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Thread: R2670 Issues

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    Default R2670 Issues

    Any R2670 gurus that can shed some light on what might be going on.

    I took a chance on a used Motorola R2670. When I received it, the appearance was great and it seemed to power up OK.

    Then I tested the generate and receive functions....nothing...completely dead.

    It does supply generate audio and PL tones since they show up on the scope when in generate mode.

    I am familiar with the 2670 since I have used one at work. This one was bought for personal use since I don't like taking the shop's equipment in the field when I am maintaining ham repeater equipment.


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    Quote Originally Posted by FMTRU140D View Post
    Any R2670 gurus that can shed some light on what might be going on.

    I took a chance on a used Motorola R2670. When I received it, the appearance was great and it seemed to power up OK.

    Then I tested the generate and receive functions....nothing...completely dead.

    It does supply generate audio and PL tones since they show up on the scope when in generate mode.

    I am familiar with the 2670 since I have used one at work. This one was bought for personal use since I don't like taking the shop's equipment in the field when I am maintaining ham repeater equipment.
    Did you check the 2 RF fuses? Gen out and antenna.

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    Not yet but we have some at work so I can check them

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    Update...the Antenna fuse is OK generate out fuse was missing. I really think it is more than just a fuse.

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    The fuse is not a perfect failsafe. If you push enough power into the GEN port on a service monitor it'll still kill the RF generator. BTDT with a R2590.
    "The Girl Scouts found several hungry REACT members at the finish line..."

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    Also, most of the operations on the 2600/2670 series are done via the RF In/Out connector, the Ant and Gen ports are for more specialized uses like OTA monitoring or Duplexer tuning. The RF I/O jack has a 50 ohm terminated 100W dummy load and attenuator on the other side of the N connector. One I have had the center pin broken loose from the hybrid and after removing the N shell, I was able to resolder the center pin to the hybrid. If someone ran too much power, 100W or more for more than a minute it will overheat and eventually smoke that attenuator hybrid. Or yours might have a broken center pin like mine. Or it's something nastier further back. Testing through the other ports (like GEN and ANT) as well as the RF I/O port will tell you how far back inside the RF chain the failure is, hopefully.

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    Since I have used a 2670 at work for the last 15 years, I felt all along that it was more than a blown fuse. I have tested from the other ports and it appears that the problem is further back in the RF chain. A service manual would help but so far i have not been able to find one on line. That said it does not hurt to cover all of the simple things first.

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    well if both gen and rx are out sounds like the high synthesizer may be bad.

    There are a number of synthesizer loops in the R26XX but the high freq one is common to gen and rx IIRC.

    You can PM if you want the unit repaired.

    Those boards are a pain since most of the good stuff is under soldered in shields.

    This is one of the comments I always make about this series is that the power on self test and "calibration" have almost zero value in verifying operations or troubleshooting.

    If you acquired one with only that level of testing/verification than it may have multiple issues ....bad sign is when the fuse is missing, Usually means other problems on the wattmeter assembly from too much power being applied to the port.

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    It was the High Synthesizer, bad VCO. Seller took care of the repair and shipping to and from.
    So far it all looks good. I guess the real test is when I align a couple of Quantars (Ham use)that I have in my personal shop.

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