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 Post subject: TRIPLETT 3423 DOESNT LOOK LIKE A 3423?
PostPosted: May Fri 01, 2020 9:15 pm 
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Joined: Apr Wed 08, 2020 7:21 pm
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I picked up a Triplett 3423 at an estate sale and for the life of me I am confused on what it really is. the unit looks different then other 3423's if googled but the meter says 3423. doesn't look like its been replaced but maybe its something else with a triplett meter? Any thoughts of what this baby is; would like to find a correct manual.

Thanks!!

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Mark AA7FY


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 Post subject: Re: TRIPLETT 3423 DOESNT LOOK LIKE A 3423?
PostPosted: May Sat 02, 2020 3:07 am 
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I have a 3423 and it looks nothing like mine, even the meter is different. Maybe an early version?


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 Post subject: Re: TRIPLETT 3423 DOESNT LOOK LIKE A 3423?
PostPosted: May Sat 02, 2020 4:09 am 
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Joined: Jan Thu 01, 1970 1:00 am
Posts: 5274
Location: Rochester NY USA
Maybe 3480 with meter replaced? Not quite... I did find the identical tester with Google image search, identified as 3423.

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 Post subject: Re: TRIPLETT 3423 DOESNT LOOK LIKE A 3423?
PostPosted: May Sat 02, 2020 5:41 pm 
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Joined: Nov Fri 04, 2011 3:12 am
Posts: 1050
Location: Parksley, VA.
Well, time to pry it open and do a comparison with a schematic.
http://pacifictv.ca/schematics/triplett3423manual.pdf

John S.


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 Post subject: Re: TRIPLETT 3423 DOESNT LOOK LIKE A 3423?
PostPosted: May Sat 02, 2020 5:46 pm 
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Joined: Feb Fri 14, 2014 4:41 pm
Posts: 34
Location: Harrod, OH
Not a 3480. The big left control under the tube sockets is "B Filament" on the 3480 and "E Bias" on yours. The 3480 also includes a VOM.

I can't say for sure what this is. I've compared it visually with the tube testers I'm aware of and can't find a match. The actual model may have been a light tan. Triplett used the same metal and made a change in the color scheme. I think the black "crinkle" (That's not the terminology Triplett used but I can't recall it right now.) with the natural aluminum came first, then later they may have switched to an all tan, both panel and case. Or vise versa.

One thing that is a little suspicious is that I do not see the Triplett logo on the panel. I'm wondering if it is someone's recreation or rebuild including a front panel. Easier to duplicate the numbers and arcs but more difficult to duplicate the logo so leave it out. If it were a factory build, it might leave the logo off if it were private labelled, the customer expecting their logo on the meter only.

You might check inside to see if it looks like it has modern wiring.

This is an interesting one.


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 Post subject: Re: TRIPLETT 3423 DOESNT LOOK LIKE A 3423?
PostPosted: May Sat 02, 2020 8:26 pm 
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Thanks to all. The other thing that is strange is the roll chart. if you zoom up on it makes little or no sense with respect to the controls. my next step is to brining up on the variac and dim bulb and try to voltage check a tube socket using a data sheet for a common tube I have (12CA5 maybe?) maybe I can recreate a roll chart by mapping voltage to knob numbers; maybe it moves to my parts stock and becomes something else in another life; the price I paid can justify paring it for other endeavors. too bad; it looks like the previous owner recapped it. Dam I need a tube tester too - guess I'm hitting ebay! ay tester suggestions, I do ham radio repair and am radio restoration?

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 Post subject: Re: TRIPLETT 3423 DOESNT LOOK LIKE A 3423?
PostPosted: May Sat 02, 2020 8:50 pm 
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I think I confirmed on thing; the roll is out of a 3480; mystery continues...


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 Post subject: Re: TRIPLETT 3423 DOESNT LOOK LIKE A 3423?
PostPosted: May Sun 03, 2020 4:07 am 
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Joined: Nov Fri 04, 2011 3:12 am
Posts: 1050
Location: Parksley, VA.
This IS an interesting one.

Looking at the front panel, it seems your tester has almost every control that a 3423 would have except for the Normal/Special switch. It has a bias control which I would expect to find in a Mutual Conductance tester.

If you glance at the schematic, Triplett used the tetrode part of the 117L7 as an oscillator. It uses a 4 khz frequency to feed the grid for GM tests which is very rare. Almost none of the Mutual Conductance testers used a relatively high frequency for the grid drive. Weston did, there is a Heathkit that did and Triplett did although they used 4 khz. Weston and the TT-1 Heathkit used a 5 khz signal. This is why I recommend you poke around the tester comparing it to the Triplett schematic. And/or measure the grid frequency. There is also a filter in the metering circuit so it reads only the 4 khz output of the tube which would not be found in an emission type from Triplett or any other manufacturer. I see a tube which could be a 117L7. That tube is not commonly used in tube testers at all. The panel also has the one switch labeled "G Circuit" which is again typical of the Triplett 3423.

Emissions testers are perfectly good to use but are basically Go/No Go testers. There is no need for 8 or 10 adjustable pots like you have and it adds expense as well as requiring adjustment at the factory.

The tube chart could be from anything. If you do have a 3423, there are Ebay sellers who have very good reprints of the manual and the tube chart.

Interesting indeed.
John S.


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 Post subject: Re: TRIPLETT 3423 DOESNT LOOK LIKE A 3423?
PostPosted: May Sun 03, 2020 3:37 pm 
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Joined: Apr Wed 08, 2020 7:21 pm
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Thank you John! I will look for a roll chart, that might answer a few questions on the set-up as it will align letters and controls. I do have a hard copy of the manual so good to go. I have a project on the bench and will finish that up and then take advantage of our stay at home and pull the triplett out again. thanks again!!

Mark


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 Post subject: Re: TRIPLETT 3423 DOESNT LOOK LIKE A 3423?
PostPosted: May Sun 03, 2020 7:16 pm 
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Roll charts are scarce; just want a pdf or excel spread sheet and I think in would be fine. I will keep searching but if someone has the 3423 roll chart data (not supplemental) I would love to chat with you? maybe make it worth your wild to re create in excel?? Fun stay at home project??


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 Post subject: Re: TRIPLETT 3423 DOESNT LOOK LIKE A 3423?
PostPosted: Jul Wed 08, 2020 5:52 pm 
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Joined: Apr Wed 08, 2020 7:21 pm
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UPDATE! Thanks to all that sent me tube data for the "real" 3423. With that and the schematic I was able to trace this thing and validate its performance to be that of the 3423 except for the normal/special switch. it measures with in 5-10% against my Hickok so i am pleased. As you can see I re-labeled the controls to match the lettering scheme of the 3423. I also took the roll chart data and the supplemental data (and any other 3423 tube data I could fine on line) into excel then printed. Again working great and thanks to the forum for getting a lost cause back on the bench! Oh by the way I am calling this the "3423-A" model because who knows?? :lol:


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 Post subject: Re: TRIPLETT 3423 DOESNT LOOK LIKE A 3423?
PostPosted: Sep Mon 06, 2021 8:28 am 
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Joined: Jul Fri 12, 2019 10:05 pm
Posts: 29
Hi Mark,

Please let me know if you have published the Excel version of the roll chart. If so, I would like to download a copy.


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