font/typeface for Tektronix binder spines - was Re: [TekScopes] Push button font
Turns out I have considered something suitable for binder spines before: View/Reply Online (#146250): /g/TekScopes/message/146250 I also took a shot of my own shelf with some sample
By
toby@...
·
#175779
·
|
Re: SC-502 transistor
From Tek specs, it's a D44H11 NPN, currently available from STMicroelectronics, OnSemi, etc. at price of approx. 90 eurocents each Icmax = 10 A Bvceo = 80V hFE 60 @ Ic = 2 A Vcesat = 1 V ft min = 50
By
unclebanjoman
·
#175778
·
|
11801C T2325 error diagnostic repair
Can anyone shed light on what is involved in repairing a unit showing that error? Thanks, Reg
By
Reginald Beardsley
·
#175777
·
|
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Ah yes, the switch is physically constructed as two gangs of 12 contacts, with two oppositely opposed wipers per gang. You can insert some pins to physically limit rotation so the two wipers never
By
Jared Cabot
·
#175776
·
|
Re: A question from the unwashed relative to: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Thank you Harvey! That is pretty much what I had surmised but I was not sure. So, I have three function generators and a few DMM etc... My RTB also has a generator and frequency counter and more.
By
Lawrance A. Schneider
·
#175775
·
|
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
I also would be interested in a set Stan
By
Stan Corbett
·
#175774
·
|
SC-502 transistor
HNY to everybody! In my SC-502 scope transistor Q855 died. It is a GE X44HR242 in TO220 case, but I was unable to get its specifications in order to find a suitable substitute. Thanks for your help
By
Giovanni IZ5PQT
·
#175773
·
|
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
ADT name to the list as well, please.
By
Stephen
·
#175772
·
|
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Hi all, I'll add my name to the list as well. You have to grab these things as they go by! Cheers Phil / W1PJE
By
W1PJE
·
#175771
·
|
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Jared, Your manual lists S3 as 4P6T. Entering that part number in Digikey shows it as 2P6T. Is there a typo somewhere?
By
Steve Goldstein
·
#175770
·
|
Re: Grid Bias Adjustment on 475A
Tom, Thanks for setting me straight. Yes, when I draw the simple schematic it's pretty obvious what's happening, and why the measured resistance of the pot has a humped profile (when you reach the
By
Jeff Dutky
·
#175769
·
|
Re: Grid Bias Adjustment on 475A
Hi Jeff, I misunderstood -- I thought that all of your pot measurements were done with at least 2 terminals isolated. If you did not isolate the terminals, your measurements don't really point to
By
Tom Lee
·
#175768
·
|
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Please add me to the list! it is an interesting project! Thanks Mike
By
Mike Usher
·
#175767
·
|
Re: Grid Bias Adjustment on 475A
Tom, I measure 2.6 K ohms between the two non-wiper terminals, but the pot is still in circuit, so this is really measuring everything that bridges the +50 V and ground planes in parallel, so is this
By
Jeff Dutky
·
#175766
·
|
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
The ballpark sounds great, count me in! Dave S.
By
Dave Seiter
·
#175765
·
|
Re: Grid Bias Adjustment on 475A
If it is indeed the trimpot, that is an unusual failure mode. I can recall seeing something similar only once, and it was due to a small sliver of solder that managed to bridge the pads connected to
By
Tom Lee
·
#175764
·
|
Re: Grid Bias Adjustment on 475A
I lifted one end of C1374 and tested it with my DMM916. It acted much more like a capacitor than like a resistor: while measuring resistance I could see it charge up (the resistance increased over
By
Jeff Dutky
·
#175763
·
|
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Yes, the PCB shops really don't like putting black solder mask on boards.? Not yellow or clear, either.? ?Best to go with standard green.? The other colors mess up their production flow.? ?Jim
By
Jim Ford
·
#175762
·
|
Re: A question from the unwashed relative to: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
This is correct. I have an FG504 and such a TM504 that I had to correct the phasing on. The FG504 in trying to reach a +-050VDC rail stacks a 32VDC and a 25VAC on top of each other for both positive
By
EJP
·
#175761
·
|
Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
One small addendum to this, the PCB's will likely not be black as that is a premium option that adds significant cost. They will most likely come in the usual green (more period accurate! :) ) to save
By
Jared Cabot
·
#175760
·
|