Date
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Driver Circuit Issue.....
Tony Eagling
Good Morning All....
I have a weird one on the bench, when I have had IC7000's with no output on any band it has always been an input/output feed or driver board issue.
The unit I am working on has RF into the driver board and DC Bias, Supply rail on the output side but almost no RF out so i thought, driver board dead, easy fix......but no....
I removed the board and it looks like new, the board tests ok on a component tester, Per Icom's advice I have reset the CPU.
My next step is to replace the driver board in case something funky is going on with it, what do the Guru's here think of a diagnostic step may have missed.
Thanks, any help is always appreciated.
Regards - Tony Eagling Vk7YBG
I have a weird one on the bench, when I have had IC7000's with no output on any band it has always been an input/output feed or driver board issue.
The unit I am working on has RF into the driver board and DC Bias, Supply rail on the output side but almost no RF out so i thought, driver board dead, easy fix......but no....
I removed the board and it looks like new, the board tests ok on a component tester, Per Icom's advice I have reset the CPU.
My next step is to replace the driver board in case something funky is going on with it, what do the Guru's here think of a diagnostic step may have missed.
Thanks, any help is always appreciated.
Regards - Tony Eagling Vk7YBG
davebb123456
Hi Tony
Have look at YouTube
TRX LAB , I think Peter had the same issue in one of his videos,
Dave 2E0DMB
On Wed, 26 Oct 2022, 22:35 Tony Eagling, <dodgem37@...> wrote:
Good Morning All....
I have a weird one on the bench, when I have had IC7000's with no output on any band it has always been an input/output feed or driver board issue.
The unit I am working on has RF into the driver board and DC Bias, Supply rail on the output side but almost no RF out so i thought, driver board dead, easy fix......but no....
I removed the board and it looks like new, the board tests ok on a component tester, Per Icom's advice I have reset the CPU.
My next step is to replace the driver board in case something funky is going on with it, what do the Guru's here think of a diagnostic step may have missed.
Thanks, any help is always appreciated.
Regards - Tony Eagling Vk7YBG
Pasquale S
Try to check if your are RF signal on Driver PCB in input, then check if your are DC bias on the PD55015 Gate, there is a resistor 1 ohm on gate, check it !!!
Regard, 73 Pasquale IW0HEX
Il giovedì 27 ottobre 2022 00:04:19 CEST, davebb123456 <davidbrowne76@...> ha scritto:
Hi Tony
Have look at YouTube
TRX LAB , I think Peter had the same issue in one of his videos,
Dave 2E0DMB
On Wed, 26 Oct 2022, 22:35 Tony Eagling, <dodgem37@...> wrote:
Good Morning All....
I have a weird one on the bench, when I have had IC7000's with no output on any band it has always been an input/output feed or driver board issue.
The unit I am working on has RF into the driver board and DC Bias, Supply rail on the output side but almost no RF out so i thought, driver board dead, easy fix......but no....
I removed the board and it looks like new, the board tests ok on a component tester, Per Icom's advice I have reset the CPU.
My next step is to replace the driver board in case something funky is going on with it, what do the Guru's here think of a diagnostic step may have missed.
Thanks, any help is always appreciated.
Regards - Tony Eagling Vk7YBG
Tony Eagling
Fault Resolved.....
Ok, I traced the missing amplification between the generated signal and the driver to bad bias on Q101 in the pre-driver stage, Q102 was behaving normally, Q101 was attenuating, sometimes a lot, sometimes it even amplified a bit.
After a lit of poking, prodding and track tracing I found the PTT 8V used to bias the pre-drivers was going astray, I then found the track went dead at a passthrough on the board and measured anywhere between 2K and 10K, so I bridged the 2 tracks with a small link wire and it is achieving full power again...
I dropped a bit of UV glue over the link and reassembled the radio, put it through it's paces and all seems tests ok
Hopefully this helps someone if they encounter the same fault :-)
Regards - Tony Eagling Vk7YBG
Ok, I traced the missing amplification between the generated signal and the driver to bad bias on Q101 in the pre-driver stage, Q102 was behaving normally, Q101 was attenuating, sometimes a lot, sometimes it even amplified a bit.
After a lit of poking, prodding and track tracing I found the PTT 8V used to bias the pre-drivers was going astray, I then found the track went dead at a passthrough on the board and measured anywhere between 2K and 10K, so I bridged the 2 tracks with a small link wire and it is achieving full power again...
I dropped a bit of UV glue over the link and reassembled the radio, put it through it's paces and all seems tests ok
Hopefully this helps someone if they encounter the same fault :-)
Regards - Tony Eagling Vk7YBG
Great job, Tony!
I think that measuring the signal path is really the only way to really repair almost anything.
I have found that sometimes these radios do have bad connections, from the ribbon cables to the feedthroughs etc.
A good 'scope and service manual are pretty much necessary tools. Well at least in the receive circuits.
Thanks for the update.
JD
KE4MD
I think that measuring the signal path is really the only way to really repair almost anything.
I have found that sometimes these radios do have bad connections, from the ribbon cables to the feedthroughs etc.
A good 'scope and service manual are pretty much necessary tools. Well at least in the receive circuits.
Thanks for the update.
JD
KE4MD