Clare Megga

[Mr Clock]

Has anyone any info on a vintage Clare megga.It looks pretty simple. I need to change the PP4 battery terminals to PP3. Wondering wether to put two PP3's in parrallel. See pics. Andy.

[Steve_P]

Don't know the model. but 2 x PP3's in Parallel should do fine. Blue is Negative, Brown Positive.

If space is a problem. then just one would probably do.

The PP4 and PP3 are both 9v Batteries...

http://www.smallbattery.company.org.uk/sbc_226.htm

Cheers,

Steve P.

[AlanBeckett]

I can honestly say that in 60 years of looking inside electronic gear I've never seen one built like that.
What's the terminal voltage on the high and low ranges?
The scales look useful though.

Alan

[Joe]

I know what you mean, Alan. If we hadn't seen the front view we'd have been thinking "Homebrew."

- Joe

[Andrewausfa]

Crumbs. I saw this for sale in its leather case and it looked interesting but as Alan and Joe have said, not quite what one expected once the back's off!

I did have a look at the time for info but nothing came up.

Andrew

[Mark R]

Blimey, I have never seen the inside of a piece of test equipment like that, scary stuff.

cheers Mark

[Mr Clock]

Thanks Steve,I checked them out for PP4's -out of stock. Be cheaper in the long run to convert to PP3. Alan, I,m not sure what the terminal voltage is, I,ve only checked for meter movement. Do you mean connecting the megga leads to a DVM and reading the voltage? Yes it is funny old bit of kit. Apart from the casing,the buttons are a bit cheap and crappy. I also have never sean anything electronic built like it. But as it cost me about a tenner and i mostly want to use it to test leaky caps and the odd insulation test,I thought it was worth it. It looks like its never been used. Andy.

[Skywave]

I reckon that that is a home-brew rebuild. Probably brought about by the original pcb having deteriorated to the point where it was simply unrepairable: it might have suffered a total burn-out. Clare are a manufacturer of quality test equipment - I don't think I need say any more.

Al.

[AlanBeckett]

Do you mean connecting the megga leads to a DVM and reading the voltage?

Andy,

Yes, that's what I meant. It's good to stress for example Capacitors at a reasonably high voltage to check for leakage.
I have a few Meggers which do that. There's a hand cranked 'Wee Megger' which will give you a nasty belt. I've also got a BM10 and a couple of battery Meggers which generate a high voltage via an inverter. I would guess that's what the transistors in yours do.

Alan

       

[Mr Clock]

Heres some more pics. I,m really puzzled by this megga. It has a substantial bakelite case which you would find on reasonble test equipment ( a tad under 1/4"-4mm thick)but with sub standard switches and wierd construction.

It looks like it was supposed to have a magic eye valve,though I,m not sure if there would have been the space for a valve. Its been replaced by four neon bulbs, these dont light up. I,m not familiar with meggas so a little in the dark as to their purpose.

From your replys and what I,ve seen, this isnt a well made megga. But I,ll try and replace the dodgy switches and if its good for testing leaky caps,I wont be too down hearted. Just a thought. Perhaps it has such a heavy case is to give the impression of quality. Bakelite being cheaper than components in the 60's?. All components seem to be RS,not sure from when. Andy.