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LITTLEWING

9v battery reversed polarity ?????

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Here's one for ya.....

I acquired a 31 year old Westone Thunder 1A a little while ago and as it sounded and played incredibly in passive mode, I never bothered about seeing how the active circuit sounded. (okay, there was a wire off one of the two battery connectors and I couldn't be arsed soldering it on again until recently...)
Anyhoo, I chucked two (admittedly different makes, one Duracell and one perfectly working one showing nearly 9v made by VMP whoever they are). Plugged in and all was sounding absolutely bleedin' awesome.
However, 2 weeks on at rehearsal I went to switch to active and it was dead as a dead thing, totally fine in passive mode. First thoughts were 'sh*t, I left it switched on and both batteries have died', so I took them out and tested them only to find the Duracell was showing 8.9v and the VMP wierdo was showing MINUS, yes MINUS 5.7v. Turning the test leads the opposite way showed 5.7v in normal 'plus' mode.

How the heck can a battery turn it's polarity backwards??? Is it because it's (probably) a foreign jobby and made cheap inside and couldn't handle pushing it's puny 9v with a proper Arnold Schwarzenneger type batt and just screwed itself ??

Right now I'm a bit loathe to put 10 quid's worth of Duracells in if there's a strange fault in the Westone circuitry.

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I'd be inclined to get a couple of supermarket own brand alkaline batteries and try those - won't be expensive and I reckon the active circuitry won't be that much of a drain anyway. The Duracell you have is still close to full charge so that's still usable. Did you put the VMP brand battery on the resoldered battery connector? If so then maybe there's a short there that affected it but I don't see how it could have gone into a negative polarity state (it'd need something pushing it that way after draining to nil charge and the only power source you have is the Duracell which hasn't drained). Bit of an odd one!

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If you see -5.7v instead of 5.7v then you've almost certainly got your DVM leads back to front.

The Thunder 1A uses an 18v supply, so the two batteries are wired in series.
That means that the cheapo battery will run out quicker than the Duracell and the whole thing, as you've found, stops working.

Best off replacing the batteries in matching pairs.

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[quote name='LITTLEWING' timestamp='1450733646' post='2935404']
Here's one for ya.....

I acquired a 31 year old Westone Thunder 1A a little while ago and as it sounded and played incredibly in passive mode, I never bothered about seeing how the active circuit sounded. (okay, there was a wire off one of the two battery connectors and I couldn't be arsed soldering it on again until recently...)
Anyhoo, I chucked two (admittedly different makes, one Duracell and one perfectly working one showing nearly 9v made by VMP whoever they are). Plugged in and all was sounding absolutely bleedin' awesome.
However, 2 weeks on at rehearsal I went to switch to active and it was dead as a dead thing, totally fine in passive mode. First thoughts were 'sh*t, I left it switched on and both batteries have died', so I took them out and tested them only to find the Duracell was showing 8.9v and the VMP wierdo was showing MINUS, yes MINUS 5.7v. Turning the test leads the opposite way showed 5.7v in normal 'plus' mode.

How the heck can a battery turn it's polarity backwards??? Is it because it's (probably) a foreign jobby and made cheap inside and couldn't handle pushing it's puny 9v with a proper Arnold Schwarzenneger type batt and just screwed itself ??

Right now I'm a bit loathe to put 10 quid's worth of Duracells in if there's a strange fault in the Westone circuitry.
[/quote]Its 'charged' from the Duracell, the 5.7V will only be there off load. Just bung a couple of pound shop alkaline PP3s in, betcha it works fine, dont be tight, theyre 2 for a quid round here.

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