Hello to the forum,
This being my first posting I just want to thank anyone in advance that shares their knowledge to help me.
I'm working on a Ranger 2990 non DX model it has the only mainboard I have ever seen in the 2950/70/90 old style radios, it is EPT295013Z.
Problem is, the clarifier does nothing to change the tuning to frequency. It is not unlocked, I tried another clarifier with the same result. But the radio does recieve on frequency in all modes anyway. The radio was this way when I bought it.
The middle wire in J118 and the one closest to front of the radio both have about 8 volts and the middle wire should change voltage when I rotate the clarifier control but does not. I'm not much at diagnosing things but follow directions well. So I'm wondering if perhaps the Tech Rick or anyone for that matter may be kind enough to help. I have read many of his posts and he seems very adept at knowing radios and their workings. Could it possibly be that D67 is bad? D59 and D61 are good if that matters. Any suggestions will be greatly appreciated.
Regards, Jim
RCI 2990 non DX
Re: RCI 2990 No clarifier control.
You may have lost the ground side of the clarifier control, which is formed by R198.
The wiring should be like so:
Clarifier control Pin 1 is Red and is connected to J118 Pin 1.
Clarifier control Pin 2 is Brown and is connected to J118 Pin 2.
Clarifier control Pin 3 is Black and is connected to J118 Pin 3, and is connected to R198 it maybe o/c or cold solder joint.
One problem this PCB suffers with is bad soldering.
The wiring should be like so:
Clarifier control Pin 1 is Red and is connected to J118 Pin 1.
Clarifier control Pin 2 is Brown and is connected to J118 Pin 2.
Clarifier control Pin 3 is Black and is connected to J118 Pin 3, and is connected to R198 it maybe o/c or cold solder joint.
One problem this PCB suffers with is bad soldering.
Rick.
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euhara
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RCI 2990 clarifier
Thanks for the reply Rick but I have checked the whole board for solder problems with a 5 inch lighted magnifier and no problems found. Guess I have to keep looking for another solution.
Regards, Jim
Regards, Jim
Re: RCI 2990 No clarifier control.
Do all test with the radio switch off and the powre plug removed.
What is the resistance between Top Pin 1 of J118 (Red wire) and ground with let me have the reading.
What is the resistance between Centre pin 2 of J118 (Brown wire) and ground with clarifier control fully CW and CCW, let me have the two readings.
What is the resistance between Bottom pin 3 of J118 (Black wire) and ground with clarifier control fully CW and CCW, let me have the two readings
What is the resistance between Top Pin 1 of J118 (Red wire) and ground with let me have the reading.
What is the resistance between Centre pin 2 of J118 (Brown wire) and ground with clarifier control fully CW and CCW, let me have the two readings.
What is the resistance between Bottom pin 3 of J118 (Black wire) and ground with clarifier control fully CW and CCW, let me have the two readings
Rick.
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euhara
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- Location: Fort Collins, Colorado
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Clarifier on 2990
Thanks Rick,
Guess you was on the right track R198 was open. Got that working now.
Same radio another problem that was also there when I bought the radio,
It has no transmit signal or audio in any mode. It receives very well in all modes, the PA audio works and turns on and off. Everything is alive except part of the transmit. Voltage at the final and driver adjust up and down between AM and SSB but the pre driver does not turn on when keyed, Q38 has no volts at the collector even after replaced. Most parts seem to be ok in the right front corner Q39 is ok etc. D74 and D75 are ok
when I key up the transmit comes on in the display and busy goes off but the on air LED doesn't light. Something is not letting the circuit be completed on transmit. Its hard for me to know what turns what on and off there. Hope it's just a switching diode or a cap. Hope you can find it from this info. Thanks much for your interest and consideration.
Regards, Jim
Guess you was on the right track R198 was open. Got that working now.
Same radio another problem that was also there when I bought the radio,
It has no transmit signal or audio in any mode. It receives very well in all modes, the PA audio works and turns on and off. Everything is alive except part of the transmit. Voltage at the final and driver adjust up and down between AM and SSB but the pre driver does not turn on when keyed, Q38 has no volts at the collector even after replaced. Most parts seem to be ok in the right front corner Q39 is ok etc. D74 and D75 are ok
when I key up the transmit comes on in the display and busy goes off but the on air LED doesn't light. Something is not letting the circuit be completed on transmit. Its hard for me to know what turns what on and off there. Hope it's just a switching diode or a cap. Hope you can find it from this info. Thanks much for your interest and consideration.
Regards, Jim
Re: RCI 2990 No clarifier control.
When you start a new fault, it is always best to start a new post, as this will help others in the future with the same fault.
Q38 TX switch, is PNP transistors, so to get it to turn you need to make the Base negative with respect to the Emitter voltage, this is done by the Zener diode D73 and R220, when the radio is in RX the diode D72 is conducting but when you go in to TX, D72 is switched off.
So in short, check that D72 has zero volts on the Anode side in TX.
If not check Q37 Collector in TX, it should be almost zero, if not try replacing Q37.
Q38 TX switch, is PNP transistors, so to get it to turn you need to make the Base negative with respect to the Emitter voltage, this is done by the Zener diode D73 and R220, when the radio is in RX the diode D72 is conducting but when you go in to TX, D72 is switched off.
So in short, check that D72 has zero volts on the Anode side in TX.
If not check Q37 Collector in TX, it should be almost zero, if not try replacing Q37.
Rick.
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euhara
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no transmit
Sorry for the error I made in posting a new problem on the same thread.
You nailed it right on the money, I replaced Q37 and everything came to life. Wish I had some of your knowledge, you diagnose radios the way I diagnose cars without seeing them.
I will start a new post for the rest of my problems. I have 4 of these 2990s I am working on and am slowly gaining. I bought them all dead and bringing them back to life. Mostly they are finished now except for a few minor problems. Like this one now it is mostly finished thanks to you but the on air LED is very dim and was bright before the no transmit happened.
Would it be ok to send a PM to you?
Again Thanks very much for helping this old man.
Regards, Jim
You nailed it right on the money, I replaced Q37 and everything came to life. Wish I had some of your knowledge, you diagnose radios the way I diagnose cars without seeing them.
I will start a new post for the rest of my problems. I have 4 of these 2990s I am working on and am slowly gaining. I bought them all dead and bringing them back to life. Mostly they are finished now except for a few minor problems. Like this one now it is mostly finished thanks to you but the on air LED is very dim and was bright before the no transmit happened.
Would it be ok to send a PM to you?
Again Thanks very much for helping this old man.
Regards, Jim
Re: RCI 2990 No TX.
I do not have a sch diagram for this radio? as it will help you find faults.
Rick.