HP E4421B error 513

[Ej]

Hi guys,

I'm new here, sorry to bother y'all.....found a E4421B 3 GHz gESG series generator working ok, but it has one flaw: error 513, Het. VCO unlock....nevertheless everything seems to work. Something is wrong with the 1 GHz PLL. Anyone seen this and knows which part should be replaced?

Thanks, Eric

[Ej]

Solved it by swapping the defective plugin with one from eBay. Not the best way but now I see no more annoying errors 

[Samogon]

513 oven is cold, usually it disapears in few minutes.

[Ej]

Your comment is not correct, oven cold is error 514, 1 GHz reference oscillator unlocked is 513.

[Samogon]

Oopsy, my bad

[Ej]

What forced me to solve it this brute force by forking out $$$ is the fact HP doesn't publish any real schematics, that's the real bad!

The reference 10 MHz oscillator to which the 1 GHz PLL is locked on this newer board is smaller then on my original plugin.