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Tek 2465B died all or a sudden.

Greetings,

I have a very low hours Tek 2465B that just stopped working the other day when I went to use it. For about the last year the digital display information on the CRT has been a little flakey, usually displaying about half an inch from the top and bottom of the CRT instead of right at the top and bottom. But every now and then the digital display infomation would jump back to where it is supposed to be. However, this did not affect any of the traces (they would always display properly) so I lived with it.

But, when I went to turn it on the other day (after sitting for about a month of no use) it ran through its start up sequence, then stopped with the CH1-ADD LED on and would not respond to *any* front panel buttons. Even the beam-find does nothing.

After powering off and on a few times it finally came up with a more normal front panel display, i.e. I could push buttons and the LED's would change and I could hear relays click inside the unit, but still no display or trace on the CRT. Also, whenever I pushed any of the buttons *all* the front panel LED's would flicker in unison. When I power the unit off or on I see a quick flash of a trace on the CRT, but I have no idea if this means anything.

This scope is by far the nicest piece of equipment I own and only because I got it at a really good price. Tektronix wants $2k to fix it (ouch) but I can't even consider something like that being a hobbiest. Usually I'd dive right in myself and try to fix it, but after removing the cover I just stood there babbling at the thing. After looking at all the unlabeled and custom TEK parts, I figured there was just no way I could begin to fix it...

If anyone has seen this problem before or can offer any insight I'd greatly appreciate it!

Thanks, Matthew

Reply to
Matthew Hagerty
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snipped-for-privacy@mundomateo.com (Matthew Hagerty) wrote in news: snipped-for-privacy@posting.google.com:

Step one is to get a service manual. Step two is to read the circuit description.(the whole thing) Step three is to check the LV power suplies.

There are also fault codes in the SVC manual,that tell from what front panel led being lit,what part of the scope has a problem.

--
Jim Yanik
jyanik-at-kua.net
Reply to
Jim Yanik

You really think I could fix it? I'm certainly willing to try, it's just a little intimidating. I will get a service manual, I've been looking for a source all morning, could you perhaps suggest one?

Thanks, Matthew

Reply to
Matthew Hagerty

snipped-for-privacy@mundomateo.com (Matthew Hagerty) wrote in news: snipped-for-privacy@posting.google.com:

Well,I suspect you have a bad hybrid IC which may be difficult to get as they are no longer made or even stocked by TEK. The only source is from "parts scopes",to the best of my knowledge.

Sources? Start with Ebay

Then; (they may not be current)

MANUALS SOURCES

pdf-manuals.com

TEKtronix Manuals for free download, FYI:

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TECH SYSTEMS 1-800-435-1516 SYNERGETICS SURPLUS 520-428-4073 PEPPER SYSTEMS 214-353-0257 MANUALS PLUS 206-531-8031 US SURPLUS 410-750-1083 E-MAIL: snipped-for-privacy@clark.net

Tektronix Used Manual Sources:

  1. Deane Kidd 27270 SW Ladd Hill Road Sherwood, OR 97140, 503 625-
7363 (also has some parts)
  1. Ed Matsuda, P.O. Box 390613, San Diego, CA 92149, 619 479-0225 voice, 619 479-1670 fax
  2. Manual Merchant: Linda Perkins, PO Box 927792 San Diego CA 92192,
619-642-0785, -0885 fax, linda snipped-for-privacy@ix.netcom.com
  1. W7FG Vintage Manuals, 3300 Wayside Dr., Bartlesville, OK 74006,
800-807-6146
  1. Manuals Plus, P.O. Box 549, TAD #601, Tooele, Utah 84074, (801)
882-7188, (801) 882-7195 Fax

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--
Jim Yanik
jyanik-at-kua.net
Reply to
Jim Yanik

TekScopes Yahoo group is your friend. Join uo and ask for help

Hugh

Reply to
Hugh Prescott

I have received a service manual (seems to be one made for the military) and began some troubleshooting. Following the main trouble flowchart the first 5 or 6 questions ask "can you see this or that on the display?", so my answer to all of these is all "no" since my display is not working.

Finally it comes to the block where I was sure I would find a problem: "Are the voltages at J119 in accordance with the table 5.1?" Unfortunately *all* voltages were exactally on target, perfectally set in the middle of the +- range. The +10V Ref is 10.0000 +- 0.0001.

The next step has me checking for a clock signal on the CPU on the control board. The clock was there and working, as well as address line activity, data bus activity, correct interrupt timing, etc.. I set the NORM/DIAG jumper to DIAG and found a good binary count on the address bus and the correct data byte on the data bus.

After that I have some problems with the procedure since the control board I have appears to be newer than the one in the manual I have. Seems the 74373's were replaced with 74573's as well as many other IC's, and the part placement is all different. I guessed at the buffers as best I could and they all seem to be working, along with the address decoder. After that the procedure ends saying to replace one or all of three IC's: the CPU and the two 74373's (573's on my board.)

That does not make sense to me though, since they all appear to be working fine. I'd rather swap the control board before attempting to mess with replacing surface mount IC's, and I want to make darn sure I'm replacing the correct part. Unfortunately I don't have spare

2465B parts just sitting around so I'm stalled.

Anyone have any suggestions as to what I might try?

Thanks! Matthew

Reply to
Matthew Hagerty

Dear Matthew,

There is a "troubleshoot flow chart" that guides you through the area "no visible display". in the manual.

I've seen never fail the cpu in the 2465Bs, so I recommend to check the HV section before changing the main board.

According to your description, the HV section might have a problem too. Any loose wires, connectors? Is HV available ( please use HV probe and be VERY careful)?

If all this turns in a nightmare for you, don't desperate: I can offer service in Germany an Italy, if you don't mind shipping.

hth, Andreas

Reply to
TekMan

Actually I've made some progress. Someone suggested I follow the display diag flowchart because they had a similar problem. So I did. I got to a step where is said to "turn grid bias R1878 full CW and grid drive R949 full CW", but I could not find R949, so I just started with the grid bias. I only had to turn it a little and my display came back!

The display is pretty messed up, but I can see the error message:

TEST 05 FAIL 44

Here are two images, one of the error and one after I hit AB TRIG to exit:

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I started following the Error Message Diag flowchart and wound up at the block that says: Refer to trigger error table at left to determine probably cause. That table says failures for 04 or 44 are:

a. U2634A, U2235, or U500 b. Line Signal

I cannot find U2634A or U2235 on any schematic or in the part locator tables, and I have no idea what Line Signal is. Is there any way I can get this down to a single failed part?

Thanks, Matthew

Reply to
Matthew Hagerty

snipped-for-privacy@mundomateo.com (Matthew Hagerty) wrote in news: snipped-for-privacy@posting.google.com:

IIRC,this means a EAROM failure,the IC that stores all the cal constants. (It's been awhile,though.)

This IC is on the processor board.

Line Signal is tapped off the PS(primary side);used for line triggering and trigger cal on startup.

--
Jim Yanik
jyanik-at-kua.net
Reply to
Jim Yanik

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