| Electronics > Repair |
| Anritsu MS2651A repair (need service manual) |
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| jkf1000:
Thanks for uploading the video but unfortunately it does not help much. I don't have the tv option installed only the rear composite out which I am unable to activate without a screen. Looking at my user manual the setting is in the system menu 3, composite mode-composite-PAL-return. I finally had chance to do some measuring for you (assuming my unit is working ok on the RF side of things) on the coax to connector X3 on the 3Ghz unit there is no output, just an input from the Local board of around 96Mhz which matches the info on my block diagram. It list the local signal on X3 to be from 94 to 106Mhz I measured the signal on my 100Mhz DSO at around 3.56v Peak to Peak. On your scan board with the "Y" output board I have 3 flashing LEDs, on yours are they flashing or constantly lit as I suspect mine are showing a fault condition relating to my failed display condition? |
| jimon:
So X3 is an INPUT not output :palm: woah thanks for the info! that explains a lot ... especially why I was not getting anything out of X3 :palm: On my board all three leds are flashing on a same time with frequency around 2Hz. If I connect a scope to Y output I get something like on the screenshot. |
| jkf1000:
I don't know what technical differences there are between your A model when compared to my B model. Do you have the block diagram available? In the absence of any sort of in-depth technical documentation or schematic it will at least give you an idea of what signals to scope for and the direction of the LO and signal paths. As I mentioned previously, apart from inside the 3Ghz convertor, all other signals should be low enough in frequency to trace with your Rigpl DSO. Just as a long shot, but if yours is just a level error have you tried running the full auto calibration routine within the menu. Also check the backup battery for 3v just in case it is not able to retain its stored values. Not made any progress with mine as yet but cleared most of the other jobs off the bench so should get back to it later. So far I have confirmed digital communication between the processor and the video chip but no sync output between the video chip and the CPLD. Without the Vsync and Hsync signals there will be no timing signals for the LCD module. I will try and source another video controller chip first and take it from there, A process of elimination without the schematic and I am in unknown territory trying to to trace and understand digital signals. Let me know if you make any progress, Karl. |
| jkf1000:
Just done a quick google search for you and to see what differences there are in the models and I found a manual specific to the "A" models. Unfortunately it is too large to attach here but it was easy to find with google, I just searched MS2651a and it was one of the first results. Download it and check around page 181 for the block diagrams which gives you the signal paths and frequencies. Karl. |
| jimon:
Found it, awesome, thanks! I'm still a bit busy with other stuff so had little time to do anything with it. Looks like their internal connectors represent PATA-ish pitch. Need to make a small cable extension so I can run RF module and be able to access back side of it (where 2nd mixer is). |
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