Hello good people at GroupDIY! I'm bringing a rough RE-501 Space Echo back to life. Today, I lost power and traced the issue to one of the secondary windings on the power transformer. These are the two yellow leads that power the solenoid and motor (112 and 113 in schemo snapshot). They're supposed to provide +13VAC and -13VAC. Under load, I'm getting the +13VAC, but nearly 0 on node 113. I then desoldered them and the lead that's +13VAC under load goes to +17VAC (should stay at +13VAC) and the one that looks dead under load goes to -7VAC (instead of -13VAC). Does this indicate a possible issue with the load (solenoid or motor), or does it appear to be more like a dying trafo winding or something else?
Next, I pulled out the bridge rectifier to test it and it was fine. I wanted to use my bench power supply which as + and - DCV to feed that circuit to see if I could get the it working normally having the correct +13/-13 DC Voltages. I set the positive lead on the bench power supply to +13VDC and connected it to the PCB where the + output of the bridge rectifier. Conversely, connected the -13VDC to the PCB where the - output of the bridge rectifier is (I used the terminals that the solenoid connects to on the PCB since those were convenient and connect directly to the bridge rectifier outputs. Also removed the bridge rectifier). Then I turned on the bench psu and it showed 13VDC and close to .5A, which is correct and the solenoid clicks in as it should, but the motor doesn't seem to spin...probably because the rest of the Space Echo circuit hasn't been turned on yet I'm guessing. So then I turn on the Space Echo power switch to turn on the rest of the unit (there's a second secondary winding (orange leads in pic) that feeds the rest of the unit). Upon engaging the Space Echo's power switch, the Amperage on the bench power supply jumps to 1-1.1Amps (draw from greater load????), and the voltage output meter on the psu drops to zero. I've attached pictures of both conditions. I should mention, that I just had the two leads (+13V and -13V) going out of the bench power supply....I didn't connect the common or ground terminals from the power supply to anything. Should ground or common terminals from the psu be connected somewhere? Any other thoughts on this behavior?
Next, I pulled out the bridge rectifier to test it and it was fine. I wanted to use my bench power supply which as + and - DCV to feed that circuit to see if I could get the it working normally having the correct +13/-13 DC Voltages. I set the positive lead on the bench power supply to +13VDC and connected it to the PCB where the + output of the bridge rectifier. Conversely, connected the -13VDC to the PCB where the - output of the bridge rectifier is (I used the terminals that the solenoid connects to on the PCB since those were convenient and connect directly to the bridge rectifier outputs. Also removed the bridge rectifier). Then I turned on the bench psu and it showed 13VDC and close to .5A, which is correct and the solenoid clicks in as it should, but the motor doesn't seem to spin...probably because the rest of the Space Echo circuit hasn't been turned on yet I'm guessing. So then I turn on the Space Echo power switch to turn on the rest of the unit (there's a second secondary winding (orange leads in pic) that feeds the rest of the unit). Upon engaging the Space Echo's power switch, the Amperage on the bench power supply jumps to 1-1.1Amps (draw from greater load????), and the voltage output meter on the psu drops to zero. I've attached pictures of both conditions. I should mention, that I just had the two leads (+13V and -13V) going out of the bench power supply....I didn't connect the common or ground terminals from the power supply to anything. Should ground or common terminals from the psu be connected somewhere? Any other thoughts on this behavior?
