EMR CORP MODEL 1650 0-1GHz 125 Watt Dummy Load -Are They Repairable?

[nokones]

I just learned that my Dummy Load took a dump and I am wondering if they are repairable and worth repairing? The casing/housing appears to be assembled with two halves and the N Female fitting has 4 screws attaching the fitting to the housing.

I didn't realize that the Dummy Load failed on me. At first, I thought that the three radios I was measuring the RF output with the Dummy Load was in a dire need of an alignment and tune since I was measuring only 7 watts of output power. I measured the three radios with three different in-line Watt meters and one of the meters and slugs were calibrated last year by Bird.

So, I packed up the three radios and headed to a Motorola Service Shop in Tucson. As I was about to leave, the technician came out to my Jeep and told me the first radio is putting out 50 watts and is on freq. I said no way. He quickly checked the second radio with the same results, and the third radio was transmitting 40 Watt, but was a tad off freq and needed an alignment. I said do it.

The first radio was Jeep radio so I put the radio back in my Jeep and remeasured the RF and it was at 48 watts. After the Tech tuned the third radio, I headed home and when I got home, my first task was to recheck the radios again. I checked two of three radios on the bench since they were loose, and they again only put out 7 watts.

So, I started replacing cables, cords, adapter connectors, ensured the power supply was putting out 14 volts. I bypassed my Anderson Distribution Block and directly connected the radio and controlhead to the power supply, only 2 watts were drawn from the power supply. So, I tried another power supply and still only two watts being pulled from the second power supply.

The only thing that I haven't changed was the Dummy load. My second Dummy load was only an UHF Dummy load and these three radios were VHF mobiles so I couldn't use the UHF Dummy load. However, I have NMO magmounts and a couple VHF mobile antennae so I hooked up the antenna to the radio in place of the dummy load. When I keyed the radio, 48 watts, hot damn. I reconnected the Dummy load, 7 watts, hooked the antenna back up, 48 watts.

I decided to get out my ohm meter and check the Dummy load resistance and it measured "OL". Although, I wasted a whole day going to Tucson with two perfectly good working radios, I did get one radio aligned and I did discover that the Dummy load failed and my meters and radios were nof the cause of measuring 7 watts.

 

[tcp2525]

9 hours ago, nokones said:

I just learned that my Dummy Load took a dump and I am wondering if they are repairable and worth repairing? The casing/housing appears to be assembled with two halves and the N Female fitting has 4 screws attaching the fitting to the housing.

I didn't realize that the Dummy Load failed on me. At first, I thought that the three radios I was measuring the RF output with the Dummy Load was in a dire need of an alignment and tune since I was measuring only 7 watts of output power. I measured the three radios with three different in-line Watt meters and one of the meters and slugs were calibrated last year by Bird.

So, I packed up the three radios and headed to a Motorola Service Shop in Tucson. As I was about to leave, the technician came out to my Jeep and told me the first radio is putting out 50 watts and is on freq. I said no way. He quickly checked the second radio with the same results, and the third radio was transmitting 40 Watt, but was a tad off freq and needed an alignment. I said do it.

The first radio was Jeep radio so I put the radio back in my Jeep and remeasured the RF and it was at 48 watts. After the Tech tuned the third radio, I headed home and when I got home, my first task was to recheck the radios again. I checked two of three radios on the bench since they were loose, and they again only put out 7 watts.

So, I started replacing cables, cords, adapter connectors, ensured the power supply was putting out 14 volts. I bypassed my Anderson Distribution Block and directly connected the radio and controlhead to the power supply, only 2 watts were drawn from the power supply. So, I tried another power supply and still only two watts being pulled from the second power supply.

The only thing that I haven't changed was the Dummy load. My second Dummy load was only an UHF Dummy load and these three radios were VHF mobiles so I couldn't use the UHF Dummy load. However, I have NMO magmounts and a couple VHF mobile antennae so I hooked up the antenna to the radio in place of the dummy load. When I keyed the radio, 48 watts, hot damn. I reconnected the Dummy load, 7 watts, hooked the antenna back up, 48 watts.

I decided to get out my ohm meter and check the Dummy load resistance and it measured "OL". Although, I wasted a whole day going to Tucson with two perfectly good working radios, I did get one radio aligned and I did discover that the Dummy load failed and my meters and radios were nof the cause of measuring 7 watts.

 

Definitely take it apart. I suspect that there is a mechanical issue such as cold solder joint, most likely around the center pin of the N connector. Doubtful you burned out the hybrid resistor. If you did, they are around $20. Get it apart and inspect and take measurements with your meter. Post pics of the insides and someone on here will give you better advice.