My trusty 2465B now has a vertically offset display on the CRT. The bottom of the normal display is now at mid-point. Has anyone seen and solved this problem? Where do I look for the source of this problem?
Thanks, AL

Good point! ?I wasn't really thinking. ?They likely are mostly silver since they tarnished black. ?Nickel will probably go greenish (or perhaps that's from the copper underneath that oxidize on a couple connectors I have).

If the concern with the Tarnex is removing it, at least on the adaptors I can sonicate them in warm water and that should be effective in removing the solution after a couple?rinses.

Dan

---

From: "bonddaleena@..."
To: TekScopes@...
Sent: Friday, February 22, 2013 3:42 PM
Subject: Re: [TekScopes] Cleaning nickel-plated adapters and input connectors? Magic formula?

?

Hi Dan. On all the TE I have, the connectors appear to be Silver plated. You could (!) carefully clean them with "Tarnex" liquid. Then clean off that stuff with Windex, etc.
Most of the time, I simply give then a quick brushing with a stainless steel detail brush, which looks like a toothbrush.

ron
N4UE?

-----Original Message-----
From: Daniel Koller
To: TekScopes
Sent: Fri, Feb 22, 2013 3:33 pm
Subject: [TekScopes] Cleaning nickel-plated adapters and input connectors? Magic formula?

?

Hi folks,

? I am sure this has been asked before, so please point me to the correct links if so. ?A quick search of the archives didn't find anything easily.

? How does one clean t he nickel-plated adapters and input connectors of old scopes? ?I am thinking of two situations here. ?The first is the BNC or UHF connectors on the panels of the scopes, that cannot be easily removed. ?The second case is things like BNC T's and BNC to UHF adapters and the like which are small and can be completely dipped in some cleaning solution.

? I have a number of adapters and connectors where the nickel is getting black, and they are filthy. ?I would Ideally like to deoxidize them so they come out shiny and new. ?Some sort of chemical dip or a series of washes would be preferred, where I can keep the amount of physical scrubbing required to a minimum. ?I envision perhaps scrubbing once with a toothbrush (maybe with tooth paste?),?wrinsing?in an ultrasonic bath, then dipping them in some magic formula that shines them up. ?Connectors on the scope would have to be brushed and washed in-situ.

? The question is, what is the magic formula?

? Thanks.

? Dan

?

On page xx of the preface:

I am not sure how many people are aware of Oil of Wintergreen penetrating properties, so I though I would point it out. Oil of wintergreen is very wet,it will creep into very close fits.

I have used it to free up stuck set screws in knobs, a few drops down the hole and let it sit for an hour and the screw will come right out.

Some pots when new had damping grease applied to the shaft/bushing area, as they age they become very difficult to turn. Two or three drops of Oil of Wintergreen in the shaft/bushing area and let it sit over night, positioned to let the oil run down the shaft and the pot will turn like new.

Synthetic Oil of Wintergreen does not seem to work as well as the real stuff. The real stuff is not cheep, .5 fl.oz. is about $7.00. It can be had at Drug stores and good cooking stores. A bottle lasts me about 10 years.

Oil of Wintergreen appears to be very inert I have not had it affect rubber or any plastics,unlike some commercial products. I am not sure about it's long term lubrication properties, it may be a good idea to follow it up with an oil.

I hope this proves as useful to others as it has been to me, besides the gear smells nice afterward.
Mark Bradley K6TAF

Change Q1222. It should be full off and the collector should be up around 90 volts or so. However, Q1223 could also be pulling that line down so change it also. You could lift the collector of Q1223 and see if the supply comes up just to rule that out. Also (2), is R1212 ok? If it were open, the same issue would be there.

Tom




----- Original Message -----
From: Chris
To: TekScopes@...
Sent: Tuesday, February 19, 2013 4:52 AM
Subject: [TekScopes] Re: Tektronix 2465 capacitors etc.



I had sent a response earlier but it didn't appear to have made it.

I checked some of the voltages on the board, but can't say I entirely know what to make of all of them (newb alert again hah)

Ok, I've got 94v on the unregulated rail
On the op-amp, pin 1 vref is 10.00v Pin 2 from the voltage divider is reading as ~1v or just under. Pin 1 is reading 15.19v.

Q1222: Emitter 8v, base is grounded of course, and 11.6v on the collector.

Q1220: (sorry, not sure which is emitter/base/collector, I'd have to look up a datasheet - more newb showing through). So looking down on the power supply as it's mounted in the chassis: 11.3v on the left pin, 94.7v on the middle pin (must be the collector) and 11.8v on the right pin.

Q1221: 94v on the collector, 11.1v on the base and 10.6v on the emitter.

I didn't measure Q1223 - hard to reach that one.

R1212: 94v on the unregulated rail side, 10.5v on the other side of it.
R1220: 94v on the unregulated rail side, 9v on the other side.

Curious how I got 15.19v on pin 1 of U1281A with a 10v ref and a 1v comparison from the voltage divider off the regulated line - looking at the datasheet it looks like it should be operating as two separate op-amps with one half regulating the 87v line and the other the 42v line, so I fired it up again and checked the voltage on all of it's pins:

pin 1: 15.57v
pin 2: 1.05v
pin 3: 10.00v
pin 4: -6.86v
pin 5: 10.00v
pin 6: 1.58v
pin 7: 15.58v
pin 8: 16.42

So thinking about it for a bit, the schematic shows a voltage of -1.53v for pin 1 (a far cry from the 15v I'm getting)which I assume is the voltage I should see when the line is regulated to 82v. And I assume then that the 16.42v is the positive power for U1281, and the -6.86v is the supply that lets it pull Q1222 low when the voltage from the voltage divider feeding pin 2 = the 10v ref from pin 3.

So I guess I learned something, but as far as using the voltages to give me an indication as to what's gone wrong I'm not sure. That will take a better man (or woman) that's more educated than I! I would have to resort to the shotgun repair method at this point - replace all the components :) (certainly not to the point of wanting to shoot the scope yet lol)

As a note, when reading these voltages they can vary a bit while checking them. Sometimes it's not uncommon to see some of the voltages vary ~0.5v it seems, so that accounts for some of the variance in the first vs 2nd measurements in areas. Earlier I was reading ~9.5v on the 87v regulated line, but tonight it was just under 9v.

Thanks!
Chris