New to me Tek 465 problems - Page 1
Forum section: electronics / repair

author: herbiemin
author_rank: Newbie
timestamp: August 12, 2021, 03:23:11 pm
content: Picked up a Tektronix 465b score off of eBay a while back for my first scope and have been reading thru the manual and trying to figure everything out. For the life of me I cannot get a trace out of the unit but noticed a possible problem. None of the three trigger mode switches will stay latched in. If I hold the auto switch pressed in I can get a line trace but haven’t gone any further. From what I can tell these three switches should latch in place when pressed? Or is there something else I am missing? Are these switches repairable or will they need to be replaced? I was going to pull the circuit board off last night so I could get to the switch bank but ran out of time. Any help greatly appreciated.

author: bdunham7
author_rank: Super Contributor
timestamp: August 12, 2021, 03:28:34 pm
content: Yes, those buttons need to stay in.An old fix-needy 465B is a challenging choice for a 'first scope' !Best of luck.

author: herbiemin
author_rank: Newbie
timestamp: August 12, 2021, 03:48:17 pm
content: Well it’s one of those situations where the unit “works well” and then when you get it the thing doesn’t actually work as well as they said. But if I can’t fix it maybe I can find a parts unit

author: med6753
author_rank: Super Contributor
timestamp: August 12, 2021, 03:50:06 pm
content: Those switches can get gummed up especially if the scope has been stored in a less than desirable environment. Deoxit spray should clean and lubricate them back to working condition.

author: herbiemin
author_rank: Newbie
timestamp: August 13, 2021, 01:05:31 am
content: So I removed the circuit board and sprayed some cleaner and worked the switches around for a while the top two stay locked in but the bottom switch never does. The little pin in the side that goes up and down doesn’t feel like it’s in the right position. It is sitting slightly out and towards the bottom where as the others are centered. How do I go about getting the pin set in the right position or how do I remove the switch pack itself? Thanks

author: herbiemin
author_rank: Newbie
timestamp: August 13, 2021, 01:16:49 am
content: Or maybe the bottom button isn’t supposed to stay latched in?

author: james_s
author_rank: Super Contributor
timestamp: August 13, 2021, 01:31:34 am
content: Is it a 465 or a 465B? I have a 465B I can take a look at if you need to know what a button does, I use it occasionally but have not had it out in a while. Fantastic scope though, it's an iconic classic. There are some places you have to be careful not to get any contact cleaner, there are some Tek experts out there who will know better than I do. Faulty capacitors in the power supply are not uncommon, it's a 40+ year old instrument so that is to be expected, but overall they are dependable workhorses that are quite repairable and a joy to use. Take your time and ask questions if you are unsure. Also if you are not accustomed to working on CRT devices, note that there are some high enough voltages lurking in some areas to knock you on your back.

author: herbiemin
author_rank: Newbie
timestamp: August 13, 2021, 01:33:49 am
content: It is just a 465 not a 465b

author: herbiemin
author_rank: Newbie
timestamp: August 13, 2021, 02:56:12 am
content: So I figured out that the bottom button is a momentary switch. So I will clean up the switches a little more and reinstall. Thanks for the help.

author: med6753
author_rank: Super Contributor
timestamp: August 13, 2021, 04:38:44 am
content: You are correct. The lower button is a reset and momentary contact. I figured deoxit would free up switch assembly. Good deal.When talking about a 465/465B it is important you are clear as to which you have. The 465 and 465B are completely different under the covers. The vertical and sweep/trigger boards were a complete redesign in the 465B. And much easier to service if you have issues with the channel 1 and 2 attenuator assemblies. The 465 is quite frankly a nightmare in this respect to service.