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Hi Ozan, After repairing the connection to S260, I gathered another set of readings. The setup was the same as before (e.g. NORM, EXT, TIMEBASE, LEVEL midway on the negative slope): Base of Q224 :

I took the assembly out and tested it and it worked. I put it back in and it doesn't work. I then noticed the solder joint that should have been holding the wire that connects to one of the switch

Now I see the description in the manual. Very interesting design, makes sense for PP-Auto mode but probably makes life complicated in non PP-Auto mode. Ozan

Comments below. The LEVEL knob does vary that voltage but issues with S260 (see below) may need to be corrected before going further.

We expect base voltages of Q234 to change with LEVEL knob (pot) but SLOPE control shouldn't make any difference. Q224 base will be at about trigger input voltage + 0.78V and Q234 base should be

Regarding S260, I see now on the schematic that the connector numbers for P260 are shown (3 and 6) so I can follow those and check the switch. Thanks, Barry - N4BUQ

Hi Ozan, I'm not sure but I think I may have found problem with the LEVEL/SLOPE control. I checked the base voltage of Q224/Q234 with the SLOPE in + and - mid-positions. In both cases, Q224's base is

@ Ozan, Correction: the shorted tantalum was C961 (2.2. uF 20V), fed by a serial resistor of 10 Ohm on the +15V power line.. This shows that such a 10 Ohm series resistor does not protect the tantalum

The following photos have been uploaded to the TEK475 Shorted +15V rail (Intermittent shortcut C961 PLUS intermittent interruption in GND rail. ( /g/TekScopes/album?id=270063 ) album

well,my scope scrubup didnt last long,now neither channels trigger!,it looks shiny tho!

John Griessen's flexible extender kit does what you want. I have used them to check out the caps on a 7A26 applying just +/-15V and watching the current consumption.

Hi Barry, My comments are below: There is a subtle reason. If you are interested (otherwise skipping is fine): We want to turn off the current to CR262 to see if it goes to low voltage state. With

Everybody: Thanks for your help and suggestions. Dear Ozan, You definitely mentioned C1387 as a potential culprit and helped me locating it (some errors in the manual , hence I could not find it

Comments interleaved with readings in brackets below. I presume you want "-" slope so as to disconnect the CQ connection point from the rest of the circuits. TP262's voltage is 11.1V which, if R261 is

Congratulations for the fix Martin. I was guessing in the same area but I don't know if I got it right in my message /g/TekScopes/message/187822 Mystery solved! Ozan

Good find Martin! Not important: In my 475 pdf C1387 is shown correctly I think in location 7D. But despite my new glasses I can't find C1387 in diagram <12>. Albert

Did you check the connections to the plates, as Raymond suggested? Sent from my iThing, so please forgive typos and brevity.

Goed gedaan, Martin! (Well done, Martin!) Raymond

Hi, I managed to repair the CRT circuit of my TEK 475. The screen intensity control and focus, is currently working as I should. I now can create nice, sharp horizontal and vertical lines in the XY

Thank you Mike! I will bookmark those articles. By the way, the individual files of Service Scope and TekScope are hosted at Kurt Rosenfeld’s excellent TekWiki site, w140.com . Dave Wise Information