#59679 Can anyone help me out with any modification information for the A5 (Control/Readout/Buffer board) for the 2465/7B scopes. I am struggling with a 2467B which has suffered the dreaded capacitor disease on the A5 board. I have replaced caps, removed and cleaned the board and replaced all ICs and passives in the vicinity and carefully checked the integrity of all traces in the affected area. However, I still get failures in Self Test 03 followed by garbage on the screen when exiting out of the self tests. So I'm now trying to logically diagnose the problem, which is where I am having difficulty. I have downloaded the (presumably) latest version of the Service Manual - 070-6863-01 - from Tek and this shows two diagrams for the A5 board, with B050000 as the break point. My first problem is that the scope has a Dutch serial number - H705488 - which I'm not sure how to relate to the Beaverton serial break point. However, the caps and ICs have 93 date codes and the A5 board is a 671-0965-06, so I'm working on the assumption that I have a post B050000 machine. Unfortunately, when trying to trace signals through the board it quickly became apparent that it didn't match up with the post B050000 diagram. Even more unfortunately, it didn't match the pre B050000 one either. Just to add grist to the mill, my bench scope is a Guernsey built 2465B, serial 105217 with IC date codes of 88 and an A5 board of 671-0965-00, which I am assuming is pre B050000. But, not only is this different to the later 2467B, it also does not match either of the diagrams in the manual, pre or post B050000. There is some mod information at the rear of the manual, but nothing which comes anywhere close to sorting out what I am seeing. To be clear, this is not just component value changes but significantly different tracking on the board, with gates and invertors appearing in completely different areas of the logic. So, if anyone has any information at all on the various phases that the A5 board went through in it's journey from rev 00 to rev 06 I would be eternally grateful. Ben |
#59680 Last time I had readout problems, it turned out to be a bad U650, displaysequencer chip. Tom
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#59683 Ooh - err the revision level of your board post dates the 2467B EPL in section 9 of the manual, which lists the -05 board as the highest. toggle quoted messageShow quoted textThere is some information on the further changes to the A5 level of the board in the changes pages at the end (page 521-524 in the PDF file), and did you spot the revised partial A5 schematic on page 535? Maybe either Stan or Hakan have the mod summary, or maybe Victor Silva can help as he seems to have a lot of experience of 2465/7 scopes (wish I could lay hands on lots of them over here). No, 671-0965-00 is for serials B050000 to B050846 2465Bs, see page 265 in the 2456B EPL in section 8 The earlier version (non-SMT) ones used and different part number for the A5 board (670-9052-02) for serials B010100 to B049999. Regards, David Partridge -----Original Message----- From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Ben Clarke Sent: 18 March 2011 20:20 To: TekScopes@... Subject: [TekScopes] Diagram for late model 24767B Can anyone help me out with any modification information for the A5 (Control/Readout/Buffer board) for the 2465/7B scopes. |
#59685 Thanks for the suggestion Tom. toggle quoted messageShow quoted textI should have said that I know the fault is on A5 as I substituted theknown good one from my bench scope (that in itself tells you howfrustrated I had become!). With the replacement A5 all was sweetness andlight. Ben At 20:38 18/03/2011, you wrote: |
#59686 Thanks David toggle quoted messageShow quoted textYes, I had spotted the revised A5 schematic, unfortunately not the bit I am interested in (the Character RAM/ROM area). I hadn't spotted that the pre B050000 board was the 670 part though. That means I have two post B050000 boards and one schematic, all different! Ben At 22:08 18/03/2011, you wrote: Ooh - err the revision level of your board post dates the 2467B EPL in section 9 of the manual, which lists the -05 board as the highest. |