Greetings.
I work in the audio industry and had my teen years in the back yard of Tektronix , so naturally gravitated to using Tek gear. I am not a collector, just a user,... I use my Tek stuff in a real working environment. Here is a partial list of my lab:
Jennifer

<7000>
7104 opt 2 & 3 1 Gig
7A29 1 GHz 50ohm single
7A19 600MHz 50ohm single
7B10 1 GHz 200mS to 2 nS x10=200pS
7B15 1 GHz Delaying " " "

R7844Dual Beam 400MHz scope
7A24 2 ch 400MHz
7A16A single 150MHz
7B92A 500MHz time base
7B92A 500MHz time base

7834 400 MHz Storage scope
7A16 single 150MHz
7A18 2 ch 75MHz 1meg
7B92A 500MHz time base
7B92A 500MHz time base

Untested, no plug-ins installed
7704A / P7001 digitizer scope

Extra 7000 series items
7A13 Diff Comparator 100MHz
7A13 Diff Comparator 100MHz
7A13 Diff Comparator 100MHz
7A17 150MHz high gain
7A18 2 ch 75MHz 1meg
7B53N 100MHz time base
7B92 500MHz time base
7D10 event count to trigger
7D11 delay time to trigger
7D14 freq counter

Other series
2247A 100MHz Portable
576 Curve Tracer
576 Curve Tracer
575 Curve Tracer
535 10MHz Scope

Also use a pretty good collection of TM500 and 5000 items including Bruce Hoffer's audio masterpieces, the AA501A and SG505 with IMD and balanced out options.

<TM 500 & 5000>
TM5000 w/rack ears
TM5000 w/rack ears
TM506 rack
TM506 rack
TM506 rack
TM506 rack
TM515 suitcase
TM501
TM501
TM503
TM504
TM504
AA501 Distortion test
AA501A Distortion test
AM503 current probe set
with A6302 Current probe
DM501 4.5 digit DMM
DM501A 4.5 digit DMM
DM501A 4.5 digit DMM
DM501A 4.5 digit DMM
DM501A 4.5 digit DMM
DM501A 4.5 digit DMM
SG502 5Hz 500KHz
SG502 5Hz 500KHz
SG502 5Hz 500KHz
SG503 leveled sine 250MHz
SG505 opt 2, balanced out, IMD
FG504 sweep gen 40MHzl
FG507 sweep gen .002 to 2MHz
PG502 pulse 10Hz to 250MHz
PG505 pulse 1Hz to 100KHz
TG501 time base gen
DC503A counter
DC505A counter
PS503A dual power supply
PS501-1
PS lab-built dual supply
SC504 40 meg scope
PS5010 power supply
PS5010 power supply
DM5010 multi meter
DM5010 multi meter
FG5010 20meg function
FG5010 20meg function
2 ) probe tool case plug in
5 ) slot covers

Guess I should have remembered to look there first...

As a last resort, you may need to look at the schematics from some other signal generators of that era and look for the same looking pin-out device. See if there is a part number for that. Transistors might just be general purpose, and crystal footprint generic so should not stop the design of a board, like the ICs would. Someone will eventually pop up with the values.
--
T. Gerbic
Central California

One of these turned up and I wonder what the 104F mod is. Anyone?

On Fri, Oct 21, 2022 at 08:47 AM, Rogerio O wrote:

....
However, the resistance of the +12V to ground was only 18R in contrast of the -12V to ground that was 2.9K.
The +12V regulator is managing to keep the volatge at the nominal voltage, but I could not identify any section of the main board circuit that would explain this low value other than a leaky C297, but this cap has been replaced when I started the repair job.
So my questions are:
1 - Is this low resistance "normal"??
2 - Is it possible that this low resistance is causing the circuit to clip, despite the +12V rail voltage value is correct ?

---
Hi Roger,
You may be seeing semiconductor junctions turning on. Does switching polarity of the ohm-meter leads change the measurement? Does changing the range of the ohm-meter change the measurement?

Observing ?+12V on channel 2 while looking at ramp signal on channel 1 can tell if supply sinking is the issue although it looks like clamping is happening at negative side.
Ozan

Dear all,
Before measuring the signals with the scope as Ozan suggested, I decided to check for continuity and shorts with the unity off.
The resistance of all pins of U350, U305, U360 and U380 to ground was greater than 2.0K.
However, the resistance of the +12V to ground was only 18R in contrast of the -12V to ground that was 2.9K.
The +12V regulator is managing to keep the volatge at the nominal voltage, but I could not identify any section of the main board circuit that would explain this low value other than a leaky C297, but this cap has been replaced when I started the repair job.
So my questions are:
1 - Is this low resistance "normal"??
2 - Is it possible that this low resistance is causing the circuit to clip, despite the +12V rail voltage value is correct ?

I will measure the waveforms with the scope as soon as I can, and post the results on the photo album.
Thanks to all,
Roger
?

You can find the manuals here, I haven't found any more info that what is in this link:

Do you have a pdf of the manual you could put in the files section?

Thanks
--
T. Gerbic
Central California

Hi,? Still searching for the information on this option board if anyone has one?? Thanks!

They have been spoken for. Thanks for the interest.

--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows

开云体育

Perhaps a systematic review might help.

The theory is that the signal progresses from generator to output without distortion (read, flat topping).?

So starting from the generator, identify the stage where the output is bad.? If there are multiple active components between good and bad, then they are all somewhat suspect.? You'd be treating the entire "block" of parts as a unit.

The theory says that an amplifier saturates (flat tops) for a number of reasons.

1) the current required to drive a load is beyond the amplifier's capability.

2) the amplifier swing is insufficient.? This is possible because of:

??? a) insufficient supply voltage

??? b) load resistance (in the amplifier)? is incorrect

??? c) load resistance in the actual load has changed (see #1)

??? d) the bias is wrong.

For (d), perhaps a bit of explanation is needed.? The common 741 op amp has an output swing of VCC+ - 1.5 volts and VCC- + 1.5 volts.? The amplifier clips at 1.5 volts less than the supply voltages.? Absent a transformer or any other kind of voltage step up device, the limit of any amplifier is the supply voltage (or both of them, if applicable).

If a supply voltage is off, or the supply voltage is *effectively* off (through a resistor/capacitor with bad components), then that makes a difference.

So I'd

1) with no steps or the control settings needed for the proper voltage and current steps, measure each voltage on the schematic.? You've checked the power supply voltages, of course, including the decoupled (R series, C to ground) ones.

2) then check to see which step voltage is bad.? This includes both the voltage swing and where the steps start and where they end.

3) analyze that circuit, trying to find the proper DC voltages and AC voltages.

Something is saturating, but what and where?

Apologies if you've done this already, but that's how I'd approach it from the start.

Harvey

On Tue, Oct 18, 2022 at 02:10 PM, Rogerio O wrote:

Dear all,
I came back and checked the signal as suggested.
The signal at the Emitter of Q310 is correct.
However I get the same "plateu" of the staircase signal at pin 7 of U350B.
I have added a photo of this signal in the photo album?/g/TekScopes2/album?id=279289.
Any other suggestion?

---
Hi Roger,
There are only few components around U350B so this is a real puzzle.?

I suggest we keep the scope at 1V/div, DC-coupled, and set trace on X axis when input is grounded. This way we can check if anything is wrong in DC sense. As far as I can tell the scope shots so far has AC coupling selected.

Then in two channel mode:
1) Look at pins 7 and 6 of U350B. We expect no signal at pin 6, and approximately 0V DC.
2) Look at pins 7 and 5 of U350B. We expect no signal at pin 5, and approximately 0V DC.
3)?Look at pin 7 of U350B and left side of R310. We expect signal at left side of R310 to have the opposite slope signal and all the steps.

If there is signal at pin 5 or pin 6 of U350B, R356 may have gone open circuit (perhaps R353 too).

If all above checks look good next step is to look at pin 7 of U350B while changing slope (relay K436-S1). U360 may be loading the output.

I believe you already checked pins 4 and 8 of U350B for proper voltages.?
Ozan

?
?

I have 4 465 part scopes I need to get rid of. One is complete,
one is 99% complete, the other two are missing various bits.
All guaranteed not to work. These came out of a firm that did
CNC repair.

I'd really prefer to not ship these and I don't have time to
part them out myself. Located around Ann Arbor, Michigan.

Prices range from $35 - $55 depending on completeness. Take
them all and get a deal (eg, $100 for all 4).

Drop me a note offlist if interested.

Paul
--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows

Dear all,
I came back and checked the signal as suggested.
The signal at the Emitter of Q310 is correct.
However I get the same "plateu" of the staircase signal at pin 7 of U350B.
I have added a photo of this signal in the photo album?/g/TekScopes2/album?id=279289.
Any other suggestion?

I'll check that out some time.

I did note that some other elements of the CAL 06 instructions were less than ideally written; for example where you need to repeat tests for CH2 after doing CH1 it simply says to repeat "n" intermediate steps but without actually? re-naming and listing them so you have to try to remember at which step you had to do certain things.

Hi all,

My 7L13 Spectrum Analyzer is back up and running but has some instability and other idiosyncrasies. After having a Tantalum fail recently, it is time to replace as many of the Tantalums as practical. I don't intend to replace them all, just the ones that I can get to without major disassembly or causing any damage. I also intend to re-seat transistors and chips that I can get to.

My problem is the removal of both the DVM Readout and DVM Analog PCBs as per the Maintenance section of the 7L13 Manual, page 6-8 in my Version to get to Tantalum cap C2000. Looks simple, should be simple ... . but the Readout PCB will not come out. I have the DVM Analog PCB out okay, everything disconnected and the Readout PCB tilted "almost" as per the photo on page 6-9 Fig 6.5B ... but not quite enough. I have the PCB 'flexed' slightly already .... I am worried about flexing the Board further and breaking it.

Has anyone here done this?? Am I missing something simple here??
Any advice??

If too difficult, I will leave it alone as it tests 'good' in circuit ....

Cheers,
Ian, Melbourne, Australia

Most of my customers were interested in the "B" scopes, so I never
did enough 2465A/2467's to remember much about them. I did do a lot
of 2465's, though.

I took a quick look at the 2467B instructions vs the 2467 instructions,
and it looks like they may be missing a step. You should put them side
by side to make sure they make sense. I think they forgot to tell you
to get out of the calibration routine by pressing trigger A/B...

One thing to note is the "standard frequency" for all of the older
scopes was 50KHz, but that doesn't show enough of the wave form to
show a peak-peak value for the bandwidth test, so they changed the
standard frequency to 6MHz for the 2465 family of scopes.

-Chuck Harris


On Sun, 16 Oct 2022 05:09:24 -0700 "NigelP"
<nigel-pritchard@...> wrote:

I have just done the CAL 06 in full using PG506 without TD pulser and
using a HP 8657B in place of a secondary levelled generator. I've
used a switchable 90dB 2GHz 1 dB step attenuator in place of the
individual 2/2.5/5X attenuators (because I don't have a complete set
of individual attenuators and the step attenuator anyway was
simpler). The attenuator sets used in the CAL work out to 6dB, 20dB
and 28dB. Most adjustments were pretty much optimised already, which
is what I expected since the scope was fundamentally operative from
the outset and there were no obvious signs of any repair/replacement
work; just one or two subjective tweaks.

One thing puzzled me though; I couldn't complete steps q-v *as
written* because no waveform actually appeared on CH2.... but it did
appear on CH1 when I connected the generator there! Is there an error
in the text? In CAL mode the channels buttons are not illuminated so
you can't tell which channel is selected.

I have just done the CAL 06 in full using PG506 without TD pulser and using a HP 8657B in place of a secondary levelled generator. I've used a switchable 90dB 2GHz 1 dB step attenuator in place of the individual 2/2.5/5X attenuators (because I don't have a complete set of individual attenuators and the step attenuator anyway was simpler). The attenuator sets used in the CAL work out to 6dB, 20dB and 28dB. Most adjustments were pretty much optimised already, which is what I expected since the scope was fundamentally operative from the outset and there were no obvious signs of any repair/replacement work; just one or two subjective tweaks.

One thing puzzled me though; I couldn't complete steps q-v *as written* because no waveform actually appeared on CH2.... but it did appear on CH1 when I connected the generator there! Is there an error in the text? In CAL mode the channels buttons are not illuminated so you can't tell which channel is selected.

Lee, You are Correct.? The outer knob comes off the shaft first by releasing the set screw.? The larger dial control bezel mechanism and pot remain, held in place by the spanner nut, ? The spanner nut is then removed, which frees the outer dial bezel which is then removed. At that point, the pot simply slides out from the back of the front panel.

? Thanks for the reply. I don't think it's correct, though. After removing the inner knob, I can see a screw on washer with two slots in it that secures the outer knob and the pot shaft together.? I managed to get it to unscrew using a pair of motorcycle brake cylinder circlip pliers, then the outer part of the knob and? the pot were released.

--
Lee K. Gleason N5ZMR
Contro;-G Consultants
lee.gleason@...