Hello med6753, many thanks for your help!
Big Progress here:
a/ CAL: Your tips re the CTT CAL procedure signal were perfect, I used the TM501 to generate the 1.000000 MHz and trusty PG502 250 MHz pulse gen to make a +0.5 ..-0.5V 5 uS fast rise squarewave. Freq exact ~ 1 HZ with DC508.
After centering transition and DC, cal CTT proceedure FINALLY worked, no "out of range".
(note, with good NVRAM data and just CTT needing CAL, failing CAL CTT returns scope to the NVRAM error test 04 fail 10)
The HOR CAL seems OK but CH1 and CH 2 vertical are off 3..5% so VERT CAL is next.
Any tips in that procedure, (have PG506)? Even if other functions CAL seem OK, should I still do a full CAL?
b/ old issue: This 2465B CTT op 06 (SN 066xxx) is losing the panel settings at next turn on and default to 50 mv/DIV AC coupling etc regardless of previous settings.
I believe that this symptom existed before the old NV RAM failed and was replaced. Besides CAL data does the NVRAM also get FP settings written at shutdown? Since NV RAM is new and works and the scope seems to initialize and shutdown normally, what can cause this symptom?
c/ Misc cleanup:
A5 board options connector J4241 mates to the option ribbon cable with 2 connectors on the A5 end and 2 more with greater separation on options end. That links A5 to CTT options board. At A5, The second connector and thick cable loop interferes with the NVRAM as the machine pin socket raises it a bit. Any reason not to just cutoff the unused connectors?
The Fan is a bit noisy, replacement is the NIDEC Beta SL? Many models exist, as fan is critical to cooling, have 12V 0.12 and 12V 0.16 A models. Any tips on best replacement part?
Usual dead graticule lamps, any pitfalls in replacing? Suggest the original incandescent lamps or try LEDs?
d/ Finally if anyone has a 2465B Options manual for sale or swap or the PDF I will appreciate, as I am missing that from my huge TEK manual library.
Enjoy,
Jon
PS: Going thru this repair and rejuvenation, I can only marvel at the electronic, mechanical and software design of the most marvelous and last CRT scope from TEK!