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 Post subject: Triplett 850 Differences
PostPosted: Jul Thu 22, 2021 3:13 am 
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Location: Bryson City, North Carolina
I understand there are different types of Triplett 850 meters.
A type 1, 2, and 3. Maybe more for all I know.
How do you tell the difference so can get the right manual and schematic?

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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Thu 22, 2021 5:08 am 
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I did the screen capture quick but generally the model number is on the meter face.

Attachment:
triplett-meter-model.jpg
triplett-meter-model.jpg [ 283.14 KiB | Viewed 818 times ]

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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Thu 22, 2021 6:02 am 
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Thanks for the reply. It seems easy enough.
My wife bought me this thing for my birthday so I was trying to prepare.
No type number on this 850 though.
I don't know the serial number as it hasn't arrived yet.

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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Thu 22, 2021 9:18 am 
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My guess would be that if there is no number, it's type 1. They probably would not have known there was going to be a 2 and 3 down the road ;-)

just a guess though. I didn't research it.

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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Thu 22, 2021 1:47 pm 
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The serial number stamped on the lower left of the meter scale will help you determine the production run the unit was manufactured under. Once you know that you will be better able to focus your efforts to obtain the correct schematic.


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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Thu 22, 2021 2:39 pm 
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I also have a 850 with no number on the scale defining the type.

As far as serial numbers go, I couldn't find one anywhere...there are some ink-stamped numbers on the back of the panel meter plastic (seen only from the inside), but this doesn't strike me as a logical place for a serial number...

Steve


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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Fri 23, 2021 5:18 pm 
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Location: Oswego, NY, USA
Just a few things I've noticed about Triplett 630 series and 850's. Only certain (usually older) production runs came with either stamped (actually engraved with pressure) or ink/hand-written serial numbers; but as we know (based on an email discussion with Mike Hahn ~2002), the original serial numbers factory notebooks were lost (nobody's quite sure why or how; possibly storm/water roof leakages & mildew growth of the notebooks), so you need to correlate those numbers to other units to "interpolate" production runs and date of production.

Triplett Type numbers are sometimes not as straight forward as we'd like. Two examples I know of from my own collection.

My model 630-L does not indicate Type 2 anywhere on its scale or on the top of the case; but I know it's a Type 2, based on its components/resistor-values and Ohms scale layout. Some early production Type 2's labeled the Type 2 only with a factory adhesive sticker placed on the top of the case, just behind the clear/lucite window, but those stickers can come off over time. All of my 850's have the older/traditional labeling "Electronic Volt-Ohmmeter", which is also the label used in their catalogs and manuals. But I've seen a few very late production 850's (only on Ebay) that read on their scales "VTVM" or in some cases "Vacuum Tube Volt Meter", but without any printed Type number. I and others have what exists of the original factory archives, from the old filing cabinets; but there's little mention of how they (engineering & marketing) assigned Type numbers or what exactly determined Type number changes, or if Type number changes were always made between production runs, or possibly sometimes in the middle of a production run (which we've seen evidence of in a few cases). Type number designations are also interesting with model 801 (lab-grade Solid-state tester); where a small/ditto (which fade with age..) addendum page indicated that Type 2 was the change from Hg/Mercury over to Carbon-zinc (or Alkaline) batteries, along with a couple required resistor value changes; but there were many 801's made that use the newer batteries which were not labeled Type 2, at least in the first 1 or 2 production runs of the Type 2. As Alan Douglas and others had taught us here on ARF, often the factory manuals and printed circuit drawings lag far behind the actual fact of what's found in some testers; definitely the case with Triplett. When these testers were still on warranty, the company didn't much care if the included manual or labeling was up to date; since they replaced or repaired any problems at no charge to the owner. DrWorry mentioned the ink-stamped numbers found on the backs of meter cases; those numbers, in most cases are not serial numbers; they are factory run production numbers; but those notebooks are also long gone.


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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Tue 27, 2021 4:12 am 
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Mr Fred Scoles, I was hoping you would lend your expertise to this question. I take it then that there are no reliable markings unless you already know the subtle differences in certain resistors or other stuff because of the lack of documented evidence. Well, gee thanks Triplett.
That's ok I guess, whatever I have to replace will just be the same part like for like as I can. I'll do the electrolytics for sure.

I got the meter in and pulled it out of the case.
I very much like the large face; it's very easy to read.
Both tubes 12AU7 and 6aL5 tested 80% on my B&K 700 ouija board.
It's very clean inside and came with an original probe that doesn't come apart. The probe has a tiny rivet pin at the base where the wire enters and appears to secure a plastic jacket around the lead wire. It measures 1.1 Megohm and uses the microphone jack (I think it is SMA 12 or something like that?). It has a very small pin ground lead about the size of transistor radio earbud. It's lead is very crumbly and I'll replace that for a 4 mm jack. That way the lead can be removed like the positive probe.
It had a Burgess (!) Industrial 700 C cell that had not leaked at all and tested 1.3 vdc. I had not seen a Burgess battery in a long long time. According to Wiki they operated from 1926 commercial production until they shuttered in 1989 after passing thru different owners. A long time anyways.
I will pick up a C cell tomorrow and do some testing and get new electrolytic caps ordered along with anything else I need.
Maybe even fire up my old RFL 829G calibrator if it still works. It's been a while since I hotted it up.

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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Tue 27, 2021 4:47 am 
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fixt wrote:
Maybe even fire up my old RFL 829G calibrator if it still works.

Is RFL "Radio Frequency Laboratories"? One of the original Boonton NJ electronics companies? Tell us more, please! Photos, pretty please?

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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Tue 27, 2021 5:06 am 
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Burgess was in trouble for a long time for poisoning their employees who were working with hazardous materials.


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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Tue 27, 2021 6:07 am 
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Location: Bryson City, North Carolina
stevebyan wrote:
fixt wrote:
Maybe even fire up my old RFL 829G calibrator if it still works.

Is RFL "Radio Frequency Laboratories"? One of the original Boonton NJ electronics companies? Tell us more, please! Photos, pretty please?


Yes it's Radio Frequency Labs. The manual says it's from Boontown. I have it and a carcass for parts. I don't use it much and it's pretty old. The carcass used a nixie tube display and it was missing when I got it for parts but otherwise intact. I'm not sure of its precision/accuracy any more but the last time I used it for an analog meter it worked ok. I always compare to other meters for a sanity check anyway.
I'll try to get a photo of it tomorrow for you. It's a beast to move about 80 lbs I think. Maybe a 100.

Edit: Its in the manual. Weight is 98 lbs. It feels heavier now than it once did.

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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Tue 27, 2021 11:46 pm 
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OK, today I replaced that tinky little jack and made up another test cable. Put a new battery in but didn't really fool with ohms function much cause I have better meters for that when I need them. That battery fits in there super tight!
Fired up the old calibrator and it worked fine. It seemed about .1-.3 volts off but that's accurate enough for an old analog meter. Got the Triplett calibrated, but I think it needs the new capacitors of course and the pots need to be cleaned. Other than that it is quite accurate enough for my uses and I'm very pleased with it.

Edit: I looked for a serial number but didn't see anything that would pass for one. There is a number on the inside of the meter on the edge that is ink stamped in addition to the meter stamping, but if it's a serial it is illegible due to the ink smearing when stamped.

For SteveByan, here are the pictures of the old calibrator I promised.
Pay no attention to any background junk, I tried to clip it out.
First is the measurement module shield from the carcass.
Attachment:
20210727_180852.jpg
20210727_180852.jpg [ 57.09 KiB | Viewed 635 times ]


The old RFL 829G. I don't know when it was made or how old it might be.
98 pounds of ...twonkies and gew gaws in that case. The transformer itself is a monstrous thing and the electrolytics are huge.
Like me, it has gained over the years or seems like it.


Attachments:
20210727_180541-crop.jpg
20210727_180541-crop.jpg [ 535.94 KiB | Viewed 635 times ]

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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Thu 29, 2021 1:31 am 
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Todd wrote:
The serial number stamped on the lower left of the meter scale will help you determine the production run the unit was manufactured under. Once you know that you will be better able to focus your efforts to obtain the correct schematic.


mine has a 1 in the lower left of meter face, like in the hard to see area. straight ahead its hard to see, you need to look top down and it stands out. I am thinking this is the series?

seems like I seen it on the inside chassis. going to get rid of this welding cable power cord shortly and will look again.


Attachments:
trip_850_type.jpg
trip_850_type.jpg [ 613.18 KiB | Viewed 607 times ]

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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Thu 29, 2021 3:39 pm 
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The "1" you see printed in the very bottom, left is not a series number; it is a number that they used that ranged from 1 up to about 7; denoting about where in the production run of that series meter movement, mainly with the stamping/machining of its field magnet parts, to achieve the specified arc-linearity and final accuracy. A number 1 is the best, which has the most linear scale placed in it. Many 850's came with a "1"; but some 630's came with 2, or up to 3; and some lower priced panel meters used the 4,5,& 6's. And many of the lower priced panel meters containing the higher numbered scales, didn't actually have the number printed on their scales; so you didn't know and really didn't care since the production panel meters, it really didn't matter, as long as the scale looked linear to the user. You'd have to measure the scales very carefully to find the arc-scale linearity differences for each of the numbers. In those days, all scales were drafted/drawn by hand (no computers), so it was a detailed, painstaking task for the engineering dept's scale drafter. Back in early '60's, one of my friends in grade school's Mom was their drafter; so he used to tell me what she went through to do that. A drafter's table & supplies required alot more space than today's laptop PC....ha. Fred


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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Thu 29, 2021 10:14 pm 
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Fred Scoles wrote:
The "1" you see printed in the very bottom, left is not a series number; it is a number that they used that ranged from 1 up to about 7; denoting about where in the production run of that series meter movement, mainly with the stamping/machining of its field magnet parts, to achieve the specified arc-linearity and final accuracy. A number 1 is the best, which has the most linear scale placed in it. Many 850's came with a "1"; but some 630's came with 2, or up to 3; and some lower priced panel meters used the 4,5,& 6's. And many of the lower priced panel meters containing the higher numbered scales, didn't actually have the number printed on their scales; so you didn't know and really didn't care since the production panel meters, it really didn't matter, as long as the scale looked linear to the user. You'd have to measure the scales very carefully to find the arc-scale linearity differences for each of the numbers. In those days, all scales were drafted/drawn by hand (no computers), so it was a detailed, painstaking task for the engineering dept's scale drafter. Back in early '60's, one of my friends in grade school's Mom was their drafter; so he used to tell me what she went through to do that. A drafter's table & supplies required alot more space than today's laptop PC....ha. Fred


thats interesting to learn Fred thks. my right side panel has no series number, just says model 850 electronic volt-ohmmeter. so where might be the 850 series number?

will look again on the chassis when I open it back up to replace the pwr cord. thks

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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Fri 30, 2021 3:05 pm 
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fixt wrote:
For SteveByan, here are the pictures of the old calibrator I promised.

Thank you! I'm amazed that Radio Frequency Labs, the progenitor of the electronics industry in Boonton, NJ, survived to the era of digital displays.

It turns out that they are still in business (as a subsidiary of Hubbell Power Systems):
https://www.rflelect.com/about-rfl/our-history

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 Post subject: Re: Triplett 850 Differences
PostPosted: Jul Sat 31, 2021 3:20 pm 
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I was trying to pin down the date on the thing once upon a time, I could only find that that the early RFL 829 was made in 1958 and I think the G series was the last of them. That's about all I know bout its history.

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 Post subject: Re: Triplett 850 Differences
PostPosted: Aug Sun 01, 2021 12:48 am 
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I just finishing changing the pwr cord. There is no ID's that I can find inside. I have what looks to be a SSS, someone engraved 'hi guys' and another telephone # and ID it looks like.

on the outer lower left on the panel there is a number. looks like a serial number?

is it possible the first series had no series number? anyone have a series #2 850?

did fixt get me chasing my tail? maybe there are no series in the 850?


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trip_850_LL.jpg
trip_850_LL.jpg [ 601.74 KiB | Viewed 503 times ]

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