Tektronix 2465B option board question. - Page 1
Forum section: electronics / testgear

author: Synthtech
author_rank: Regular Contributor
timestamp: April 08, 2022, 06:47:35 am
content: I just purchased a 2456B that is stalling during boot-up with the "ADD" LED illuminated. I checked the processor card and sure enough there are the expected leaking SMD electrolytics which I have removed and am in the process of cleaning up. I have a question if anyone might be able to assist me - I notice that the internal photos of most of the 2465B's that I see on the web don't have anything beside the two power supply boards but my unit has a board installed between the power supply and the chassis beneath the A5 board and it's plugged into the A5 board by a ribbon cable. It must be an option card of some kind. Until I can get the 'scope to boot I can't look for options from the front panel, does anyone know what this board might be? I guess I am asking which optional card sits between the A5 board and the power supply cards. I have seen other options but they were usually attached to the top cover rather than the mainframe. Photo attached.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: April 08, 2022, 02:12:48 pm
content: Does the scope happen to have 10MHz ref input BNC on the back???

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: April 08, 2022, 02:42:23 pm
content: Synthtech...Take a look here to (possibly) see your options board in the Mechanical Drawings. Likely option 06, or 09.https://www.eevblog.com/forum/testgear/tektronix-option-1e/msg729949/#msg729949

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: April 08, 2022, 02:55:36 pm
content: and... here is one version of the options manual. Take a look at pdf pages 54, and 55.https://www.atecorp.com/ATECorp/media/pdfs/data-sheets/Tektronix-2445B-2455B-2465B_Manual.pdf

author: MarkL
author_rank: Unknown
timestamp: April 08, 2022, 03:04:23 pm
content: From the 2465B Options Service Manual, it appears to be one of A25, A26, or A27:A25 671-1340-00 TV Option 05A26 671-0982-00 Combo TV + CTT (Counter/Timer/Word recognizer) Option 05/06/09A26 671-1795-04 Combo HDTV + CTT Option 05H/06/09A27 671-1341-00 CTT Option 06/09From your photo it looks like there's a Lemo connector on the back panel for the external word recognizer, so I would expect it's an A26 or A27. And it's looking a little sparse on half the board, so I'm guessing it's just the CTT option 06/09.There should be a board number on it somewhere which should match one of the above, or if not at least identify what it is.

author: Synthtech
author_rank: Regular Contributor
timestamp: April 09, 2022, 08:38:53 am
content: Thanks everyone, I have to apologise, all I had to do was to look at the options plate on the back![ Specified attachment is not available ]

author: Synthtech
author_rank: Regular Contributor
timestamp: April 09, 2022, 08:59:20 am
content: Quote from: SoundTech-LG on April 08, 2022, 02:42:23 pmSoundTech-LG yes it does.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: April 11, 2022, 02:07:53 pm
content: Your Option 1E is the 10MHz Ref input. Why I initially asked if it had the connector for it.Have fun!

author: Synthtech
author_rank: Regular Contributor
timestamp: April 13, 2022, 11:33:22 am
content: Quote from: SoundTech-LG on April 11, 2022, 02:07:53 pmIf I can fix the ‘scope by cleaning up the SMD capacitor leaks I will definitely give that option a try. Thanks!

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: April 13, 2022, 02:03:19 pm
content: Don't forget... that circuitry may appear good, and until you verify every resistor, it may be compromised on the underside. I found particulary in the pot adjustable bridge circuit... which is hard to measure properly while the resistors are in circuit.

author: Synthtech
author_rank: Regular Contributor
timestamp: April 14, 2022, 11:55:42 am
content: Quote from: SoundTech-LG on April 13, 2022, 02:03:19 pmOn one end of the board I found an open circuit trace to one of the bypass caps on pin 14 of a 7400 that was caused by the single leaking electrolytic at that end but which would not cause the error that I am seeing. At the other end of the board where the DAC is and several electrolytics had leaked I un-soldered all of the SMD caps and resistors and the trim pot near them and cleaned the board and buzzed out all of the traces, I haven’t found any issues there but I will replace any cap and resistor that I removed with new parts. I’ll put it all back together and check the voltages that the trim pot sets and calibrate it and If it doesn’t work after that I’ll scrap the ‘scope as I have so many other machines to service and this ‘scope isn’t essential to my workshop, it would have been a nice one to use if it worked but not essential.If I can clear that error I will Go ahead and remove the power supply and re-cap it and read out the RAM and replace the chip before the battery fails.

author: SoundTech-LG
author_rank: Frequent Contributor
timestamp: April 14, 2022, 02:30:00 pm
content: Don't give up! We will try to help you through to the success!!!

author: Synthtech
author_rank: Regular Contributor
timestamp: April 14, 2022, 08:38:09 pm
content: Quote from: SoundTech-LG on April 14, 2022, 02:30:00 pmThanks! It would be great o get it running. CRT ‘scopes still have a real place on the work bench, especially for audio work, they can display artifacts quickly In a way that an LCD can’t.