On pcb A3, two are 20uF 50V and one is 100uF 50V. We replaced them with equal value caps, also from Mouser.
Once this was done, we powered it back up and went through some checks. This is detailed under 'Basic Functional Checks', section 3-5 in the 8903B operation manual.
You will need an oscilloscope as well.
Anyway, we had an issue with the output voltage. Setting it to 1.0V, we only got 0.545V. The frequency was OK. So, all following tests were also out.
Now, we also happen to have the 8903A operation manual. There, the above tests are called 'Operator's Checks', section 3-10. In that section, they are actually point to fault finding instructions if the readings are out, and it just so happened that a low output voltage level was covered.
So, we went ahead and follwed those fault finding isntructions as set out in the 8903A Operator's Checks section 3-10.
Not really sure why they did not add these in the 8903B manual....because without those fault finding hints, we would have had a heck of a time trtying to figure this out.
So, we recommend that you obtain BOTH the 8903A and 8903B manuals!!
In the end, it turned out that the calbration was out by a small amount, as detailed on SHEET 9 in the 8903B manual. Once we re adjusted those areas, bingo, it was reading correclty and we got 1.000V output level when 1V was selected.
All other areas and functions, so far, seem to be good.
As we get into more detailed operation of our 8903B, we will cover those here, so stay tuned!