One more thing on used press buying that bit us: check the servo motor encoder type and whether replacement encoders are still available. We bought a 2012-vintage press with Heidenhain absolute encoders that were discontinued. When one failed 8 months in, the replacement was a $9K special order with 14-week lead time. Press sat idle for 3 months.
Now I always check: (1) is the encoder still in production, (2) does the seller have a spare, (3) what's the lead time from the distributor. If the answer to #1 is no, negotiate a spare encoder into the purchase price. A $2K encoder in the parts cabinet is cheap insurance against a $150K/month production loss.
On the capacitor check — you can also look at the drive's power-on hours vs. cap rated life. Most electrolytic caps are rated 40,000-60,000 hours at 40°C. If the drive shows 35,000+ hours, budget for a cap replacement regardless of what the ripple measurement shows. The degradation curve is exponential — they can go from "fine" to "dead" in a few months once they start failing.