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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
By Jared Cabot · #175857 ·
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
By Ed (SCSKITS) · #175856 ·
Re: Quick question 564B
Ok, Thanks Chuck.
By Stephen · #175855 ·
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
By Kevin · #175854 ·
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
By Chuck Harris <cfharris@...> · #175853 ·
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
By Jean-Paul · #175852 ·
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
By Chuck Harris <cfharris@...> · #175851 ·
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 ?
By Stephen · #175850 ·
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
By Jean-Paul · #175849 ·
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
By nicmatfr <nic_o_mat@...> · #175848 ·
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
By Jean-Paul · #175847 ·
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.
By iMac · #175846 ·
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
By Peter Mulvey · #175845 ·
Re: SC-502 transistor
Thank you to everybody! I have enough information to attempt a transplant. I'll post here the outcome Giovanni
By Giovanni IZ5PQT · #175844 ·
Re: Slightly OT: How can I dissolve Potting Compound?
Hi Dennis, I believe it's not worth the effort, I'd personally build a new one using instructions from Sam's Laser FAQ: https://www.repairfaq.org/sam/laserhps.htm#hpstoc You'll find wealth of
By Nenad Filipovic · #175843 ·
Re: Slightly OT: How can I dissolve Potting Compound?
Supposedly a 50/50 mix of formic and acetic acids will do the trick but I've never tried it. DaveB, NZ
By Dave Brown · #175842 ·
Re: Slightly OT: How can I dissolve Potting Compound?
My approach to this sort of problem (I¡¯ve done it twice in the past thirty or so years) has been to use an Xacto knife to cut the potting compound away. I never did find a solvent that seemed to
By Dave Daniel · #175841 ·
Re: A question from the unwashed relative to: I built a TM500 mainframe tester...
Just a thought: I wonder if there are TM500 modules which are particularly picky on correct functioning of the mainframe. Such a module would - use all or most of the interface - show malfunction
By Martin · #175840 ·
Re: Slightly OT: How can I dissolve Potting Compound?
I guess the point I was getting at but missed, was that it was labeled as containing acetone, but nothing else.? I try to stay away from beauty products (they wouldn't help me- hahaha!), but when it
By Dave Seiter · #175839 ·
Re: Slightly OT: How can I dissolve Potting Compound?
Also xylene. Be careful of MEK, it will dissolve rubber gloves. -- Richard Knoppow dickburk@... WB6KBL
By Richard Knoppow · #175838 ·