Topics

TM50X transistors

froggiegremlin
 

Hello all: Just got a blown TM503, the MOT power transistors on the heatsink in the back power supply, are blown. Manual has =

PNP Tek 151-0373-00 >MJE2901

NPN Tek 151-0349-00 >MJE2801 selected


Any thoughts on modern and easily obtainable replacements?

Digikey?

What is the selection for the NPN MJE2801?

MANY THANKS!


Kind Regards,

Jon

 

On Wed, 28 Dec 2011 14:20:26 -0000, "froggiegremlin"
<crypto-museum@...> wrote:

Hello all: Just got a blown TM503, the MOT power transistors on the heatsink in the back power supply, are blown. Manual has =

PNP Tek 151-0373-00 >MJE2901

NPN Tek 151-0349-00 >MJE2801 selected


Any thoughts on modern and easily obtainable replacements?
I looked into this a couple of months ago and concluded that the BD809
(NPN), BD820 (PNP), MJE2955T (PNP), MJE3055T (NPN), TIP33C (NPN), and
TIP34C (PNP) would be readily available acceptable substitutes in
roughly that order.

Just be careful of the pinouts. The Tektronix TO-127 parts are ECB
while the TO-220AB and TO-247 parts listed above are BCE. I have not
done a serious search for a modern high power part with the same
pinout or TO-3 parts (for high power compartments?).

The 2N5191 (NPN) 2N5194 (PNP) or 2N5192 (NPN) 2N5195 (PNP) are lower
power, 40 watts instead of 90 watts, but might work in non-power
supply compartments and have the same ECB pinout in a TO-225AA
package. The BD439 (NPN) BD440 (PNP) or BD441 (NPN) BD442 (PNP) are
similar with an ECB pinout in a TO-126 package but 36 watts. I
suppose you could parallel them with emitter ballast resistors but
that is just as much work as dealing with the wrong pinout nevermind
the mounting considerations.

What is the selection for the NPN MJE2801?
As far as I know, the 151-0349-00 is the raw stock number and the -05
version was selected after a 72 hour burn in. If they selected for
anything, I imagine it was a minimum current gain of 25 hfe at 3 amps.

santa0123456
 

I looked into this a couple of months ago and concluded that the BD809
(NPN), BD820 (PNP), MJE2955T (PNP), MJE3055T (NPN), TIP33C (NPN), and
TIP34C (PNP) would be readily available acceptable substitutes in
roughly that order.

Just be careful of the pinouts. The Tektronix TO-127 parts are ECB
while the TO-220AB and TO-247 parts listed above are BCE.
What about BD911/BD912 selected for a minimum Hfe higher than the
datasheet minimum? I used them without problem if I remember well.

 

On Wed, 28 Dec 2011 20:45:45 -0000, "Christian"
<christian.servais@...> wrote:

I looked into this a couple of months ago and concluded that the BD809
(NPN), BD820 (PNP), MJE2955T (PNP), MJE3055T (NPN), TIP33C (NPN), and
TIP34C (PNP) would be readily available acceptable substitutes in
roughly that order.

Just be careful of the pinouts. The Tektronix TO-127 parts are ECB
while the TO-220AB and TO-247 parts listed above are BCE.
What about BD911/BD912 selected for a minimum Hfe higher than the
datasheet minimum? I used them without problem if I remember well.
My list is not exhaustive. :)

I probably did not include them because STM's web site blows. BD909
through BD912 should work fine but they have the same TO-220AB pinout
difference. I will add them to my list.

The things I would watch for are high Ft or hfe causing oscillation,
low hfe requiring excessive drive, and high leakage causing thermal
runaway.

 

--- In TekScopes@..., David <davidwhess@...> wrote:

On Wed, 28 Dec 2011 14:20:26 -0000, "froggiegremlin"
<crypto-museum@...> wrote:

Hello all: Just got a blown TM503, the MOT power transistors on the heatsink in the back power supply, are blown. Manual has =

PNP Tek 151-0373-00 >MJE2901

NPN Tek 151-0349-00 >MJE2801 selected


Any thoughts on modern and easily obtainable replacements?
I looked into this a couple of months ago and concluded that the BD809
(NPN), BD820 (PNP), MJE2955T (PNP), MJE3055T (NPN), TIP33C (NPN), and
TIP34C (PNP) would be readily available acceptable substitutes in
roughly that order.

Just be careful of the pinouts. The Tektronix TO-127 parts are ECB
while the TO-220AB and TO-247 parts listed above are BCE. I have not
done a serious search for a modern high power part with the same
pinout or TO-3 parts (for high power compartments?).

The 2N5191 (NPN) 2N5194 (PNP) or 2N5192 (NPN) 2N5195 (PNP) are lower
power, 40 watts instead of 90 watts, but might work in non-power
supply compartments and have the same ECB pinout in a TO-225AA
package. The BD439 (NPN) BD440 (PNP) or BD441 (NPN) BD442 (PNP) are
similar with an ECB pinout in a TO-126 package but 36 watts. I
suppose you could parallel them with emitter ballast resistors but
that is just as much work as dealing with the wrong pinout nevermind
the mounting considerations.

What is the selection for the NPN MJE2801?
As far as I know, the 151-0349-00 is the raw stock number and the -05 version was selected after a 72 hour burn in. If they selected for
anything, I imagine it was a minimum current gain of 25 hfe at 3 amps.
Here are the selection criteria for the 151-0349-05 (selected from 151-0349-00):
After 72 hour burn-in;
BVceo => 60V, =< 80V @ I(CE) = 200ma
BVcbo => 75V, =< 95V @ I(CB) = 100uA
Icbo =< 100uA @ V(CB) = 60V
Iebo =< 10uA @ V(CE) = 4V
HFE => 25, =< 100 @ V(CE) = 2V, IC = 3A
V(BE(on))) =< 1.4V @ V(CE) = 2V, IC =3A

Cheers,
Dave M

kd8dey
 

--- In TekScopes@..., "David" <dgminala@...> wrote:



--- In TekScopes@..., David <davidwhess@> wrote:

On Wed, 28 Dec 2011 14:20:26 -0000, "froggiegremlin"
<crypto-museum@> wrote:

Hello all: Just got a blown TM503, the MOT power transistors on the heatsink in the back power supply, are blown. Manual has =

PNP Tek 151-0373-00 >MJE2901

NPN Tek 151-0349-00 >MJE2801 selected


Any thoughts on modern and easily obtainable replacements?
I looked into this a couple of months ago and concluded that the BD809
(NPN), BD820 (PNP), MJE2955T (PNP), MJE3055T (NPN), TIP33C (NPN), and
TIP34C (PNP) would be readily available acceptable substitutes in
roughly that order.

Just be careful of the pinouts. The Tektronix TO-127 parts are ECB
while the TO-220AB and TO-247 parts listed above are BCE. I have not
done a serious search for a modern high power part with the same
pinout or TO-3 parts (for high power compartments?).

The 2N5191 (NPN) 2N5194 (PNP) or 2N5192 (NPN) 2N5195 (PNP) are lower
power, 40 watts instead of 90 watts, but might work in non-power
supply compartments and have the same ECB pinout in a TO-225AA
package. The BD439 (NPN) BD440 (PNP) or BD441 (NPN) BD442 (PNP) are
similar with an ECB pinout in a TO-126 package but 36 watts. I
suppose you could parallel them with emitter ballast resistors but
that is just as much work as dealing with the wrong pinout nevermind
the mounting considerations.

What is the selection for the NPN MJE2801?
As far as I know, the 151-0349-00 is the raw stock number and the -05 version was selected after a 72 hour burn in. If they selected for
anything, I imagine it was a minimum current gain of 25 hfe at 3 amps.
Here are the selection criteria for the 151-0349-05 (selected from 151-0349-00):
After 72 hour burn-in;
BVceo => 60V, =< 80V @ I(CE) = 200ma
BVcbo => 75V, =< 95V @ I(CB) = 100uA
Icbo =< 100uA @ V(CB) = 60V
Iebo =< 10uA @ V(CE) = 4V
HFE => 25, =< 100 @ V(CE) = 2V, IC = 3A
V(BE(on))) =< 1.4V @ V(CE) = 2V, IC =3A

Cheers,
Dave M
MJE2901 directly crosses to a NTE 183
MJE2801 directly crosses to a NTE 182
Midwest Surplus electronics has a peg board with a lot of ECG/NTE parts and may have it in stock
800-523-3690

 

On Thu, 29 Dec 2011 00:32:58 -0000, "kd8dey" <kd8dey@...> wrote:



--- In TekScopes@..., "David" <dgminala@...> wrote:



--- In TekScopes@..., David <davidwhess@> wrote:

On Wed, 28 Dec 2011 14:20:26 -0000, "froggiegremlin"
<crypto-museum@> wrote:

Hello all: Just got a blown TM503, the MOT power transistors on the heatsink in the back power supply, are blown. Manual has =

PNP Tek 151-0373-00 >MJE2901

NPN Tek 151-0349-00 >MJE2801 selected


Any thoughts on modern and easily obtainable replacements?
I looked into this a couple of months ago and concluded that the BD809
(NPN), BD820 (PNP), MJE2955T (PNP), MJE3055T (NPN), TIP33C (NPN), and
TIP34C (PNP) would be readily available acceptable substitutes in
roughly that order.

Just be careful of the pinouts. The Tektronix TO-127 parts are ECB
while the TO-220AB and TO-247 parts listed above are BCE. I have not
done a serious search for a modern high power part with the same
pinout or TO-3 parts (for high power compartments?).

The 2N5191 (NPN) 2N5194 (PNP) or 2N5192 (NPN) 2N5195 (PNP) are lower
power, 40 watts instead of 90 watts, but might work in non-power
supply compartments and have the same ECB pinout in a TO-225AA
package. The BD439 (NPN) BD440 (PNP) or BD441 (NPN) BD442 (PNP) are
similar with an ECB pinout in a TO-126 package but 36 watts. I
suppose you could parallel them with emitter ballast resistors but
that is just as much work as dealing with the wrong pinout nevermind
the mounting considerations.

What is the selection for the NPN MJE2801?
As far as I know, the 151-0349-00 is the raw stock number and the -05 version was selected after a 72 hour burn in. If they selected for
anything, I imagine it was a minimum current gain of 25 hfe at 3 amps.
Here are the selection criteria for the 151-0349-05 (selected from 151-0349-00):
After 72 hour burn-in;
BVceo => 60V, =< 80V @ I(CE) = 200ma
BVcbo => 75V, =< 95V @ I(CB) = 100uA
Icbo =< 100uA @ V(CB) = 60V
Iebo =< 10uA @ V(CE) = 4V
HFE => 25, =< 100 @ V(CE) = 2V, IC = 3A
V(BE(on))) =< 1.4V @ V(CE) = 2V, IC =3A

Cheers,
Dave M
MJE2901 directly crosses to a NTE 183
MJE2801 directly crosses to a NTE 182
Midwest Surplus electronics has a peg board with a lot of ECG/NTE parts and may have it in stock
800-523-3690
Another good match and with the right pinout as well but wow NTE
replacements are expensive. Changing the transistors in my TM504
would cost more than twice as much as I paid for the whole thing.

tmillermdems <tmiller@...>
 

--- In TekScopes@..., David <davidwhess@...> wrote:


Just be careful of the pinouts. The Tektronix TO-127 parts are ECB
while the TO-220AB and TO-247 parts listed above are BCE. I have not
done a serious search for a modern high power part with the same
pinout or TO-3 parts (for high power compartments?).

Also watch out that you use a proper insulator for the mounting hole. The Tek transistors had molded plastic to insulate from the mounting stud.

Martin Mehlhose
 

hello Jon,

I have a NOS Tek spare 151-0349-00 in my box, you can get it from me.
Original parts are always the best replacements.

greetings
Martin


What is the selection for the NPN MJE2801?

MANY THANKS!

Kind Regards,

Jon


um-gs@...
 

Hi,
having had the same problem (blown power transistor), I found this forum and the topic.
Just to add - there are direct replacement (same case and pin out) transistors available on ebay: NTE182/183

Best Regards, Gordian

 

Hi Gordian,
Thank you for the alternative part numbers for the TM pass transistors. These will probably be fine in the right TM5xx mainframe. However everyone needs to be aware that Tek changed the pass transistors a few times because the transistors they were using became obsolete or hard to get.

The pin out of the pass transistors changed when that happened. At one point Tek realized this would probably happen again and they modified their PC Boards with extra pads on the board so wire jumpers could be installed to adjust for any orientation of the pins during manufacturing.

It was so annoying to figure out which pass transistors were needed for which mainframes that Jerry Scheltgen and I created a table of which pass transistors were used in which TM5xx/TM5xxx mainframes. It is in our archives at
https://groups.io/g/TekScopes/files/TM5xxx%20Pass%20Transistor%20List.pdf

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of um-gs@...
Sent: Friday, May 22, 2020 2:15 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] TM50X transistors

Hi,
having had the same problem (blown power transistor), I found this forum and the topic.
Just to add - there are direct replacement (same case and pin out) transistors available on ebay: NTE182/183

Best Regards, Gordian





--
Dennis Tillman W7pF
TekScopes Moderator

Michael W. Lynch
 

On Fri, May 22, 2020 at 02:26 PM, Dennis Tillman W7pF wrote:


The pin out of the pass transistors changed when that happened. At one point Tek realized this would probably happen again and they modified their PC Boards with extra pads on the board so wire jumpers could be installed to adjust for >any orientation of the pins during manufacturing.<<


Dennis,

Any Idea when TEK might have started adding these pads that you speak of? I installed some new pass transistors in my RM506 and had to do some "creative" adaptations of the transistors that I was able to buy, Perhaps I was simply not seeing these pads on my unit? Or are these pads simply too obvious to overlook?

Thanks!

--
Michael Lynch
Dardanelle, Arkansas

 

Hi Michael,
I should have been clearer. I was referring to the mainframes where the pass transistors were mounted on a PC Board of some kind. In some mainframes they were mounted on part of the chassis and a little 3 wire lead set was used to connect the transistor over to the PC Board. Those chassis mounted ones weren't a problem because the leads could go into the PCB in whatever order they needed to be in.

The later TM5xx PCBoards where the transistor leads were soldered directly into the board had 3 holes for the transistor leads. About 1/4" away was another set of 3 holes parallel to the first 3 holes. You could not miss a PCB that had this special arrangement of holes to accommodate whatever order the transistor's leads were in.. Those other 3 holes went to the all the other places the pass transistor had to go to. There was no connection between the first set of holes and the second set of holes until you inserted short jumpers between them. If your transistor's leads were in the right order you inserted 3 jumpers straight across from one set of holes to the other set. If you transistors leads were in a different order you inserted jumpers so they shuffled the leads into the correct order needed.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Michael W. Lynch via groups.io
Sent: Friday, May 22, 2020 12:53 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] TM50X transistors

On Fri, May 22, 2020 at 02:26 PM, Dennis Tillman W7pF wrote:

The pin out of the pass transistors changed when that happened. At one point Tek realized this would probably happen again and they modified their PC Boards with extra pads on the board so wire jumpers could be installed to adjust for >any orientation of the pins during manufacturing.<<
Dennis,

Any Idea when TEK might have started adding these pads that you speak of? I installed some new pass transistors in my RM506 and had to do some "creative" adaptations of the transistors that I was able to buy, Perhaps I was simply not seeing these pads on my unit? Or are these pads simply too obvious to overlook?

Thanks!

--
Michael Lynch
Dardanelle, Arkansas





--
Dennis Tillman W7pF
TekScopes Moderator

Michael W. Lynch
 

Dennis,
Ah!  That makes perfect sense now that you explained it like that.  My TM506 Rackmount did not have those type of holes.  It would have been nice if it did.

Thanks for the detailed explanation.

Michael Lynch 479-226-0126 Home Phone479-477-1115 Cell Phonemlynch001@...@gmail.commlynch003@...

On Friday, May 22, 2020, 7:19:15 PM CDT, Dennis Tillman W7pF <@Dennis_Tillman_W7pF> wrote:

Hi Michael,
I should have been clearer. I was referring to the mainframes where the pass transistors were mounted on a PC Board of some kind. In some mainframes they were mounted on part of the chassis and a little 3 wire lead set was used to connect the transistor over to the PC Board. Those chassis mounted ones weren't a problem because the leads could go into the PCB in whatever order they needed to be in.

The later TM5xx PCBoards where the transistor leads were soldered directly into the board had 3 holes for the transistor leads. About 1/4" away was another set of 3 holes parallel to the first 3 holes. You could not miss a PCB that had this special arrangement of holes to accommodate whatever order the transistor's leads were in.. Those other 3 holes went to the all the other places the pass transistor had to go to. There was no connection between the first set of holes and the second set of holes until you inserted short jumpers between them. If your transistor's leads were in the right order you inserted 3 jumpers straight across from one set of holes to the other set. If you transistors leads were in a different order you inserted jumpers so they shuffled the leads into the correct order needed.

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Michael W. Lynch via groups.io
Sent: Friday, May 22, 2020 12:53 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] TM50X transistors

On Fri, May 22, 2020 at 02:26 PM, Dennis Tillman W7pF wrote:

The pin out of the pass transistors changed when that happened. At one point Tek realized this would probably happen again and they modified their PC Boards with extra pads on the board so wire jumpers could be installed to adjust for >any orientation of the pins during manufacturing.<<
Dennis,

Any Idea when TEK might have started adding these pads that you speak of? I installed some new pass transistors in my RM506 and had to do some "creative" adaptations of the transistors that I was able to buy,  Perhaps I was simply not seeing these pads on my unit?  Or are these pads simply too obvious to overlook?

Thanks!

--
Michael Lynch
Dardanelle, Arkansas





--
Dennis Tillman W7pF
TekScopes Moderator

 

jon,

we have tons of the real 151-0349 new parts in stock, see here:
https://www.sphere.bc.ca/test/tek-parts/tekparts2.html
they ship cheaply in a padded envelope.

regards,
walter