Flintlock flanger help

[Hangingmonkey]

Im having a hard time biasing the flanger (i always have a hard time with flangers). Im at the stage of trying to get the frequencies in the 69.9-2.6 range of the manual pot. Whats happening is that i have to get c max at full turn to get it at 69.9 but then when i turn manual cw and adjsut the c range i have to turn it fully the other direction to get 2.6mhz. Turning the manual ccw again just gets me in a vicious circle, having gone back and forth with the process several times. Is this normal?  Im getting to the point where the range of the trimmer doesnt get me to the frequency I need to be at within its range.
Any thoughts about this?
Heres a pic. I know i need to post voltages, which i will by the end of the day

[Scruffie]

Okay, verified you have 15V at the test point, yes?

Any substitutions made at all?

C26, what value did you use and did you measure the cap prior to installation? Is it a tayda ceramic?

[Hangingmonkey]

Hi Scruffie. 15v confirmed. I measured all the components prior to installing and c26 was measured, it's a tayda mlcc

[Scruffie]

What's frequencies can you get it to go between?

Do you have a spare 1M resistor laying around? Try tacking it in parallel with R54, looking at the old schematics, one lists the value for it as 68k -75k, as it's been doubled, 68k doubled = 136k. 150k in parallel with 1M = 130k, close enough for jazz and should extend the range a bit.

[Hangingmonkey]

Ok, tried a 1m resistor in parallel with r54 but still same problem. I can't get 69.9 with c max at full cw rotation and have to tweak c range to get to that frequency. Then turning manual cw I have to turn c range ccw most of the way back to get 2.6mhz. Then going back to manual ccw again, I get 7.7-57.3khz
That's with the 1m attached.

[Scruffie]

The trimmers do interact a lot so it can take some time to get the balance right so there may not be an issue but, if I follow, seems like C26 could be a tad too high or tad too low in value... (if I follow I think it's too high) I don't have my prototype on hand to test exactly which with and i'm running on 2 hours sleep

It can be finicky, but you'll get there, doesn't seem like there's any major issue, just some tweaking to be done... or a wrong value still.

Just to be sure though, can you give the voltages for IC5, 6 & 8

[Govmnt_Lacky]

HAve you tried to follow the mooseapotamus videos for calibrating the A/DA? I was flustered and experiencing the same problems with my A/DA clone until I watched. They help A LOT!

[Hangingmonkey]

Thanks Scruffie, I appreciate the help, especially on 2 hrs sleep. I hope these voltages make sense....

Ic5
1-4.8
2-4.8
3-11.5
4-0.4
5-0.3
6-11.5
7-11.5
8-8.5
9-5.9
10-5.9
11-7.4
12-99.1mV
13-13.9
14-13.9

Ic6
1-14
2-101mV
3-7.5
4-14.1
5-14.1
6-14.1
7-11.7
8-11.7
9-11.7
10-7
11-7
12-11.7
13-14
14-14.1

Ic8
1-2.2
2-3.9
3-3.9
4-11.6
5-4.9
6-4.9
7-5.9
8-14.9

[Hangingmonkey]

HAve you tried to follow the mooseapotamus videos for calibrating the A/DA? I was flustered and experiencing the same problems with my A/DA clone until I watched. They help A LOT!

Thanks, I didn't know such a thing existed. I was thinking earlier today, I wish there was a video of the calibration.  I'll check it out

[Govmnt_Lacky]

Thanks, I didn't know such a thing existed. I was thinking earlier today, I wish there was a video of the calibration.  I'll check it out

Yep! Dont remember if they are linked from his site or not but, you can probably find them by a YouTube search. 

[Scruffie]

Thanks Scruffie, I appreciate the help, especially on 2 hrs sleep. I hope these voltages make sense....

Ic5
1-4.8
2-4.8
3-11.5
4-0.4
5-0.3
6-11.5
7-11.5
8-8.5
9-5.9
10-5.9
11-7.4
12-99.1mV
13-13.9
14-13.9

Ic6
1-14
2-101mV
3-7.5
4-14.1
5-14.1
6-14.1
7-11.7
8-11.7
9-11.7
10-7
11-7
12-11.7
13-14
14-14.1

Ic8
1-2.2
2-3.9
3-3.9
4-11.6
5-4.9
6-4.9
7-5.9
8-14.9

11V on ground Are you reading these while still in Hz mode?

[Hangingmonkey]

I don't think so but I'll double check when I get back from work

[Hangingmonkey]

Right, well I managed to get the frequencies in range, had to remove the 1m parallel resistor but watching the biasing videos on YouTube really helped as I understood what I was doing better. I havent gone to the next stage of trimmer twiddling as 130am here so will see how it goes tomorrow.

I just realised that some of the voltages I gave were dodgy, mainly due to the new dmm which auto selects and displays units, even mV which I'm not used to and didn't realise that's what I was reading. Sorry for all the noob errors, and I'm coming up to 3 yrs of building as well!!! (Slaps forehead)

Anyway, I hope these readings make sense. 

Ic 5
1-14
2-14
3-0.1
4-7.3
5-5.7
6-0
7-0.4
8-0
9-0
10-0.3
11-0.3
12-0
13-0.26
14-11

Ic6
1-14.2
2-0.1
3-7.4
4-14.3
5-14.3
6-14.3
7-0
8-0
9-0
10-7.1
11-7.1
12-0
13-14.2
14-14.3

Ic8
1-2.3
2-4
3-3.9
4-0
5-5
6-5
7-5.8
8-15.1

Hope they make sense, there's a lot of zeros there, I can see in ic6 they all connect to gnd on the schemo but not sure what a lot of the pins on ic5 do.

[blearyeyes]

Just curious if you got this working.

I am staring down this build with fear and trepidation......

[Hangingmonkey]

Just curious if you got this working.

I am staring down this build with fear and trepidation......

No, not yet, I've put it on hold for a moment to look at it with a fresh pair of eyes. My above post said that I managed to get it in the correct frequency range, I was wrong. I was biasing it late at night and was exhausted after a long day at work. For some reason I read 2.2Mhz on the dmm as 2.6 and didn't realise till I went back to it the following evening!!! 
Going to look at it again on the weekend.  Probably going to start by checking all the components.
How's yours coming along?