F-1X has Loud Hum

[VPMAC59]

I have an older F-1X that I adore.  It has always had a noisy direct out, but I don't use it to record so it has been tolerable.  Last week the pre-amp developed a loud hum and a faint electrical burning smell (no smoke).  Not a normal ground loop hum, but an outrageously loud hum.  I plugged my bass directly into the power amp and it worked perfectly - dead quiet.  It is clearly the preamp.  Has anyone seen a similar problem or have ideas on potential cause?

Since I no longer play out I don't want to invest a lot in repairs.  Thanks for any help or suggestions.

[mica]

If you take the lid off, try and take a sniff around and see if you can identify where the smoky smell is strongest (wait at least 15 minutes after powering off as there is a high voltage trace on the circuit board!).

But it sounds like the problem is most likely in the power supply board. You can send in just the board for testing as it unplugs from the circuit and unscrews from the chassis. You can also send your F-1X in for testing. There is no charge to test and figure out what's going on. We'll let you know the price of repairs before we do anything and you're welcome to have us return it without servicing. Make sure you send to our new address in Rohnert Park, CA