Well, I guess I blew the buffer as nothing lit up (tube included) with connection to the 12v battery. The fuse is fine and I don't see anything untoward when I open the preamp but the next step is finding someone to repair this if possible. Thank you all for your help as always. Dave
If I remember correctly, the Dodd Buffer has a LM7806 TO220 case voltage regulator for the tube filament voltage for the 6H30 dual triode since it needs 6.3VDC. Most likely this blew when the battery connections were reversed. If the tube filament is not lit, then the buffer will not work.
There should also be a large diode at the grey Powercon 12V connector on the chassis for reverse voltage protection.
The buffer maybe fine, just the 7806 is bad.
