Motorola R2400 Communications Service Monitor

[wkirkpatrick]

Anybody have any trouble shooting knowledge for the R2200/R2400 series Service Monitor? I have had mine for around 25 years and it is in pristine condition, however it has a issue that has come up in the last couple of years. After being on for approximately 15-20 minutes it turns off. If you cycle the power switch to off and back on it will come back on and again after 15-20 minutes turn off. There is a relay that latch's and you can hear it unlatch when you power cycle.

I have the Service Manual and there are a couple of items that can cause the issue, Over temperature, over/under voltage, etc. My current problem is I do not have the extender board service kit and really can't do any serious measuring of test points. The unit works fine with the exception of the RF Vernier Control that probably needs a little use.

This is my first post so any ideas would be appreciated!

Bill K

 

[RFI-EMI-GUY]

Probably a bad power supply capacitor.

 

[wkirkpatrick]

Probably a bad power supply capacitor.

Thanks.....that was my only guess also being the age of the unit. However really wanted to get some input from others. With CORVID-19 and asked to remain home, now would be a good time to start tearing it apart. Thanks!

 

[wkirkpatrick]

FYI... After probing around with a scope looking for anything out of order, I went the capacitor route replacing some off the bigger caps in the low voltage power supply and it did not fix the intermittent shutdown problem. The last resort and what I should have done years ago when this problem started, was to bypass the thermal switch, TS1, on the main interconnect board that's supposed to open if the temperature reaches 75C or 167F. Problem solved! Unit was left on for 12 hrs and inside temp never got above 105 degrees with the covers on the unit and temp probe near the device. The Motorola Part Number is 80-80397A26 and I doubt I will replace it. I left myself a note on the inside cover that I did bypass the part for future reference. It is very easy to bypass with a piece of #30 wire from the bottom side of the main interconnect board!

 

[tedlaw]

Greetings Folks ! Have you ever had any issues with the attenuator being hard to turn on the R2400? Also, is it suppose to turn in both clockwise and counter clockwise. I am considering buying a used R2400. If so, did you have a fix.

 

[arlo]

I have a 2200 with the shut down problem. Have not attempted repair. Unit also has the stiff attenuator problem. It will turn both directions, just a bit hard.