ICOM IC-R7000

[chr999chr]

Hi All

I am trying to bring back to life an old R7000. I have repaired the PSU which brought it back to life. Then there was no SSB rx the needle went hard right. I found a faulty diode on the IF board. All seems to be working apart from low receive on all frequencies. it is about 4 or so S points down everywhere. I have re capped the PSU, DC-DC converter and the IF board. All voltages seem to be reasonable from the DC-DC converter. I don't think its out of alignment as its everywhere and I could probably recover maybe 1/2 S points on an alignment but not 4 or so.

Any ideas on where to go next? Any common faults?

 

[spongella]

Not familiar with that radio but I've restored quite a number of radios (both xmtters and rcvrs) over the years. Alignment would be your best bet if you have the test equipment to perform it. I've worked on old radios that in the end didn't need alignment but there were a few that performed better after adjustment. If you can get ahold of the repair manual with alignment procedures, see what's involved. Calibrating the S meter is sometimes part of the alignment process.

Also, with old radios there's always a possibility that someone in the radio's past has made adjustments without proper knowledge.

You seem very competent in repair so realignment makes sense. Good luck and I hope you get the 7000 up to speed.

 

[RFI-EMI-GUY]

Hi All

I am trying to bring back to life an old R7000. I have repaired the PSU which brought it back to life. Then there was no SSB rx the needle went hard right. I found a faulty diode on the IF board. All seems to be working apart from low receive on all frequencies. it is about 4 or so S points down everywhere. I have re capped the PSU, DC-DC converter and the IF board. All voltages seem to be reasonable from the DC-DC converter. I don't think its out of alignment as its everywhere and I could probably recover maybe 1/2 S points on an alignment but not 4 or so.

Any ideas on where to go next? Any common faults?

The RF front end(s) plural, because there are several band sections, are Varactor tuned and I think slaved from VCO steering voltages. If those are out of whack due to power supply ripple ( a known problem) or voltage gain discrepancy, the sensitivity will suffer. Perhaps the schematic and the pots associated with tuning those sections will give a clue.

 

[chr999chr]

The RF front end(s) plural, because there are several band sections, are Varactor tuned and I think slaved from VCO steering voltages. If those are out of whack due to power supply ripple ( a known problem) or voltage gain discrepancy, the sensitivity will suffer. Perhaps the schematic and the pots associated with tuning those sections will give a clue.

I have re capped the psu and the dc-dc converter. I will check the voltages for ripple.

 

[RFI-EMI-GUY]

The tuning procedures on those receivers, though pretty involved, do offer some test points that might give a clue to any signal loss. Also you might take a look at the signal levels instructed in the manual. That design was from an era when signal generators were often rated at Open Circuit" values. I will confess to being rusty on that concept and whether it would show a low or high sensitivity of the RX when fed with a modern (actual terminated value) generator. The difference would be 6 dB.

 

[Napalm]

My 7000 went the same way. It now sits in storage, sadly. There was a guy who would restore these but I'm not sure if he's still around. I feel like he was in Georgia.