Dennis, you're a saint! Sorry that no good deed goes unpunished! Happy New Year, Tom Sent from my iThing, so please forgive the terseness and typos.

Chuck, Thanks for that as I did not feel qualified to make such a statement, based on my very limited knowledge of the subject. Appreciate that you have confirmed that I am not totally without a

Dennis, THANK YOU. I know that we do not say this enough for all that you do to keep this group running smooth. You are GREATLY appreciated! Sincerely, -- Michael Lynch Dardanelle, AR

That and perhaps what he asserts is nonsense? The grid is most assuredly biased relative to the cathode on this, and probably any, CRT. -Chuck Harris Michael W. Lynch via groups.io wrote:

Hello Many moons ago I saw a topic on here regarding the 2230 and a storage display problem and as far as I could tell it never reached a conclusion. Unfortunately it is the problem I have now...or

This morning I mailed 76 of Peter Keller's books. These went to 72 people in the USA who ordered Peter's book. At the request of our currently shorthanded post office staff I have been asked to wait

David, This may be the source of confusion for those of us not as well versed in these issues. Regardless of your fine technical explanation, TEKTRONIX still calls R1375 "GRID BIAS" on the

I also would be interested in a set of boards if they aren't too pricey. A source of the mechanical parts is plug-ins for the 5000 series scopes e.g. 5103, 5440, which use exactly the same form

" unable to get a visible spot on screen at the +15 V intensity level as indicated in the service manual. I had to crank the intensity up nearly to maximum, and then the trim pot (R1375) for grid bias

Jeff, Can you measure the voltage drop across the diode? That is partially how I discovered the "bad" VR1374 on my 475. You should measure 82V across the diode. Here is my conversation with Chuck

Why bother trying to find unobtainum parts when Tektronix specifies "official" modern/current production substitutes (see crossref document)?

Can't help you with data on those GE transistors but WB Parts seems to have has a pile of them in stock: https://www.wbparts.com/rfq/5961-01-048-5632.html They were used by the military and exist

Hi Giovani, Look for the Tektronix part number in the service manual, it should be something like 151-0426-00. Then use the semiconductor cross reference (big PDF file):

Turns out I have considered something suitable for binder spines before: View/Reply Online (#146250): https://groups.io/g/TekScopes/message/146250 I also took a shot of my own shelf with some sample

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

Can anyone shed light on what is involved in repairing a unit showing that error? Thanks, Reg

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

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.

I also would be interested in a set Stan

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