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IC-R7000 questions

RFI-EMI-GUY

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Dec 22, 2013
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This excellent vid reveals why lytic cap replacement can be the deciding factor in aligning an R7000;
There is a well known service note at ICOM website for the DC-DC convertor as wll as a low sensitivity note. Some things he should have checked 2 hours earlier in the video before poking around the RF alignment. The PLL steering line voltage alignment would reveal the DC voltage problem right away.
 

db_gain

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Sep 13, 2014
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That's true. I always see if innernets has some faq on the rig in question as far as service bulletins and whatnot.
 

RFI-EMI-GUY

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I think one of the service notes indicated that 13.8 V power supply ripple can affect the RF tracking filter as well.

No doubt other capacitors will age in these sets, but if someone inexperienced tries to shotgun the entire radio changing all the capacitors, the likelihood of putting one in backwards, or the wrong one, or a solder bridge, is pretty high and troubleshooting something like that would be difficult.

Better to fix what is known to be broken. If say the audio is distorted or weak, tackle that problem separately, change only the parts in a certain section based on measurement.
 

exK3JTP

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A few years ago I obtained an old ICOM (R70 or R7000, cannot recall), and when I removed the covers discovered hidden DC wiring harness terminating with a Molex DC jack that fit the space on the rear panel to the right of the AC power, usually covered by a screwed in brass plate. The 7000 was never marketed as DC optional (as far as I know) but ICOM may have fitted some with DC. Plugged into the jack was the "jumper" that shorts the DC when using normal AC. Runs much cooler on DC. Great radio, but ICOM did not offer the scanning option of resuming a scan at, or a preset time after, completion of a transmission.
 

N1FKO

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Great radio, but ICOM did not offer the scanning option of resuming a scan at, or a preset time after, completion of a transmission.
The IC-R7000 offers four scan resume options, resume on squelch close, forced resume after 5 seconds, forced resume after 15 seconds, and no resume (scan halts on squelch open).
 

RFI-EMI-GUY

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A few years ago I obtained an old ICOM (R70 or R7000, cannot recall), and when I removed the covers discovered hidden DC wiring harness terminating with a Molex DC jack that fit the space on the rear panel to the right of the AC power, usually covered by a screwed in brass plate. The 7000 was never marketed as DC optional (as far as I know) but ICOM may have fitted some with DC. Plugged into the jack was the "jumper" that shorts the DC when using normal AC. Runs much cooler on DC. Great radio, but ICOM did not offer the scanning option of resuming a scan at, or a preset time after, completion of a transmission.
My R7000 shipped with a blank plate and it had the DC connector coiled inside and the DC cable kit option had instructions to install the connector onto the rear. I have said this before, but if you power on any of the R7000, R71 or R9000 with the DC jumper removed the power supply will rise to 18.5 to 19V (by poor design) because it is unloaded. If you stick the jumper back on you will blow the meter light etc.
 

majoco

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Dec 25, 2008
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There is a mod to make the squelch work as 'normal' but there's no adjustment of the delay time - it appears to be about 4 seconds. I made a mod to a KDK FM 2030 2m transceiver waaay back in the 80's - the receiver had no delay at all on signal fall. The mod involved nothing more complicated than a simple resistor/capacitor/diode combination which worked well. I'm sure others have looked for a simple solution for the R7000 so there's not a lot of point in me re-inventing the wheel!

After all, it's not designed to be a scanner, more of a monitor on a single frequency - and in that mode the squelch works admirably!
 

kruser

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There is a mod to make the squelch work as 'normal' but there's no adjustment of the delay time - it appears to be about 4 seconds.
Somewhere, there is a mod to add a user variable delay time after signal loss.
I think it used one of the switch positions on the external rotary Delay control on the front panel but I could be wrong on that.
Mine was built on a small board tucked away inside the radio. This board had a pot on it that set the delay time for when the external control was set to whatever position was used to enable the internal delay board.
It worked well but not being able to alter the actual delay time required opening the radio to change that time with the pot on the homebrew delay board. I remember it being a very simple circuit to build and wire into the factory scan control circuit.
I think it offered a new delay time from zero to about 8 seconds.

Who knows where this mod came from but it was likely something I'd found on mods.dk website back in the day.

_______________________________________________________________________________________________________________________________

I also did a mod that doubled the memory channels by enabling the second half of the ram memory chip that Icom used in these radios.
There was also a mod that involved a different ram chip that could add thousands of memory positions but I opted to use the existing ram chip as supplied from the factory.
I simple SPDT or DPDT mini toggle switch allowed the user to switch between the original bank of ram or the unused half.
The logic in the radio could only address 100 memory positions so even with the mod, you could only access 100 memory channels at a time.

A year or so after doing this ram mod, my BR2032 backup battery started suffering a very fast discharge.
I had to disassemble the radio in order to find and measure the current draw across my 2032 battery cell. The discharge current was very high and a new cell would be discharged in a matter of hours instead of years or months like normal.
I traced the high current draw to the OEM Ram chip on the board.
It was only showing high current when I switched in the extra half of ram that Icom never used.
I double checked my wiring from when I first did the ram mod but my wiring all checked out fine. I removed all traces of that mod as it was just too easy to accidently switch the super mine toggle switch I'd used to change the ram banks.

The original half of ram that was used by Icom with its original design is still in use in my R7000 and has had no problems. The life of the BR2032 cell is again normal and has gone for years now.

I don't know if the original unused half of the OEM ram chip simply failed or if accidently switching to/from the unused section of ram in the chip was damaged if switched while the power was on. I always made it a point to switch the ram banks while power was off but I know there were times it was switched while the radio was on. I don't recall any safety buffering on any of the leads to/from the ram chip so it was probably not a very well thought out mod but it did work.
Or... Icom used a chip that was only guaranteed to work with the first half of ram capacity and the unused half was never supposed to be used. That's just a guess but could be a real guess knowing the technology available when these radios were designed and made.
I don't recall anyone else having an issue with their memory channel ram chip failing causing excessive current draw across the BR2032 backup cell but it's very possible it has happened to others than myself.
I did find a spare ram chip after the 2nd half failed in my OEM chip but it's never been needed so it sits in a chip carrier here and likely to never be found if needed!
 
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