IC-R7000 questions

[LostInNewMexico]

I have a R7000 that's been in storage since 1995, nine years in a hot attic in Florida. I want to revive it and use in setting up a radio telescope.

1. Obviously, battery is dead. Nothing in the Instruction Manual or Service Manual. What do I replace it with?

2. As I remember, the unit gets very hot. I would like to replace the the power supply with an external linear 13.8 volt supply. Any specific recommendations?

3. Although the unit worked perfectly at last use I am inclined to do a complete electrolytic capacitor replacement without further ado. Advisable?

Thanks for any information. Larry

 

[kruser]

I have a R7000 that's been in storage since 1995, nine years in a hot attic in Florida. I want to revive it and use in setting up a radio telescope.

1. Obviously, battery is dead. Nothing in the Instruction Manual or Service Manual. What do I replace it with?

2. As I remember, the unit gets very hot. I would like to replace the the power supply with an external linear 13.8 volt supply. Any specific recommendations?

3. Although the unit worked perfectly at last use I am inclined to do a complete electrolytic capacitor replacement without further ado. Advisable?

Thanks for any information. Larry

The battery is a typical CR2032 or 2016 3 volt lithium coin cell with solder tabs for the most part. I'm sure it was specific to Icom but any like cell will work. You can either solder in a 2032 or 2016 coin cell holder or get a cell with solder tabs. It is placed across the top of the processor on the logic board, There is a metal plate that holds the DC - DC convertor board and any option boards that must be removed to gain access to the logic board. Icom simply used stiff solder plated wires to extend above the processor where the OEM cell is soldered. I don't recall if the board is marked with polarity but the cell should be or it can be measured with a meter. Even though those cells were not rechargeable plus the circuit in the R7000 has a blocking diode, the diode leaked a small amount. This was enough to keep the original cell charged up and useable for 30+ years in some cases! This was true for those that had there R7000's powered on much of the time. It is not needed if you won't use the memories and don't mind entering your frequency each time you power the radio on.

Yes, they can run hot. I ran mine using an external large AGM type battery kept charged by an external 20 amp power supply. Of course I run several other radios along with the R7000 so 20 amps is not needed for just the 7000.
I'd suggest a good Astron linear power supply with maybe 10 amps or so constant current available. I think HRO sells the Astron line.
I don't have a model number handy though but it should be a simple choice. You said linear so I assume you know to stay away from switching types!
A 10 to 12 amp supply should run fairly cool plus will give you extra capacity in case you have other equipment that may need power down the road.
They do help reduce the heat inside the R7000 chassis.
The R7000 probably draws under 2 amps in reality but oversizing an external power supply is just good insurance in my opinion. You could probably safely half the size down if cost is a factor.

I did find model specific cap kits for the R7000 on eBay. I went ahead and did mine but not until I had fixed most of the common problems.
Icom released several service bulletins for this radio over the years. Many of the problems seemed to be electrolytic cap failures from what I recall.
I recall cap failures on the DC to DC convertor board and some on the front panel board that houses the display. I know there were more but my memory is foggy. You should be able to find most of the service info via web searches.
It did have failures of caps in the power supply section also but if you plan on running from external, those caps don't come into play and can be left as is if you want. I still rebuilt mine so it was ready for AC power if needed.
I also wire tied the little power jumper plug that gets removed from the DC connector on the rear panel to the chassis just in case I did need to go back to the internal supply.
At some point, I did a complete alignment on my old R7000. It did help in some areas so you may consider that if you have the test equipment.

I'd try and see how the radio behaves before you dive in and just start replacing caps myself. You may find it works perfectly!
If the cap kits are still available, it may be a good idea to buy a kit just to have though.
Another big problem I had was the flex cable that connects the EL display to the display board. That flex cable seems to not like carrying the current needed for the EL panel. I finally mirrored the cable in mine and soldered jumpers along the existing cable to fix my display problems. That job was a major pain but it worked. If your display works and is good and bright, leave it alone!

I'm going from memory with what I all typed here but it should be accurate.

Good luck in getting the old R7000 running well again. They were nice radios and are still very useful today!

 

[iMONITOR]

Reading this brought back a lot of fond memories, especially the day I picked one up at Michigan Radio, along with the IC-R71a! Thanks for posting!

 

[majoco]

The only problems I have had with my R7000 - memory battery gone flat, Cr2032 stuck to the sidewall and leads run to the original pins - display fading out, paralleled the flexible PC board filament traces with thicker wire directly from the transformer and replace all the power supply capacitors on the display board - run from an external 12volt supply (make sure it's 12 volts!!) - drill holes in the top and bottom panels and glue mesh on the inside - and it's been going every day for two years or more..... great receiver!

 

[RFI-EMI-GUY]

Actually a BR2032 is a preferred battery for those radios because there will be some leakage current through the diode that will put a slight charge on the battery and cause it to leak electrolyte. The leaded BR2032 cnan be purchased from Digikey. These are fine radios, worthy of restoration.

 

[RFI-EMI-GUY]

The power transformers in thise units run warm and a solution is a small CPU fan to move the air. A friend had his transformer fail and I located a suitable replacement for about 45 bucks, the power supply requires a load or its voltage will creep up to above 18.5 V. Never remove or replace the DC jumper on the rear while powered on.

 

[N1FKO]

The original part number for the battery was BR2032-1T2.

It can be found at Digi-Key and Newark as BR-2032/F2N.

For a linear power supply, I'd use the Astron RS-12M (smallest one with a meter on it).

 

[kruser]

My bad, BR-2032 is correct. The CR and BR are both non-rechargeable type cells but they do use different Lithium chemistries between them.

 

[LostInNewMexico]

At some point, I did a complete alignment on my old R7000. It did help in some areas so you may consider that if you have the test equipment.

I'm guessing but IF I do a complete cap replacement, the alignment should be done AFTER. Also in what order should I do the IF stages?

I'm torn about getting the proper test equipment, I think a sweep signal generator, oscilloscope and frequency counter should suffice. Anything else essential? If it gets too pricey maybe I should go with an R8600, but then I am left with a non-working 7000. Owning a non-working piece of equipment goes against my gut instincts.

Although my budget is limited, I really should get proper test equipment. My current planning is to go with a 1 meter disc and downconvert from X band to something in the 1 - 2 GHZ range. The more I research this the more complicated it gets. I got my EE degree when eight semester hours of vacuum tubes was required and transistors were squeezed in at the end.

 

[Hit_Factor]

Matt KD8ZB, in Michigan, is one of two Icom repair centers if you get in over your head.

 

[kruser]

I'm guessing but IF I do a complete cap replacement, the alignment should be done AFTER. Also in what order should I do the IF stages?

I did end up getting an R8600 and then. a second! So my R7000 does not get near as much use these days but I so still use it along with an R9000 and let them sit on "quiet" frequencies waiting for signals.

I actually aligned mine right after purchase as it suffered some serious shipping damage. A lady in Maine who is a school teacher sent it packed in a large cardboard box with absolutely zero stuffing or filling or padding! Then the post office lost the box. A week later they called and found the box pushed under some kind of shelf. Oddly, my local mail person claimed he had tried to deliver it three times and it was set to go back. I was ticked. I had been in contact with the sellers post office and they knew the school teacher plus remembered shipping the box for her. Small towns! They also gave me the shipping number but could see it had been delivered to my post office.
When I made it to my post office, they gave me a box with holes poked through the sides. They let me open it and the radio itself appeared intact. I later found that the N antenna connector is what had broke through the box as it had actually bent the rear chassis where it is mounted. Must have been some pretty hard hits.
The optional remote control was also included. She had put it inside a plastic sandwich baggie along with some other small items. The remote was smashed to pieces! I mean, a lot of pieces. I managed to get it back together using super glue and tape and then epoxy near the corners to try and make it last. The PCB was broken in three pieces so it needed some TLC also. It worked though and still works to this day. Some of the housings plastic pieces were missing but they were what held it together and nothing functional. They probably fell out as the baggie had a huge hole tore through it.

I straightened the chassis and did a thorough visual inspection looking for cracked boards or dislodged components from the rough shipping but everything looked okay amazingly. The radio seemed to work okay but did have reduced sensitivity somewhere in the 160 MHz area I think. That's when I did the first alignment which did bring everything back to spec. My guess is the rough shipping knocked something out of tune.
The R7000 worked great for several years. I'd mounted a cooling fan on it as well as powered it from an external supply the entire time.
It finally started getting finicky and testing revealed bad caps on the DC converter board. That's when I recapped the radio.
Even though many of the caps are more power related, I still ran it through another alignment as I found doing that easy and also very fun. Today I may not as my eyesight is no longer near what it was back then!

I can't say about any certain order of alignment, I just followed the service manual in its entirety when aligning mine. I do recall a few steps that needed to be done several times until no further improvement was seen on the test equipment but I don't recall what part of the alignment that was.

Amazingly even with the poor shipping, my R7000 still runs just fine to this day and reception compares to the R9000 and still close to the R8600s. I find this amazing considering the radios age and what it must have went through in transit from Maine to Missouri.

The school teacher was very apologetic and I could tell she was also very upset. She was ready to start a refund when I called to tell her it had been found! Her postman told me she was an elderly lady who had retired quite some time earlier so I did not have the heart to tell her about the shipping damage and that she needs to improve her packing skills!

Good luck with your R7000. They are actually fairly easy to work on, especially with your experience with older vacuum tube tech. Just be careful with some of the small conductors they use for the board to board connections!

 

[MUTNAV]

Is the batteries purpose similer to the one on ICOMS IC-R71, where if (and when) the battery dies everything is lost, not just the memory but the settings to make the radio actually function to begin with? I think KIWA or another company offered to put a new ROM in, that wouldn't brick the radio when the cell dies.

 

[majoco]

The memory in the R7000 is not volatile like the R71. The R71 is a paper weight if you let the battery die as it loses all of its operating software.

 

[RFI-EMI-GUY]

Is the batteries purpose similer to the one on ICOMS IC-R71, where if (and when) the battery dies everything is lost, not just the memory but the settings to make the radio actually function to begin with? I think KIWA or another company offered to put a new ROM in, that wouldn't brick the radio when the cell dies.

No thankfully all you will lose are channel memories when you remove and replace the battery in the R7000. If you have an R71 that has lost its mind Piexx and one other company make replacement boards with the radio operating system in EPROM.

 

[MUTNAV]

Well that's good, the memory arrangement with the R71 reminds me of the HP-2 where the data card that holds the operating system will get corrupted with a simple loss of power. Good to know.

Thanks
Joel

 

[LostInNewMexico]

They are actually fairly easy to work on ...

That's music to my ears. You mentioned the IC-R9000 so I looked it up. Way cool! It also referenced an add-on PAN-2000 FFT, cooler still. Stop please, I might get so addicted to this retro stuff that I'll never get around to finishing design and build of my radio telescope. I guess I'll have to get together some of my "junk" and list it on fleabay.

Cheers from the high desert, Larry

 

[RFI-EMI-GUY]

I'm guessing but IF I do a complete cap replacement, the alignment should be done AFTER. Also in what order should I do the IF stages?

I'm torn about getting the proper test equipment, I think a sweep signal generator, oscilloscope and frequency counter should suffice. Anything else essential? If it gets too pricey maybe I should go with an R8600, but then I am left with a non-working 7000. Owning a non-working piece of equipment goes against my gut instincts.

Although my budget is limited, I really should get proper test equipment. My current planning is to go with a 1 meter disc and downconvert from X band to something in the 1 - 2 GHZ range. The more I research this the more complicated it gets. I got my EE degree when eight semester hours of vacuum tubes was required and transistors were squeezed in at the end.

Unless the tuning was out of wack, changing electrolytic capacitors should not affect it. If it seems to work up to snuff I would not realign it. If it does not, I would check and align in this order 1) The reference oscillator TCXO, 2) The VCO tuning voltages, 3) The tracking front end filters (which depend on VCO voltage to track). The IF stages should not normally need adjustment. There may be a second oscillator for the frequency bands above ~550 MHz that should be checked for accuracy.

 

[majoco]

Also in what order should I do the IF stages?

The downloadable service manual will answer all of your questions, but if you don't have the test gear or the experience I would tend to send it away for a re-alignment.

 

[RFI-EMI-GUY]

^^^^ what he said!

The IF stages require a lot more care to adjust and unless you do so correctly the radio will perform badly. That said, the service manual is the only way to tune this radio properly. Unless you gave prior experience, you should probably send it off. Replacing capacitors that are known to be bad like the PS or DC-DC convertor is easy. Doing a wholesale capacitor changeout is risky. Fix only what is broken first.

 

[db_gain]

This excellent vid reveals why lytic cap replacement can be the deciding factor in aligning an R7000;