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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.

Ron,
Ok now try to clear 04 diagnostic with
EXER 3 as described in other post I sent. Calibration may need to be done if values aren’t correct.

Craig, all pinouts of U2101 have intact connection to the next component and the resistor ladder resistors ohm correctly including connection to +10V Ref. The C2010 measures 15.8 ?F.

pac085, I received an Amazon XGPro T48. Doesn’t seem to work at all. Version 12.75 software reads everything FF, says it PROG’s - nothing written. v12.85 software only gives programmer not connected. Not a fan.

I copied the Qservice startup .bin file and did start up; it’s a little different result. I still have a Test 04 error, but when cleared with A/B only two trace lines, but no gibberish on readout.

Thx, Ron

Hi all,

I had a breakthrough over the weekend with my balky 492P. Rapping the VR module with a rubber screwdriver handle brought back the missing ~20 dBm of amplitude in fits and starts, so I replaced it with a spare and it seemed fine, working as expected with reference levels.

I was super excited until I started it up the next day and it had crapped out again: on the -20 dBm reference level, a -20 dBm signal is 2-3 divisions down from the top. Sadly, I did not check 110 MHz IF output power while it was working, so have no idea if I was on the right track with that.

Having resurrected (for now) my new HP 5350B counter,[1] I was curious to measure the LO frequencies.

The 1st LO on manual sweep can vary from 1.894 to 6.680 GHz. The service manual says the YIG has a tuning range of 2.072 to 6.35 GHz,[2] so I guess this is okay?

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.

thanks,
Adam

[1] The counter reads 999.9998 MHz on the 1 ns output on my TG501
[2] page 5-5 of 492P service manual for SN B029999 and below
[3] page 3-45 ibid
[4] page 3-44 ibid

I appreciate it H?kan. Information on the rack mount versions of the 500 series is pretty hard to come by.

I agree, WR probe may not be useful especially if you have a LA. With WR option back case have a BNC for trigger output. It is possible to re-wire it for 10MHz input for better CTT time resolution. Even it may not be that useful if you already have a frequency counter.

Yes, I have a Racal Dana 1998 with higher resolution, high stability option and GPSDO.
I would not bother with messing with option 1E (even if it seems easy to do) if it was just for 8 digit precision/resolution. If it were for the scope timebase it would be another story, but it seems apparently impossible.

In that case Dallas -> FRAM change is not applicable, at least it is not a drop in replacement. Your board has an accessible battery, if you are careful and supply a secondary power source you can change the battery without losing contents. You could even decide to put a battery holder for future replacement.

Yes, but having a battery it's really pissing me off, provided all the mess it causes. It reminds me about Icom IC-751A transceiver (and family), it has the MCU program loaded in SRAM(!), if you lose the battery charge, the radio becomes a paperweight.


Anyway I would like to go from SRAM to FRAM.
If this would not be possible eventually I could change the battery.

Having an EPROM burned would allow me to regenerate values in SRAM if something goes bad during the battery surgery operation.
Temporarily substituting the firmware eprom with this one that has a program and my cal data in it to populate again the SRAM.

I have the BOM, once it will be clear to me that/if my 2465B can support a FRAM I will decide how to proceed.

Giuseppe Marullo
IW2JWW - JN45RQ

That’s awesome, Craig! Greatly appreciated. I was thinking it was U2550 on schematic <1>, like a dope. I’ll run through it later tonight.

Thx, Ron

On Tue, Mar 18, 2025 at 07:00 AM, Giuseppe Marullo[iw2jww] wrote:

I don't have a eeprom programmer but I will buy one if needed.

I'd like to see more discussion about using a Pi, to program the FRAM.
The logic levels... AFAIK.. are compatible.
Could do it in Python.
Why not?
--
Roy Thistle

Ron,
I have added pictures to photo area albums. Review this album.

/g/TekScopes/album?id=301356

Craig