neonmagic

Valve amp questions...

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OK, an update and it's not good news I'm afraid.  

Neither Cyber 845 monobloc will seemingly power up.  I plugged One of them into a different power board, nothing.  I plugged a small desk fan into the original power board and it powered on straight away.  

So...this leads to more questions on my part...

given that they haven't been powered on for a few years, would the valves perhaps take several minute before they'd start go glow?  (I don't think so).  

It's possible that the fuses have gone (both of them though, what are the odds of that!).  What do you guys think?

Should I test the fuses for continuity, to see if they are still good?  How do I tell which end of the fuse is positive and negative?  I do have spare fuses for them (bought them tonight).  

I guess I should swap out the AC power cord to eliminate the current AC cords, but what are the odds of both AC power cords failing...I suspect I'd have a far better chance of winning 1st price in Lotto than that happening!

Is there a way to test the valves themselves (E88C and 5687 and 845) via their connection pins to see if they have a fault using my voltmeter?  If so, how?  I''d need very specific instructions on how to do this for all 3 valve types, images best (dummy here!).  

Speaker cables for both amps are firmly plugged in at both the speaker and 845 amp ends.  Interconnects from monoblocs to preamp are also plugged in.  So, there should be a load presented to the amps.  

edit: all valves seem to be seated correctly - just triple checked tonight.

Some extra information on the power issues that occurred at my house - neither 845 unit was powered on when the power failed.  A fuse blew at the electrical box, as well as the safety switch.  Both had to be replaced by an electrician, but One of the 2 safety switches was turned off by the electrician as something was causing the safety switch to short (i..e a short somewhere in the house that ultimately led back to the safety switch in question).  No other devices in the household were damaged by this power failure.  I would find it odd that only the 2 845 amps were damaged by the power failure, even though they weren't on, and nothing else was damaged.  Again, that'd be akin to winning Lotto imho...edit: this issue left half the house without power - power from the street terminated to 2 of the safety switches, each of them powering roughly half of the house and One of them (the problematic One) was turned off by my electrician.  Guess who's half it affected...as it didn't affect anything that my late mum used, she refused to get the problem seen to by an electrician, and I was not working, so couldn't afford to do so myself.  Nor should I have had to do so, since I did not own the house.  Since then, my mum passed away, and the electrical problem was looked at in January 2018 and the issues identified that caused the power issues.  There was 2 years of non usage of said amps between the original issue and January 2018 when the issue was identified and fixed.  Yes, I know I should have gotten them up and running back in January 2018...I'm a procrastinating guy at the best of times...

As you can imagine, this is rather upsetting...

Edited by neonmagic

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DO NOT TRY TO TEST AN 845 VALVE USING YOUR VOLTMETER, THERE IS 1200 VOLTS DC ON THE VALVE BASES AND IT WILL KILL YOU IF YOU GET IT WRONG.

Where in the country are you so that we can suggest an engineer local to you that can help?

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1 minute ago, wizmax said:

DO NOT TRY TO TEST AN 845 VALVE USING YOUR VOLTMETER, THERE IS 1200 VOLTS DC ON THE VALVE BASES AND IT WILL KILL YOU IF YOU GET IT WRONG.

Where in the country are you so that we can suggest an engineer local to you that can help?

If I unplug the 845 valve from the amp, surely it is safe to test the pins on the base of the valve itself?  I wouldn't be trying to test the amps actual circuity (I'm not that stupid lol!).  If there is no power provided to the 845 valve, and it is not plugged into the amp, how can it be dangerous?   

I'm in Australia, but I am not working and there is zero chance of me being able to afford for an engineer/tech to look at them...

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As wizmax says, DO NOT try and check these amps with your meter. It is apparent that you do not have the expertise to do this and it is likely you will come to harm. I realize it's unfortunate that you can't afford to get them repaired but it's better to be without hifi rather than DEAD!

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Provided the amplifier is connected to the mains the lethal voltages will be on the valve base pins. Even when the amplifier is not connected to the mains the current stored in the reservoir capacitors can still give you a shock. 

Keep well away.

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OK...let me try to clarify...if I unplug the 845 valve from the amp and it is standing alone (the actual 845 valve itself), by itself, where does it get any power (AC or DC) to present an issue?  This doesn't make sense to me.  This is like me unplugging a kettle's AC cord from the power point and testing the pins for continuity...sorry, but I'm just not seeing logically how a valve that's got no power going to it can present a health issue?

I'm well aware that if the amps are connected to mains power, but turned off, there is still an electrical hazard.  

I'm well aware that caps store energy, even for a particular time after being powered off.  

I've been building my own computers for 20+ years without issue.  

Edited by neonmagic

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The capacitors can store energy for quite some time and even though you might have disconnected the mains supply you can still get a substantial shock. A kettle doesn't have any caps or other components that can store electricity so once a it is disconnected from the mains supply it is safe to work on. I really don't think you have the ability to solve the problem as you say that you don't know which is positive or negative of a fuse, that says it all. If you insist that you want to check them out then you must make sure that you have removed the power cables and that the storage capacitors are fully discharged

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Fess up time, I have misread your intention, I thought you were going to test the valve socket. 

You can not test a valve with a multimeter.

Sorry for the confusion.

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Super Wammer
56 minutes ago, neonmagic said:

If I unplug the 845 valve from the amp, surely it is safe to test the pins on the base of the valve itself?  I wouldn't be trying to test the amps actual circuity (I'm not that stupid lol!).  If there is no power provided to the 845 valve, and it is not plugged into the amp, how can it be dangerous?   

I'm in Australia, but I am not working and there is zero chance of me being able to afford for an engineer/tech to look at them...

OK, so, it is one thing at a time.

I am taking it that both amps are completely dead. There is little point in trying to check things like heater continuity with the valves in this sort of situation, especially as you are not in your comfort zone doing this. Also, I doubt it would bring extra info to the party as it is more likely that the mains fuses gave blown if everything is completely dead. Is it likely that both monos fuses have blown at the same time? No, but it is not impossible especially if you had a power surge.

Can you access the fuses to check their continuity with your new meter? Re your question earlier, fuses do not have positive and negative so that does not matter.

In Australia do you have fused plugs like we have in the UK or are the only fuses in the amps?

Oh, I know you wouldn't do it but do not ve tempted to see if there is any voltage on the valve sockets. As has been said it could be over 1000v and could be live for a long time after the amp is powered down. You should easily tell if the amp is powering up just by looking and listening.

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Did you notice when you powered them up if the small signal valves were active, if not then I would suggest that you check for continuity of your power cords. If they have no fuses then it's possible that there are fuses in the IEC connector on each amplifier, if so then remove and test them for continuity also

Edited by mr.me

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Image result for Opera Consonance Cyber 845 monoblocks

If they are the same as these then it looks as though there is a fuse draw located below the IEC connector

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1 hour ago, wizmax said:

Fess up time, I have misread your intention, I thought you were going to test the valve socket. 

You can not test a valve with a multimeter.

Sorry for the confusion.

All good.  I would have thought it'd be possible to somehow test continuity via the valve pins (I'd need to know which pin outs are what, etc of course, which I don't).  

I would NEVER even remotely try to attempt to diagnose the innards of the amps themselves.  No sir.  I might be a bit dense, but I am not that stupid!

27 minutes ago, Fourlegs said:

OK, so, it is one thing at a time.

I am taking it that both amps are completely dead. There is little point in trying to check things like heater continuity with the valves in this sort of situation, especially as you are not in your comfort zone doing this. Also, I doubt it would bring extra info to the party as it is more likely that the mains fuses gave blown if everything is completely dead. Is it likely that both monos fuses have blown at the same time? No, but it is not impossible especially if you had a power surge.

Can you access the fuses to check their continuity with your new meter? Re your question earlier, fuses do not have positive and negative so that does not matter.

In Australia do you have fused plugs like we have in the UK or are the only fuses in the amps?

Oh, I know you wouldn't do it but do not ve tempted to see if there is any voltage on the valve sockets. As has been said it could be over 1000v and could be live for a long time after the amp is powered down. You should easily tell if the amp is powering up just by looking and listening.

If someone explains to me how to test the heater continuity on the valves themselves (NOT the amps!!!!) and does some in a clear and concise manner, I think I could follow the instructions.  

Both units would have been plugged into mains, but not powered up when the power failed.  There's prolly another 30 items that were plugged into AC mains at the same time and not a single One of those items died.  Surely, I'd have be very unlucky to have both amps die!  

Yes, I can access both fuses in the amps and test them with my voltmeter - but it is near midnight here now in Australia and time for bed.  I will test them sometime tomorrow.  Our AC power cords typically do not have fuses in them.  I do have spare AC power cords, so I can swap them over (process of elimination).  

I come from a long background in IT, so I am a rather logical person, used to logic troubleshooting.  

The amps are dead.  No hum.  No glow from either the 845, 5687 or E88CC valves (although the latter 2 are typically very faint).  

What are the odds of just the 2 power outlets on the power board that the amps connect to dying (and the other 3 outlets still being good)?  I did not swap the plug into another outlet on said power board, but probably should do this just to make sure.  I will also try another power board tomorrow.  

16 minutes ago, mr.me said:

Did you notice when you powered them up if the small signal valves were active, if not then I would suggest that you check for continuity of your power cords. If they have no fuses then it's possible that there are fuses in the IEC connector on each amplifier, if so then remove and test them for continuity also

Yes, that is the plan that I had decided upon.  I will (tomorrow):

a) swap power board with a new and unused unit

b) swap AC power cord with a new and unused unit

c) test fuse for continuity

d) swap fuse with a new 5am slow blow fuse that I purchased earlier tonight

I was very gentle with the big 845 valves when cleaning them, as to avoid (as much as possible) any jolting that may potentially damage the innards of the 845s.  Still, it is possible that both were somehow damaged, despite my best attempts to be very gentle.  As I understand it, if the 845 valves are dead, then the circuit will not be complete and the 2 driver valves will not power up and glow.  

8 minutes ago, mr.me said:

Image result for Opera Consonance Cyber 845 monoblocks

If they are the same as these then it looks as though there is a fuse draw located below the IEC connector

Yes, the rears of the amps are identical between the original 845 units and the newer 845S units.  The above images are of the newer 845S units btw.  I can most certainly slide out the fuse holder(s).  

Give that I now know that fuses don't have a +/-, it is logical to assume that it does not matter which way you put the fuse in the fuse holder.  

Many thanks for everyone's replies, greatly apprecated.  

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I'll just add that apart from my pet rats, I have had on and off again issues with wild mice in my room (it's impossible to stop them from entering my room).  I haven't seen a mouse in my room in 14 months though.  I guess it is possible that they could have gotten inside the amps (I am not sure if the base/bottom of the units is sealed or open or not).  Rodents tend to go for cables that have live power going through them (they can sense the electrical field).  If there was no power going to said amps, they wouldn't touch internal cables etc (no electrical field to attract them).  

The One pet rat that does get onto the floor to free range, has only been doing so for the past Six months, and I watch her like a hawk when she is on the floor.  She gets onto the top of the amps, but I have never seen her try and get under the amps (there's not enough clearance for her to do so anyway - she's a fatty lol!).  

Both amps worked up to the night of the power failure (I had them on and working a few hours before the power failure occurred, without issue).  

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OK...just tested One the fuses with my voltmeter, and checking to make sure that I tested it correctly.  

Red probe lead to Positive terminal on voltmeter.

Black probe lead to Common terminal on voltmeter.

Set the unit to "buzz" (which as far as I understand, is for testing continuity)

put One probe on One end of the fuse, and the other probe at the other end.  

Is this correct?

When I do this, my voltmeter buzzes, which as far as I understand, means continuity, i.e. the circuit is unbroken, i.e. the fuse is AOK.  

I have not checked the other fuse (yet), but if this fuse is AOK, and said amp doesn't power up, then logic would dictate that it's not the fuse at issue, and testing the other fuse is probably pointless.  

Since I am still up, I might as well go and test and swap the power board and AC adaptor and see what happens.  

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