I bought this 2213A on ebay due to needing a quick solution low cost scope for some immediate work I needed to get done without using one of my regular bench scopes. In general it mostly needed recapping as its showing some ripple on both traces when in the lower 2-10mV input ranges even while on GND. All LV PS voltages are on spec, but ripple seems a bit higher than specified limits, so I replaced most secondary elco caps, and traces got cleaner, but still there is still some residual ripple (still about 0.4mV) on the traces. Also need to change C940 and C906 the big 75uF 450V power input cap, suitable replacements I did not have on hand. Was also thinking of changing all the other smaller bypass caps (mostly 2.2uF, 3.3uF, 22uF and 100uF) that are located throughout A1 and some on the two other smaller boards (A4 timing and A2 input attenuators). The 100&22uF are obviously radial elcos and will surely benefit from replacement, but some (mostly the 2.2uF and 3.3uF) are shiny silvery color axial parts, not sure if they are actually electrolytics or tantalum. Anyone know, or has tested/changed these during a recap?

I wanted to also share the part of dealing with the really bad vertical jitter, as it might help someone else down the line having to deal with a similar situation. I found that the jitter was also responding quite a bit to soft thumping with the eraser end of a pencil on the A2 input attenuator board metal shield, and after removing the shield the 4 small attenuator modules seemed to react the most to physical stimulus. These four small plastic modules are either marked 10X or 100X, and each has two small adjusment screws inside. The modules are actually plugged into the board, so they are easy to remove by just carefully lifting it on one side and rocking them back and forth at the same time. At first I though that maybe one or more of the connecting pins might be facing a loose contact, but all the receptacles on the board seemed to be a very tight fit. Next I was able to pop off the white nylon cover of these attenuator modules, and i saw it contains a small circuit board that is soldered in six places to the connecting pins. Under a strong magnifying glass I could see that some of these solder spots looked pretty much like a text book cold solder joint around the round end of the pin, so I proceeded to carefully reflow each of them. Then plugged the attenuatos modules back into the board, and no jitter at all anymore. Problem gone!

So something to keep in mind if anyone has vertical jitter problems on 22xx scope.

I bought this 2213A on ebay due to needing a quick solution low cost scope for some immediate work I needed to get done without using one of my regular bench scopes. In general it mostly needed recapping as its showing some ripple on both traces when in the lower 2-10mV input ranges even while on GND. All LV PS voltages are on spec, but ripple seems a bit higher than specified limits, so I replaced most secondary elco caps, and traces got cleaner, but still there is still some residual ripple (still about 0.4mV) on the traces. Also need to change C940 and C906 the big 75uF 450V power input cap, suitable replacements I did not have on hand. Was also thinking of changing all the other smaller bypass caps (mostly 2.2uF, 3.3uF, 22uF and 100uF) that are located throughout A1 and some on the two other smaller boards (A4 timing and A2 input attenuators). The 100&22uF are obviously radial elcos and will surely benefit from replacement, but some (mostly the 2.2uF and 3.3uF) are shiny silvery color axial parts, not sure if they are actually electrolytics or tantalum. Anyone know, or has tested/changed these during a recap?

I wanted to also share the part of dealing with the really bad vertical jitter, as it might help someone else down the line having to deal with a similar situation. I found that the jitter was also responding quite a bit to soft thumping with the eraser end of a pencil on the A2 input attenuator board metal shield, and after removing the shield the 4 small attenuator modules seemed to react the most to physical stimulus. These four small plastic modules are either marked 10X or 100X, and each has two small adjusment screws inside. The modules are actually plugged into the board, so they are easy to remove by just carefully lifting it on one side and rocking them back and forth at the same time. At first I though that maybe one or more of the connecting pins might be facing a loose contact, but all the receptacles on the board seemed to be a very tight fit. Next I was able to pop off the white nylon cover of these attenuator modules, and i saw it contains a small circuit board that is soldered in six places to the connecting pins. Under a strong magnifying glass I could see that some of these solder spots looked pretty much like a text book cold solder joint around the round end of the pin, so I proceeded to carefully reflow each of them. Then plugged the attenuatos modules back into the board, and no jitter at all anymore. Problem gone!

So something to keep in mind if anyone has vertical jitter problems on 22xx scope.

On Thu, Jan 3, 2019 at 05:01 PM, tom jobe wrote:

Thank you for the 2213A reply!
As far as I know, all of the aluminum electrolytic capacitor are
suspect, as well as the the X2 and Y2 film capacitors that see the input AC.

Tom, these would be C900 0.15uF, and C902/C903 0.0022uF correct?
And I thought explosive Rifa caps where only limited to the 2465x scopes.

On Thu, Jan 3, 2019 at 05:01 PM, tom jobe wrote:

I have never changed any of those silvery axial capacitors, but then I
may have never done the 22XX re-cap job the way it should be done either.

Without changing those small tubular caps, by any chance do you remember if your traces where still showing any ripple (not thermal noise) on the lower 2-10mV ranges? As is mine are still showing about 0.4mV (one minor div) on the 2mV range. Looks like a small amplitude irregular square wave. And btw there is actually at least one capacitor (C715 22uF on the timing board) that is used to filter a reference voltage applied to the inverting input of U715, so getting that one replaced should probably be important as well.

C906 and C940 are of course on the A list. But I will definitively change out all the smaller blue radial caps as well and see how the ripple looks. If anything visible is still wiggling on the traces after that, then maybe I'll go for the small shiny axial caps as well. Thing is to get to some of these, the whole timing and input attenuator boards will have to come off to access that area of A1. And maybe even the CRT.

On Thu, Jan 3, 2019 at 05:01 PM, tom jobe wrote:

I have never changed any of those silvery axial capacitors, but then I
may have never done the 22XX re-cap job the way it should be done either.

Without changing those small tubular caps, by any chance do you remember if your traces where still showing any ripple (not thermal noise) on the lower 2-10mV ranges? As is mine are still showing about 0.4mV (one minor div) on the 2mV range. Looks like a small amplitude irregular square wave. And btw there is actually at least one capacitor (C715 22uF on the timing board) that is used to filter a reference voltage applied to the inverting input of U715, so getting that one replaced should probably be important as well.

C906 and C940 are of course on the A list. But I will definitively change out all the smaller blue radial caps as well and see how the ripple looks. If anything visible is still wiggling on the traces after that, then maybe I'll go for the small shiny axial caps as well. Thing is to get to some of these, the whole timing and input attenuator boards will have to come off to access that area of A1. And maybe even the CRT.