Greetings,
I am having a problem with a GM300. The TX light flashes and no display. I have tried to read and force write to it. It just errors out. It was active when it started this. I was monitoring some law enforcement and cut off in the middle if traffic and the display went out and the TX light flashing. What can I do to restore the radio?
Thank you
Mike
GM300 Problem. Flashing TX
Moderator: Queue Moderator
Re: GM300 Problem. Flashing TX
Hello:
Probably would help if you gave the model number and what freqs you entered to be sure its in band.
I'm assuming its a VHF and likely in band programming.
So ill toss out a possibility to check.
The radio has a cpu crystal that needs to fire up properly to work.
This is Y801 on the bd and operates at 7.776 mhz.
Id check and see if its generating 7.776 MHz .
Its also a known problem with the inter connecting pins from logic bd to rf bd to give screwy symptoms and if they lost good conductivity you might be able to dis assemble the bds and clean the pins and reassemble and get the radio working again.
If you have the old style pins then they do advise them being replaced but I have simply cleaned several that came back top working again without replacing the pins with new style.
Id check those two and front control head plug ins to be sure in secure.
Satelite
Probably would help if you gave the model number and what freqs you entered to be sure its in band.
I'm assuming its a VHF and likely in band programming.
So ill toss out a possibility to check.
The radio has a cpu crystal that needs to fire up properly to work.
This is Y801 on the bd and operates at 7.776 mhz.
Id check and see if its generating 7.776 MHz .
Its also a known problem with the inter connecting pins from logic bd to rf bd to give screwy symptoms and if they lost good conductivity you might be able to dis assemble the bds and clean the pins and reassemble and get the radio working again.
If you have the old style pins then they do advise them being replaced but I have simply cleaned several that came back top working again without replacing the pins with new style.
Id check those two and front control head plug ins to be sure in secure.
Satelite
Re: GM300 Problem. Flashing TX
Model: M43GMC29C2AA3 I tried the pins between the boards. No difference. I do get a beep when turning on and button beeps. The volume is all the way up and the beeps sound as if the volume was very low. I also tried another face. No change. It was on a shelf monitoring law enforcement when it went out. I have no way to check the 7.776 freq.
Re: GM300 Problem. Flashing TX
EPROM info.
V25.01 1993
5102463J19
HLN8121A 951B
Bottom:
EBA (AZ)
ZX05BY9DM
V25.01 1993
5102463J19
HLN8121A 951B
Bottom:
EBA (AZ)
ZX05BY9DM
-
jackhackett
- Posts: 1515
- Joined: Tue Jun 10, 2003 8:52 am
Re: GM300 Problem. Flashing TX
It's not likely to be the feedthru connector problem, that has completely different symptoms.
It's not likely to be 'out of band' programming, as it was working and then quit.
Getting beeps and a flashing light would indicate the CPU is still working.
It could be in an 'out of lock' condition, although I don't recall if that would make the display go out or not.
Another possibility is that the EEPROM or Custom Gate Array is bad. These radios are getting old, and EEPROMS do not last forever.
Since you say you were unable to read or program the radio I would lean towards the EEPROM.
It's not likely to be 'out of band' programming, as it was working and then quit.
Getting beeps and a flashing light would indicate the CPU is still working.
It could be in an 'out of lock' condition, although I don't recall if that would make the display go out or not.
Another possibility is that the EEPROM or Custom Gate Array is bad. These radios are getting old, and EEPROMS do not last forever.
Since you say you were unable to read or program the radio I would lean towards the EEPROM.
Re: GM300 Problem. Flashing TX
What replacement chip do I need for it? Would you have any numbers for me to look for?
Thank you
Thank you
Re: GM300 Problem. Flashing TX
Hello:
That's a good call jack Hackett -I hadn't thought about the eprom - I bow before you
The eprom that jackhackett is referring to is used in both the GM300 VHF and UHF mobiles that have 16 channel capability in there build.
The 8ch GM300 will not use this same eprom chip.
Eprom V25.01 part number from Motorola is a HLN8121A .
The 1993 is just the year it was made so not much info to be had there.
The GM300 eprom V25.01 is programmed onto a 28 pin eprom that is a 27C256 memory chip so a good known working V25.01 eprom chip cpould be read and burned onto another blank 27C256 eprom to duplicate the exact eprom chip needed.
Do you by chance have a working GM300 16ch radio you could swap the eproms out for a test ?
I do have a copy of the GM300 V25.01 eprom and a prom reader/burner and blank new 27C256 eproms that I could if that fixes your issue make one if you couldn't locate another.
Satelite
That's a good call jack Hackett -I hadn't thought about the eprom - I bow before you
The eprom that jackhackett is referring to is used in both the GM300 VHF and UHF mobiles that have 16 channel capability in there build.
The 8ch GM300 will not use this same eprom chip.
Eprom V25.01 part number from Motorola is a HLN8121A .
The 1993 is just the year it was made so not much info to be had there.
The GM300 eprom V25.01 is programmed onto a 28 pin eprom that is a 27C256 memory chip so a good known working V25.01 eprom chip cpould be read and burned onto another blank 27C256 eprom to duplicate the exact eprom chip needed.
Do you by chance have a working GM300 16ch radio you could swap the eproms out for a test ?
I do have a copy of the GM300 V25.01 eprom and a prom reader/burner and blank new 27C256 eproms that I could if that fixes your issue make one if you couldn't locate another.
Satelite
Re: GM300 Problem. Flashing TX
I do have another, but do not have access to it right now. The radios are 35 miles away from me at an aquaintessence's place and I have to wait until our schedules align so we can get together. We used them for a temporary repeater some time ago and they are in his storage. I am hoping that I can get to them very soon due to me missing a radio for monitoring. I will report as soon as I find something out.
Thank you
Mike
Thank you
Mike
-
jackhackett
- Posts: 1515
- Joined: Tue Jun 10, 2003 8:52 am
Re: GM300 Problem. Flashing TX
EPROM has the firmware, EEPROM has the codeplug.
EPROM might be in a socket, easy to try a different one if it is.
I think the EEPROM is usually soldered in. Older radios like Maxtrac had a Dallas chip instead, don't think the GM300s ever had those.
Might be a good idea to go through and check voltages, such as regulated 5 and 9 volts to make sure they're good before ripping out any chips.
EPROM might be in a socket, easy to try a different one if it is.
I think the EEPROM is usually soldered in. Older radios like Maxtrac had a Dallas chip instead, don't think the GM300s ever had those.
Might be a good idea to go through and check voltages, such as regulated 5 and 9 volts to make sure they're good before ripping out any chips.
Re: GM300 Problem. Flashing TX
Hello:
The GM300 8ch has a soldered in eprom.
The 16 ch has a 28 pin eprom in a 28 pin socket just as the maxtrac 300 16ch mobiles have.
I have his exact GM300 vhf 16 ch model number he posted and I have opened it up to confirm this.
So he could easily swap an eprom to see if it came back to working.
Id still keep the eprom with the working mobile but do it as a swap for test only.
He didn't say exactly how much testing he could do but limited as I see it since he did say he had no way of checking the launch 7.776 MHz crystal so I'm just assuming some here.
Satelite
The GM300 8ch has a soldered in eprom.
The 16 ch has a 28 pin eprom in a 28 pin socket just as the maxtrac 300 16ch mobiles have.
I have his exact GM300 vhf 16 ch model number he posted and I have opened it up to confirm this.
So he could easily swap an eprom to see if it came back to working.
Id still keep the eprom with the working mobile but do it as a swap for test only.
He didn't say exactly how much testing he could do but limited as I see it since he did say he had no way of checking the launch 7.776 MHz crystal so I'm just assuming some here.
Satelite