DW, My "ZERO Line trace" stays flat, right against the bottom of the CRT graticule. When testing a transistor with the steps set to 1, I see two lines, the first is that "zero line trace" at the

Michael, Thanks for the reply. From what you observed I am not getting the same results. The phenomenon I am experiencing seems to be an issue with improper biasing on the base terminal. When you

A schematic for the -00 version of the board is in the datasheet link on the TekWiki page to which Dennis pointed. DaveD

Hi Eric, I can't help with a schematic, but there is some information on this card on TekWiki at http://w140.com/tekwiki/wiki/067-0912-00 Dennis Tillman W7pF

I am thinking about trying to tackle a calibration on my 7854. I have confirmed that the digital and analog sections are out of adjustment. The digital section is about .8 division left of center. In

They did not use the same part number for two different parts. The 455 and 465M both use the U550 designation in their schematics, both use the identical TEK part # 152-0635-00. 152-0635-00 is the

Thanks Chuck 73 Richard W4MCD

This is my newest 7A26 (main PCB code 670-2549-21)! S/N 709928, so Heerenveen. It's the only one in my collection with a green PCB and 155-0078's with date code "429", I guess that's 8429. Raymond

Hi Roger, Since these components constitute most of the common parts, I had done some testing in that area. I checked Vbe across Q820 / Q840, Q860 / Q880 and they were correct. I pulled Q860 and Q880

Hi John, I know the problem with the trimmer caps. I found several that had no effect, initially blaming that on the lack of HF content in the signal as it appears and not expecting a multi-device

Hi John, Both edges show the same behavior. Raymond

Omit, previous message as I see your title, plainly states, "available for free".... Still waking up, here. Good price for a hobbyist with little to spare. Best email is Cjuried@... and phone is

Sure. Cjuried@... how much are you a asking?  Chris Juried, WRCB719 FCC Licensed RF Coordinator Audio Engineering Society (AES) Member   InfoComm-Recognized AV

Hi Szabolcs, By any chance, are you related at all to the violinist Joseph Szigeti? --Cheers, Tom -- Prof. Thomas H. Lee Allen Ctr., Rm. 205 350 Jane Stanford Way Stanford University Stanford, CA

Hi, This could be a lot of things. But the first thing is to check the power supplies. If you don't have the service manual, first get it from for example TekWiki:

Thanx for the info David. I had the same experience with trace intensity variations on a 547. After several hours searching and measuring it was a voltage variation on the grid of V800, and so

John Miles KE5FX has an excellent "Service Notes" on his web-site that detailsa lot of information about what needs to be done with an old 492/494 Tek Analyzer. Apart from this information, I also had

Raymond, A simple test - lift one end of each of CR860, CR880 and see if the signal behaves as it should. Roger

Raymond, The picture suggests that the signal might be switching from the full bandwidth to the 20MHz version at around the 40% level. Have you looked at the biassing of Q860, Q880 and also for

Raymond, The 7A26 has a number of small ceramic trim caps of a design that has proved to be prone to going open circuit. You may have failures at the same point of both channels, unlikely as that