Notifications
Clear all

Plunged into darkness!

 
sideband
(@sideband)
Famed V-Ratter Moderator
Posts: 3985

My workshop is in the loft and has been for around 10 years. It's not ideal and I keep meaning to improve the area but slightly hampered by the position of the water tank....builders never put these things where you would like them....

Anyway last night I was settling down for a spot of alignment (the Jason FM tuner recently bought for nostalgic reasons). I blew the dust off my Advance signal generator last used about a year ago and proceeded to connect the various items. It all started well and following the instructions in the Jason handbook I started with the 2nd IF transformer peaking up the modulated 10.7Mhz. Suddenly there was a click from the bench cut-out and everything went off except for the secondary lighting (which runs directly off the mains). I've had the bench cut-out randomly trip before so just reached over to reset it. Everything came back on and I was just about to start again (having allowed everything to warm up again after a couple of minutes) when the same thing happened. 'Damn cut-out' I thought...pressed it again and it all came back for a few seconds and failed again. I suspected that something might not be quite right and pressed it a third time......everything went off including the secondary lighting! Do you realise how dark it is in a loft with no lighting at all? I SHOULD keep the battery lantern up there for just such emergencies. The biggest problem is that whatever happened tripped the main circuit breaker and all the upstairs power and light was off so I couldn't even see the loft hatch......I know the layout of the loft well but in total darkness (and I mean TOTAL) it's a different matter!

I headed in the general direction of the hatch which means negotiating the large platform that holds the water tank and working your way through the eaves whilst trying not to put your foot in the wrong place (it's not all boarded.....)! Somehow I got through all that OK but still didn't quite know where the hatch was. Whilst groping about I touched a box with some papers in and knew that I was close (and what pipe is this I've just found....)? I then found my feet on solid ground so to speak and a few seconds later there was a reassuring clang as my foot touched the ladder. I then had to reach down and feel which way round I was in relation to the ladder. OK sorted....down we go........! 

I should add that this was at around 11:30 last night and everyone else was in bed....! Having descended the ladder with dim light filtering from the hallway I went downstairs to retrieve the battery lantern that I should have had with me...

First an examination of the consumer unit showed that the upstairs RCD had tripped. As the power in the workshop was off anyway I reset it and everything came back on. Reassuringly lit once again I then went back up into the loft and although the secondary lighting was back on I had the lantern with me. I just turned everything off and closed up shop for the night and will investigate later. Having thought about it since, I suspect it was the Advance generator that caused the blackout. It's rarely used and I suspect the mains filter components have seen better days. Like most of the older equipment it is only two-core mains but it was earthed via the Jason tuner and the headphone amp. Both the headphone amp and tuner have been used for long periods together. The only addition was the Advance. I shall investigate later!

One thing is certain, I'll keep the lantern up there in future. It's the first time I've been plunged into total darkness for 10 years but once was enough!

 

 

ReplyQuote
Topic starter Posted : 07/09/2019 8:35 am
Nuvistor
(@nuvistor)
Famed V-Ratter Registered
Posts: 4206

Glad you found your way to safely, I keep a couple of torches around the house plus the one on the phone which is never far away. 

Recollections of trying to find my way to the bathroom in the early hours when we had the three day week many years ago, stubbed toes and bad language.

 

ReplyQuote
Posted : 07/09/2019 9:11 am
Lloyd
(@lloyd)
Noble V-Ratter Registered
Posts: 1592

Oh dear! I used to have a similar problem in my old workshop, it was in a row of 1970’s garages with no windows, with the door shut it was pitch black in there, with only the faint glow of all the CRT’s for a few seconds after the lights go out. I bought myself an emergency light fitting that comes on in the event of mains failure, it was most useful! There were a number of times when the power went off for whatever reason and that light made it much easier and safer to find my way to the consumer unit, or just the door if it was a proper power cut. 

It became a little redundant after I installed solar powered lighting, I still have it in a box somewhere, but I guess the rechargeable battery is past it by now.

they are not too expensive, I think mine was only £11, and now there are LED ones which are brighter and the batteries last a bit longer.

 Regards 

Lloyd 

ReplyQuote
Posted : 07/09/2019 9:36 am
PYE625 liked
PYE625
(@pye625)
Famed V-Ratter Registered
Posts: 4998

It has happened to me and has made me think about installing an emergency light, something like this .....

index
ReplyQuote
Posted : 07/09/2019 9:39 am
Cathovisor
(@cathovisor)
Illustrious V-Ratter Registered
Posts: 5576
Posted by: @sideband

Do you realise how dark it is in a loft with no lighting at all?

Not in my loft - it has holes in the roof.

That aside, I have plans to put a skylight in the roof at some time despite it only being used for storage, but if I were to use it for other purposes (I've long thought about a nice vintage Hornby-Dublo layout up there as H-D stuff should stand the variations in temperature) I really would be thinking about a maintained light near the exit.

ReplyQuote
Posted : 07/09/2019 10:21 am
Boater Sam
(@boater-sam)
Reputable V-Ratter Registered
Posts: 422

Its good to keep your phone with you, then you have a light and if you have an emergency whilst alone you can get help too.

Sam.

ReplyQuote
Posted : 07/09/2019 12:00 pm
sideband
(@sideband)
Famed V-Ratter Moderator
Posts: 3985
Posted by: @boater-sam

Its good to keep your phone with you, then you have a light and if you have an emergency whilst alone you can get help too.

Sam.

Yes....but it was on charge downstairs. Good point though since I could have used the torch function.

ReplyQuote
Topic starter Posted : 07/09/2019 2:29 pm
sideband
(@sideband)
Famed V-Ratter Moderator
Posts: 3985

What surprises me most is that I was able to negotiate the somewhat awkward route back to the hatch in total darkness without stepping on anything important. I have boxes of bits and pieces around and of course there are pipes that I need to watch out for. The pipe I encountered is actually the overflow pipe from the tank so I instinctively knew that I was only feet from the hatch. Normally I miss the pipe when getting back to the hatch but having walked into it I realised I was too far to the left and then when I felt the firm floor underfoot I knew that I was almost there. 

Not something I wish to repeat. I'll be much more prepared in future.

Even more respect for blind people!

 

ReplyQuote
Topic starter Posted : 07/09/2019 2:41 pm
sideband
(@sideband)
Famed V-Ratter Moderator
Posts: 3985

Well I was right about the reason for the blackout. It was the Advance generator and a VERY leaky Hunts filter cap. The date in the generator is 1957 and I don't think they had such things a 'Y' caps in those days. The mains input consists of a filter choke and a couple of mica caps from neutral - earth and live - earth. The caps are 5000pF at 500V. There is no 'X' cap fitted. 5000pF is about the largest allowed for a Y cap and my stock only goes as far as 3300pF. They would have to do!

Fitting the replacement caps was easy and achieved by wiring them directly across the mains pins with an earth connection from the centre. Once this was done, there were no more drama's and the generator was once more working well and I was able to complete the alignment of the Jason tuner. I'll conclude that in the 'Jason' thread.

js1024 SAM 0024

 

The leaky capacitor

js1024 SAM 0026

 

Just over 1k!!

js1024 SAM 0030

The replacement Y caps fitted

js1024 SAM 0031

General view of the mains input and modulator section which I recapped a couple of years ago. 

I should have done the Y caps at the same time.

 

 

 

ReplyQuote
Topic starter Posted : 07/09/2019 9:33 pm
PYE625 liked
Cathovisor
(@cathovisor)
Illustrious V-Ratter Registered
Posts: 5576

Is that an Advance B4, Rich?

ReplyQuote
Posted : 07/09/2019 10:48 pm
turretslug
(@turretslug)
Honorable V-Ratter Registered
Posts: 528

I wonder if the "mica" capacitor is actually one of the paper-dielectric-encased-in-Bakelite types, like the infamous "Micamold" decouplers that plague US kit of the '40s? It looks rather like one of them. The well-known AR88 and BC348 receivers are afflicted with them and invariably need a prolonged culling session to get them to rights. 5000pF sounds the right ball-park for a Micamold type. (Possibly nowadays, they wouldn't get away with a name that implies that they're something that they aren't!).

ReplyQuote
Posted : 07/09/2019 10:58 pm
sideband
(@sideband)
Famed V-Ratter Moderator
Posts: 3985
Posted by: @cathovisor

Is that an Advance B4, Rich?

It certainly is! Ex Philips from around 1985 when they basically gave these away to anyone who wanted them. I've probably had it longer than Philips did......

ReplyQuote
Topic starter Posted : 07/09/2019 11:44 pm
sideband
(@sideband)
Famed V-Ratter Moderator
Posts: 3985
Posted by: @turretslug

I wonder if the "mica" capacitor is actually one of the paper-dielectric-encased-in-Bakelite types, like the infamous "Micamold" decouplers that plague US kit of the '40s? It looks rather like one of them. The well-known AR88 and BC348 receivers are afflicted with them and invariably need a prolonged culling session to get them to rights. 5000pF sounds the right ball-park for a Micamold type. (Possibly nowadays, they wouldn't get away with a name that implies that they're something that they aren't!).

Well I thought it was mica....it seems too small for a 500V paper type. I suppose it's done well considering its position in the circuit. Incidentally the second cap of this type was perfect. The bridge measured it as 4900pF. In size it reminds me of those old brown encased mica types with the three coloured dots.

ReplyQuote
Topic starter Posted : 07/09/2019 11:51 pm
Cathovisor
(@cathovisor)
Illustrious V-Ratter Registered
Posts: 5576
Posted by: @sideband

Well I thought it was mica....it seems too small for a 500V paper type

Hit it wiv an 'ammer.... you know you want to!

ReplyQuote
Posted : 08/09/2019 12:12 am
sideband
(@sideband)
Famed V-Ratter Moderator
Posts: 3985

I might crush it in the vice......!

ReplyQuote
Topic starter Posted : 08/09/2019 8:52 am
turretslug
(@turretslug)
Honorable V-Ratter Registered
Posts: 528

Come to think of it, if its brother did test out perfect, then they may well genuinely have been mica dielectric types. I'd put a (small!) wager on them both being badly leaky if they had been of the "Micamold" paper dielectric type, I'm not sure that I've ever come across one of these that wasn't leaky over 40 or so years of applying ohm-meters! Both the Eddystones here (670A and 750) had brown-case square 10nF capacitors as output stage grid couplers (referred to as "that" elsewhere) and with my jaundiced outlook on Micamold types, I removed and replaced with 630V polyesters. In fact, testing them (even under high voltage), showed them to be very high resistance so they may well have been genuine mica types. They certainly felt strangely heavy, possibly suggestive of mica rather than the Micamold's paper. Silver is also dense, though I don't suppose they put any more of that in than necessary! I don't regret changing them though as even tiny leakage can have a marked effect on anode current and as the two output valves concerned were the long-suffering UL41 and N78 types I wasn't going to give them a harder time than I could avoid. I gather that there is a silver migration syndrome that is becoming more prevalent in these once highly regarded types as the decades roll by.

This thread includes an advert that  implies that, even when new, Micamolds were acknowledged as a compromise component;

 

 

ReplyQuote
Posted : 08/09/2019 10:44 am
Red_to_Black
(@red_to_black)
Noble V-Ratter Registered
Posts: 1746

I second what a previous poster recommended, ie. fitting an emergency bulk head light at the exit point, these can be obtained from about a tenner these days, LED to boot, the only difference is I would probably make it non-maintained for SBs purposes.

ReplyQuote
Posted : 06/10/2019 4:44 pm
Terry
(@terrykc)
Famed V-Ratter Rest in Peace
Posts: 4018
Posted by: @turretslug

This thread includes an advert that  implies that, even when new, Micamolds were acknowledged as a compromise component;

All I can see there is a blurred image. The original is available here, on page 119 of the pdf and claims it as being a wartime economy. It makes interesting reading with phrases such as 'function satisfactorily', 'adequate alternates' and 'considerable economies'!

This is the July 1944 issue but nowhere can I find any reference to exactly when it appeared but someone was very quick of the mark placing the ad on page 5!

I like the reference on page 71 to waxed paper capacitors as "Drippers" but I don't think the cartoon on page 54 is in particularly good taste.

ReplyQuote
Posted : 07/10/2019 2:04 pm
turretslug
(@turretslug)
Honorable V-Ratter Registered
Posts: 528

Thanks for that interesting follow-up Terry- I assume that I'd failed to spot that the image posted in the Antique Radio Forums thread was an externally hosted one? It made for an absorbing browse- yes, the terminology in the ad was an excellent example of damning with faint praise! Especially in an era when ads tended to resort to hyperbole over the most mundane things and before regulators got real teeth.

I liked "drippers", too- very apt, and they were obviously recognised as prone to going leaky and warming up even then. As to the cartoon, I guess it was a time of strong feelings and widespread "trench humour", I've seen wartime cartoons that would make folk swallow hard and go rather quiet today with what is now seen as quite shocking racism and nationalistic prejudice. And that was just from the Allied side....

Colin

ReplyQuote
Posted : 11/10/2019 12:13 pm