Re: A question from the unwashed relative to: I built a TM500 mainframe tester...
Tha me to all, I have not had the opportunity to review any of the literature or watch the video. I appreciate everyone filling in the blanks for me! -- Michael Lynch Dardanelle, AR
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Mlynch001
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#175864
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
I should perhaps point out that since there are 12 connections on each of two sides of the backplane connectors that someone might want to gain access to, it is very easy to run out of space on the
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Colin Herbert
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#175863
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Re: A question from the unwashed relative to: I built a TM500 mainframe tester...
If anyone else needs some more info on what the tester was intended to do when Tektronix came up with the idea, it is useful to check out Tekwiki (https://w140.com/tekwiki/wiki/067-1201-99), as indeed
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Colin Herbert
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#175862
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Some time ago I had similar thoughts on accessing the connections to the pass transistors, as well as accessing the 25 VAC connections. I had a problem on one of my TM50X mainframes with one of these
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Colin Herbert
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#175861
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Re: A question from the unwashed relative to: I built a TM500 mainframe tester...
Yep, the mainframe tester tests for short/leakage and beta, along with the DC and AC voltages, and phasing of the two floating AC windings.
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Jared Cabot
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#175860
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
Hi Larry, I might well be interested in a board set, so long as the cost and shipping to London, UK aren't too crazy. I have been intending to build one of these testers for a while and have a few of
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Colin Herbert
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#175859
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Re: A question from the unwashed relative to: I built a TM500 mainframe tester...
Yes, These will cause a cascade of failures with certain modules. I always try to at least diode check those pass transistors before inserting any module or powering up. So your Mainframe tester
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Michael W. Lynch
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#175858
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Re: A question from the unwashed relative to: I built a TM500 mainframe tester...
The trick is a bad pass transistor can quickly kill a module, which can then go on to kill another slot in the mainframe, etc etc. Using a module (that isn't the purpose built tester) to test the
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Jared Cabot
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#175857
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
I just used a prototype board and brought the pins out. I am sure that the traces on a dead plug in could be isolated and used as well. I find that many of the transistors read lower gain than
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Ed (SCSKITS)
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#175856
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Re: Quick question 564B
Ok, Thanks Chuck.
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Stephen
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#175855
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2230 storage deja vu
Hi all Quite a lot of years ago there was a topic posted here that went on for some time but never reached any conclusion as to the cause of the problem...unfortunately the exact problem I think I'm
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Kevin
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#175854
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Re: Quick question 564B
It is a cute little scope, but very low bandwidth, something like 10MHz. Its HV transformer suffers from the epoxy disease that affects 547 scopes. They are quiet, not having a fan, and the plugins
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Chuck Harris <cfharris@...>
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#175853
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Re: Slightly OT: How can I dissolve Potting Compound?
Dennis the 26 cm Spectral tubes are the most popular, used in physics labs These use 5 kV open ckt current limited transformers and run at 5 - 20 mA. The optical spectrum is dependent on gas mix, and
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Jean-Paul
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#175852
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Re: Grid Bias Adjustment on 475A
The mesh is an electrostatic lens that magnifies the limited vertical and horizontal deflection to fill the viewing screen area. This is done to allow a lower deflection plate voltage on a fairly
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Chuck Harris <cfharris@...>
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#175851
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Quick question 564B
Hi all, and Happy New Year 2021, Is a 564B a good grab, is it desirable at all? It¡¯s not considered a 500 series, right? 56x family I suppose... Thanks ?
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Stephen
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#175850
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Re: How to clean Helitrim potentiometers?
Hello perhaps you are confusing Helipot a multiturn precison 3,5,10,15 turn potentiometer with internal 1 turn pcb mounted trimpots or single turn controls? If you can pr¨¦cis your questions with
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Jean-Paul
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#175849
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Re: font/typeface for Tektronix binder spines - was Re: [TekScopes] Push button font
I'm sorry I arrive pretty late in the conversation. There are online tools to identify fonts, with easy yes/no questions. I used one once to find which font was used on Philips instruments (for a
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nicmatfr <nic_o_mat@...>
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#175848
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Re: Slightly OT: How can I dissolve Potting Compound?
Dear Dennis: We worked on arc and gas lamp ballasts since 1970s. Then designed and manufactured 12 kV HV modules, in 1980s..1990s. The encapsulant is a very high solids epoxy, specially cured. We used
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Jean-Paul
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#175847
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
HI Please,Larry,add me to the list.I am located at Spain. Regards.
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iMac
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#175846
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Re: I built a TM500 mainframe tester, and updated the design. Someone might find this useful?
I would also be interested in a set of the boards, please add my name to the list. I am in Dublin, Ireland so I am aware that shipping will be somewhat more than the nominal amount suggested. I am
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Peter Mulvey
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#175845
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