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Post by frankv on Jan 16, 2023 21:22:57 GMT -5
Hi,
I tried to fire up my RPA-1 after a couple of years and it goes from yellow to blue after you turn it on but then instantly switches back to yellow. This happens even with nothing connected. Trying to turn it back on with the front switch after that does nothing, I have to turn it back off in the rear before I can repeat the initial sequence (yellow, blue, yellow). The unit has a fuse in the back and two inside, visually they look good. Emotiva no longer services this model, they sent me the schematic but I'm afraid a repair would cost several hundred dollars which may not be worth it. Any ideas?
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Post by ttocs on Jan 16, 2023 23:02:26 GMT -5
First guess is capacitors are no longer functioning well.
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Post by frankv on Jan 16, 2023 23:53:36 GMT -5
First guess is capacitors are no longer functioning well. Forgot when I bought it but I have old amps dating back to the 70s that are still working fine, hard to believe capacitors could be the culprit. Guess that’s not something I can test on my own? And if that turns out to be the problem, one should replace all the capacitors with better ones, but not sure that’s economical vs just buying a new amp. |
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Post by vcautokid on Jan 17, 2023 0:16:26 GMT -5
Not at all surprising. Even amplifiers from the 70s actually even more so could have electrolytic capacitors out of specifications, but will still function, though at possibly reduced performance. Electrolytic Capacitors are an odd beast. They may continually reform through use, but they will only continue to fall out of specifications more, and more. That is normal over time. True of any audio component that uses electrolytic capacitors. Big question mark on the RPA-1, is it worth fixing? And possibly what is wrong with it. There are a few reasons why an amplifier will go into protection. A short inside somewhere. High DC offset. Also maybe even some blown rail fuses inside. I forget if the RPA-1 uses them. You might luck out and replacing one or both might fix it, or it will blow again. Remember fuses go out for a reason. An over current condition usually from a short somewhere. I am willing to bet the electrolytic capacitors are suspect. Replacing all them is not a bad idea. The RPA is certainly old enough to warrant that. That is not a for sure cure. It could be a bad transistor, or diode, as well as capacitor(s) causing the issue. The worst case could be the microprocessor that governs the function of the amplifier is gone. And that is not replaceable. Everything else is. From the pre drive to the outputs, those are common parts. But anything proprietary like the controller board, then it maybe a lost cause.
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Post by vcautokid on Jan 17, 2023 0:23:27 GMT -5
As a part deux. Check all the voltages to see where you lose the voltage, and work backwards. The schematic is your road map to the circuit layout. Most amplifiers have key voltages that make them run. I don't know if the RPA-1 will give you enough time to measure. But one of the first checks if possible is bias current at idle and DC offset. After that check for voltages if present at the appropriate stages of the amplifier. Work forward to measure the voltages, when you find a voltage drop or drop to zero, work backwards till you get the voltage again. It will at least localize where the issue might be. I realize this is troubleshooting 101. But it is better than nothing.
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cawgijoe
Emo VIPs 
"We made too many of the wrong mistakes." - Yogi Berra
Posts: 4,914
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Post by cawgijoe on Jan 17, 2023 8:02:30 GMT -5
First guess is capacitors are no longer functioning well. Forgot when I bought it but I have old amps dating back to the 70s that are still working fine, hard to believe capacitors could be the culprit. Guess that’s not something I can test on my own? And if that turns out to be the problem, one should replace all the capacitors with better ones, but not sure that’s economical vs just buying a new amp. If you can replace capacitors on your own, the cost is not bad. The problem is that you really need to isolate what the problem is rather than just throwing parts at it. If you have the test equipment and capability to test yourself, that's ideal. If not, a local tech can do it with schematics, but it will cost you some money. It may be worth the diagnostic cost to at least fine out if you should repair or replace. |
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Post by leonski on Jan 17, 2023 17:44:28 GMT -5
Caps.....and by this I mean the big PS Electrolytics, do not age well when simply sitting on a shelf. They dry out.
And I'll bet that EMO does not use a top-tier cap in that application. Like ELNA or Rubycon or Nichicon or a few others.
That being said? Since warranty is not an issue, POP THE TOP and have a look.
Signs of the PS caps going bad? Bulging / Leaking are first. You can sometimes Smell burned resistors / electronics......
USE PLENTY OF LIGHT......
This is a commodity part and buying the BEST will not be that much more $$$ than buying junk. And if you can do it yourself?
Even less $$$
Also? 2 costs involved here. Repair and Replace. A repair guy may quote a diagnosis fee. Than offer to forget that IF you go
ahead with the repair. For replace? Deduct the value of your 'For Parts' RPA-1
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Post by 405x5 on Jan 18, 2023 9:33:57 GMT -5
Hi, I tried to fire up my RPA-1 after a couple of years and it goes from yellow to blue after you turn it on but then instantly switches back to yellow. This happens even with nothing connected. Trying to turn it back on with the front switch after that does nothing, I have to turn it back off in the rear before I can repeat the initial sequence (yellow, blue, yellow). The unit has a fuse in the back and two inside, visually they look good. Emotiva no longer services this model, they sent me the schematic but I'm afraid a repair would cost several hundred dollars which may not be worth it. Any ideas? My advice would be to invest in a new amplifier and get back to the fun. Unless you are a qualified amateur tech. It’s a waste of your time and effort to deal with that. You COULD put it on ebay (parts only local pickup). High bidder might get back your efforts for listing etc. |
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Post by frankv on Jan 18, 2023 15:18:26 GMT -5
Thanks for the input. Nothing looks unusual to me on the inside, the fuses appear to be ok and the capacitors show no physical issues. One oddity is that the voltage selector switch on the back is in what appears to be the 230V position (per the labels next to the switch) but it says 115 on the red selector switch itself. This has worked for me in the past and unlikely, though not impossible, that the switch has been moved since as it is recessed. I found an image of the RPA-1 and the corresponding RSP-1 online, and the RPA-1 image was identical to mine, but the RSP-1 had it reversed (switch shows 115 when in the left position which is 115V per the labels. Any chance the amp could behave if the voltage selector is really in the 230V position and I plug it into 115V? Here is an image of the RSP-1 voltage selector (on mine the switch is in the opposite position but it reads 115 on the switch itself). If the image does not show, right-click and open it in new tab.  |
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Post by donh50 on Jan 18, 2023 15:37:43 GMT -5
Flip the switch and see?
Unless a cap is blown that is probably not the problem, though a coupling cap could do it. There are so many possibilities that, unless you have a schematic and decent debug skills, it is probably best left to a tech. You could look for DC on the output that might indicate a device or bias problem, though easier with a 'scope than a voltmeter if it immediately shuts down. I would probably start by tracing the protection circuit in the schematic to see what might cause shutdown, but it may go to a CPLD or other logic circuit and so even then be hard to nail down.
My other suggestion would be to post the schematic here, maybe ASR and DIYaudio, to let others have a look (if that's OK with Emotiva).
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Post by leonski on Jan 18, 2023 18:02:38 GMT -5
Thanks for the input. Nothing looks unusual to me on the inside, the fuses appear to be ok and the capacitors show no physical issues. One oddity is that the voltage selector switch on the back is in what appears to be the 230V position (per the labels next to the switch) but it says 115 on the red selector switch itself. This has worked for me in the past and unlikely, though not impossible, that the switch has been moved since as it is recessed. I found an image of the RPA-1 and the corresponding RSP-1 online, and the RPA-1 image was identical to mine, but the RSP-1 had it reversed (switch shows 115 when in the left position which is 115V per the labels. Any chance the amp could behave if the voltage selector is really in the 230V position and I plug it into 115V? Here is an image of the RSP-1 voltage selector (on mine the switch is in the opposite position but it reads 115 on the switch itself). If the image does not show, right-click and open it in new tab. I HATE those switches! It is remotely possible that the switch was installed UPside Down.....so the labeling on the amp does not match that on the switch? I see 2 screws for the switch, so I may be 'flippable' and still work, but the switch and amp enclosure labels no longer agree.... This is a 100:1 LongShot ... at least! If your switch is upside down relative to the image you provide? I think the 115 or whatever will be read from the OTHER side of the amp.....I'm not phrasing this right! |
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Post by frankv on Jan 19, 2023 1:24:16 GMT -5
Thanks for the input. Nothing looks unusual to me on the inside, the fuses appear to be ok and the capacitors show no physical issues. One oddity is that the voltage selector switch on the back is in what appears to be the 230V position (per the labels next to the switch) but it says 115 on the red selector switch itself. This has worked for me in the past and unlikely, though not impossible, that the switch has been moved since as it is recessed. I found an image of the RPA-1 and the corresponding RSP-1 online, and the RPA-1 image was identical to mine, but the RSP-1 had it reversed (switch shows 115 when in the left position which is 115V per the labels. Any chance the amp could behave if the voltage selector is really in the 230V position and I plug it into 115V? Here is an image of the RSP-1 voltage selector (on mine the switch is in the opposite position but it reads 115 on the switch itself). If the image does not show, right-click and open it in new tab. I HATE those switches! It is remotely possible that the switch was installed UPside Down.....so the labeling on the amp does not match that on the switch? I see 2 screws for the switch, so I may be 'flippable' and still work, but the switch and amp enclosure labels no longer agree.... This is a 100:1 LongShot ... at least! If your switch is upside down relative to the image you provide? I think the 115 or whatever will be read from the OTHER side of the amp.....I'm not phrasing this right! I actually makes sense, but alas, nothing works in the other position so they just used reverse polish notation. Emotiva provided me with the schematics, I'll try to find a local technician who doesn't charge a fortune for a quick diagnostics. |
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Post by 405x5 on Jan 19, 2023 11:08:51 GMT -5
Your new amplifier is waiting patiently in the wings!
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Post by 405x5 on Jan 19, 2023 11:12:07 GMT -5
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Post by leonski on May 2, 2023 0:57:39 GMT -5
First guess is capacitors are no longer functioning well. PS capacitors DO dry out after years just sitting...... You have nothing to lose by pulling the cover and giving it a good look. The big PS caps should not bulge or leak. I any of them do, replace ALL. Fuses? Remove fuses (or pull UP one leg if clipped to a board) and actually check with a meter. They can fail right AT the cap and be invisible to a casual scan. Low value caps? These can fail and unless you have good vision, you just can't tell...... Link to a meter available had Home Despot. While is it 35$ or so? I wouldn't go cheaper. This appears to be a good meter and is a KLEIN, a known name...... You might be able to spend a little more and get a Fluke..... |
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