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Author Topic: Motorola P1225 hand held just beeps on xmit  (Read 212 times)

N2NJO

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Motorola P1225 hand held just beeps on xmit
« on: March 18, 2021, 07:05:55 AM »

Out of the blue, when I try to xmit on this older (probably early 90's) Moto P1225 hand held, all I get are a flashing red & audible beeps. I initially thought it was a antenna issue (high swr), but not so, it does in on it's one rubber duck antenna.  I'm figuring the CPU xmit section is messed up somehow.
I have the Service Manual on this, but I don't see ant 'reset' function. I removed the battery pack for a few minutes, but no change. I have it sitting in it's charger, power off, connected to a outdoor VHF antenna (tuned), it's rarely used.  Receive is Ok.

Any ideas?
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K5LXP

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Re: Motorola P1225 hand held just beeps on xmit
« Reply #1 on: March 18, 2021, 11:31:17 AM »

Former motorola bench tech, fixed thousands of HT's.  Does it receive at all?  Kinda sounds to me like it might be being starved for current.  First electrical things to check are the battery, battery contacts and the on/off switch.  Anything resistive in this path will cause a voltage drop on transmit. 

Mark K5LXP
Albuquerque, NM
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N2NJO

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Re: Motorola P1225 hand held just beeps on xmit
« Reply #2 on: March 18, 2021, 12:39:54 PM »

In bold; "Receive is Ok."

It now appears to be a bad battery pack, I'm charging another, I don't recall this never happened before. When the pack dies, it's dead, no half on, half off like this. I'll used this on & off for probably 15 years.
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KF5LJW

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Re: Motorola P1225 hand held just beeps on xmit
« Reply #3 on: April 02, 2021, 08:59:58 AM »

No when batteries, especially NiCad start to crap out the internal resistance goes up. Put it on a charger, and amazingly your battery charges in 5 minutes. Turn on the radio, and the voltage sags like a discharged battery.  Pull it out and check the voltage, it is OK.

Classic symptom.
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N2NJO

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Re: Motorola P1225 hand held just beeps on xmit
« Reply #4 on: April 02, 2021, 09:45:08 AM »

Is this behavior (on the part of the radio, not the battery pack) changed since this old design (from the early 90's)? Receive is ok, but when one xmits the radio just quits completely (powers down) instead of just not xmtiing?
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N2AYM

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Re: Motorola P1225 hand held just beeps on xmit
« Reply #5 on: April 23, 2021, 06:10:20 AM »

In bold; "Receive is Ok."

It now appears to be a bad battery pack, I'm charging another, I don't recall this never happened before. When the pack dies, it's dead, no half on, half off like this. I'll used this on & off for probably 15 years.

rechargable batteries have never been designed and built to last that long and if you had one
that lasted that long you would be the rare lucky one. :)
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WB6BYU

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Re: Motorola P1225 hand held just beeps on xmit
« Reply #6 on: April 23, 2021, 04:56:05 PM »

Probably one or more cells have shorted in the
battery pack.  Receiver still runs on the reduced
voltage, but not the transmitter.

Could also be a corroded contact in the battery
circuit (or a battery fault) that drops the voltage
too far with the load current in transmit mode.

Those things (bad batteries and corrosion) do
happen over time.

I finally switched to AA battery holders for my
HTs because I don’t use them enough to keep
the  batteries up.

N2NJO

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Re: Motorola P1225 hand held just beeps on xmit
« Reply #7 on: April 24, 2021, 03:32:08 AM »

Understood about the power situation. Unfortunately, one can't substitute individual cells for their battery pack in this. This was my first (and only 'non consumer' hand-held) that wasn't just a receiver.  I failed to realize the additional power drain on xmit. ;)
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