Tektronix 314 - Repair of BNC / Disassembly - Page 1
Forum section: electronics / repair

author: Thilo78
author_rank: Regular Contributor
timestamp: March 19, 2016, 07:58:15 pm
content: Hey guys,I'm stuck while repairing my Tek 314.One of the BNCs is loose, and I wanted to fix that.Unfortunately, I can't reach them.Disassembly got stuck right after I removed the top board (Storage Board A5).I couldn't remove the Horizontal Board A4. And I couldn't yet find out how to reach the Attenuator Board A1 with the BNCs.ANd I totally failed to remove the Power Supply, as its screws are blocked by the Horizontal Board.Does anyone know how the actual disassembly procedure (meaning the order of removing parts) is?The Service Manual is not quite conclusive to me.Thanks in advance!Thilo

author: JoeO
author_rank: Frequent Contributor
timestamp: March 19, 2016, 08:30:00 pm
content: http://w140.com/tekwiki/wiki/314

author: PaulAm
author_rank: Frequent Contributor
timestamp: March 20, 2016, 04:52:25 pm
content: Those scopes are pretty well packed. Take a look at the 335 manual. The maintenance instructions are fairly clear on removing boards for that scope, maybe it will give you enough hints for your problem.

author: Thilo78
author_rank: Regular Contributor
timestamp: March 20, 2016, 06:15:58 pm
content: Thanks for the hint with the 335.I'll give it a try.It's a tough little beast to do mechanical repairs on.Adjusting is far easier. E.g., I had to readjust the trace rotation.It's as easy as taking off the cover, removing a plastic shield and turning the pot. Nice design, after all.Probably, proper disassembly is pretty straight forward. Only problem is, that I can't figure out the sequence from the service manual.For example, I can't tell if it's necessary to remove the CRT at any point. The pictures show the boards removed with the CRT in place.On the other hand, the power supply and the horizontal board seem to be interdependent. You can't remove one with the other in place.At least it seems...Will try again next weekend, when I'm back home.As soon as I have fixed that BNC, it becomes worthwhile to go through the calibration procedure, as I fear this to be a future failure point.In other words: I'll have to fix that BNC, anyway.

author: Martin.M
author_rank: Frequent Contributor
timestamp: March 28, 2016, 10:19:01 am
content: the SONY Tek are all a little crazy inside,there is a different to the 400 series what is easy to repair.Please make a picture when it`s donegreetingsMartin

author: Thilo78
author_rank: Regular Contributor
timestamp: March 28, 2016, 11:41:00 am
content: The Tek 314 is kind of a logic puzzle. It's just not obvious, in what order you're supposed to remove the modules...I'll take some photos when I finally approach the topic.Currently, I've put it aside because I felt like tackling the RFT EO174A and because the Tek is currently working fine.So no urgency there for me

author: tggzzz
author_rank: Super Contributor
timestamp: March 28, 2016, 12:34:04 pm
content: You do have the service manual, don't you.If you can't find a free one, then you can buy a scan for $15 athttp://artekmanuals.com/manuals/tektronix-manuals/I have one for my 492AP, and it is significantly better than any of the free one. I am therefore a happy customer.

author: Thilo78
author_rank: Regular Contributor
timestamp: March 28, 2016, 01:35:13 pm
content: Yes, I have the service manual.I think it came from elektrotanya.com, when I bought the 314.It works out fine, except that they don't really describe the order of disassembly.But I'll work that out as soon as I dive deeper.I left it alone after I got stuck with removing the horizontal board.

author: Thilo78
author_rank: Regular Contributor
timestamp: October 14, 2017, 09:20:53 pm
content: OK, finally an update from my side.The BNCs for channels 1 and 2 have finally been swapped.After putting the repair aside as it wasn't really necessary to fix and I didn't have time, I approached it again.I finally was able to make sense of the descriptions in the service manual.As for the sequence of disassembly: After removing the case, you proceed to remove the CRT bezel. Undo two screws and take it off.This also releases the catch on the front cover of the storage and horizontal module. This again can then be removed by undoing the centre screw at the back.Be careful, as there are a few wires going to the horizontal deflection plates and to the HV power supply.After that remove the power supply sections. A lot of screws and even more connectors have to be undone.Take notes of the connections! Not all are easily found in the schematics.With the power supply removed you can proceed to remove the acquisition board. First thing that has to go is the shielding. After that you desolder all connections around it and take it off.You'll also have to remove the cam shaft for vertical DIV adjustment.After all that you can now remove the metal piece that holds all the BNCs.For details see the photos. If you want to try it yourself, get in touch.(Photos not in sequence)

author: Thilo78
author_rank: Regular Contributor
timestamp: October 14, 2017, 09:27:09 pm
content: Final result.(Wanted to show more photos from the disassembly, but the forum won't let me post them)

author: Thilo78
author_rank: Regular Contributor
timestamp: October 14, 2017, 09:29:09 pm
content: Or does it?