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Hardware, Cabling, Installations / FT-857/RRC-1258 floating -ve power supply issue
« on: 2012-12-31, 15:13:03 »
This post may help those with an FT-857 – I would also like to know why this problem occurs!
I have owned an FT-857 version of the RRC-1258 MkII for several weeks now. I have two separate ADSL Broadband connections into my home and I successfully tested ‘on the bench’ from the FT-857 head unit, via Remoterig across the Internet, to the FT-857 main unit. Round trip delay was approximately 60ms. On every occasion, the FT-857 successfully powered up and powered down remotely without hanging.
I then moved the FT-857 main unit and RRC-1258 remote unit to my remote location. Round trip delay across the Internet is approximately 50ms. Fortunately my remote location is only a short drive away. On repeated occasions, as soon as I pressed the power button on the FT-857 head unit, relays within the FT-857 main unit would activate but it would then ‘lock up’ (I know this because on several test sessions I was at the remote location whilst a member of the family pressed the power button back home!). As recommended by Microbit, I can remotely power cycle the FT-857 but this would NOT reset the transceiver. The only way was to connect the head unit directly to the main unit as in normal operation. The symptoms seen on the control RRC-1258 were a successful SIP connection (yellow LED full on) but no incoming audio stream (flashing red LED). I spent ages checking and changing everything (UDP ports, remote ADSL router, jitter parameters etc). As I work in networking I even connected a network analyser to check packet flows. I assumed that it must have been a network problem. The SIP packet decodes were showing missing ‘8V ON OFF’ status indications. The FT-857 and the RRC-1258 are fed from the same DC power supply. Although I didn’t see why this would be a power supply problem I changed the power supply – AND EVERYTHING WORKED OK!
I still can’t understand why this would make a difference. Both power supplies were measured and delivered 13.5 volts so no under voltage issue. The only difference between the two power supplies was that the ‘failing’ supply (an Icom PS85) is a switched-mode supply with an ISOLATED –ve supply (ie not bonded to the power supply chassis and mains earth supply) whilst the ‘working’ power supply (a Daiwa PS304) is a linear power supply with the –ve supply grounded to the power supply chassis and mains earth. I tested this ‘on the bench’ back home as well as remotely and every time the Icom PS85 would result in ‘lock up’ of the FT-857 whilst the Daiwa PS304 was fine. I am glad all is working but any suggestions why this this problem occurs would be appreciated – particularly as the FT-857 and RRC-1258 are fed from the same DC supply, as recommended by Microbit.
I have owned an FT-857 version of the RRC-1258 MkII for several weeks now. I have two separate ADSL Broadband connections into my home and I successfully tested ‘on the bench’ from the FT-857 head unit, via Remoterig across the Internet, to the FT-857 main unit. Round trip delay was approximately 60ms. On every occasion, the FT-857 successfully powered up and powered down remotely without hanging.
I then moved the FT-857 main unit and RRC-1258 remote unit to my remote location. Round trip delay across the Internet is approximately 50ms. Fortunately my remote location is only a short drive away. On repeated occasions, as soon as I pressed the power button on the FT-857 head unit, relays within the FT-857 main unit would activate but it would then ‘lock up’ (I know this because on several test sessions I was at the remote location whilst a member of the family pressed the power button back home!). As recommended by Microbit, I can remotely power cycle the FT-857 but this would NOT reset the transceiver. The only way was to connect the head unit directly to the main unit as in normal operation. The symptoms seen on the control RRC-1258 were a successful SIP connection (yellow LED full on) but no incoming audio stream (flashing red LED). I spent ages checking and changing everything (UDP ports, remote ADSL router, jitter parameters etc). As I work in networking I even connected a network analyser to check packet flows. I assumed that it must have been a network problem. The SIP packet decodes were showing missing ‘8V ON OFF’ status indications. The FT-857 and the RRC-1258 are fed from the same DC power supply. Although I didn’t see why this would be a power supply problem I changed the power supply – AND EVERYTHING WORKED OK!
I still can’t understand why this would make a difference. Both power supplies were measured and delivered 13.5 volts so no under voltage issue. The only difference between the two power supplies was that the ‘failing’ supply (an Icom PS85) is a switched-mode supply with an ISOLATED –ve supply (ie not bonded to the power supply chassis and mains earth supply) whilst the ‘working’ power supply (a Daiwa PS304) is a linear power supply with the –ve supply grounded to the power supply chassis and mains earth. I tested this ‘on the bench’ back home as well as remotely and every time the Icom PS85 would result in ‘lock up’ of the FT-857 whilst the Daiwa PS304 was fine. I am glad all is working but any suggestions why this this problem occurs would be appreciated – particularly as the FT-857 and RRC-1258 are fed from the same DC supply, as recommended by Microbit.