Mains ground is connected to frame at scope interior.

Good! -- But is the soldering iron grounded? -- If not, it is advisable to first determine the magnitude of the maximum leakage current - then, if said current is small, ground the external metal surfaces of the soldering iron... Otherwise you will very likely damage components should you use the iron on equipment while it (the equipment) is connected to the mains...

If, on the other hand, the iron is grounded -- then either its ground or the scope's ground is faulty...

Best regards
HP

 

[
Iron is not grounded ; i' ll ground it exteriorly and connect it to scope ground. Is that OK.

 

@patpin

Another change of plan -- So... I'll be happy to continue helping you here!
Please remove the socket from the tube, then connect the meter (makeshift EHT probe attached) between the socket connections for pin 10 and pin 12

Note the EMF at the CCW, MID and CW settings of R69 -- also note the pot setting corresponding to the lowest EMF --- If you find that the maximum EMFs are sufficiently low that you may directly use the meter - please preform the procedure without the probe!

Let me know how it goes!

Best regards
HP

 

socket[/U] connections for pin 10 and pin 12
HP

Thanks for beeiing back!
On my diagram the pins 10 and 12 are not connected. On the other hand on the tube they are connected! What are the for and do you really mean between them or rather measuring both of them referenced to the frame? I can do no harm branching the mains without te connection to the tube?

 

(makeshift EHT probe attached)

Please explain what you mean by this.

 

On my diagram the pins 10 and 12 are not connected. On the other hand on the tube they are connected! What are the for

They are the connections to the horizontal deflection plates (X1 and X2) --- Measuring the EMF between the socket contacts (for pin #10 and pin #12) will show the differential output of the X amplifier -- it is important that the scope is set to a mode that would produce a dot (with no sweep) on the screen if the display was working. By noting the EMF at different angles of the X position control (R69) we may get an idea as to the 'health' of the horizontal 'dc balance'...

I can do no harm branching the mains without te connection to the tube?

Do you mean you are concerned that the scope may be damaged by operating it with the CRT socket disconnected? -- Unlikely inasmuch as all connections (except the filament) are 'high impedance' however inasmuch as the cathode return and floating 'EHT' points may be troublesome, it would be best if you worked out a method of 'bringing out' conductors from pins #10 and #12 such that the socket could remain connected to the tube during operation...

Warning: During operation pins #10 and #12 will be significantly (electrically) 'elevated' above the chassis -- please take care to keep the meter and leads away from the chassis during the test!

[
Iron is not grounded ; i' ll ground it exteriorly and connect it to scope ground. Is that OK.

Yes, but it would be best to always disconnect the scope from the mains before preforming any soldering!

Best regards
HP

 

PS there appears to be a difference between D61 telequipment and the D61a; The link (#61 http://www.hobbielektronika.hu/forum/getfile.php?id=262895
I gave was for the D61; mine is a D61a; the main diff. are the triggering circuits as mentioned in http://ukradio.info/Telequipment/;
I had not mentioned the difference before. The diagram I have put on #8 is the one for my device D61a.
On the correct diagram fig 5 for the D61a pin 10 and 12 are not connected, but as I mentionned above mine are! Dont get it. Have to add that mine was modified by the company for "prolonged phosphorisation " in order to be able to see slowly changing signals, but I dont think this is the purpose of pin 10/12??

 

Please explain what you mean by this.

I meant that you should connect your DIY 'high voltage' probe to the meter when you initally preform the test -- that way there will be no damage the meter should the differential EMF be unexpectedly high...

 

I did not disconnected the tube yet but performed the measuring BETWEEN pin 10 and 12.
it is 100V; Intensity, focus, R69 have no influence. Does this indicates something to you or is the disconnection of the socket crucial?

 

PS there appears to be a difference between D61 telequipment and the D61a; The link (#61 http://www.hobbielektronika.hu/forum/getfile.php?id=262895
I gave was for the D61; mine is a D61a; the main diff. are the triggering circuits as mentioned in http://ukradio.info/Telequipment/;
I had not mentioned the difference before. The diagram I have put on #8 is the one for my device D61a.
On the correct diagram fig 5 for the D61a pin 10 and 12 are not connected, but as I mentionned above mine are! Dont get it. Have to add that mine was modified by the company for "prolonged phosphorisation " in order to be able to see slowly changing signals, but I dont think this is the purpose of pin 10/12??

As long as the CRT is 1324Y or 1346Y the X-Deflection plates are connected to pins #10 and #12
See here: http://frank.pocnet.net/sheets/084/1/1300Y.pdf

Have to add that mine was modified by the company for "prolonged phosphorisation "

Tubes of different persistence figures are typically offered with the same basing -- that said, please try to find a number on the tube to be sure...

Best regards
HP

 

As long as the CRT is 1324Y or 1346Y the X-Deflection plates are connected to pins #10 and #12
See here: http://frank.pocnet.net/sheets/084/1/1300Y.pdf


Tubes of different persistence figures are typically offered with the same basing -- that said, please try to find a number on the tube to be sure...

Best regards
HP

I cannot see the tube number since the top cover is rivetted but I guess differencees are mainly in the interior coating of the tube...

 

I did not disconnected the tube yet but performed the measuring BETWEEN pin 10 and 12.
it is 100V; Intensity, focus, R69 have no influence. Does this indicates something to you or is the disconnection of the socket crucial?

It is important that the scope is set to a mode that does not produce horizontal sweep (e.g. "X-Y" or "Ext Horz", etc...) -- otherwise the 'AC componient' of the EMF will interfere with the DMM readings...

 

I guess differencees are mainly in the interior coating of the tube...

That's usually the case...

 

I did not disconnected the tube yet

That's a good idea! -- it's best not to disconnect the tube!

 

@patpin

Based upon the image of the scope in the manual -- please set the Time/Div control to "Ext X" for the test...

 

@patpin

Based upon the image of the scope in the manual -- please set the Time/Div control to "Ext X" for the test...

This is what I did. See results above. in the link #91, I do not see the ratings for X1-X2...

 

in the link #91, I do not see the ratings for X1-X2..

Scroll all the way down then look at the drawing of the socket (upper left) notice that X1 and X2 are assigned to pins #10 and #12 respectively

This is what I did.

Do you mean that the results cited in post #89 were made with the Time/Div control set to 'Ext X'? If so, are you absolutely certain that R69 has no effect?

 

On the correct diagram fig 5 for the D61a pin 10 and 12 are not connected, but as I mentionned above

I see my statement was erratic... Those are coming from HOR pos in fig 3 diagram

 

Scroll all the way down then look at the drawing of the socket (upper left) notice that X1 and X2 are assigned to pins #10 and #12 respectively


Do you mean that the results cited in post #89 were made with the Time/Div control set to 'Ext X'? If so, are you absolutely certain that R69 has no effect?

Indeed No effect in the stated position 'EXT X". I measured with the probe! I guess I safely can repeat with the DMM directly in order to have more exact values?

 

I see my statement was erratic... Those are coming from HOR pos in fig 3 diagram

FWIW: If you look at Fig #3 you'll see the X1 and X2 lines (top right) -- The connections are not shown in Fig 5 merely because that diagram is not concerned with deflection circuitry...