Re: 7A26 no signal
Thanks for the guidance, I suppose I have to take the cleaning challenge first as there are couple of suggestions for it. As I didn't get any signal to R130... I am also getting another unit to
By
Jouko Koskinen
·
#173841
·
|
Re: A Couple Restorations
Bob, Where are you located? there is a small handheld Tektronix scope in a surpus store near me and that I can probably get cheaply. As best as I can remember it is a 2xx model but I don't remember
By
-
·
#173840
·
|
Re: Resistor in series
Hi Tom, You must have done that calculation before the thread caught my attention. I've checked everything I wrote, and I don't see anywhere that I have said, "but they might still have made a
By
Chuck Harris <cfharris@...>
·
#173839
·
|
Re: To pay for Peter Keller's Book ...
Thanks larry
By
Lawrance A. Schneider
·
#173838
·
|
Re: (OT) Where to go for 70s IBM hardware? I'm looking for a terminal.
I have a pile of old IBM and Telex terminals from a local school system when the state moved away from old IBM mainframes. They are stored in my garage, but I am unable to get to them without help.
By
Michael A. Terrell
·
#173837
·
|
Re: Resistor in series
Carbon Composition resistors absorb moisture. Bake them for a while before tossing them out. Also, high value resistors require voltage across them to work at their marked value This used to be
By
Michael A. Terrell
·
#173836
·
|
Re: 7A26 no signal
I have just checked input resistances on a working-to-spec 7A26, the results are quite unexpected!. If I use an analogue meter and have the 7A26 powered off then in the 10mV position the DC
By
Roger Evans
·
#173835
·
|
Re: Why you MUST USE the PayPal "FRIENDS and FAMILY" option for Peter's book
I thought about this a bit, with the huge volume of paypal transactions every day across the world, the actual number of horror stories would have to be a fraction of a fraction of a percent.
By
Jared Cabot
·
#173834
·
|
Re: Delay Time Position Vernier
I don't recall seeing it in any Service Manual, but our good friend H?kan has produced a document on the topic: http://www.hakanh.com/dl/docs/hardtofind/dtmsettings.pdf Colin.
By
Colin Herbert
·
#173833
·
|
Re: Tektronix 492A input attenuator repair ????
Once I had the same issue with the 492 attenuator. Taking it carefully apart, one of the wafers was burned. I was able to manufacture a wafer myself, using very thin teflon laminate and 0402 SMD
By
Ulf Kylenfall
·
#173832
·
|
Re: Resistor in series
OK, yuzz made me look. I found the schematic for the 475A, and my quick assessment is that there's nothing special about low capacitance or inductance or precise value of the R1356/R1544 combo. I also
By
Ed Breya
·
#173831
·
|
Re: 7A26 no signal
Colin and Juoko, If the 7A26 is arranged anything like the 475 then cleaning the AC/GND/DC coupling switches is almost exactly the same as cleaning the rest of the attenuator switches: soak a narrow
By
Jeff Dutky
·
#173830
·
|
Re: (OT) Where to go for 70s IBM hardware? I'm looking for a terminal.
Wish I had kept my Commodore PET/CBM systems... -Dave
By
Dave Seiter
·
#173829
·
|
Re: Why you MUST USE the PayPal "FRIENDS and FAMILY" option for Peter's book
John Goller wrote: I don't have particular issues, other than complaints about this particular process (not being offered the options that would have made this process easy), and about the quality of
By
Jeff Dutky
·
#173828
·
|
Re: Resistor in series
Hi Jeff, I've only taken a quick look at the circuit, but it doesn't look overly fussy about the exact resistance value, so the carbon comps you bought are likely to be fine if they are still within
By
Tom Lee
·
#173827
·
|
Re: Choosing the right replacement cap
Dave, Thanks. I saved the URL. Ananda
By
Ananda
·
#173826
·
|
Re: Resistor in series
Tom, Yes, I had anticipated that these NOS components might not have retained their specified values. I've been going through my father's effects while working on his scopes and finding all sorts of
By
Jeff Dutky
·
#173825
·
|
Re: Resistor in series
Jeff, I don't know what the circuit context is here, but if carbon comp types were originally used, then the exact value isn't that critical. If they have drifted badly (typical after many years), and
By
Ed Breya
·
#173824
·
|
Re: Resistor in series
Hi Jeff, You are correct that, depending on value, metal film resistors can have significant inductance (relative to the carbon comp version). In this particular circuit, though, you are looking at
By
Tom Lee
·
#173823
·
|
Re: Delay Time Position Vernier
Colin, I've looked at five different scopes with a delay vernier and only one of them (a 2215) seems to be set at something other than 0.0 at the extreme CCW rotation. All three 475s and the 475A that
By
Jeff Dutky
·
#173822
·
|