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Gordon, I'm in Swindon and will happily look at it using my 7104 scope, if that is going to help. Regards, Norman

Hi. I'm hoping someone in the UK can spare the time to give me a little practical help with a pulse generator. I don't have leveled oscillators, standardizers etc, and generally only very occasionally

Be careful measuring the 6.3 volt filament voltage; it is held very close to the -3000 volt cathode voltage by R418. You can check that the HV oscillator is operating by measuring the AC voltage at

The situation with the custom ICs is not all that bad. They very rarely fail and replacements can be found. I would sure try to diagnose any problem which caused the IC to fail though. Install a

The manual says it should work in the mainframes which lack the power good signal so I wonder if something else is going on with either the mainframes or the SG5010.

This should not happen unless there is a DC imbalance in the input circuits. The self calibration command which can be run after the oscilloscope warms up for 15 minutes is suppose to remove any DC

I replaced one of these caps last year in order to get the scope working at all. It's almost certainly LVPS switching noise I'm seeing. Is it time for E=mc^2? (Efficiency = mass cap change) Yeah. I

I want to say no. The answer will, of course, determine where it's being injected. It doesn't seem to change the amplitude of the ripple, but it does displace the trace vertically (usually downward)

Hi Ed, Congratulations. I have always thought it would be next to impossible to replace one or a few contacts. Your post gives me hope. Dennis Tillman W7PF

The recently fixed 7904 (PS problems) that also had no readout in the A-horizontal is now fixed, readout-wise. Replacing the individual contacts on the connector was not that hard to do, except for

Well, now I have to tell my VOM story. Many years ago, I had collected some nice old Weston brand VOMs for cheap - they had the ohms range burned out for the usual reason. So I'd fix that part and

Most of the cap reliability problems are with dry tantalum varieties. These were popular in the 1980-90s because they offered much higher capacity per unit volume than aluminum electrolytic caps. BTW,

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AFAIR, the LVPS +5 V output uses a pi filter (2 C's to gnd, 1 L between them). Did you check / replace all (output) caps in the LVPS? It may be remaining LVPS switching noise feed-through you're

I just found a post over on the antique radio forums that said if you have to clean the contacts to not spray the phenolics with deoxit as it can ruin the calibration of the ranges. Well....what's

My first multimeter was a Triplett 630-APL, the mirror scale version.I ordered it with the padded leather case, cost me $65.00 in about 1963 0r 64.I still have it and it works.?Leon Robinson ??

Does the displayed ripple change with vertical sensitivity? Is the displayed ripple synchronous with the ripple on the +5 volt supply? I do not think the graticule output circuit will work correctly

The 76xx series of 100 MHz oscilloscopes has a similar perplexing pattern. The 7603, 7613, and 7623 which were all released in 1973 use

W.E. could be Western Electric - the outfit that made the parts for telephones back in the day. Ed

Same here with my 475. All filter caps on my 475 are original and it was recommended to leave them be. John I also refurbed a 475 (c. 1973) over this past winter, and it came complete with all the