[time-nuts] fluke.l monitor for Thunderbolt

Steve steve65 at suddenlink.net
Sun Jun 5 19:23:55 UTC 2011


Thanks for the suggestions. There is continuity to the PCB in the iCruze.

Not sure what to make of the voltage levels on pin 2 of the DB9. Using 
just a scope connected to the Thunderbolt, the voltage switches from -10 
to +10. With the laptop connected, it switches from -9 to +9. With the 
iCruze connected, it switches from -6 to +6.

I don't know if the -6 to +6 is normal, but it seems low to me for RS-232.

Taking the troubleshooting to the next level on the iCruze involves 
desoldering a 16-pin header. I dunno . . . .


On 6/5/2011 4:56 AM, David Bobbett wrote:
> Steve,
> The two lines of text are what the iCruze will display when it thinks 
> it doesn't have any data. The RS232 input on my system can be 
> unplugged and that is exactly what is shown on the display in those 
> circumstances.
> Personally, I would start with the simple stuff, just continuity check 
> the '232 lines from the iCruze plug all the way back to the PCB.
> If that doesn't work, there's a circuit diagram of the device on 
> Didier's web site.
> 73 de David, G4IRQ
> On 04/06/2011 22:17, Steve wrote:
>> About a year ago I installed one of the iCruze monitors from fluke.l 
>> on a Thunderbolt GPS receiver. I paralleled the iCruze with the 
>> serial port on my laptop PC. Sometimes the PC was connected, 
>> sometimes not. The iCruze worked OK either way.
>> Last week I noticed the iCruze was no longer functioning as before. 
>> It now alternates between two lines of text: "Trimble LED Monitor" 
>> and "Waiting for GPS". Whether the laptop is connected or not does 
>> not make a difference. The laptop running tboltmon works ok with or 
>> without the iCruze paralleled across the serial data line.
>> I substituted another Thunderbolt and saw the same results.
>> The iCruze has about 10VDC on its power input.
>> I not particularly competent at serial communications or 
>> oscilloscopes, but on the DB9 feeding the iCruze I can see the 
>> transition of voltage from about -6VDC to about +6VDC. I didn't look 
>> at those voltage levels when I installed the iCruze last year so I 
>> don't know if that's what it has always been or not.
>> I have rebooted the iCruze several times as well as the Thunderbolt 
>> and laptop, no change in iCruze behavior.
>> Any advice as to where to go from here?
>> Thanks.
>> Steve
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