I powered down and unplugged my working REL Studio II for a planned power outage to repair a utility pole. Two hours later, when I turned the sub back on, the drivers relay began to click on/off. No sound could be heard except for a brief moment when the relay tried to connect the speaker drivers to the audio circuits. Needless to say, my sub is no longer working.
Visual inspection of the board show the caps to be in like new condition (no bulging or leaks anywhere). In fact the whole board looks brand new.
This sub was always left on and only turned off either due to infrequent power outages (storms) or when away for an extended time. Otherwise, the powered sub is always on.
Has anyone experienced this where only the relay is faulty or is it the power supply causing the clicking? I haven't tested any voltages yet needing advice on what/where to test. See image below for the relay picture. I can't find a schematic for this unit.
I did measure the relay's coil voltage and it fluctuates with each click - rising to a few volts then falling to zero. My digital meter is not fast enough to catch it because the click is so fast.
Thanks
Visual inspection of the board show the caps to be in like new condition (no bulging or leaks anywhere). In fact the whole board looks brand new.
This sub was always left on and only turned off either due to infrequent power outages (storms) or when away for an extended time. Otherwise, the powered sub is always on.
Has anyone experienced this where only the relay is faulty or is it the power supply causing the clicking? I haven't tested any voltages yet needing advice on what/where to test. See image below for the relay picture. I can't find a schematic for this unit.
I did measure the relay's coil voltage and it fluctuates with each click - rising to a few volts then falling to zero. My digital meter is not fast enough to catch it because the click is so fast.
Thanks
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Can you suggest an EPCOS replacement? The "soda cans" measure 50 mm diameter and are 77 MM high. I believe the lag connectors are 22 mm apart. I assume these are polar, but there is no polarity marking on the caps or the board (maybe underneath?). These are 10,000 uF 100VDC caps. I have not found an EPCOS one that matches.
I can empathize with your situation. I have some old hi-fi gear that has needed repair in the past, multiple times, and sometimes this has been complicated by difficulties sourcing the requisite parts. The REL Studio II is quite an old unit, I believe around 25 years old. Have you tried to get an electronics repair technician to look at the problem? The relay not engaging could be symptomatic of an issue elsewhere that is amenable to repair.
Have you considered replacing the plate amp with a new one purchased off the shelf? It may prove a little difficult to get something to fit, and if the aesthetics aren't extremely critical then a workable solution might be achievable even if a perfect fit isn't possible.
Have you considered replacing the plate amp with a new one purchased off the shelf? It may prove a little difficult to get something to fit, and if the aesthetics aren't extremely critical then a workable solution might be achievable even if a perfect fit isn't possible.
I have tried a couple of local repair shops, but they won't touch this amp (English parts/ hard to source). The relay is protecting the drivers as designed. Something has failed likely producing DC offset. When the relay clicks on, the safety circuit senses the problem and the drivers are disconnected. This is near instant. The failing part could be anything (output transistors, caps, etc.). It's not a diode or resistor (I checked those). Ironically, the board looks brand new. I was hoping to see an exploded cap! I have had that happen and it is so simple to fix.
Could you suggest a plate amp that could replace this one? A 300 watt amp would do the trick. I would need a way to take high level input as my preamp has no sub-out capability (Krell).
Could you suggest a plate amp that could replace this one? A 300 watt amp would do the trick. I would need a way to take high level input as my preamp has no sub-out capability (Krell).
Out of curiosity, I tested the MOSFET output transistors using a multimeter using the diode setting. Attached is the spec sheet for the N & P Mosfet's.
Interestingly, the 905's tested normally. But the 900's did not. I used this procedure:
1) Set the DMM to the diode range.
2) Keep the mosfet on a dry wooden table on its metal tab, with the printed side facing you and leads pointed towards you.
3) With a screwdriver or meter probe, short the gate and drain pins of the mosfet. This will initially keep the internal capacitance of the device completely discharged.
4) Now Touch the meter black probe to source and the red probe to drain of the device.
5)You should see an "open" circuit indication on the meter.
6) Now keeping the black probe touched to the source, lift the red probe from drain and touch it to the gate of the mosfet momentarily, and bring it back to the drain of the mosfet.
7) This time the meter will show a short circuit (sorry, not short-circuit rather "continuity).
The results from the point 5 and 7 confirms that the mosfet is OK.
I am wondering if this is source of my problem? I tested the caps and they are good! (what a surprise).
Any ideas?
Interestingly, the 905's tested normally. But the 900's did not. I used this procedure:
1) Set the DMM to the diode range.
2) Keep the mosfet on a dry wooden table on its metal tab, with the printed side facing you and leads pointed towards you.
3) With a screwdriver or meter probe, short the gate and drain pins of the mosfet. This will initially keep the internal capacitance of the device completely discharged.
4) Now Touch the meter black probe to source and the red probe to drain of the device.
5)You should see an "open" circuit indication on the meter.
6) Now keeping the black probe touched to the source, lift the red probe from drain and touch it to the gate of the mosfet momentarily, and bring it back to the drain of the mosfet.
7) This time the meter will show a short circuit (sorry, not short-circuit rather "continuity).
The results from the point 5 and 7 confirms that the mosfet is OK.
I am wondering if this is source of my problem? I tested the caps and they are good! (what a surprise).
Any ideas?