Find the manufacturer of some precision resistors

[giacomo]

Hi guys, do anyone know who is the company that has produced these resistors ? MC ?

[giacomo]

Ok, i found a chinese blog that talks about these resistors:

https://www.geek-workshop.com/thread-296-1-1.html

They are from a British company Mann Components Limited then acquired by Vishay in the 80ies

[Gyro]

Yes, Mann Components. Some of the Vishay datasheets can still be matched up to the acquired parts range.

https://www.eevblog.com/forum/testgear/my-shunt-collection-(ucurrent-passive)/msg858336/#msg858336


P.S. That's a very nice collection that you have there. The 1R cries out to be used as a 4-terminal current shunt.

[giacomo]

Yes, Mann Components. Some of the Vishay datasheets can still be matched up to the acquired parts range.

https://www.eevblog.com/forum/testgear/my-shunt-collection-(ucurrent-passive)/msg858336/#msg858336


P.S. That's a very nice collection that you have there. The 1R cries out to be used as a 4-terminal current shunt.

Thank Gyro, for the smaller ones maybe MR93 and MR600 ? The datasheets resemble my resistors, but there are no real picture, just a drawing and i do not find any real images. Also they produce those resistors with a wide range of T.C from 2ppm up to 6000ppm.

Did you find any datasheet ?

For the 4 terminal one i found an ebay seller with an idential resistor but a different code that lands to a Vishay datasheet

Suffix C ? 3ppm/°C

I guess the code may hide the t.c 2C 2ppm and so on.. Also the chinese blog talks about a t.c that should be something like that

[Gyro]

It was the LR500 datasheet that I was thinking of (for the 4N/C), but you have already found that one. Yes, my assumption would be 1W, 3ppm/'C (although you would probably want to run at less than half that for long term measurement stability). I restrict mine (at the top of the thread I linked) as a 100mA shunt (0.1W) with inverse parallel diodes to protect it against accidental overload.

Vishay would have phased out most of the smaller ones in favour of their own foil resistors for lower production cost, but I think it would be reasonable to assume typically 5ppm/'C or better for the other ones.

Vishay do still list the MR600 series [EDIT: as you say, sorry], which may be relevant to the smaller ones - in terms of package sizing vs power rating anyway. https://www.vishay.com/search?searchChoice=part&query=MR600

I think we must have salvaged the same instrument for these resistors, as I have a similar collection. I can't remember what it was though (maybe Solartron?) It was a long time ago. Some of the values were probably custom.

[giacomo]

I take the majority of those resistors from a datron 1059 in bad shape and with faulty panaplex display 3-4 years ago. Since panaplex replacement are pretty rare a prefered to savaged it instead of repair. i think that panaplex used or nos (if you find any) are more worty on the highier end ones like the 1061 1062 1071 7075 etc

Yes, the same resistors are present in my solartrons, but i have not savaged these ones

[Gyro]

Ha, no. Don't salvage your working Solartrons (I'm still trying to remember whether some of mine came from a batch of miscellaneous precision resistors now that I purchased, although I think I remember removing the 1R one from something).

Yes, the Datron 105x have them. I have a collection of 1030, 104x and 105x models. The Panaplex displays on those are standard (replaceable) Sperry / Beckman SP33x and SP35x series. The later ones (1061 onward) use an unobtanium custom Panaplex display. I'll stay with mine. 

[giacomo]

Ha, no. Don't salvage your working Solartrons (I'm still trying to remember whether some of mine came from a batch of miscellaneous precision resistors now that I purchased, although I think I remember removing the 1R one from something).

Yes, the Datron 105x have them. I have a collection of 1030, 104x and 105x models. The Panaplex displays on those are standard (replaceable) Sperry / Beckman SP33x and SP35x series. The later ones (1061 onward) use an unobtanium custom Panaplex display. I'll stay with mine. 

My first repairs have been a Datron 1041 and a 1051, the 1ohm resistor may came from the current option for the datron 1059.

At the time a picked those up because i paid them 15€ a piece on ebay (no other offers apart mine) and a wanted to start repair something..

In retrospective.. i am feeling a little guilty even if the 1059 was the worst of the batch (aesthetically)


I need to buy some voltage reference the KX LTZ1000 is the best candidate. I need it to futher test the solartrons that i will post as soon as i finish to read all the threads about them.

Since component supplyeis have been costantly delayed my order since the start of the pandemic i was looking around for resistors alternative.. These may be good but not good enought i think.

[Gyro]

I've never had a Datron with a current option - it's actually something that I don't miss on a decent bench DMM. It's more convenient and technically better to use external shunts (hence my shunt collection)  and use the 10mV range for minimum burden. It also means that you can leave the shunts in circuit and just move the meter leads around as necessary.

If it's any consolation, I think the 1059 was by far the least useful of the bunch - No 10mV range (not even 100mV on AC), no 4-wire ohms. Poor compromises for having a current range. 

I run a 1030 (very flexible AC RMS), a 1055 (DCV only) and a 1041M (DCV, AC RMS, 4 wire active guard ohms).... Plus spares.


Edit: Yes, they're certainly the most economical set of precision resistors that you're going to find!

[Labrat101]

This company OK they are not the same color but Mil grade.
RX70 0.25W 1 4W 0.01% 5PPM

https://www.yoycart.com/Product/41899493872/

also have the 4 wire type

PS Really nice collection

[dobsonr741]

How about these new-old-stock resistors?

The only labels on them:
P-0
10K
+/-0.05%
R-1

Does not look like the Chinese RX70, no epoxy spill at the leads.

[Terry Bites]

They look a lot like General Resistance parts.
Get onto Rhopoint's site and have a look.

[bidrohini]

You can see here: https://www.rhopointcomponents.com/product-category/components/resistors/precision-ultra-precision-resistors/