Ryk M185 Sequencer - per step repeat and gate mode

[ryk]

Yeah okay, I shouldn't have pushed my luck with two builds. First one was A-Ok, and then I build the next one, running into all sorts of weirdness (but hopefully from a common source).

Any direction is much appriciated!

Sorry to hear about the problems.
It is hard to tell from the video, but are the green LEDs 'dancing' about whilst you adjust the 8-way switches and the pots.
One quick test, could you try putting the PIC from the working unit into the 'weird' unit, to check there is no problem with the PIC.

ryk

[gaston]

Thanks for the answer, yeah, we can call it dancing hehe. Another very strange thing that happens is that if I have the max stages to 8, and the tempo set to bottom CCW, the sequencer will just run one stage (#1), then when increasing the tempo the sequencer starts running 8 stages again. It’s like the controls kind of affect each other in some kind of way.

I unfortunately needed to sell the other one rather quickly, but hindsight is 20/20 and should have of course waited until I had both built in case of exactly this scenario.

Maybe I should start trying to fix the #7 pot and take it from there, any tips which components could be involved in that issue?

[ryk]

Maybe I should start trying to fix the #7 pot and take it from there, any tips which components could be involved in that issue?

Hi
You mentioned in the previoud post that the #7 pot test ok, how did you test it ?

The only problem now is that you have something crazy going on with the stages control, hence
the dancing green LEDs, so it will be dificult to set the HW test to Stage 7 for testing.

So first we need to fix the dancing green LEDs.
One the panel PCB, orientated with LEDs at the top, viewed from the component side.
Please check for continuity to GND on the top pin of R3 [ please use a GND on the Main PCB ]
Also check for continuity on LHS pin of VR2 [ tempo ] and LHS pin of VR1 [gate time ]

When the HW test mode is stable:
To test #7 pot, I would recomend, starting the seq in HW test mode.
Then use the rotary stages control to set stage 7.
Use a DC meter to check the voltage on D8 and the centre PIN of VR5 [ #7 [pt ]
Also check the reading of the bottom pin of VR5, [ the PIN nearest the LEDs ]

[gaston]

Hi
You mentioned in the previoud post that the #7 pot test ok, how did you test it ?

Yes, sorry, might have been a bit unclear. I tested it the first time I booted it up, the module seemed okay and I could go through all switches and pots in HW-mode. All checked out except #7 (VR5). Then I rebooted it, and the all around weirdness started.

So first we need to fix the dancing green LEDs.
One the panel PCB, orientated with LEDs at the top, viewed from the component side.
Please check for continuity to GND on the top pin of R3 [ please use a GND on the Main PCB ]
Also check for continuity on LHS pin of VR2 [ tempo ] and LHS pin of VR1 [gate time ]

R3 checks out, 5v bottom pin, 0v top pin.
Also LHS pin on VR1 and VR2 reads 0v. Checking against a GND pin on the power-pinheader on the main panel.

[gaston]

Hmm, maybe this can be helpful information.

I powered it on (without any buttons pressed), stopped the sequencer, used the "next" button to get to Stage 7. Turned the pot to full CW. And checked D8, and VR5. (Against main pcb GND)

VR5 middle pin gives positive 4.81v.
D8 bottom pin gives around ~2v (!) negative, fluctuating between -1 and -3 very irregularly..

Checking neighboring stage 6, D11 and VR6 with same settings gives 4.81v positive on both bottom pin D11 and middle pin VR6.

I actually replaced D8 with a new diode but got identical results, so at least a faulty diode is ruled out.

[ryk]

R3 checks out, 5v bottom pin, 0v top pin.
Also LHS pin on VR1 and VR2 reads 0v. Checking against a GND pin on the power-pinheader on the main panel.
Top

Can you check continuity to GND for these, not the voltage.

VR5 middle pin gives positive 4.81v.
D8 bottom pin gives around ~2v (!) negative, fluctuating between -1 and -3 very irregularly..

Checking neighboring stage 6, D11 and VR6 with same settings gives 4.81v positive on both bottom pin D11 and middle pin VR6.

I actually replaced D8 with a new diode but got identical results, so at least a faulty diode is ruled out.

That sounds like D8 is not connected to VR5.
Can you check continuity between the bottom leg of D8 and the middle pin of VR5, they should be connected.

[gaston]

Can you check continuity to GND for these, not the voltage.

Oh, okay, sorry, I'm still pretty new at this stuff so didn't catch that.
But yes, multimeter set to continuity check, getting beeps at LHS pin on VR1 & VR2, as well as R3 top pin, against GND power pin on main panel.

That sounds like D8 is not connected to VR5.
Can you check continuity between the bottom leg of D8 and the middle pin of VR5, they should be connected.

And here no beep, no continuity - as expected bottom pin D11 and middle pin VR6 gets a beep (for reference).

[ryk]

That sounds like D8 is not connected to VR5.
Can you check continuity between the bottom leg of D8 and the middle pin of VR5, they should be connected.

And here no beep, no continuity - as expected bottom pin D11 and middle pin VR6 gets a beep (for reference).

Oh dear.

You will need to fix the track between D8 and VR5, is it broken ?
Just solder a small piece of wire betweem them to repair the conection. [ see blue track on picture ]

Screen Shot 2020-07-01 at 17.03.36.png

For the stages control, it sounds like something is wrong with the rotary switch.

Can you take apart the PCBS, and performs some checks on the Panel PCB.
Please check for continuity between the centre [ square ] pin [ on the uderside of the Panel PCB ] and the marked
header PIN [ both marked in light blue, see PIC below ]

If this is ok then:
Check for continuity between the centre [ square ] pin [ on the uderside of the Panel PCB ] and the numbered pads
for each switch position.

Screen Shot 2020-07-01 at 17.10.51.png

[gaston]

Oh dear.

You will need to fix the track between D8 and VR5, is it broken ?
Just solder a small piece of wire betweem them to repair the conection. [ see blue track on picture ]

No sign of it being broken, but soldered a small bridge and now the pot works like the others!

For the stages control, it sounds like something is wrong with the rotary switch.

Can you take apart the PCBS, and performs some checks on the Panel PCB.
Please check for continuity between the centre [ square ] pin [ on the uderside of the Panel PCB ] and the marked
header PIN [ both marked in light blue, see PIC below ]

Yes, it checks out.

If this is ok then:
Check for continuity between the centre [ square ] pin [ on the uderside of the Panel PCB ] and the numbered pads
for each switch position.

And also each switch position checks out. Hmm.

[ryk]

Yes, it checks out.
And also each switch position checks out. Hmm.

Ok.

Can you put the module back together [ carefully ]
Power up into Hardware Test mode.

On the Main PCB check the voltage on PIN 25 of the PIC chip for each setting of the the rotary switch.
It should go from 0v to about 4.9v crom 1 to 8.

28pin_DIL.png

If not check the voltage on the pin below of the highlited PIN header on the Main PCB

Screen Shot 2020-07-01 at 19.28.00.png

If nothing here also, then the is a problem with your PIN header soldering or tracks.



Check for the same voltage on the Panel PCB PIN Header highlited on the pic below.

Screen Shot 2020-07-01 at 19.30.11.png

[gaston]

If not check the voltage on the pin below of the highlited PIN header on the Main PCB

Bingo. I have no idea how this happened, but on the socket for the PIC chip, the metal connector for pin 25 was pushed out so the pin didn't reach the bottom of the pcb/soldering area, removed the solder on the pad, pushed it back through and reapplied the solder, and now it seems to work perfectly - passed the hardware test with flying colours.

And, thanks for your time so much, top notch support. Happy the error was simple in the end, a bit embarrassed that it was and that I missed it when rechecking, but yeah, thanks

[ryk]

Bingo.