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Hi Alex,
? I am back from vacation now, catching up at work, so I still don't have too much time to reply, but nevertheless read through all your messages. ?Also there is nothing like having a copy of a printed manual at your side.
? I may have missed it, but didn't see what the power supply voltages were. ?I saw the discussion of the -150 vs. the +100 and both were within 5% so those are OK for now. ?But what about the +225, +350 and +500? ?Ripple on the supplies is also important. ? You can get a crude measurement of the peak to peak ripple by switching the DVM to AC Volts and measuring each PS rail to ground (remember when you do this that you may be leaving a high voltage across the DC-blocking capacitor in the DVM and you want to short the leads together before using the meter to measure any low voltage circuitry). ?I don't believe the problem you are seeing is with the PS but it is nonetheless essential to know that it is working, and how well.
? Tubes: ? without a tube tester it is more difficult to know what is going on, but there are a lot of things you can do. ?First of all, a visual inspection of the tubes is a go/no-go sort of test. ?An obviously bad tube may not have a good filament and will not light up. ?Also, check the getters. ?They should be shiny. ?A cracked tube will have a fully oxidized getter and it will be turned into a white film. ?These are definitely no good. ?A tube that is old or has been overheated may end up with a thin getter. ?It is less shiny, and may begin to exhibit color interference fringes at the edges of the metal film. ? Suspect these tubes, but that doesn't necessarily mean the tube is bad. ?A tube that is passing too much current will have a plate that glows red. ?Usually this is a good reason to shut the instrument off and troubleshoot the circuit cold, before you kill the tube. ?Finally, check for gas (with the room lights out) - a gassy tube will tend to glow purple inside. ? Besides the gas regulator tubes, it is not typical for tubes to glow (other than the filament) so these can be suspect. ??
? BUT, Tek circuits are conservative. ?They will often work with very marginal tubes, including some that just test "bad" on a tube tester. ?For this reason, I would be careful about replacing tubes outright. ?The circuit may have been calibrated with the bad tube in it and it may work just fine. ?Be especially careful about replacing tubes that are pairs in differential amps and the vertical circuits. ? You don't want to have to carry out calibration steps until you fix the fundamental problems first. ?The cal's may be fine.
? You can swap some tubes to troubleshoot, but mark where they came from. ? I'm looking now at the main sweep generator circuit. ?One tube (V193A for the 545A) is a cathode follower that delivers a voltage to the "Sawtooth Main Sweep" output on the front panel. ?The other, V193B does the same for "+Gate Main Sweep". ?That's all that tube does and it's not critical, so voila!... you have a spare 6DJ8 to play with.
? Bumble bees: ?My recommendation is not to replace ANY of them until you can logically prove you need to do so to get the scope to work. ?Many of these are gain compensation capacitors, bypass or isolation capacitors and are used to tweak the performance and are not really critical. ?My scope worked for many years with leaky capacitors and I only replaced them when necessary to get the scope to function or calibrate correctly. ?When I did go in this last time, I replaced a bunch of them in the horizontal circuits and they were ALL cracked, obviously leaky or measured bad. ?Performance of the scope improved considerably BUT, it was functional before the repair. ? My point is a blind replacement of all of them will take time, ?and may be a distraction from the real problem. ?Just suspect that any one might (likely *is*) bad, but try to troubleshoot towards the goal of getting the scope to work.
One other note on bumble bees. ?There may be one in series with the Vertical Signal Out banana plug on the front panel. ?If this one is leaky, you will be connected through it's leakage resistance + 15K to the -225V supply. ? So instead of getting a few volts peak-to-peak corresponding to the vertical signal, you'll get a nasty -225V shock. ? It appears that the sweep outputs are directly connected to the cathodes of the 6DJ8 follower, so it's not an issue there, but just keep that in mind when measuring signals at the front panel. ?The vertical signal out capacitor is perhaps one you should replace right away if it's a bumble bee type.
? Now, all of this is just helpful advice, but doesn't get at the root of the problem in your scope and I am confused by the discussion of the sweeps. ?Unless I missed some steps you described, it seems to me that you have a horizontal amp problem. ? If you set the scope to external sweep, with the controls centered, you *should* get a dot in the middle of the screen. ? The Horizontal Position control should move the spot fully from the left side to the right side and the neon lamps above the CRT should indicate accordingly. ?The 5x Magnification switch should make that motion 5x more sensitive to the horizontal position. ? If you don't get this response, then you certainly have a horizontal amplifier problem and you should start troubleshooting there.
? The horizontal amp has 3 6DJ8's and a 6CL6 and it's a fairly simple differential circuit to measure through. ?Note however, that in external sweep mode, the delaying trigger circuit is re-configured as an external sweep amplifier. ?I am looking at a 545 manual, and this may be different in the 545A. ?So, more to check there, but it should still be easily traceable with DC voltages all the way through. ? ...and checking the PDF version of the 545A manual on BAMA now, I see that in the A, there is a separate external amplifier consisting of V314A/B, another 6DJ8. ? There seem to be, as stated earlier, significant differences between the 545, 545A and 545B, so you really need the correct manual. ?As it is, my 545 was partially upgraded to a 545A, particularly with modifications to the HV oscillator circuit, so I need both manuals!
? Also, be careful while doing this and turn the CRT intensity down so you don't inadvertently burn a spot on the screen.
? Anyway, I hope this helps and I am not typing into the wind. ? Good luck on your scope repair and it seems to me from what you describe and show in pictures that is it imminently repairable, and relatively close to 100% functional. ?There are some difficult to get parts in that scope, but given that you have a nice bright trace on the screen, the essential parts are working. ?My 545 is from 1957 or so, perhaps "upgraded" in 1965, and re-furbished and calibrated by me in 1980, with minor repairs since then, and it's been my go-to scope since then. ?It's just nice to look at, but it's also a very useful and fully functional instrument, so you won't be disappointing when you get yours working.
Oh, and if it has not been mentioned before, make sure you have 3% silver solder! ?There may still be a roll of it stuck on the chassis of the instrument on ?a little white plastic spool about 1" in diameter. ?I don't know where it's located on the 545A. ?If not, get some on e-bay. ?If you don't use silver solder you quickly pull the solder off the ceramic terminals and make a mess when you re-solder. ?It's important to use the right stuff to maintain the aesthetic appearance of the circuitry as well as functionality. ?That's yet another incentive to troubleshoot logically and think before you solder. ?These are beautiful instruments so it pays to keep them that way.

Dan