spectra AVL problem

rsqemt911 · Post by **rsqemt911** » Tue May 11, 2004 1:17 am

i recently bought a 800mhz spectra A5 that was converted to a an Auto Vehicle Locator (AVL) ... it programs fine, but does not transmit from the palm mike ... the radio also has another perculiar anomaly ... when you apply power to the ignition wire on the accesory plug, the radio turns on by itself ... you cannot turn it off via the power button once it is powered up ... remove power from the ignition wire, it stays on until you press the power button ... i am far from an expert and quite frankly have no clue what i am doing ... i have a friend who does know what he is doing looking at it along with the local motorola radio shop ... none of them as of yet have been able to solve this problem ... my ambulance service curently has 2 more radios like this that seem to do the exact same ... any help from her would be greatly appreciated
please write me back at [email protected] ...thanks

60hzEE · Post by **60hzEE** » Tue May 11, 2004 5:12 am

Sounds like someone installed JU7 on the back of the control head. This bypasses Q51, which is used to apply A+ when the power button is depressed and held. True for most all spectra heads, except the very old ones.

Looking at the back of the head PC board, JU7's location is directly under the rather big FET in the lower right hand corner of the PC board. Right under the bottom soldered lead from the FET, oriented vertically. If you remove JU7 (or wire or solder bridge) across the pads, that should do it. There could he another jumper next to it, JU1. It should be removed for on/off switch T/R control. JU2, oriented horizontally, immediately to the left of JU7, should be installed. The chip jumpers should say "000" on top of them.

I don't know why the radio won't key up, unless it is JU1 or JU2 configuration. With JU1 out and JU2 in, the on/off switch enables all, with power applied to the accessory ignition sense pin.

Lee

RKG · Post by **RKG** » Tue May 11, 2004 6:25 am

Spectras used as RF links for AVLs are modified in the control head interface board so that the radio modem can key the radio. I don't know the particulars of the modification, but I suspect that replacing the entire interface board with a stock one will reset most of the mods.

sglass · Post by **sglass** » Thu Sep 21, 2006 12:39 pm

60hzEE wrote:Sounds like someone installed JU7 on the back of the control head. This bypasses Q51, which is used to apply A+ when the power button is depressed and held. True for most all spectra heads, except the very old ones.

Looking at the back of the head PC board, JU7's location is directly under the rather big FET in the lower right hand corner of the PC board. Right under the bottom soldered lead from the FET, oriented vertically. If you remove JU7 (or wire or solder bridge) across the pads, that should do it. There could he another jumper next to it, JU1. It should be removed for on/off switch T/R control. JU2, oriented horizontally, immediately to the left of JU7, should be installed. The chip jumpers should say "000" on top of them.

I don't know why the radio won't key up, unless it is JU1 or JU2 configuration. With JU1 out and JU2 in, the on/off switch enables all, with power applied to the accessory ignition sense pin.

Lee

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ysing the search button save my ass today.

Thanks to tvsjr for tellign me ju7 and 60hzee for posting this.

free pitcher for you two at dayton