Motorola r 2600 not working

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N9CZV
Posts: 148
Joined: Sat Dec 01, 2001 4:00 pm

Motorola r 2600 not working

Post by N9CZV »

I have a Motorola R-2600 Service Monitor that the tuning knob has stopped working. All else works fine. Any help would be appreciated


David
jry
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Joined: Fri Feb 06, 2004 3:14 pm

Re: Motorola r 2600 not working

Post by jry »

you may be able to drop the front cover and check to see if the know is getting 5V

the pins are 1GND 2 optical A (up? ) 3 Optical B (down ?) 4 +5volt.

Could be the just the opto isolator in the knob. You may need to get the manual to chase it back any further.

You may wnat to try the old trusty re-seat the cables from the FP to the processor board.
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N9CZV
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Re: Motorola r 2600 not working

Post by N9CZV »

I have tried that with no luck. Do you know if the knob outputs neg or pos pulses?
jry
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Joined: Fri Feb 06, 2004 3:14 pm

Re: Motorola r 2600 not working

Post by jry »

not sure ...there is a cap on the FP PCB for the 5v to the knob assembly. May want to make sure thats not shorted and that your getting 5v to the knob encoder.

You could pull it and test externally ... you may need to google the info on the knob to see if it needs any pull ups or pull downs on the outputs
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N9CZV
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Re: Motorola r 2600 not working

Post by N9CZV »

Did that and there is 5 volts on the knob
jry
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Joined: Fri Feb 06, 2004 3:14 pm

Re: Motorola r 2600 not working

Post by jry »

if the knob assembly has power but does not output pulses in either direction especially if tested standalone I would go ahead and replace it.

There may be an OEM part number on it since I think these may be pretty standard ( HP Agilent uses a similar part in its 859X fron panels )
ChanceWolf
Posts: 16
Joined: Mon Mar 19, 2007 7:34 pm
What radios do you own?: Saber R, Micom XF, R2600B, MXs

Re: Motorola r 2600 not working

Post by ChanceWolf »

Mine just did the same thing after a fair period of disuse, but just working the knob back and forth got it suddenly working again, and no problem since. Now if the flyback would only stop acting up...
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N9CZV
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Re: Motorola r 2600 not working

Post by N9CZV »

Problem turned out to be a bad optocoupler
jry
Posts: 481
Joined: Fri Feb 06, 2004 3:14 pm

Re: Motorola r 2600 not working

Post by jry »

did find a source for the flyback ...expensive but could not find another cross reference . It did work perfect though. The monitor is an industrial TTL 7" CRT that was made by Motorola Display technologies. Good news is that the display module can be replaced by other solutions ... LCD/TFT based monitor was used in the later vintages for example.
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