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ohm meter battery

On Thursday, March 20, 2014 12:16:03 AM UTC-4, snipped-for-privacy@gmail.com wrote :

lt battery in a VTVM. I have an RCA WV98C Senior Voltohmyst VTVM that is in perfect condition but doesn't get used very often. This battery retrofit c ircuit takes power from the 6.30 volt filament transformer and is built aro und an LM317. With a trim pot you set it for 1.55 volts and you never have to change a battery again. It also needs to occupy an area no larger than t he battery presently does.

s going to leak and rot the inside of the unit. I was going to build the ci rcuit but it occurred to me that I should probably be concerned about the c urrent that the LM317 will be dissipating when the meter is used on the low ohms range. Does anyone have a feel for the size that an adequate sized he at sink should be in order to handle this? Thanks, Lenny

I do own several digital voltmeters and they do have their place. You can't beat a digital for making precise measurements. But there is a bit of a se ntimental value here too. I built this meter from a kit when I was a kid in 1963. Since then I've repaired a lot of TV sets and other things with it o ver the years, and although I don't use it much anymore it's nice to still be able to when the need arises. So just where the hell do you come off ins ulting me?

I'm just curious now. Did you ever try to peak or null a circuit with a dig ital? It's a pain in the ass. How about looking for a change in logic state ? I prefer seeing an immediate change rather than watching a decay. Why don 't you try going on the grid of a tube with a low impedance meter and see w here that gets you? Mine has an 11 meg ohm impedance. It won't load a vacuu m tube circuit. So much for my piece of shit meter, huh?

But I have a better idea Trevor. Why don't you take your prize digital you' ve raved about and stick it in your ass? That way you'll never lose it, and it will always be available. Lenny

Reply to
captainvideo462009
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Unless it's a Duracell!

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Reply to
dave

I have had both Energiser and Duracell 9 volt batteries leak. Inside there are multiple cells thinner than a AAA battery. Usually the liquid oozes up through the terminals which destroys the battery plug.

Reply to
chuck

On Thursday, March 20, 2014 12:16:03 AM UTC-4, snipped-for-privacy@gmail.com wrote :

lt battery in a VTVM. I have an RCA WV98C Senior Voltohmyst VTVM that is in perfect condition but doesn't get used very often. This battery retrofit c ircuit takes power from the 6.30 volt filament transformer and is built aro und an LM317. With a trim pot you set it for 1.55 volts and you never have to change a battery again. It also needs to occupy an area no larger than t he battery presently does.

s going to leak and rot the inside of the unit. I was going to build the ci rcuit but it occurred to me that I should probably be concerned about the c urrent that the LM317 will be dissipating when the meter is used on the low ohms range. Does anyone have a feel for the size that an adequate sized he at sink should be in order to handle this? Thanks, Lenny

Besides the things I've already mentioned regarding digital vs. analog, I'v e tried checking transistors and diodes with a digital, and I suppose that you can do it but perhaps it's because I've been doing this all my life wit h something like a 260, trying to do this with a digital drives me nuts. An d Trevor you asked how you insulted me. You referred to my meter as a "piec e of shit". You've never used it nor have you ever seen it. So where the he ll did that come from? You may have your own opinions but there was no reas on for that comment. Lenny

Reply to
captainvideo462009

I'm not sure that's relevant: the alkali (usually potassium hydroxide) will have corroded the aluminum, and you cannot dissolve the corrosion!

There's a few options for removing batteries in this situation, including lathe-and-boring-tool, but I'd trash the flashlight.

Reply to
whit3rd

On Thursday, March 20, 2014 12:16:03 AM UTC-4, snipped-for-privacy@gmail.com wrote :

lt battery in a VTVM. I have an RCA WV98C Senior Voltohmyst VTVM that is in perfect condition but doesn't get used very often. This battery retrofit c ircuit takes power from the 6.30 volt filament transformer and is built aro und an LM317. With a trim pot you set it for 1.55 volts and you never have to change a battery again. It also needs to occupy an area no larger than t he battery presently does.

s going to leak and rot the inside of the unit. I was going to build the ci rcuit but it occurred to me that I should probably be concerned about the c urrent that the LM317 will be dissipating when the meter is used on the low ohms range. Does anyone have a feel for the size that an adequate sized he at sink should be in order to handle this? Thanks, Lenny

I finally found the Website where I originally found the circuit. I liked t he second schematic. It's isolated from chassis ground. Here's the link:

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Reply to
captainvideo462009

Lye will dissolve the corrosion. Too bad it will dissolve the flashlight too. Eric

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Reply to
etpm

Trevor Wilson scribbled thus:

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There is no way that I will give up using my AVO8...

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Reply to
Baron

Yeah, I'd missed the aluminum body bit. Unless this is a collectable flashlight is should be binned...

John :-#)#

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Reply to
John Robertson

My experience is either Duracell or Everready alkaline batteries will leak. This is based on batteries that were stored in circuit in arcade games (pinball and video) since 1980 that I subsequently opened, serviced, serviced and then sold between 2004 and 2011.

Some leaked, most did not. I have lots of pictures...somewhere.

John :-#)#

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(Please post followups or tech inquiries to the newsgroup) 
John's  Jukes Ltd. 2343 Main St., Vancouver, BC, Canada V5T 3C9 
(604)872-5757 or Fax 872-2010 (Pinballs, Jukes, Video Games) 
                      www.flippers.com 
        "Old pinballers never die, they just flip out."
Reply to
John Robertson

For what it's worth...

More than a decade ago I bought four toy "Insecto Bots", new. They came with three AAA alkaline cells installed, from some totally unknown manufacturer.

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I'd opened them a few times to check, and the cells had not leaked. They still powered the units, though a bit weakly. The other day I finally discarded them. There were no signs of leakage.

Yes, cells leak, and yes, Duracell seems more likely to leak than others, and yes, I've had leaking cells on rare occasions. But why some people here have had such terrible experiences, I don't know.

If it'll make you feel better... About ten years ago I bought a box of 1000 AAA Polaroid cells on eBay. They're wrapped in pairs, in cellophane. About a quarter of them have leaked, producing a powdery deposit.

Reply to
William Sommerwerck

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