Electronics > Repair
Anritsu MS2651A repair (need service manual)
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jkf1000:
Post back when you have more time spare or anything more you need me to measure. I have questions about the signals around the ACRTC chip which you could scope for me when time permits, Karl.
jimon:
Sure, I'll do it tomorrow evening, anything in particular you want to know? I've tried to look for ACRTC-ish chip/marking, but can't find it ... board next to LCD mostly contains 74-ish chips and CPU board doesn't look like have this marking. So where I should look?
jkf1000:
The ACRTC is the HD63484 on the main processor board. It is the main process chip for the display. What I need to know is what if anything is happening on your Hsync and Vsync lines which are pins 13 and 14. I was expecting to see cmos level timing signals to control the display timing but not getting any thing like it. I am still trying to diagnose the root of my display issue but not making much progress so far. Karl
jimon:
Thanks for the waiting, here hsync and vsync signals. Please let me know if you want me to probe more!
jimon:
jkf1000, do you have IF 110.695 MHz anywhere ? I was poking all around RF block ... and meh .. sure I found 100 MHz from getting from X3, and than it's was all over RF traces (was poking around 2nd mixer and VCO) with level around -30 dBm. Looks like it was leaking to VCO output trace with level around -35 dBm.

Looks like 110.695 MHz should go through backplane, but I cannot find anything with oscilloscope going through RF block connector to backplane :/ I would really appreciate if you poke there and check if IF is present.
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