MEP002A Frequency Meter Troubleshooting

[VA350]

I need help troubleshooting my frequency meter. It is not reading anything. The meter and transducer are good. I replaced both with a known good meter and transducer. The generator is working perfectly other than this.

 

[Harleyd315]

Do you have a seperate handheld hz meter? Is the trouble with the meter or the genset?












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[jbk]

meter and transducer are common problems. get the tms to help troubleshoot.
get yourself a hand held to check your freq. (kill a watt) is a cheap one.

 

[Harleyd315]

Do u have a/c power into the transducer?

 

[Speddmon]

Verify you have the transducer hooked up properly and that you have 120 volts feeding it. If you do, then you probably have a bad transducer. It may have been good on the other unit, but there is no guarantee it is good now.

 

[ETN550]

The meters have a very small max to full scale. Usually the ultra fine print on the meter face will say what is full scale.

I pull the frequency box and attach a 120vac household suicide cord to it and then put a known good meter on it. Leave it on overnight if drift is an issue.

Most of the transducers can be repaired in a couple of hours for about $2 or less worth of Radio Shack capacitors. If the box has screws on it don't touch them. Drill out the rivets and open up the box. Identify the capacitors and replace them. Look for burnt diodes, if any, and replace. The larger wire wound resistors may burn if the capacitors go out but those resistors are probably still good as is.

If you cannot do this and solder new capacitors in than an electronics supply / repair store can usually do it in a day for less than the cost of a new box. I think a new box is around $150 and unless just made its capacitors are already aging towards a failure.

Most have an adjustment screw that can set the meter at 60.0 with the suicide cord. Then re-assemble.

Most of these applications pull the power offof the 120 outlets wiring. run the gen and measure at the outlet, then the box input. If input 120 is at the box then verfy output with a good meter, and if none then re-capacitor the box.

 

[Grega]

Goog info ETN50. Just got a mep 002a up and running today, (froze up injection pump], and noticed that the freq. guage runs around the pegged end after checking with a kill a watt meter at 60 hz. Have 120 volts at the input of the transducer. What should I have at the output. I have another mep 002a. Maybe I could swap the meter or transducer to see which is bad.

 

[ETN550]

Goog info ETN50. Just got a mep 002a up and running today, (froze up injection pump], and noticed that the freq. guage runs around the pegged end after checking with a kill a watt meter at 60 hz. Have 120 volts at the input of the transducer. What should I have at the output. I have another mep 002a. Maybe I could swap the meter or transducer to see which is bad.

I'm not as familiar with the larger meters as I tend to work on the smaller units and their meters are a little smaller in diameter. They are typically micro amps full scale. Most have tiny print barely readable on their face. It might read 20uA FS which would mean 20 micro amps full scale. So if 65 is the top scale and 55 is the bottom scale then 65-55=10 hz per 20uA and 60 would be half scale or 10uA. At least that is the way the small meters work on the 016B and 701A. Remember there is usually a pot inside the box that can be turned to get the meter on 60 when the box is fed exactly 60 from the house 120vac. If the box has a white plastic screw then the pot is behind the screw. Just remove the screw and fish around with a fine screwdriver through the hole. I have seen other boxes with no external plug but still have an adjustment inside. Just have to drill out the rivits which is easy because they are aluminum rivits. I have fixed two and calibrated this way so far worked good.

 

[Grega]

Didnt see a plug or screw. I will take the transducer off tomorrow or next, remove the rivits, and see what I find inside. THANKS for the info. Greg

 

[Grega]

Took the transducer off tonight. It must be of a differant kind because the back side is packed witha clay like substance with no screw. Think im S.O.L on repairing it.

 

[ETN550]

Yeah, that's not like the ones on the smaller units. See below for the ones I have dealt with. The big component with the foam on it is the adjustable pot. This style was easy to solder in new caps.