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 Post subject: Help, do you think this meter has original finish?
PostPosted: Apr Sun 20, 2003 3:08 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 258
Location: Redmond, WA, USA
It just arrived today, and it has a black wrinkle case, with a silver wrinkle face. It's not silver hammertone, but possibly silver wrinkle, or silver over black wrinkle. I would love to determine if these meters had a silver face like this.<BR> <A HREF="http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2167674804" TARGET=_blank>http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2167674804</A> <P>Also, note it has no rectifier (per-se), and no power transformer. It has a resistance line cord (which is no good), and no line isolation either.<P>Looks like there is a handy spot on the back of the front panel to mount a filament/isolation transformer though.<BR>


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 Post subject: Help, do you think this meter has original finish?
PostPosted: Apr Sun 20, 2003 3:47 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 37195
Location: Livermore, CA
Hi<P> Are you sure someone didn't take parts from a meter and make their own? <P> How can you use a VTVM that isn't isolated from the line?<P>------------------<BR>Norm


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 Post subject: Help, do you think this meter has original finish?
PostPosted: Apr Sun 20, 2003 4:10 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 258
Location: Redmond, WA, USA
I don't know Norm, it looks commercially made, perhaps it was assembled as a kit though, the wiring isn't very neat. It looks as though it could have been used as part of a mail order training course.<P>As for how do you use a VTVM that isn't isolated from the line? Very very carefully I guess. :-)<P>I have some Stancor 6-12 volt 1-2 amp. transformers with dual primaries. With only 300 mA load on the 6 volt vindings, I could probably use one of the primaries as a poor man's isolated 120 volt winding. <P>This is obviously a really cheap piece of test gear, but it might be fun to get it working (safely). It has scales for voltage, current, resistance, capacitance, inductance, and even dB. I'll that bet the accuracy (or lack of same) is downright awesome. The meter scale and the selector ranges seem to match. The meter scale has a lot of fine detail.<P>------------------<BR>


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 Post subject: Help, do you think this meter has original finish?
PostPosted: Apr Sun 20, 2003 6:14 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 30698
Location: Pocasset, Cape Cod, MA
I would put that at 1936, give or take, and I expect the silver is original. It's the sort of thing I'd expect to see in a Lafayette catalog, but I checked 1935, 36 and 37 without success. The first Radio Craft ad I noticed was in Dec. 1936 but that was tiny, with no illustrations, and that model wasn't noted.<P>As far as line isolation goes, the AC/DC radio chassis of that day were hot anyhow, so what's the difference if the VTVM was too? I suppose you were expected to plug it in the right way around.<P>------------------<BR>


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 Post subject: Help, do you think this meter has original finish?
PostPosted: Apr Sun 20, 2003 6:35 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 258
Location: Redmond, WA, USA
Well Alan,<P>I guess you had a 25 percent chance of getting both plugs right, and a 50 percent chance of blowing a fuse. In those days, you probably would have blacked out the room as well.<P>Alan, if you find any kind of ad or catalog mention, or if anyone finds a schematic, I would sure appreciate a scan of it.<P>Interestingly enough, the brand name Superior Instrument Co. on the front panel looks to me like a knockoff of the Supreme Instrument Co. style.<P>For those with broadband (or lots of patience), here are a couple of closeups of the meter scale and function selector (aprox. 259k each).<P> <A HREF="http://ec-magic.com/allmeter.JPG" TARGET=_blank>http://ec-magic.com/allmeter.JPG</A> <BR> <A HREF="http://ec-magic.com/allmeter-sel1.JPG" TARGET=_blank>http://ec-magic.com/allmeter-sel1.JPG</A> <BR> <A HREF="http://ec-magic.com/allmeter-name.JPG" TARGET=_blank>http://ec-magic.com/allmeter-name.JPG</A>


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 Post subject: Help, do you think this meter has original finish?
PostPosted: Apr Thu 24, 2003 9:18 pm 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 3162
Location: Cockatoo, Victoria, Australia
That's an interesting meter, sure has a lot of functions squeezed out of little. I guess it only worked on DC supply. One oddity, the low resistance range reads in reverse. The M will indicate thousands (of ohms), not Meg ohms. It would be interesting to see a schematic. Since it seems to be original you should be able to trace it out easily. if you do that, can you post it for us to see please. Nice photos.<BR>Don Black.<P>------------------<BR>


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 Post subject: Help, do you think this meter has original finish?
PostPosted: Apr Thu 24, 2003 9:52 pm 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 1025
Location: Yardley, Pennsylvania
A quick search came up with Superior TV-60 Allmeter Multimeter. <A HREF="http://www.w7fg.com/manuals.php?find=S&page=2" TARGET=_blank>http://www.w7fg.com/manuals.php?find=S&page=2</A> Just a WAG but also thought it may use a DC supply. I don't see any type or rectifier or power supply. Battery operation would give you the best isolation. Perhaps designed to be powered off the same battery that powers the radio? Could the full scaler adjustment be meant to adjust the meter to the battery B+ voltage. <P>Paul<P>------------------<BR>


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 Post subject: Help, do you think this meter has original finish?
PostPosted: Apr Fri 25, 2003 2:47 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 974
An ad in the August '38 Radio Craft shows a restyled version with a rectangular meter, but the backgrounds are black and silver (presumably) in the same places. The copy doesn't say that it's a VTVM, but does give the power consumption as 6 watts, and also says it has a "0-1 d'Arsonval meter". So it probably has a 1000 ohm/volt meter, and the tube is just for a measurement oscillator.<P>------------------<P>


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 Post subject: Help, do you think this meter has original finish?
PostPosted: Apr Fri 25, 2003 4:01 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 30698
Location: Pocasset, Cape Cod, MA
We're getting closer. The first ad for it is in June 1937. Looks just like yours, cost $10.40, and says it runs on AC or DC (but the capacitance range only works on AC). I could mail a xerox.<P>------------------<BR>


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 Post subject: Help, do you think this meter has original finish?
PostPosted: May Tue 06, 2003 7:11 am 
Member

Joined: Jan Thu 01, 1970 1:00 am
Posts: 258
Location: Redmond, WA, USA
Many thanks for the copy of the ad, Alan. Now I know for sure the silver wrinkle front is original.<P>After further investigation, the 6A7 tube is connected as a diode, believe it or not. And aside from the 6A7 filament, the AC line is capacitively coupled to the rest of the circuit, one side with .25 uF, and the other with 1.0 uF.<P>Unfortunately the function switch looks like it has had a major rewiring, almost like a whole deck was moved. The chance of finding a schematic, and the limited usefulness of a meter like this has led me to a decision. This piece of gear will be for display only. The 'fan' shaped meter makes it look pretty old and interesting.<P>------------------<BR>


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