This is not too unusual. A lower priced item like that is usually considered to be BER - beyond economical repair. So by the time you pay for a technician's time, parts, and downtime, you might as well have just replaced it with a new in-warranty instrument. If course a hobbyist wants access to parts for DIY repair, but they don't care.
I noticed something else recently at Agilent, that they are neutering some service manuals by removing schematics! Case in point, my E3620A power supplies. They no longer offer repair for these, but replace the unit outright if there is a (warranty) issue, and suggest that the customer buys a replacement when out of warranty. The service manual that is currently available has no schematics, but the one I downloaded years ago does. Their explanation is simple and outrageous: (paraphrasing) we don't repair them any longer so we removed repair information from the manual. Almost everything in there is a common off-the-shelf through-hole component, but they somehow figure that nobody needs the service information any longer.
If you own Keysight/Agilent/HP gear, download and archive the service manuals now. Don't wait for a failure, because you might find yourself without a schematic and parts lists.