Tin Whiskers in an OC171. AF114, AF117 etc.. - UK Vintage Radio Repair and Restoration Discussion Forum

Racalfanatic · 9th Dec 2008, 10:32 pm

Hi All,
I removed three faulty OC171 transistors from my Eddystone EC10 Receiver.
I removed the base and the following photos are what I saw:

http://img.photobucket.com/albums/v2.../OC171/tw2.jpg
http://img.photobucket.com/albums/v2.../OC171/tw3.jpg
http://img.photobucket.com/albums/v2.../OC171/tw5.jpg

mark pirate · 10th Dec 2008, 12:09 am

Excellent photos

. If you search the forums you will find a very interesting thread on this very subject.

Paul Stenning sent some AF11x transistors to NASA for disection, fascinating thread.

Mark

Colin · 10th Dec 2008, 12:45 am

Wonderful pics ... how did you take them?

kalee20 · 10th Dec 2008, 1:46 pm

Brilliant photos, congratulations!

What always beats me about this, is why Mullard et al used a tin plated metal can? Tin whiskering wasn't a new phenomenon in the 1960's, even though it was not well understood!

Station X · 13th Dec 2008, 12:58 pm

Perhaps they thought that the equipment these transistors were installed in would be thrown away after a few years. They wouldn't have expected people to be repairing such sets nearly 50 years later.

Steve_P · 13th Dec 2008, 1:17 pm

Maybe not here, but NASA are involved in research on this because of (and this would be a great idea for a sci-fi film)....

AF117's in space.

Cheers,

Steve P.

Geoff 555 · 13th Dec 2008, 4:01 pm

UMM I wonder what they used in HAL?

Cheers.
Geoff.

ukcol · 13th Dec 2008, 4:43 pm

This would be the thread that Mark was refering to.

https://www.vintage-radio.net/forum/...light=whiskers

Steve_P · 13th Dec 2008, 6:27 pm

Geoff - They probably used AF117's. Why it wen't strange....

Cheers,

Steve P.

JHGibson · 14th Dec 2008, 1:31 am

VK3JEG had a problem with a whiskered OC171 in his EC10 and replaced it with a modern silicon transistor. For his notes, go to www.qsl.net/vk3jeg/edd_ec10.html
John.

Racalfanatic · 15th Dec 2008, 11:01 pm

Quote:

Originally Posted by Colin

Wonderful pics ... how did you take them?

Hi Colin,
I used a simple compact camera in macro mode, aperture priority with the aperture stopped right down, spot metering and a halogen reading lamp!

paulsherwin · 15th Dec 2008, 11:33 pm

Quote:

Originally Posted by Racalfanatic

I used a simple compact camera in macro mode, aperture priority with the aperture stopped right down, spot metering and a halogen reading lamp!

It shows what excellent pictures can be taken with quite modest equipment these days.

No more discussion of cameras in this thread please folks, it's OT for the forum.

Paul

9th Dec 2008, 10:32 pm	#1
Racalfanatic Retired Dormant Member Join Date: Aug 2007 Location: Stoke-on-Trent, Staffordshire, UK. Posts: 105	Tin Whiskers in an OC171. AF114, AF117 etc.. Hi All, I removed three faulty OC171 transistors from my Eddystone EC10 Receiver. I removed the base and the following photos are what I saw: http://img.photobucket.com/albums/v2.../OC171/tw2.jpg http://img.photobucket.com/albums/v2.../OC171/tw3.jpg http://img.photobucket.com/albums/v2.../OC171/tw5.jpg Last edited by Racalfanatic; 9th Dec 2008 at 11:01 pm.

10th Dec 2008, 12:09 am	#2
mark pirate Dekatron Join Date: Mar 2008 Location: Worthing, West Sussex, UK Posts: 5,185	Re: Tin Whiskers in an OC171. AF114, AF117 etc.. Excellent photos . If you search the forums you will find a very interesting thread on this very subject. Paul Stenning sent some AF11x transistors to NASA for disection, fascinating thread. Mark Last edited by Darren-UK; 10th Dec 2008 at 12:13 am. Reason: FSK problem fixed.

10th Dec 2008, 12:45 am	#3
Colin Heptode Join Date: Jun 2004 Location: Ilkley, West Yorkshire, UK. Posts: 656	Re: Tin Whiskers in an OC171. AF114, AF117 etc.. Wonderful pics ... how did you take them? __________________ Colin Armstrong

10th Dec 2008, 1:46 pm	#4
kalee20 Dekatron Join Date: Feb 2007 Location: Lynton, N. Devon, UK. Posts: 7,087	Re: Tin Whiskers in an OC171. AF114, AF117 etc.. Brilliant photos, congratulations! What always beats me about this, is why Mullard et al used a tin plated metal can? Tin whiskering wasn't a new phenomenon in the 1960's, even though it was not well understood!

13th Dec 2008, 12:58 pm	#5
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: Tin Whiskers in an OC171. AF114, AF117 etc.. Perhaps they thought that the equipment these transistors were installed in would be thrown away after a few years. They wouldn't have expected people to be repairing such sets nearly 50 years later. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.

13th Dec 2008, 1:17 pm	#6
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Tin Whiskers in an OC171. AF114, AF117 etc.. Maybe not here, but NASA are involved in research on this because of (and this would be a great idea for a sci-fi film).... AF117's in space. Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

13th Dec 2008, 4:01 pm	#7
Geoff 555 Heptode Join Date: Jan 2008 Location: Bristol, UK. Posts: 981	Re: Tin Whiskers in an OC171. AF114, AF117 etc.. UMM I wonder what they used in HAL? Cheers. Geoff.

13th Dec 2008, 4:43 pm	#8
ukcol Rest in Peace Join Date: May 2003 Location: Harlaxton, Lincolnshire, UK. Posts: 3,944	Re: Tin Whiskers in an OC171. AF114, AF117 etc.. This would be the thread that Mark was refering to. https://www.vintage-radio.net/forum/...light=whiskers

13th Dec 2008, 6:27 pm	#9
Steve_P Dekatron Join Date: Sep 2003 Location: Bolton, Greater Manchester, UK. Posts: 6,644	Re: Tin Whiskers in an OC171. AF114, AF117 etc.. Geoff - They probably used AF117's. Why it wen't strange.... Cheers, Steve P. __________________ If we've always had it, why is the Car Boot open? You're not sneaking another Old TV in are you...?

14th Dec 2008, 1:31 am	#10
JHGibson Retired Dormant Member Join Date: Apr 2003 Location: Salt Spring Island, BC, Canada Posts: 368	Re: Tin Whiskers in an OC171. AF114, AF117 etc.. VK3JEG had a problem with a whiskered OC171 in his EC10 and replaced it with a modern silicon transistor. For his notes, go to www.qsl.net/vk3jeg/edd_ec10.html John.