Bang, but then it works!

[Diver300]

I recently dug out an old Video8 camcorder, to transfer some 10 - 20 year old tapes to DVD and to hard disk. It's a Sony CCD-TRV11E PAL, if that makes any difference.

The power supply for it is a Sony AC-V16, UK spec, that came with it. The power supply is huge by modern standards, and has a switch on it to switch between using the camcorder and charging the battery. It's rated at 110 - 240V, 50/60Hz, 20W. The output is 7.5V 1.8A to power the camcorder or 10V 1.1A to charge the battery. It has a BS1363/A (standard UK) plug with a 5A fuse, made by Hitachi, moulded onto the cable. The cable is two core.

Anyhow, the battery is almost certainly dead by now, so I was going run the camcorder directly from the power supply. I had the camcorder plugged into the power supply, and I plugged the power supply into a 6-way adaptor (US speak - "powerstrip").

There was a flash and a bang, and half the house went dead.

The damage was the 13 A fuse in the plug for the 6 way adaptor, the 32 A breaker for that part of the house had tripped, and there is a burn mark on one of the pins of the power supply plug.

The 5A fuse in the power supply plug didn't blow. The ELCB (US speak "GFI") didn't trip.

When I had replaced the fuse in the 6-way adaptor and reset the breaker, I went and plugged the power supply into a different circuit, with no 6-way adaptor, directly into the wall.

It worked fine. The power supply also worked fine when plugged back into the 6-way adaptor.

Anyone got any idea what happened?

 

[Diver300]

After posting, I was thinking that I must have missed something.

I looked inside the camcorder power supply. There's a 1.5 A fuse, obviously OK, and no visible damage.

So I opened up the 6-way adaptor. The photos speak for themselves, really.

What I think has happened is that the live bus is quite close to the neutral one. The shutter is the red bit that stops anything contacting the live and neutral connectors unless something if first pushed into the earth socket. The shutter slides from the neutral socket to right over the live bus. Some debris, a strand of flex left over from manufacture maybe, got dragged from the neutral to the live bus.

The two photos wth the red bit shown over the connectors are with it in its open and closed positions.

So there was nothing wrong with the camcorder power supply that hadn't been used in years. It just happened to be the thing that I plugged in the time the 6-way adaptor, that is in use all the time, shorted.

 

[Hero999]

I recently dug out an old Video8 camcorder, to transfer some 10 - 20 year old tapes to DVD and to hard disk. It's a Sony CCD-TRV11E PAL, if that makes any difference.

The power supply for it is a Sony AC-V16, UK spec, that came with it. The power supply is huge by modern standards, and has a switch on it to switch between using the camcorder and charging the battery. It's rated at 110 - 240V, 50/60Hz, 20W. The output is 7.5V 1.8A to power the camcorder or 10V 1.1A to charge the battery. It has a BS1363/A (standard UK) plug with a 5A fuse, made by Hitachi, moulded onto the cable. The cable is two core.

Anyhow, the battery is almost certainly dead by now, so I was going run the camcorder directly from the power supply. I had the camcorder plugged into the power supply, and I plugged the power supply into a 6-way adaptor (US speak - "powerstrip").

There was a flash and a bang, and half the house went dead.

The damage was the 13 A fuse in the plug for the 6 way adaptor, the 32 A breaker for that part of the house had tripped, and there is a burn mark on one of the pins of the power supply plug.

The 5A fuse in the power supply plug didn't blow. The ELCB (US speak "GFI") didn't trip.

When I had replaced the fuse in the 6-way adaptor and reset the breaker, I went and plugged the power supply into a different circuit, with no 6-way adaptor, directly into the wall.

It worked fine. The power supply also worked fine when plugged back into the 6-way adaptor.

Anyone got any idea what happened?

The large electrolytic reservoir capacitor in the might've become depolarised. The first time you powered it, the capacitor shorted the mains and drew a huge current which repolarised it. The second time, the capacitor had been repolarised and restored to a working condition so there wasn't a problem.

Why do you need a camcorder to transfer old tapes to DVD?

Can't you just connect a VCR to a DVD recorder?

 

[Hero999]

After posting, I was thinking that I must have missed something.

I looked inside the camcorder power supply. There's a 1.5 A fuse, obviously OK, and no visible damage.

So I opened up the 6-way adaptor. The photos speak for themselves, really.

What I think has happened is that the live bus is quite close to the neutral one. The shutter is the red bit that stops anything contacting the live and neutral connectors unless something if first pushed into the earth socket. The shutter slides from the neutral socket to right over the live bus. Some debris, a strand of flex left over from manufacture maybe, got dragged from the neutral to the live bus.

The two photos wth the red bit shown over the connectors are with it in its open and closed positions.

So there was nothing wrong with the camcorder power supply that hadn't been used in years. It just happened to be the thing that I plugged in the time the 6-way adaptor, that is in use all the time, shorted.

There you go, that's obviously the problem.

I really hate the way the forum software doesn't warn you when someone else has posted before you press the submit button.

 

[3lectrokid]

that happend to my extension lead when i used it to power my laptop. i plugged the power supply into the extension lead and it went bang. however it worked later on that day when i had the guts to try it.

 

[Nigel Goodwin]

There you go, that's obviously the problem.

I really hate the way the forum software doesn't warn you when someone else has posted before you press the submit button.

Silly thing to say, how could it?.

 

[Hero999]

Silly thing to say, how could it?.

Easily, lots of other forums I use do it, the algorithm is simple.

When a user views a page record the number of posts in a thread.

When the user presses the reply button, check to see that the number of posts is the haven't increased before their post is added.

If someone else has posted, display a message warning them that other replies have been made whilst they were editing their reply, take them back to the editing page, where they can see the updates to the thread and make amendments if they wish.

Go back to the beginning.

 

[Diver300]

Why do you need a camcorder to transfer old tapes to DVD?

Can't you just connect a VCR to a DVD recorder?

They are Video8 tapes. I'm not using the camera bit of the camcorder, only the playback bit.

VHS players are common. I think we have 3 or 4, not that we have used any in ages. However Video8 recorders that aren't camcorders are rare, and they were never cheap.

 

[ParkingLotLust]

I seem to recall tape adapters, that you could put a Video8 tape into (for example - I dont recall exactly what format(s) they had), and you put that into a regular VCR.

 

[Nigel Goodwin]

I seem to recall tape adapters, that you could put a Video8 tape into (for example - I dont recall exactly what format(s) they had), and you put that into a regular VCR.

Sorry, your recall is faulty - the adaptors you're thinking of took VHS-C tapes and fitted a standard VHS VCR. It wasn't (and still isn't) possible to do that with Video8, it's entirely different, mechanically and in the way it's recorded.

 

[ParkingLotLust]

Ahh okay, my mistake!

 

[Diver300]

I've just had another fault like this. A very similar short, which blew the 32 A circuit breaker / ELCB. There is a significant flash mark near the neutral connector, and a mark on the live bus-bar that is just above that. The shutter would have moved from the neutral connector away from the live bus-bar, so I can't see how anything got to the bus-bar. However, there are various bit of conductive debris which could have caused it.

 

[JimB]

Just looking at your pics from 6 years ago (time flies when you are enjoying yourself!), I don't see that the strips actually touched each other.
Either there was some other conductive debris in the extension block, or the shutter has rubbed on the busbar and built up a thin film of conducting material which has vapourised and made a momentary short circuit between line and neutral.
Weird.

JimB

 

[Diver300]

Just looking at your pics from 6 years ago (time flies when you are enjoying yourself!), I don't see that the strips actually touched each other.
Either there was some other conductive debris in the extension block, or the shutter has rubbed on the busbar and built up a thin film of conducting material which has vapourised and made a momentary short circuit between line and neutral.
Weird.

JimB

I came to that conclusion as well. In the recent case there were similar marks on the neutral socket and the live busbar.

I think that the busbars should be away from the movement range of the shutters, or insulated. On both of these the plastic shutter is very close or touching both the socket and the other busbar. Obviously the shutter doesn't normally conduct, but it seems that can change.