I think I blew out my GP350!

Josh · Post by **Josh** » Sun Dec 09, 2001 8:08 pm

Today, a terrible thing happened. My GP350 started overheating and then stopped working all together.

I've dropped the radio several times during my ownership, today, I dropped in onto the floor and as usual the radio aws still trucking along. I with the mind-set that "this radio can't be broken" was proven wrong. A couple hours later, after using it non-stop (rx only), the battery flat out died. I was receiving signals with it just fine, until I pressed the TX button and the radio beeped the low battery warning and went dead. Assuming the battery finaly died (after using the battery for about 8 or more hours all together), I attached a fully charged one. For some reason, the radio gave me a low battery beep, but I figured I forgot to charge this replacement battery, too, by mistake, so I decided to run the battery until it just quit working. After using it for about 10 or 15 minutes, I noticed that it felt warm. Of course, I had been holding it in my hand the whole time, so I decided to shut if off and take off the battery...the metal chassis was burning hot! I was pretty alarmed at this. I let the radio cool off and put the battery back on and turned the radio back on, too. It didn't come back on for long after that- just long enough to beep and give a low battery warning beep before it shut off again. It hasn't come back on since.

Later, at home, I took it apart. Didn't see anything burnt up on the board, but I did see the white stickers on this inside of the chassis had blackened in a couple places where the components on the board are covered with a shielding with small holes in it. Something under there was getting hot. After not being able to turn on the radio, I swapped mother boards with a different GP350, and got it to turn on (the radio was running with the battery contacts and electronics from a different gp350). The radio quicky got hot again and tracked it down to a 1/2" by maybe 2" blue component with some major grounding attatchements on it. Part number "SHW5066" then underneath it "9638" I am not totally sure if this was the component getting hot or not, but the whole area, especially the large grounding pieces of metal were, as well as components in that general area of the board. I also noticed a black, rectangular, unmarked component was soldered in right, but was loose from its solder pins. There are two similar looking components on the chassis piece behind the battery contacts (was not a fuse). Could this be what is causing my radio to overheat and function improperly? If so, It may have broken loose in the fall. What is the blue thing on the board with all of the grounding contacts on it (part SHW5066)?? Has anyone else had similar problems?

Also, I'd like to add that while the radio does not turn on fully assembled, exchanging the motherboard with another radio, allows it to work, and also exchanging the PC board where the battery contacts are with a different GP350 turns that GP350 on, too. So, for some reason the chasis and the motherboard don't want to work together. But they will work when switched with other radio's components.

Please help me out.

Finally, if this message does not make a whole lot of sense, it is because I am pretty tired. I will re-read it and hopefully fix it. I am also sorry that I don't know what all of the components are, but hope that someone- anyone can decipher it.

Thanks
-Josh

raymond345 · Post by **raymond345** » Mon Dec 10, 2001 2:00 am

Hi there. Yes it looks like bad solder joints
got the parts heated up. u also burnt the main fuse of the radio. It sounds like a bit of components to service .

Post by **wavetar** » Mon Dec 10, 2001 5:09 am

That large blue rectangular component is your RF Power Amplifier, which is apparently running at full tilt even when the radio is not transmitting. You'll probably see the radio drawing several amps of current just sitting there on a power supply. This caused your power fuse, located on the + battery contact board, to blow. I have seen this before, it is likely that you need a new power amplifier, hard to tell without seeing it but you definitely need it to be looked at by a qualified technician.

Todd

Josh · Post by **Josh** » Mon Dec 10, 2001 9:35 am

On 2001-12-10 08:09, wavetar wrote:
That large blue rectangular component is your RF Power Amplifier, which is apparently running at full tilt even when the radio is not transmitting. You'll probably see the radio drawing several amps of current just sitting there on a power supply. This caused your power fuse, located on the + battery contact board, to blow. I have seen this before, it is likely that you need a new power amplifier, hard to tell without seeing it but you definitely need it to be looked at by a qualified technician.

Todd

The fuse did not blow. I tested it (it had 4A written on it). It had good continuity in it. I will see about buying a new small black rectangular piece (still don't know what this component it) and solder in a new one.
-Josh

RCVMO · Post by **RCVMO** » Mon Dec 10, 2001 12:49 pm

Don't forget the ref. crystal on the bottom of the motherboard. That's the first thing that becomes unsoldered or cold solder joints over anything else. My place of employment loves to chuck their 350's against the wall when they can't get there way. Just have to get them anotherone and repair the original. Good luck!!!!!!!!!!!

Will · Post by **Will** » Mon Dec 10, 2001 6:12 pm

That "black rectangular" componet mounted on the contact board on the metal chassis is a RF Choke and should have close to zero oms resistance.

Josh · Post by **Josh** » Tue Dec 11, 2001 12:33 pm

Will:

Can I send this radio to you to look at, and possibly fix? Motorola Shops are just out of my budget. Send me your address, and wahtever other information I need either in a private message or e-mail me direct

Thanks. (Also, this GP350 is worth more to me than that GP300 UHF that I spoke abuot in my other posts, so this one would have priority)

-Josh
[email protected]

<font size=-1>[ This Message was edited by: Josh on 2001-12-11 15:34 ]</font>

Will · Post by **Will** » Wed Dec 12, 2001 1:36 pm

Josh, I would be glad to look at your GP350.
I will e-mail you the address.
Thanks,
Will

57Shasta · Post by **57Shasta** » Sat Dec 15, 2001 9:30 am

You should check to see if any solders are broken around the antenna mount/jack. Transmitting without a good connection to the antenna will turn the inside of the radio into a mini microwave oven!

Josh · Post by **Josh** » Sat Dec 15, 2001 7:25 pm

On 2001-12-15 12:30, 57Shasta wrote:
You should check to see if any solders are broken around the antenna mount/jack. Transmitting without a good connection to the antenna will turn the inside of the radio into a mini microwave oven!

Believe me, if the fix were this simple I would have already done something about it. This problem has absolutely nothing to do with me transmitting and getting the radio hot, because under my ownership, this radio has been used 99% of the time for rx only. Furthermore, the radio quit qorking properly while in RX mode (and when it was working o.k. it received excellent--far better than most other radios I've used)
-Josh