The Motorola Syntrx has a well-earned reputation as a rugged and reliable radio.  In fact, the term "bulletproof" is often used to describe them.  Their popularity evolves from this ruggedness.

Unfortunately, the Syntrx employs bipolar (fusible link) PROM's to store program information, and these are one-time-programmable devices.  That means a new device each time the radio requires reprogramming.  These PROM's are long obsolete and supplies are very hard to find - and expensive when you can find them.

The idea of using adaptors employing EPROM's isn't new, and it isn't rocket science either.  But it does require a fiddly printed circuit board.  Years ago, SkyLine's founder developed such an adaptor for use in his clients' fleets.  The design has evolved steadily, and due to repeated requests this adaptor is now being made available to end users.

Two views of our EPROM adaptor for Motorola Syntrx

Right-click to enlarge images

The adaptor uses a 2716 EPROM, which accommodates the Syntrx maximum of 100 channels.  A 2732 can also be used and, if the user arranges a bank switch, a total of 200 channels (in two banks) can then be programmed.

The pins on the adaptor will insert directly into the PROM socket in the Syntrx although they are thicker than IC pins, and that is how they are generally installed.   For the purists requiring a more elegant job, we recommend removal of the PROM socket and installation of two socket strips (ex Altronics P-5390).  This work needs to be carefully executed as the plated through holes need to be completely cleared, and the tracks on the radio's double-sided PCB can be damaged if care is not taken.

There are EPROM adaptors on the market which have additional components and require connection to a +5V point on the radio PCB.  The simpler SkyLine design has now been in use for over ten years without issues.

Note that this board cannot be fitted if the large "L"-shaped selcall board is installed.

This latest layout revision will fit with either the standard 5ppm reference oscillator or the optional 2ppm reference oscillator.

These adaptors are suitable for both wideband and narrowband operation.

Normally, proprietary Motorola software is required to program the PROMs and create the file for an EPROM.  Apparently there is also third party software to generate (E)PROM image files.  Do NOT ask us for software as we cannot supply it.   Where adaptors are ordered with EPROMs fitted, we can arrange programming to user requirements.

Contact us for further information and quantity supply.

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