开云体育

"In the hv section, see if the .01mfd condensers are ceramic or tubular" Are the ones you refer to high voltage types IE 1KV +?

Yesterday I pulled the CRT in order to clean the X & Y plates connecting pins. I cleaned the CRT, it wasn't too mucky. I checked the connections at the start but always a bit wary of them due to corrosion etc elsewhere in the scope. I tried to removed the oxidation of the pins with 800 grit wet & dry as well as twisting by hand a small drill bit inserted into the spade type crimped connections.

I noticed the trace had moved to the right a bit after this & whilst trying to take V measuements on the X/Y CRT pins my meter probe slipped, big sparks & a small bang, switched off. I'd vaporized a wire lead to V574B and a 47r grid stopper. Interestingly the trace is now the opposite of what it was stuck on the RHS.

This leads to once again suspect the horizontal amplifier but I'll still check the EHT supplies etc & make sure all connected components are in spec or caps not leaky. I can test up components up to 10KV using a vintage equivalent of a Megger. Here's a link to the videos so far - not the best filmed & produced films but should show whats what.

Thanks again for all your help & support, Andy.

I should probably update the PDF of the manual on the TekWiki site. That'll
take a bit longer.

DaveD
KC0WJN


On Fri, Mar 21, 2025 at 16:08 Dave Daniel via groups.io <kc0wjn=
[email protected]> wrote:

I have been skimming this thread, since I have a 7934, but not really
paying close attention to it.

I have an original 7934 manual from Tektronix, dated May 1986. It does have
pages 6-22 and 6-23. I can scan and upload them or send them privately.
It'll take me a day or two to do that.

DaveD
KC0WJN


On Fri, Mar 21, 2025 at 15:51 Bill via groups.io <wpgold3637=
[email protected]> wrote:

After looking at 3 totally different scans of the same printing of the
7934 manual I don't believe that pages 6-22 and 6-23 were in any manuals
from the first printing. My three scans show file sizes of:
1. 112,361 KB Title "7934 Oscilloscope (1986) WW.pdf" 464 pages
long
2. 210,637 KB Title "7934.pdf" (SECURED)
470 pages long
3. 72,903 KB Title "Tektronix-7934-service,user-ID2530.pdf" 501
pages long
#3 in the "schematics" section, the pages have been scanned 1/2 page at a
time for those pages that were probably "B"size in the original manual.

In

some cases they were scanned in 1/3 page at a time.
#2 in the "schematics" section the pages are scanned the whole page at a
time.
#1 same as #2.
There are other differences in the "schematics" sections with sizes of

the

pages, when I go through the pages at the same magnification settings of
the Adobe Reader. #2 has some protection applied and is "SECURED". I
can't use the "Snapshot Tool" from the "Tools" menu. In one scan I can

see

the holes for the spiral binding which the others don't have on the same
page. There are other differences on the placement of some texts. But
that could be from the scanning process. I don't know.
My conclusion and best guess is that, believe it or not, Tektronix did

NOT

print those missing pages in the first printing dated "May 1986". GASP!
There are pages of "CHANGE INFORMATION" in the back of each scan. One
shows signs of being stapled while others don't show this.
However is anyone can find those missing pages please scan and post them.
Bill

I have been skimming this thread, since I have a 7934, but not really
paying close attention to it.

I have an original 7934 manual from Tektronix, dated May 1986. It does have
pages 6-22 and 6-23. I can scan and upload them or send them privately.
It'll take me a day or two to do that.

DaveD
KC0WJN


On Fri, Mar 21, 2025 at 15:51 Bill via groups.io <wpgold3637=
[email protected]> wrote:

After looking at 3 totally different scans of the same printing of the
7934 manual I don't believe that pages 6-22 and 6-23 were in any manuals
from the first printing. My three scans show file sizes of:
1. 112,361 KB Title "7934 Oscilloscope (1986) WW.pdf" 464 pages
long
2. 210,637 KB Title "7934.pdf" (SECURED)
470 pages long
3. 72,903 KB Title "Tektronix-7934-service,user-ID2530.pdf" 501
pages long
#3 in the "schematics" section, the pages have been scanned 1/2 page at a
time for those pages that were probably "B"size in the original manual. In
some cases they were scanned in 1/3 page at a time.
#2 in the "schematics" section the pages are scanned the whole page at a
time.
#1 same as #2.
There are other differences in the "schematics" sections with sizes of the
pages, when I go through the pages at the same magnification settings of
the Adobe Reader. #2 has some protection applied and is "SECURED". I
can't use the "Snapshot Tool" from the "Tools" menu. In one scan I can see
the holes for the spiral binding which the others don't have on the same
page. There are other differences on the placement of some texts. But
that could be from the scanning process. I don't know.
My conclusion and best guess is that, believe it or not, Tektronix did NOT
print those missing pages in the first printing dated "May 1986". GASP!
There are pages of "CHANGE INFORMATION" in the back of each scan. One
shows signs of being stapled while others don't show this.
However is anyone can find those missing pages please scan and post them.
Bill

After looking at 3 totally different scans of the same printing of the 7934 manual I don't believe that pages 6-22 and 6-23 were in any manuals from the first printing. My three scans show file sizes of:
1. 112,361 KB Title "7934 Oscilloscope (1986) WW.pdf" 464 pages long
2. 210,637 KB Title "7934.pdf" (SECURED) 470 pages long
3. 72,903 KB Title "Tektronix-7934-service,user-ID2530.pdf" 501 pages long
#3 in the "schematics" section, the pages have been scanned 1/2 page at a time for those pages that were probably "B"size in the original manual. In some cases they were scanned in 1/3 page at a time.
#2 in the "schematics" section the pages are scanned the whole page at a time.
#1 same as #2.
There are other differences in the "schematics" sections with sizes of the pages, when I go through the pages at the same magnification settings of the Adobe Reader. #2 has some protection applied and is "SECURED". I can't use the "Snapshot Tool" from the "Tools" menu. In one scan I can see the holes for the spiral binding which the others don't have on the same page. There are other differences on the placement of some texts. But that could be from the scanning process. I don't know.
My conclusion and best guess is that, believe it or not, Tektronix did NOT print those missing pages in the first printing dated "May 1986". GASP! There are pages of "CHANGE INFORMATION" in the back of each scan. One shows signs of being stapled while others don't show this.
However is anyone can find those missing pages please scan and post them.
Bill

Based upon the command syntax that is documented in the 070-9650-02 manual, I have begun writing a Node-Red interface to fully control the system using a dashboard2 interface. I use the RS232 port into hardware running Node-Red ( as Raspberry Pi will do). The dashboard can be formatted to be mobile phone friendly, so I can control the unit with a handheld "remote" Kinda cool. I can post the .json file once I get it more user friendly, if there is any interest.

Hello Peter,

On my scope U4 is not mounted so there is no setting.
On U3 I got the following configuration:
KD24 KD25 KD26 KD27 KD28 KD29 KD30 KD31
U3 0 0 0 1 1 0 0 0

Any suggestion how to setup the scope to TDS640 with the configuration?

Regards,

Wamor

Craig, here’s one link:



Ron

On Mar 19, 2025, at 00:03 , Adam R. Maxwell via groups.io <amaxwell@...> wrote:

The 2nd LO maxes out at 2178 MHz in band 1. This is an old 492 with the cavity 2nd LO that has a tuning slug in the side, but it cannot be adjusted to 2182 MHz per the service manual.[3] If I disconnect the cable on the +10 dBm output of the 2nd LO, though (which goes to the four-cavity filter of the 2nd converter), the front panel output of the LO is at 2182 MHz as expected.

At this point, my guess is a bad 2nd LO, but apparently the Shaper and Bias board next to it tunes and sweeps(?) the 2nd LO. I left out a cal step of adjusting 1st LO and 2nd LO Sweep,[4] so maybe that warrants a closer look, as I thought the 2nd LO operated at a fixed frequency. None of this explains why it worked for a while on Saturday, though; some temperature dependency is all I can think of.

Reading TFA and TFM again, the 2nd LO SWEEP is only sent at spans ≤50 kHz/div in bands 1-3. Probing the shaper board, I could indeed see a ramp at those spans, so clearly that wasn't what was pulling the 2nd LO frequency down at full span. Since the cavity oscillator itself is obviously capable of 2182 MHz, I figured the control voltage must be wrong…and happened to have another bias/shaper board to swap in. LO (ha!) and behold, it was now running at ~2190 MHz, and I was able to adjust it down to 2182. As a bonus for 2nd LO frequency correction, the Phase Lock now works properly, which makes me happy.

I assume a resistor has drifted or maybe a diode is dead in the nonlinear amplifier. The replacement doesn't have the fancy dual zener reference, so maybe I'll look at it again someday.

Another problem possibly found: it's been starting up deaf when cold (no zero spike, just baseline noise), and suddenly comes alive. Tonight I plugged the 100 MHz output into a 7104 when I started the 492 up, and the 100 MHz oscillator was dead. Also swapped that out, but the replacement doesn't quite make -20 dBm. The original has an air variable cap in the middle fully meshed, which seems fishy.

In spite of this progress of sorts, a -20 dBm signal is still 30 dB below the top of the display, so I'm still missing something.

thanks,
Adam

Ron,
Good to hear you have the required equipment.
Where did you come up with the Tek-derived US Army service manual, TM-09078B-40/2? I haven't seen one for the 2465B.

Craig

I recently acquired a 7934, and was stepping thru the service manual I downloaded from Tekwiki. Its missing pages 6-22 and 6-23 and every copy I could find was also missing the same pages. Anyone have a copy that would be willing to provide the missing pages? Or better an original manual for sale?

Mark
W7HPW

Craig,

I think I have most of the equipment listed are either in the Tek service manual or the Tek-derived US Army service manual, TM-09078B-40/2, which gives non-Tek equipment-alternatives like the WaveTek’s listed below. I may have to scrabble for a couple of the attenuators or what-not but hopefully I can work my way through it. Thanks for your help!

Ron

Ron,
Well the question marks are definite need for calibration. It is a very time consuming process which will take several hours. Like spending all day on Saturday without any distractions. The directions are kinda intimidating as to what the person that wrote it means in some of it. So read directions carefully. It not uncommon to have some tests fail and that adds to discouragement. But take your time and you will get thru it. Each section must be completed without errors or it won’t save to move onto next procedure.
You need basically most of what is on Table 4-1 in the service manual to get thru it. So review that list and read procedure before starting.

Craig

Hello H?kan,

Thank you for the information!
I will take it into account. Until now the scope is working perfectly.
I only got the annoying message in the error log.

Regards,

Wamor

Craig, I tried TEK2465B Serial B066505 EAROM.BIN from the groups.io website, and the unit powered up without Test 04 Fail! Only two traces and a few extra question marks on the readout, though. I reloaded the original read of the Dallas DS1225Y SRAM, and was back to 4 traces but with many question marks on the readout. Per your suggestion, I went through the EXER 03 procedure using the original DS1225 read SRAM. I was then able to get out of diagnostic mode, but upon power-up, I’m back in it again with Test 04 Fail.

My interpretation of all this is that the original read was somehow corrupted, and the unit is functioning. Which means I should have photographed the SRAM data pages.

I recently recapped a Tek TM503 and have another working 2565B. I also have supposedly working PG506 and TM501 generators, as well as a WaveTek 145 & a 191 Pulse Generator. I guess I get to learn how to calibrate, unless you have another suggestion.

Thx, Ron

On Thu, Mar 20, 2025 at 12:51 PM, wamor2006 wrote:

Does somebody have some advise how to get rid of this message

As far as I know TDS620 and TDS640 don't share the same Firmware although the version numbers are the same.

/H?kan

Hello Peter,

Thank you for your quick response!!
I do have the schematics of the TDS520 so I can locate U3 and U4 and the corresponding resistors on my TDS620 (=>TDS640).
I will open my scope tomorrow so I can send you the ID of my scope.
The only thing what I see in the schematics is that only 3 pin's of U3 and U4 are connected with resistors.
The other pin's are fixed to +5.1V or ground. This confuses me with the code you gave me (=>8 bits)
I only could configure 3 pins of U3 and 3 pins of U4 with resistors (=> 6 bits).
Do I have to split the ID between U3 and U4?

Regards,

Wamor

Andy,

In the hv section, see if the .01mfd condensers are ceramic or tubular. If the latter, replace with film or ceramic types. You can increase the capacitance if you want to say .015mfd. The 56,000 ohm resistor to the screen and plate should be 5W. The decoupling condenser and the .001mfd across the primary could be bad. See if the valves are good. The resistors in the high voltage are likely out of tolerance. That will cause the voltages to be off. In these sections of these types, I used 1% 2W types. I also replaced carbons in mine with 1% types with a few of 5% in areas where I had them and the tolerance is fine. There are a number of resistors in these series that are too small in wattage and will show overheating. Check the pots in the horiz. sections. The pots could be bad/dirty. The .01mfd condensers in the power supply are known to become leaky. Orange Drops are a good type to use as replacements. Clean the high voltage section. The black dirt that gets there is a leakage path. This includes the crt. I have seen the crt black on the funnel. This was slick. Cleaning helped.

Mark

Hi Wamor,

Some years ago i started to fill a table with model's IDs. Maybe, is your
case: the Processor board ID does not correspond to Acq configuration.
See U3, U4 on Proc. board.
This two are on:
00E0 0000 Register (read only) ID Register 1
00E0 0001 Register (read only) ID Register 2
Try this ID and send your to me, please:
TDS640A 1 1 0 0 1 0 1 0

Regards,

Peter

Contact me offboard, if you need a part of schematics from TDS520 regarding
this registers, because this board does not allow attachments

чт, 20 мар. 2025?г. в 14:51, wamor2006 via groups.io <tektronix=
[email protected]>:

Hello everybody,

I managed to upgrade my TDS620 to a TDS640 by changing resistors on the acquisition-board.
I now have 4 channels active and this is working fine and the scope reports that it is a TDS640.
The only thing which is bothering me is a message added in the error-log every time when I start the scope.
Error: 242 wrong hardware configuration
Acq number of digitizer probe, expect: 2, actual 4

This is not limiting the functionality but is just annoying.
Does somebody have some advise how to get rid of this message?

Regards,

Wamor

I changed R803 the 56k anode resistor for V814 to 68k to reduce V800's screen grid voltage, & adjusted the EHT to minimum. The CRT display is a lot less bright but I still have no intensity adj and the display is still half width of the CRT. The OP of V800 is way lower than spec. I can only suppose the forward bias V of the silicon diodes is less than a 5642 valve diode: the datasheet gives no voltage spec.

Next I'll check all the resistors in the potential dividers that feed the focus & intensity pots and power supplies again. BTW I have limited focus adj.

Andy.