Electronics > Repair
Wavetek 2520a 0.2-2,200MHz RF sig gen repair
dazz1:
Hi
I tried lifting the 4x 10uF 25V Tants on the 18V supply. One was blown apart. The other 3 are OK. With these tants connected to air, the short is still there.
There are still 26x 1uF 25V tants on the 15V supply.
The search continues.
Dazz
Chris56000:
Hi!
Could you please possibly email me a copy of, or provide a link to, the incomplete manual please?
If one of these generators comes up in the future that I can buy than I can draw out the missing sheets again!
Chris Williams
dazz1:
--- Quote from: Chris56000 on May 03, 2021, 06:12:41 pm ---Hi!
Could you please possibly email me a copy of, or provide a link to, the incomplete manual please?
--- End quote ---
The manual is too big to email or post.
Based on the figure numbers (different to the drawing numbers), it appears the missing drawings were not included in the original manual.
Reconstructing the missing drawings would be made more complex because some parts of the circuit are fitted but not used.
Dazz
dazz1:
Hi
I discovered that the main board has connectors on the bottom side that connect through to PCBs inside the enclosures on the other side of the equipment.
When I pulled the main board the short disappeared.
I isolated the short to a Tant in the Oscillator module.
When I refitted the mainboard and applied power, a Tant on the main board released the magic smoke.
All of the failed 25V Tants are on the +18V rail. I have replaced them with 35V Tants.
So now all the power rails are at the correct voltage.
The self test and auto-calibration has failed.
There are multiple control loops so now I need to work my way around these to find the next fault.
Dazz
dazz1:
Hi
A local RF company http://www.rftest.co.nz/ with a ton of test equipment and expertise let me use a Thermal Imaging Camera on the main board.
This was before I knew that there were still connected boards below the main board. The thermal imaging camera was very sensitive and easily showed temperature differences of 1 degree C. It did sense the slight temperature variations of current carrying tracks and components. It correctly showed no hot components on the main board.
It was the camera that convinced me I needed to look harder at the equipment to trace what turned out to be a shorted Tant cap on another board.
Dazz
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