ovation fuzz from the late 60's/// help me resurrect it?

[pinkjimiphoton]

hey Rob,
did ya ever get the tuner part drawn up?


gonna go change the q's in it to what i reccomended above, and see if it brings it to life a bit more. stay tuned bro!!

[Rob Strand]

hey Rob,
did ya ever get the tuner part drawn up?

I haven't forgot.  I'm waiting for a chunk of time where I can do it in one hit.
ATM, I'm just cleaning up stuff in small dribs and drabs.

[pinkjimiphoton]

i feel that!
i actually could see the surface of my bench. for like, a couple hours. noddanymore lol

[Rob Strand]

OK I finally got around to doing the Tuner.

I found a few issues which I've highlighted under "Unknowns" on the schematic.  In addition to those notes,
- There was one resistor without value on you parts value markup (R7) which I could derive from the other values.
- The value of R20 (47R) was marked as 98R. I'm pretty sure this is 47R.
- I've also guessed/calculated the value of the Trimpot RV2.

Under the "Unknown" section on the schematic:
- Looking at your first and second revision wiring notes, when I look at the white wire on SW1b it looks like the PSU is getting switched into the Top Boost switch.  This doesn't make sense.   Unfortunately I can't unravel where it should go since it kind of makes sense as is. 
- There's also some ambiguity with the Brown wire on SW1a and the Lamp Brown wire.

These aren't big issues but there's something a bit weird going on there.

Anyway here's the schematic and the part designators for the Tuner:





If you want to go over it to check it, or you (or anyone else) sees anything wrong please post the problems and I'll fix it.

[pinkjimiphoton]

hey rob,
looks good man!
i will check my notes when i get a chance to see where stuff went, i believe the tuner on switch only has them two connections, and it definitely goes to channel 2 pin 10 i remember that. but i will check as soon as i can. kinda a busy weekend, so please bear with me!!

[Rob Strand]

i will check my notes when i get a chance to see where stuff went, i believe the tuner on switch only has them two connections, and it definitely goes to channel 2 pin 10 i remember that. but i will check as soon as i can. kinda a busy weekend, so please bear with me!!

Cool, see how you go. I struggled with those parts a bit.

The way I understood it is Tuner #6 (Gray) goes to Channel 2 #4.  So basically that's the E tone passing to the input of of channel 2 - so you hear the tuner tone in channel 2; as per the manual.

The other connection is Tuner #10 which is the signal from Channel 1.  So what that does is feed a signal tapped of channel 1 into the tuner so you can use silent tuning using the tuning lamp light; again as per the manual.

I was thinking either Tuning #6 or Tuner #10 could go through the switch to isolate the tuner from the channels. However, since one side of the switch kills the power to the tuner it will probably work without switching those signals out.    When I look at the switches I can't see any switching of either of those signal (but that could be me misunderstanding some detail).

What I see on the tune switch is one side switching power to the tuner (Sw1a as shown).   However I'm puzzled where Sw1b goes!  It does go somewhere!

[pinkjimiphoton]

yessir, i guess i gotta take the mofo apart again. i wanna update the fuzz section anyways and see if it will work in the unit like the standalone does.

may take a couple days

[Rob Strand]

yessir, i guess i gotta take the mofo apart again. i wanna update the fuzz section anyways and see if it will work in the unit like the standalone does.

may take a couple days

OK see how far you get.  I might have another look at you old wiring doc, new/revised wiring docs and the pics again.  I'm pretty sure I can't work it out since a couple of things didn't agree.