OK, so that voltage tells us that the 220V supply is not being overloaded and therefore the problem is in the power supply.
Can you 'scope D1101 anode and cathode with DC coupling and note the value of the positive and negative peak of the two waveforms.

 

Hi.
Reference to common chassis ground, D1101 anode is 150V peak; cathode is +95 V -no ripple.
With my emergency toy oscilloscope, limited to 20V/div, cannot see/read the entire waveform amplitude.

 

Do you have a X10 probe to able to see the whole waveform?
Those voltages suggest D1101 or its connection has a problem. 150V into the diode shoud produce 150V out, not 95V.

 

Hi Albert.
With the 10X probe, D1101 anode, like 260Vpp ref ground :

 

It's not p-p I'm interested in, it's the positive peak voltage above ground that I'm after. So the scope needs to be DC coupled and the line with no signal set near the bottom of the screen then look at how far above that baseline the positive peak is. If D1101 and the capacitor is OK the 220V rail should be equal to that positive peak value.

 

Hi.
Checked again, and the valleys are 140V below zero line = -140V
The peaks are 120V above zero line = +120V
Referenced to ground chassis.

 

Can you repeat that measurement on the anode of D1102 (or cathode of D1104 - same place).

 

Anode of D1102 : +127V peaks above zero line, clipped peaks.
-45V valleys below zero line.
172 Vp-p
Referenced to chassis ground

 

Can you repeat the measurement at D1101 cathode, please.
These measurements are not consistent with each other. Does the 220V rail voltage change with time?

 

Unless I'm missing something, the only way I can see for putting any charge into C1101 is via D1106 (i.e. through the load on the 120 V rail) or via C1102 and D1105.

 

Cathode of D1101 constant 100V, zero ripple, referenced to ground chassis.

 

The peaks are 120V above zero line = +120V

Cathode of D1101 constant 100V, zero ripple, referenced to ground chassis.

So anode of D1101 goes up to 120V, but the cathode remains at 100V.
Therefore D1101 is either faulty or not connected.

 

"Across C1101 there is minus 25V !"

Sorry if I missed the details on these - please point me to the post number if I did (for some reason I can't get browser to search the thread!):

How was that measured? Right across the cap? With a meter?

What is the voltage at the negative end of C1102 relative to ground?

 

I just had a quick look back through the posts, and D1101 had not been tested. I thought it was so did not think of getting it replaced.
But the symptoms point to D1101 being open. Try replacing it and see how that goes.

 

I just had a quick look back through the posts, and D1101 had not been tested. I thought it was so did not think of getting it replaced.
But the symptoms point to D1101 being open. Try replacing it and see how that goes.

I agree but TS has replaced D1101 - post #1 - hence I am confused.

 

I agree but TS has replaced D1101 - post #1 - hence I am confused.

I wonder if there is a dry joint or a PCB break, like a crook feed through?
Externet, can you please check for continuity between the transformer toD1101, and from D1101 to the cap?
It really sounds like an open there.
And what diode did you use?

 

Reference to common chassis ground, D1101 anode is 150V peak; cathode is +95 V -no ripple.
With my emergency toy oscilloscope, limited to 20V/div, cannot see/read the entire waveform amplitude.

I should have paid more attention, sorry.
The above indicates D1101 is not working.
Either the diode is faulty or there is an open circuit somewhere there.

 

Thank you.
D1101 anode to transformer 'brown' = 0.1Ω
D1101 cathode to capacitor+ = 0.1Ω

Before first post, D1101 was replaced with 1N4007, capacitor C1101 replaced with 47μF 400V as first troubleshooting attempt. Symptoms exactly the same as with original parts, No improvement.

The oscilloscope worked perfectly a week ago, not turned on nor moved/touched since then, showing the failure at turn-on, before use.
The 2 top and 2 right clipped waveforms on post 19 stop the horizontal sawtooth sweep from rising/advancing by the center of screen, forming the 'blips' That is the clipped +220V. When magnifier is on, raster gets a little wider but far from full screen.

Vertical works fine, shows the amplitudes.

I will put more effort to the TR1102 area...

 

Show that whole picture so we can see what all the settings are set to.

 

Does the 220V supply any other circutry, perhaps brightness/blanking or EHT generation?
What is the ripple on the 220V?
Please recheck the voltages of the 120V and 220V.
(Something is really screwy...)