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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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#1
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Tek 2246 scope, need transistor
Hello: Upon removing the case from my 2246 scope, the case snagged on
the heat sink of one of the transistors in the "VO Gain" section of the main PC board (not the processor board), breaking the leads of this transistor. The transistor is a round metallic 3-lead transistor labelled " Motorola logo, 0846, 8641". It is one of a pair and has a slip-on metallic heat sink attached. I have been unable to identify or cross-reference this transistor, and would appreciate any help in identifying (and hopefully obtaining) another pair of transistors. Thank you in advance Todd K4RR |
#2
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Tek 2246 scope, need transistor
todd wrote in
oups.com: Hello: Upon removing the case from my 2246 scope, the case snagged on the heat sink of one of the transistors in the "VO Gain" section of the main PC board (not the processor board), breaking the leads of this transistor. The transistor is a round metallic 3-lead transistor labelled " Motorola logo, 0846, 8641". It is one of a pair and has a slip-on metallic heat sink attached. I have been unable to identify or cross-reference this transistor, and would appreciate any help in identifying (and hopefully obtaining) another pair of transistors. Thank you in advance Todd K4RR All I could find online was the US military PN for that part; 6625-01-275- 4766 The TEK PN is;151-0846-00 8641 is the mfg.date code.(your scope was probably built in 1986-87.) -- Jim Yanik jyanik at kua.net |
#3
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Tek 2246 scope, need transistor
On Jun 6, 6:59 pm, Jim Yanik wrote:
todd wrote groups.com: Hello: Upon removing the case from my 2246 scope, the case snagged on the heat sink of one of the transistors in the "VO Gain" section of the main PC board (not the processor board), breaking the leads of this transistor. The transistor is a round metallic 3-lead transistor labelled " Motorola logo, 0846, 8641". It is one of a pair and has a slip-on metallic heat sink attached. I have been unable to identify or cross-reference this transistor, and would appreciate any help in identifying (and hopefully obtaining) another pair of transistors. Thank you in advance Todd K4RR All I could find online was the US military PN for that part; 6625-01-275- 4766 The TEK PN is;151-0846-00 8641 is the mfg.date code.(your scope was probably built in 1986-87.) -- Jim Yanik jyanik at kua.net Here is a site advertising TEK spares (including Hard to find). This may help you further. http://www.sphere.bc.ca/ Regards, Ravi. |
#5
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Tek 2246 scope, need transistor
todd wrote:
Hello: Upon removing the case from my 2246 scope, the case snagged on the heat sink of one of the transistors in the "VO Gain" section of the main PC board (not the processor board), breaking the leads of this transistor. The transistor is a round metallic 3-lead transistor labelled " Motorola logo, 0846, 8641". It is one of a pair and has a slip-on metallic heat sink attached. I have been unable to identify or cross-reference this transistor, and would appreciate any help in identifying (and hopefully obtaining) another pair of transistors. Thank you in advance Todd K4RR I got this hit for Tek semiconductors: http://www.electromechanicalparts.co...TEKTRONIX.html Also, I checked a Tek IC reference I had but of course discretes are absent. If you cannot locate real spares and if the other transistor of the pair is good, determine its characteristics (curve tracer, test bench setups, etc.) and shop for equivalents. Regards, Michael |
#6
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Tek 2246 scope, need transistor
"todd" wrote in message oups.com... Hello: Upon removing the case from my 2246 scope, the case snagged on the heat sink of one of the transistors in the "VO Gain" section of the main PC board (not the processor board), breaking the leads of this transistor. The transistor is a round metallic 3-lead transistor labelled " Motorola logo, 0846, 8641". It is one of a pair and has a slip-on metallic heat sink attached. I have been unable to identify or cross-reference this transistor, and would appreciate any help in identifying (and hopefully obtaining) another pair of transistors. Thank you in advance Todd K4RR -Go to http:\\groups.yahoo.com -register -subscribe the "TekScopes" group (copy and paste the name, there's a group whith a similar name) -when you can access it a search for Mr. Yanik's ref: 151-0846-00 finds several threads. some quotes: " the Tek cross ref says these are 2N3866A NPN RF power transistors in a TO-5/39 can, but this part does not work when installed in the scopes, and the manuals say there is trouble with any transistor that does not have the base connected to the case." " These were a custom Tek mod of the standard part. If you don't use the correct part you will have all sorts of problems with frequency response and oscillations as you move your hand or the cover near these parts (been there - done that)." So it looks like you have to find an original... Best Regards Steve Sousa |
#7
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Tek 2246 scope, need transistor
"Steve Sousa" wrote in message anews.com... "todd" wrote in message oups.com... Hello: Upon removing the case from my 2246 scope, the case snagged on the heat sink of one of the transistors in the "VO Gain" section of the main PC board (not the processor board), breaking the leads of this transistor. The transistor is a round metallic 3-lead transistor labelled " Motorola logo, 0846, 8641". It is one of a pair and has a slip-on metallic heat sink attached. I have been unable to identify or cross-reference this transistor, and would appreciate any help in identifying (and hopefully obtaining) another pair of transistors. Thank you in advance Todd K4RR -Go to http:\\groups.yahoo.com -register -subscribe the "TekScopes" group (copy and paste the name, there's a group whith a similar name) -when you can access it a search for Mr. Yanik's ref: 151-0846-00 finds several threads. some quotes: " the Tek cross ref says these are 2N3866A NPN RF power transistors in a TO-5/39 can, but this part does not work when installed in the scopes, and the manuals say there is trouble with any transistor that does not have the base connected to the case." " These were a custom Tek mod of the standard part. If you don't use the correct part you will have all sorts of problems with frequency response and oscillations as you move your hand or the cover near these parts (been there - done that)." So it looks like you have to find an original... Best Regards Steve Sousa Perhaps the broken leads can be repaired on the existing part? How about finding a TO-92 case transistor with very close specs and build a shield around it connected to the base? |
#8
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Tek 2246 scope, need transistor
"James Sweet" wrote in
news:Ophai.21$pd5.18@trnddc02: "Steve Sousa" wrote in message anews.com... "todd" wrote in message oups.com... Hello: Upon removing the case from my 2246 scope, the case snagged on the heat sink of one of the transistors in the "VO Gain" section of the main PC board (not the processor board), breaking the leads of this transistor. The transistor is a round metallic 3-lead transistor labelled " Motorola logo, 0846, 8641". It is one of a pair and has a slip-on metallic heat sink attached. I have been unable to identify or cross-reference this transistor, and would appreciate any help in identifying (and hopefully obtaining) another pair of transistors. Thank you in advance Todd K4RR -Go to http:\\groups.yahoo.com -register -subscribe the "TekScopes" group (copy and paste the name, there's a group whith a similar name) -when you can access it a search for Mr. Yanik's ref: 151-0846-00 finds several threads. some quotes: " the Tek cross ref says these are 2N3866A NPN RF power transistors in a TO-5/39 can, but this part does not work when installed in the scopes, and the manuals say there is trouble with any transistor that does not have the base connected to the case." " These were a custom Tek mod of the standard part. If you don't use the correct part you will have all sorts of problems with frequency response and oscillations as you move your hand or the cover near these parts (been there - done that)." So it looks like you have to find an original... Best Regards Steve Sousa Perhaps the broken leads can be repaired on the existing part? How about finding a TO-92 case transistor with very close specs and build a shield around it connected to the base? did the part that broke off your scope have it's base connected to the case? I don't recall that for the 2246. 2N3866A does not ring any bells for that 151-0846 part number,either. -- Jim Yanik jyanik at kua.net |
#9
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Tek 2246 scope, need transistor
-Go to http:\\groups.yahoo.com
-register -subscribe the "TekScopes" group (copy and paste the name, there's a group whith a similar name) -when you can access it a search for Mr. Yanik's ref: 151-0846-00 finds several threads. I second Steve S's suggestion. The TekScopes group membership are numerous and very helpful. Members include some Tek retirees. Much helpful info collected there. I'm sure someone has fixed your particular problem before. * To change settings online go to: http://groups.yahoo.com/group/TekScopes/join (Yahoo! ID required) This URL is also the "join" web page. Good luck, -- John English |
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