[time-nuts] Tektronix TM500 Series Help

Don Latham djl at montana.com
Sun Jan 3 06:43:25 UTC 2010


Try these guys:
http://www.sphere.bc.ca/test/
I've dealt with them for Tek parts in the past; they are quite good.
Don

----- Original Message ----- 
From: "Don @ True-Cal" <True-Cal at swbell.net>
To: <time-nuts at febo.com>
Sent: Saturday, January 02, 2010 1:33 PM
Subject: [time-nuts] Tektronix TM500 Series Help


> Happy New Year to all!
>
> In working on my TM501 which serves as the power supply for my AM503B 
> current probe, I had to dismount the 2 series pass transistors from the TM 
> case (heat sink). After repair (filter caps) and during remounting the 
> circuit board, Q12 transistor TO-127 case fractured while bending the 
> leads. This transistor is one of the two series pass transistors that some 
> TM-Series modules use as external mounted power devices. These two 
> transistors are used mostly with PSxxx power supply modules. They are not 
> actually used as active components of the TM501 and fortunately for me, 
> not used with the AM503B module so I am up and running again. I would like 
> to fix this situation so I could use this TM501 with any/all modules.
>
> The manual (and device) says Q12 is an NPN, SI, Selected, TO-127 SJE924. 
> For completeness, the complementary Q10 is a PNP, SI, TO-127 SJE925. These 
> transistors types are the same across any TM-Series mainframe.
>
> I can't find any SJE or MJE 9xx reference. Does anyone have a cross 
> reference or know of a substitute device for these transistors? I tried a 
> MJE3055 which is very general purpose and it does not work with a PS503A 
> power supply module. This, plus the word "Selected" in the manual, says to 
> me that something (Hfe?) must be fairly critical. Another alternative is 
> someone with a junker TM mainframe that would be willing to pull one or 
> both of these transistors.
>
> Regards...
> Don
> _______________________________________________
> time-nuts mailing list -- time-nuts at febo.com
> To unsubscribe, go to 
> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there. 




More information about the time-nuts mailing list