Countdown Phaser not responding to trimmers

[matopotato]

[in the following I`m referring to the .pdf-schemo, coz your pix are too small for my eyes]

...
Start:
all elcos concerned oriented correctly? (C30, C32, C33, C34, C35, C36, C38).

Yes, and I checked all electrolyte ones for orientation. That is those having - to ground checked out, and the others I checked against one of the "next component points" in the schematic.

IC5+IC6 have the correct power-supply-voltage at their corresponding power-pins?
(IC5: pin4 0V/pin11 +15V) (IC6: pin4 0V/pin8 +15V).

IC5, p4=15,13V
IC6, p8=14,96V
and the grounds were zero.

Turn all "LFO"+ "HF" (trim-)pots to center-position, then move each of these (trim-)pots one by one slowly left and right, to see if the HF changes at any of these movements.

I tried with jumping T&R and later R&S respectively. It stays at 1,23 MHz and swings up to 1,25 MHz. Although a bit jumpy it is still a sort of very small sweep, but still a sweeping motion. No turning of any pot seem to affect this except for RANGE which clearly makes it move between 1,225 and 1,285 MHz.

[matopotato]

check the value of R67.

Marked Yellow Purple Black Gold Brown yields 47R and DMM says 46.8 Ohm, so that should be OK.

[matopotato]

Scratch that...


https://au.element14.com/multicomp/78l15/linear-voltage-regulator-15v-to/dp/4642557

https://www.ti.com/lit/gpn/lt1054


The pdf schematic shows the 9v input goes through IC11 which is a boost converter  this should have higher than about 17vdc on pin 6   which connects to the pin 1 input of the IC12 via the two diodes D6 D7 

Pin 3 of IC12 should have  the regulated 15Vdc on it.  It can also be measure on the positive pin of C45 if its easier to access

IC12 Seems a bit fishy...
If I google it says, looking at the flat side that Left to right is Pin 1,2,3


Looking at the PCB marking, that would make the socket match left to right Pin 1,2,3




But when I check connectivity I get connection between Left most "pin 1" and the 15V checkpoint. In the schema to the right.
And "pin3" beeps with D7 cathode.
But in the schematic this is written as 1 going to D7 and 3 going to 15V
Schematic says VI for 1 and VO for 3, but then the numbers again seem contradicting vs the google pinout.



I guess I could just flip the 78L15, but would like to know if I am wrong, it won't fry anything...
Kind of a long shot since the build, kit and schematic has been around for quite some time, then I couldn't possibly be the first one facing this...

[puretube]

Shame on me! I typoed wrong pin-numbers to the voltages in reply#11 - corrected 
Your supply-voltages for the LFO look okay!
But the "sweep" isn`t as large as it should be.
It`s hard to watch & measure the amplitudes of the LFO-signals with a DMM.
An old analog meter with a pointer would be nice to use. Scope would be perfect.
But maybe you can try to get some max/min voltages reading on pins 7 & 8 of IC5, which should be slowly moving up & down a few volts, when the SWPMOD & SWEEP pots are turned fully CCW.
If they don`t move up & down, the LFOs don`t oscillate.

[matopotato]

Shame on me! I typoed wrong pin-numbers to the voltages in reply#11 - corrected 
Your supply-voltages for the LFO look okay!
But the "sweep" isn`t as large as it should be.
It`s hard to watch & measure the amplitudes of the LFO-signals with a DMM.
An old analog meter with a pointer would be nice to use. Scope would be perfect.
But maybe you can try to get some max/min voltages reading on pins 7 & 8 of IC5, which should be slowly moving up & down a few volts, when the SWPMOD & SWEEP pots are turned fully CCW.
If they don`t move up & down, the LFOs don`t oscillate.

Ok, will try.
I have an old 1-ch scope I can try. Time to get to know-it.
The DMM is good for Hz measures though.
Any thoughts on the pinout and schematics numbering of the 78L15?

[duck_arse]

check the value of R67.

Thanks
In the instructions I read about R65 and R66 being sensitive to de iations so I measured a few until I found two that matched quite well.
For R67 I didn't go that far, other than verifying it's value (as all Rs) before soldering.
Is R67 also more sensitive to deviations?
Or is it more a case of avoiding 4k7 47k kind of problem?
Will double-check tonight.

your voltages look right everywhere if you take into account a fault. see IC5.2 outputs what it has at input, 5V12. see IC6.2 is fed that voltage thru 2 resistors, and reads about 4V. but then that 5V is also fed thru some resistors and your shorting link to the other input, but now only reads bugger all, or SFA. and the output of IC6.2 can only follow its inputs. so - measure the resistance between pin 14 [? I can't squint them out either] of IC5 and pin 2 [?] of IC6. measure from the IC pin to IC pin, just to make sure.

and with regulators and transistors and IC's - it NEVER pays to try turning them around. get the datasheet for the part in your hand first. then know what you are doing, and you only need do it once.

[matopotato]

I thought more pixels meant better resolution. But will re-post pics with more mobile friendly resolution later tonight.

[matopotato]

check the value of R67.

Thanks
In the instructions I read about R65 and R66 being sensitive to de iations so I measured a few until I found two that matched quite well.
For R67 I didn't go that far, other than verifying it's value (as all Rs) before soldering.
Is R67 also more sensitive to deviations?
Or is it more a case of avoiding 4k7 47k kind of problem?
Will double-check tonight.

your voltages look right everywhere if you take into account a fault. see IC5.2 outputs what it has at input, 5V12. see IC6.2 is fed that voltage thru 2 resistors, and reads about 4V. but then that 5V is also fed thru some resistors and your shorting link to the other input, but now only reads bugger all, or SFA. and the output of IC6.2 can only follow its inputs. so - measure the resistance between pin 14 [? I can't squint them out either] of IC5 and pin 2 [?] of IC6. measure from the IC pin to IC pin, just to make sure.

and with regulators and transistors and IC's - it NEVER pays to try turning them around. get the datasheet for the part in your hand first. then know what you are doing, and you only need do it once.

Thanks, will test tonight.
The regulator flip question is based on google pinout, DMM connectivity test and schematics pin numbering seemingly not matching eachother. I tried to post some pics above, but better pics might show what I mean better.

[MP_Quokka]

In your pics it shows the IC12 regulator which looks like its an STMicroelectronics device. This data sheet from RS shows it has "backwards pins" 

https://docs.rs-online.com/83f9/0900766b81712999.pdf

Pin 1 is Output as traced on your PCB socket.  So its probably correct the way the flat side is drawn on the PCB.

Fig 3 in the datasheet has a test circuit,  you could breadboard it up and measure the pin voltages to confirm?  You would need about 18V or higher supply on pin 3, but should get 15V on pin 1.

I would fit the reg again on the board and measure the pin 1 output and make sure its 15V

[matopotato]

In your pics it shows the IC12 regulator which looks like its an STMicroelectronics device. This data sheet from RS shows it has "backwards pins" 

https://docs.rs-online.com/83f9/0900766b81712999.pdf

Pin 1 is Output as traced on your PCB socket.  So its probably correct the way the flat side is drawn on the PCB.

Fig 3 in the datasheet has a test circuit,  you could breadboard it up and measure the pin voltages to confirm?  You would need about 18V or higher supply on pin 3, but should get 15V on pin 1.

I would fit the reg again on the board and measure the pin 1 output and make sure its 15V

Thanks, yes I should pay more attentionnto details. I ignorantly thought a 78L15 is a 78L15...
And sorry, forgot to send the values.
Reg pin 1 read 15.02V and goes to the 15V test point.
Pin3 goes to the D7 diode amd has 16.8V. (How the 9v far left make pin 3 get ~17V is beyond my knowledge but that's what a fev caps and diodes seem to do...

[matopotato]

I tried to upload new pictures, but no matter what they are still quite small in the forum.
Only thing one can do is click them, then click the picture and open in new tab and zoom in. Tried various settings but couldn't figure it out.
Reposting in unchanged format anyway.

[anotherjim]

How come we have an LFO sweep voltage from IC5 pin 8 but static voltage elsewhere?
I don't quite follow the sweep control in this thing.
If IC5.3 is the LFO sweep integrator, then IC5.1 is its controlling Schmitt trigger and if so its output pin1 should switch high-low as the sweep integrator changes up/down direction.
For the CD4016 switches doing the phasing, you can clock the Ctrl (control) inputs at any supersonic speed you like, but if the clock doesn't change its duty cycle, the value of the switches in the phase filters remains constant. So the LFO ramp has to change the duty of the 4047 oscillator somehow. The schematic for the 4007 MOSFET array is unhelpful. It needs a redraw to show its internal transistors in the circuit - there are only 6 of them.
Anyway, the Range pot needs to be set so R82 connects more to the output of IC5.3, that is the pot wiper on lug 2 turned to lug 3 if it's wired as per the scheme.

[puretube]

Reg pin 1 read 15.02V and goes to the 15V test point.
Pin3 goes to the D7 diode amd has 16.8V. (How the 9v far left make pin 3 get ~17V is beyond my knowledge but that's what a fev caps and diodes seem to do...

IC11 magically ~ doubles the input voltage. See fig.20, pg.17 (+fig.12, pg.10)
https://www.ti.com/lit/ds/symlink/lt1054.pdf?HQS=dis-mous-null-mousermode-dsf-pf-null-wwe&ts=1667399734411&ref_url=https%253A%252F%252Fwww.mouser.ca%252F

[matopotato]

Reg pin 1 read 15.02V and goes to the 15V test point.
Pin3 goes to the D7 diode amd has 16.8V. (How the 9v far left make pin 3 get ~17V is beyond my knowledge but that's what a fev caps and diodes seem to do...

IC11 magically ~ doubles the input voltage. See fig.20, pg.17 (+fig.12, pg.10)
https://www.ti.com/lit/ds/symlink/lt1054.pdf?HQS=dis-mous-null-mousermode-dsf-pf-null-wwe&ts=1667399734411&ref_url=https%253A%252F%252Fwww.mouser.ca%252F

Cool!
I probably put the voltage values on the opposite pins. Makes more sense now.
Thanks.

[matopotato]

How come we have an LFO sweep voltage from IC5 pin 8 but static voltage elsewhere?
I don't quite follow the sweep control in this thing.
If IC5.3 is the LFO sweep integrator, then IC5.1 is its controlling Schmitt trigger and if so its output pin1 should switch high-low as the sweep integrator changes up/down direction.
For the CD4016 switches doing the phasing, you can clock the Ctrl (control) inputs at any supersonic speed you like, but if the clock doesn't change its duty cycle, the value of the switches in the phase filters remains constant. So the LFO ramp has to change the duty of the 4047 oscillator somehow. The schematic for the 4007 MOSFET array is unhelpful. It needs a redraw to show its internal transistors in the circuit - there are only 6 of them.
Anyway, the Range pot needs to be set so R82 connects more to the output of IC5.3, that is the pot wiper on lug 2 turned to lug 3 if it's wired as per the scheme.

Thanks Jim!
I will have to digest this a bit.
I have to confess though I am still a bit at a loss as to what to try next.
I beleive the pcb and schema is fine, others have succeeded. The components I could measure came out.ok.  So something is wrong on my part, my build. Not sure where to start the process.
I can reflow the solderpoints, but as a general indiscriminate action it is a bit blunt and might even risk losening stuff that are ok right now.

Come the weekend I will get the scope up and explore all replies and learn from them.as well.

At one point is suspected the CLKRANGE multi turn trimmer, but eventually got it to measure 0 to 20k. A bit slippery getting the probe points in right.

[anotherjim]

Scope can tell us a lot. We like pretty pictures of waveforms.

[matopotato]

Scope can tell us a lot. We like pretty pictures of waveforms.

"Where do you want these scope probings done?"
(... and 'out on Highway 61' is not a useful answer for me...)

[puretube]

Inspecting the top-right "functional diagram" on page 1 of this 4007-datasheet:
https://www.ti.com/lit/ds/symlink/cd4007ub.pdf?HQS=dis-mous-null-mousermode-dsf-pf-null-wwe&ts=1667470405163&ref_url=https%253A%252F%252Fwww.mouser.de%252F
and checking the datasheet of this 4047:
https://www.ti.com/lit/ds/symlink/cd4047b-mil.pdf?HQS=dis-mous-null-mousermode-dsf-pf-null-wwe&ts=1667473111601&ref_url=https%253A%252F%252Fwww.mouser.de%252F
we can identify it working as a free-running astable multivibrator, (IMHO with constant pulsewidth), whose frequency can be varied from ~35kHz to ~650kHzwith a 1M pot between pin2 and pin3. (plus 200Ohm limiting resistor).
Now we can re-draw the HF-generation-section like this:



So IC7.1 is just an ordinary P-MOSFET used as a voltage-controlled resistor.
Correction of the handdrawn schemo: pins4+5 NOT used!
IC7.2 & IC7.3 are just ordinary inverters, wired in parallel.
(the drawing-symbols for IC7 in the orig. schemo are quite, ahemm,  misleading ...)

p.s.: the unlabeled pins to the south of IC8 are 7,8,9,12

[puretube]

With a pot (1M) temporarily hooked up to pins2&3 of IC8, AND one end of R89 lifted out of the PCB, your c*cked-wah-sound should morph into phasing, when turning the pot.
Also the frequency of your testpoint should change remarkably.
Try it. This will assure us that only the LFO and its surroundings is the culprit.
(Don`t accidentally short pins while power is on!)

[matopotato]

With a pot (1M) temporarily hooked up to pins2&3 of IC8, AND one end of R89 lifted out of the PCB, your c*cked-wah-sound should morph into phasing, when turning the pot.
Also the frequency of your testpoint should change remarkably.
Try it. This will assure us that only the LFO and its surroundings is the culprit.
(Don`t accidentally short pins while power is on!)

Great! Thanks for the effort. Will try during weekend. As well as any verifications I  have missed above.
It is good to have a way to verify the LFO being ok or not