Hi friends,
I hope this is the right place to post this--I'm never sure if I'm doing something right, especially when I'm new to a forum, as I am to this one!

I've been hunting high and low for a 1N881 switching diode 200V 50mA and have come up with bupkis! There surely must be a cross reference to a compatible diode, but I'm coming up with zilch on that, too.

If anyone is smarter than I am and can figure out what I need and where to get it, I'd sure be grateful!!

It's all our dog's fault anyway. Bumped the arm for some affection right at a critical point and the soldering gun fried several circuits! He didn't mean it, but it's sure put us in a world of hurt now!

Please can someone get him out of the doghouse and help me out? (Not literally--he has the run of the household, and I don't mean a doghouse! LOL)

Thank you,
Diane

 

Hi friends,
I hope this is the right place to post this--I'm never sure if I'm doing something right, especially when I'm new to a forum, as I am to this one!

I've been hunting high and low for a 1N881 switching diode 200V 50mA and have come up with bupkis! There surely must be a cross reference to a compatible diode, but I'm coming up with zilch on that, too.

If anyone is smarter than I am and can figure out what I need and where to get it, I'd sure be grateful!!

It's all our dog's fault anyway. Bumped the arm for some affection right at a critical point and the soldering gun fried several circuits! He didn't mean it, but it's sure put us in a world of hurt now!

Please can someone get him out of the doghouse and help me out? (Not literally--he has the run of the household, and I don't mean a doghouse! LOL)

Thank you,
Diane

Hi Diane, welcome to the nuthouse.

http://nte01.nteinc.com/nte\NTExRefSemiProd.nsf/$all/E857EC7BA65AFCF485257910007DFF55?OpenDocument
NTE says that their NTE116 is a replacement.

which Newark and others carry https://www.newark.com/nte-electronics/nte116/standard-diode-1a-600v-do-41/dp/29C4420

If you are really worried, type "diode cross reference lookup" into google https://www.google.com/search?clien...1......0....1..gws-wiz.......0i71.wJjk3_OJU9s and one by one got through them. Compare the data sheet for the hits with the data sheet for the 1N881.

Hope it helps.

 

Hi Diane, welcome to the nuthouse.

http://nte01.nteinc.com/nte\NTExRefSemiProd.nsf/$all/E857EC7BA65AFCF485257910007DFF55?OpenDocument
NTE says that their NTE116 is a replacement.

which Newark and others carry https://www.newark.com/nte-electronics/nte116/standard-diode-1a-600v-do-41/dp/29C4420

If you are really worried, type "diode cross reference lookup" into google https://www.google.com/search?clien...1......0....1..gws-wiz.......0i71.wJjk3_OJU9s and one by one got through them. Compare the data sheet for the hits with the data sheet for the 1N881.

Hope it helps.

THANK YOU! I tried looking at all those cross references but my stupid computer wouldn't compute with NTE for some reason!! Thank you for the help!!
Diane

 

Well, as it turns out the NTE116 is NOT compatible, so I'm back to square one. Help anyone??
Diane

 

Well, as it turns out the NTE116 is NOT compatible, so I'm back to square one. Help anyone??
Diane

Well, that's too bad. So, what are the characteristics of the 1N881 that differ from the NTE116? NTE116 datasheet is here http://www.nteinc.com/specs/100to199/pdf/nte116.pdf

That diode, the 1N881, looks like it is pretty old. I see it listed here https://www.rsp-italy.it/Electronics/Databooks/Semicond/_contents/D.A.T.A.'s Semiconductor Diode and Rectifier 1961.pdf Page 40, line 1303c

and here https://www.datasheet.live/index.php?title=SpecialdfViewer&url=https://pdf.datasheet.live/31943fe2/vishay.com/1N486A.pdf

I don't see anything special about it as far as I know (which may not be enough). In fact, this old Fairchild book http://bitsavers.trailing-edge.com/..._dataBooks/1978_Fairchild_Diode_Data_Book.pdf lists the common 1N4003 as the closest equivalent (page 1-46).

So, at this point, I am wondering what the application/project/equipment is that you need it for and whether there is another explanation for why the diode needs replacement.

 

There is the attached data sheet as well.

It looks non-critical so anything that will physically fit while meeting the current and voltage requirements should operate.

 

Hello,

There is nothing much special about the diode:



Found in this old book:
https://the-eye.eu/public/Books/bit...sociates/1987_DATA_Book_Diodes_Edition_54.pdf

Bertus

 

Hello,

In the following PDF there is stated that the 1N881 can be replaced by an 1N4003 (an 1N4007 will also work).

Bertus

 

The cross reference sheet is very useful--thanks for that.

I am completely flumoxed. Every cross reference I'm coming up with is not working. The magic answer apparently lies in being 50 milliamp, not 1 amp.

I found an old geocities webpage that has dozens or hundreds of cross reference numbers to a 1N881 and was lucky enough to find another page that will cross reference those. Many of them are crossing to NTE116 which isn't working. After changing the 1N881s with NTE116 compatibles, it worked even LESS than before--now it doesn't transmit OR receive.

I have data sheets for the 1N881 to compare to compatibles. It is NOT comparing to NTE116, NTE178MP, NTE109, NTE112, NTE125. The NTE552 MIGHT be close enough.

These are in a Johnson Messenger 223 CB radio.

I remain flumoxed but grateful for your input and assistance.

I value your input! Keep it coming, please!
Diane

 

The cross reference sheet is very useful--thanks for that.

I am completely flumoxed. Every cross reference I'm coming up with is not working. The magic answer apparently lies in being 50 milliamp, not 1 amp.

I found an old geocities webpage that has dozens or hundreds of cross reference numbers to a 1N881 and was lucky enough to find another page that will cross reference those. Many of them are crossing to NTE116 which isn't working. After changing the 1N881s with NTE116 compatibles, it worked even LESS than before--now it doesn't transmit OR receive.

I have data sheets for the 1N881 to compare to compatibles. It is NOT comparing to NTE116, NTE178MP, NTE109, NTE112, NTE125. The NTE552 MIGHT be close enough.

These are in a Johnson Messenger 223 CB radio.

I remain flumoxed but grateful for your input and assistance.

I value your input! Keep it coming, please!
Diane

When you say "Every cross reference I'm coming up with is not working." what do you mean?
Have you actually tried a diode, or do you mean that you can't find a 50mA diode? The 1A is more than you need. You don't need a smaller value, 1A is enough, and more.

What problem are you having?

 

To be clear, this particular diode has no critical specifications. It is a simple rectifier diode which could be replaced be a large number of other didoes without a problem.

Do you have a schematic for the radio?

 

Yeah, I was just going to ask if you could identify the diode using this http://w5rkl.com/wp-content/uploads/2015/02/Johnson-Messenger-223-schematic.pdf

A lot of these nerds..erm I mean experts, might be able to see a reason for that peculiarity.

 

Apparently, the only one on the schematic with a part number...

 

Sorry--what's in my head is getting lost in translation on the way to the keyboard. Every cross is not showing a 50mA. The crosses are showing 1A. These 1As are not switching (on this switching diode). We HAVE replaced it with NTE116 compatibles and now it neither transmits nor receives. Yes, we have the schematic for it.

The above references clearly show the 1N881 at 200 V and .05A with which we totally agree.

I'm getting confuseder as we go along.
Diane

 

Apparently, the only one on the schematic with a part number...

View attachment 172963

why wouldn't it be this one?

 

Yeah, I was just going to ask if you could identify the diode using this


why wouldn't it be this one?

It could well be, and I'd have mentioned it if I saw it!

 

In any case, the only diode I see there that is critical is D3, since it is marked "detector".

Can you see anything about the circuit for D1 or D2 that makes the lower current rating important, or would prevent the radio from transmitting and receiving?

I think the TS is mistaken about the reason for the failure to operate. I could be wrong, but I'd be surprised.

 

It was transmitting before changing the diodes (but not receiving). After changing the diodes with the NTE116 compatible, it was not transmitting. The oscillator was running but wasn't mixing in the mixer.

One basic thing I learned a long time ago is if doing something makes something not work, undo what you just did. I'm not discounting that it could be coincidental, but very suspicious, that the only thing that changed was replacing the 1N881 with a NTE116.

 

In any case, the only diode I see there that is critical is D3, since it is marked "detector".

Can you see anything about the circuit for D1 or D2 that makes the lower current rating important, or would prevent the radio from transmitting and receiving?

I think the TS is mistaken about the reason for the failure to operate. I could be wrong, but I'd be surprised.

Yeah maybe, that is what I was getting at in post #5, but I don't know....she may have some very good reasons why she suspects the diode. Ideally, one would locate some new old stock on the bay or maybe a CB enthusiasts site and do a "correct replacement". But, the dog is to blame and who knows what the dog had in mind!

It's all our dog's fault anyway. Bumped the arm for some affection right at a critical point and the soldering gun fried several circuits! He didn't mean it, but it's sure put us in a world of hurt now!

 

It was transmitting before changing the diodes (but not receiving). After changing the diodes with the NTE116 compatible, it was not transmitting. The oscillator was running but wasn't mixing in the mixer.

One basic thing I learned a long time ago is if doing something makes something not work, undo what you just did. I'm not discounting that it could be coincidental, but very suspicious, that the only thing that changed was replacing the 1N881 with a NTE116.

No slight intended but are you sure you've got the polarity correct?