the new features. I'm not 100% certain, but I think the III didn't have this.

SYNCHRONAR 2100 (Mark III): Riehl Time Corporation

* Features: Hours:Minutes (24 hour; or 12 hour with AM/PM indicator which appears as a single LED element in the display);
* Date;
* Day:Seconds;
* Leap Year;
* Rate Adjustment 16 seconds per year increments (+/- 8 secs/year accuracy)
2 slide switches

SYNCHRONAR 2100 (Mark IV): Custom Circuits Corporation

* Features: Two time zones (Hours:Minutes;seconds) (24 hour or 12 hour - AM/PM indicator feature removed);
* Date;
* Day:Seconds;
* Leap Year;
* Rate Adjustment 8 seconds per year increments (+/- 4 secs/year accuracy);
* Automatic Daylight Savings Time Adjustment;
* Alarm;
* Stopwatch;
* Flashing timer
2 slide switches

[Sully008]

Thank you for that, liquid crystal. I guess one way to see if it's a Mk IV would be to try the different functions listed in the instructions. If it works, then it's a Mk IV, if not, a III.

[Synchroserious]

Yes, everything Liquid crystal said is correct.There is no Jog needed for MK III.The one other thing added to a MK IV is the delayed reaction (6 seconds)of setting to prevent accidental setting.

The simplest way to tell the difference between MK IV or MK III is the serial #. If it does not begin with #4 it is a MK III.If it is alreay open the MK III chip is rectanglar shape and the MK IV chip is square.

I will tell you that 99% of the opened up modules sold at ebay(not by me) as "MK 3/4" were MK III,s.

[Sully008]

Howard,

Do you have instructions for setting a MkIII? I've got instructions for a I, II, and IV. Curiously, I've never seen Mk III instructions on the 'net. Just as an update, I've found another module that works, display is good on it as well. I'm going to attempt to replace the display on the other module that is missing a segment.

Yes, everything Liquid crystal said is correct.There is no Jog needed for MK III.The one other thing added to a MK IV is the delayed reaction (6 seconds)of setting to prevent accidental setting.

The simplest way to tell the difference between MK IV or MK III is the serial #. If it does not begin with #4 it is a MK III.If it is alreay open the MK III chip is rectanglar shape and the MK IV chip is square.

I will tell you that 99% of the opened up modules sold at ebay(not by me) as "MK 3/4" were MK III,s.

[Keatah]

I always like to say my re-built Mark IV *does* have an AM/PM indicator.
Right away / left toward

You've got 6 seconds to read the display :)