Diode recommendations

[Moving Ahead]

I bought a 1960 pioneer tube receiver recently. There are 2 diodes ( 1NA9 ) which look like they're in the receiver end, see schematic in previous thread
http://www.audiokarma.org/forums/showthread.php?t=646270
Should I replace them or leave them alone?
Does anybody know the diode spec? Is it Ge or Si?
If a replacement is recommended; what diode would you recommend?
Many thanks for your help.

 

[larryderouin]

I'd leave them alone, unless proven bad. As for replacement, no idea.

 

[Tom Bavis]

If they're glass diodes, leave 'em alone.