need about 6-10 MPS-u45 or CEN-u45.  Anyone have any spares or know good spot to get them?  I'll even take an old system 80b driver board that is no longer being used!

thx

I had purchased some from Ed at Great Plains Electronic,
a while ago:

http://www.greatplainselectronics.com/

I unfortunately have no extra spares at the moment
(will need to order more soon).

Cheers,
- Sylvain.

Ok after some research mpsu45=cenu45=nte272--a much more widely available part.  feel free to have a gander at the datasheets--let me know if I missed something!

cenu45: http://www.chipcatalog.com/Datasheet/4635B0DDBB90ED1D7CC54A3F19C54F83.htm

nte272 : http://www.nteinc.com/specs/200to299/pdf/nte272.pdf

hmm looks like nte272 isn't any easier to find--chrissakes why does this have to be so complicated  

Quoted from theothermenace

why does this have to be so complicated  

part of the *fun* of they hobby

Make sure you perform the mandatory ground mods
along with connectors/pins checks and replacement if needed,
while you are at it. Pay a particular attention to the
large harness/connectors between the MPU and Driver boards.
(otherwise more component frying could occur)

Much info available on the web:
http://www.pinrepair.com/sys80/index1.htm#ground

Cheers,
- Sylvain.

For those not following this thread on CGCC, another industry standard part# that could be used in place of the MPSU45 is a 2N6548.  It's the same part electrically, but it's in a TO202 package instead of the 152-02.

I could probably purchase some of these directly from a Mfg @ work, but the minimum might be 100pcs, so would only make sense if enough people needed them. (maybe I could re-stock Ed @ GPE )

D.

So I ordered a replacement part from the pinball resource (mps-w45a) the only thing is is that electrically they are the same but the heat dissaption with the 45a's is a fraction of that with the original u45's.  I questioned pinball resource on this but have yet to get a response.  Anyone have any thoughts on this?  the u45 was a TO-220 package while the 45a is a TO-92 package style (smaller)

The heat dissipation spec is typically quoted with transistors
mounted on a suitable heatsink, with thermal grease compound.

On these Gottlieb driver boards, there are no heat sinks for
those TO-220 darlington drive transistors, as not much heat
is dissipated in them at all, in normal working operations of
the pinball machine.

In any case, for a TO-220 or TO-92 transistor, there is really
not much heat you can dissipate from either of those, in
free air/no heatsink... Sure, a TO-220 can dissipate a bit more,
but not for long (with no heatsink) before it will self-destroy due
to thermal runaway (in a circuit where the transistor is partially
conducting).

While your replacement transistors are smaller, they should still
operate correctly, providing the connectors are fine (especially the
large MPU to driver board one), and the ground mod performed
(and the load OK (no shorted coils, and good diode/proper orientation
across coil !!)).

Otherwise the new transistors will short again, regardless if they are in
a TO-220 or TO-92 package.

Good luck!

Cheers,
- Sylvain.

Thats some great info!!! thanks!!!

Quoted from theothermenace

So I ordered a replacement part from the pinball resource (mps-w45a) the only thing is is that electrically they are the same but the heat dissaption with the 45a's is a fraction of that with the original u45's.  I questioned pinball resource on this but have yet to get a response.  Anyone have any thoughts on this?  the u45 was a TO-220 package while the 45a is a TO-92 package style (smaller)

Hi Guys!

The MPSW45A is a heavy duty version of the MPSA13 but is NOT a good sub for an MPSU45/CENU45.

The A13 transistors are sized to drive one lamp and the U45 transistors are sized to drive two lamps -- sized to solidly drive them over long durations.  The thermal resistance of a W45 transistor is only slightly lower (better) than that of an MPSA13 transistor. But, the MPSW45 transistor --WILL-- still overheat if driving two #44 lamps continouosly.  
To properly drive two lamps - you must use the U45 type transistor with the TO-202 type case for proper heat dissipation.

Ed (GPE)

Ed at maaca ?! COOL!!   Hi ED!