Batboard

Can anyone confirm that the four-pin in-line connector in the lower left-hand corner of the Saber main board (as viewed from the front), into which the four-conductor flex cable from the speaker and microphone of the front shield assembly is plugged, has the following pinout, left-to-right, as viewed from the front?
1. mic-
2. speaker
3. speaker
4. mic+
Since the microphone appears to be a electret mic, the mic- and mic+ denote the polarity of bias voltage provided to the mic element from the main board.
Also, does anyone know the specified impedance of the speaker?
If someone has a couple of spare front covers with speakers, mics, and flex cables for a non-ruggedized submersible (i.e., non-secure) Saber I, please PM me.
Thanks.

APX wrote:Can anyone confirm that the four-pin in-line connector in the lower left-hand corner of the Saber main board (as viewed from the front), into which the four-conductor flex cable from the speaker and microphone of the front shield assembly is plugged, has the following pinout, left-to-right, as viewed from the front?
1. mic-
2. speaker
3. speaker
4. mic+
Since the microphone appears to be a electret mic, the mic- and mic+ denote the polarity of bias voltage provided to the mic element from the main board.
Also, does anyone know the specified impedance of the speaker?
If someone has a couple of spare front covers with speakers, mics, and flex cables for a non-ruggedized submersible (i.e., non-secure) Saber I, please PM me.
Thanks.

Pin 4 is on the outside corner and is grounded in the radio. Also, just because your Saber I is non-secure does NOT mean that it's submersible. The housing you are looking for is P/N NHN6384A for the submersible model, however there are plenty of seals that have to be in place and in good condition. Then it would have to pass a vacuum test (yes, we vacuum tested them, not pressure tested them. They had to hold the rated vacuum for two minutes) to be rated submersible.

Thanks for your reply. Not knowing the official pin numbering, I apparently reversed the order.
From the end toward to the center of the radio to the end toward the corner of the radio (right-to-left as viewed from the front), the pins are apparently as follow:
1. mic +
2. speaker
3. speaker
4. mic ground
That pinout seems to work properly.

Although the 15E05106U cases and the escutcheons are marked "submersible," I use that term loosely, as these are junk radios that saw heavy fire department use. The cases are both warped from heat and cracked, so they'll be lucky to survive a few raindrops, much less submersion. The goal of this somewhat futile exercise was to turn a pile of junk radios into a couple of "disposable" radios to hand out in situations where they might never be seen again. They just have to look good on a service monitor, no matter how bad they look to the naked eye. Thanks for the details of what makes a radio officially submersible, especially the part numbers and the vacuum testing.

Do you know if the stainless steel front cover plate is designed to provide any RF shielding or just to hold the speaker and microphone (and optionally the memory expansion module for the 1E model) in place? All of the modules under the front cover seem to be well shielded, so I'm guessing the front cover is mainly mechanical in purpose.

The front plates do provide RF shielding. Just a little side note, for such a small speaker, it has quite a strong magnet. If you get complaints of speaker rattle, you will find quite a bit of metal filings there. In my first response to you, I forgot to mention that the internal speaker has an impedance of 28 Ohms.