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jdelgoulet
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Post by jdelgoulet » Mon Apr 30, 2018 7:33 am

(grrrr 1% resistors :bang:)

Test #1 :

- Voltage at pin 6 of IC-4 while changing octave of VCO-1.
- Voltage at pin 6 of IC-8 while changing octave of VCO-2.
- Voltage at pin 6 of IC-13 while changing octave of VCO-3.

Test #2 :

- Voltage at collector of Q6 while changing octave of VCO-1 (or pin 2 of Q8).
- Voltage at collector of Q19 while changing octave of VCO-2 (or pin 2 of Q21).
- Voltage at collector of Q32 while changing octave of VCO-3 (or pin 2 of Q34).


Image

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SMonk
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Post by SMonk » Mon Apr 30, 2018 11:10 am

jdelgoulet wrote:(grrrr 1% resistors :bang:)
Yeah, sorry about that. I realize it will make my MME 4% less fat and warm than it could have been...
Test #1 :

- Voltage at pin 6 of IC-4 while changing octave of VCO-1.
- Voltage at pin 6 of IC-8 while changing octave of VCO-2.
- Voltage at pin 6 of IC-13 while changing octave of VCO-3.

Test #2 :

- Voltage at collector of Q6 while changing octave of VCO-1 (or pin 2 of Q8).
- Voltage at collector of Q19 while changing octave of VCO-2 (or pin 2 of Q21).
- Voltage at collector of Q32 while changing octave of VCO-3 (or pin 2 of Q34).
IC-4, IC-8 and IC-13 all gives the same voltages as i turn the relevant octave switch (-7.55, -6.17, -5.87, -5.57, -5.28 and -4.99), but test 2 is more interesting (i hope):

Q6 gives -0.30, -2.7 to -2.3, -2.35, -2.27 -2.24 and -2.22 but Q21 is stuck at -2.05 and Q34 at -1.88 regardless of octave position.

So, what does this mean?

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jdelgoulet
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Post by jdelgoulet » Tue May 01, 2018 1:01 am

It means that the issue is not on the octave switch or octave switch buffer and as thought around the expo converter. We will now try to track down which part of the expo is faulty.
Let's start with the following test :

Test #3 :

- Voltage at pin 6 of IC-2 while changing octave of VCO-1.
- Voltage at pin 6 of IC-6 while changing octave of VCO-2.
- Voltage at pin 6 of IC-10 while changing octave of VCO-3.

Test #4 :
Could you post a HR picture of the back of the analog board. We are interested in the area around the tempcos.

PS : My remark concerning the 1% resistor was not about sound. It was about the fact that debugging a board with only 1% resistor using photos is very difficult. You could have place let say a 100ohm resistor instead of a 10k and we could not notice it. In an expo converter where we are talking about 20 mv for an octave change that could make a huge difference ... :mrgreen:

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SMonk
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Post by SMonk » Tue May 01, 2018 12:11 pm

jdelgoulet wrote:It means that the issue is not on the octave switch or octave switch buffer and as thought around the expo converter. We will now try to track down which part of the expo is faulty.
Let's start with the following test :

Test #3 :

- Voltage at pin 6 of IC-2 while changing octave of VCO-1.
- Voltage at pin 6 of IC-6 while changing octave of VCO-2.
- Voltage at pin 6 of IC-10 while changing octave of VCO-3.
IC-2: (from highest to lowest setting) -4.930, -4.910, -4.890, -4.870, -4.850, -4.759
IC6 and IC10: both stuck att -4.990 regardless of setting
Test #4 :
Could you post a HR picture of the back of the analog board. We are interested in the area around the tempcos.
Image
PS : My remark concerning the 1% resistor was not about sound. It was about the fact that debugging a board with only 1% resistor using photos is very difficult. You could have place let say a 100ohm resistor instead of a 10k and we could not notice it. In an expo converter where we are talking about 20 mv for an octave change that could make a huge difference ... :mrgreen:
ok, i understand.

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jdelgoulet
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Post by jdelgoulet » Tue May 01, 2018 12:31 pm

Is it me or I'm seeing a lot of bad solder joins ?

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SMonk
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Post by SMonk » Tue May 01, 2018 1:16 pm

jdelgoulet wrote:Is it me or I'm seeing a lot of bad solder joins ?

Image
I usually solder resistors from the component side, which sometimes make the joints look bad on the rear side. But they aren't really.

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Post by Jop » Tue May 01, 2018 3:03 pm

What a joy to build the MME :tu: The boards are very nice to work with, solder flows perfectly and the instructions are out of this world! Thanks Julien.

Just plugged power and all seems good. only thing is that my noise level is a bit low. I would like to select a noisier transistor, which one should I pull out?

Thanks.

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jdelgoulet
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Post by jdelgoulet » Wed May 02, 2018 1:24 am

@Jop : thanks for the kind words !
Before selecting a new transistor did you have a try adjusting R328 (cf picture below). Otherwise Q86 is the 'noise' transistor (cf picture below).

Image

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jdelgoulet
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Post by jdelgoulet » Wed May 02, 2018 1:41 am

@Smonk :

Test #4 :

- Voltage at pin 6 of IC-6 while changing frequency knob of VCO-2.
- Voltage at pin 6 of IC-10 while changing frequency knob of VCO-3.

Test #5 :

- Voltage at pin 3 of IC-6 while changing frequency knob of VCO-2.
- Voltage at pin 3 of IC-10 while changing frequency knob of VCO-3.

Image[/b]

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SMonk
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Post by SMonk » Wed May 02, 2018 9:45 am

jdelgoulet wrote:@Smonk :

Test #4 :

- Voltage at pin 6 of IC-6 while changing frequency knob of VCO-2.
- Voltage at pin 6 of IC-10 while changing frequency knob of VCO-3.

Test #5 :

- Voltage at pin 3 of IC-6 while changing frequency knob of VCO-2.
- Voltage at pin 3 of IC-10 while changing frequency knob of VCO-3.
IC-6 goes from -4.980 to -5.002 on both pin 3 and 6 when i turn the frequency knob.
IC-10 is unaffected by the knob, with -4.990 on both pins.

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jdelgoulet
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Post by jdelgoulet » Fri May 04, 2018 8:11 am

Test #6 :

- Apply a variable CV to the EXT-MOD input and check if frequency of all the VCOs change.


Now, even if you answered it already, I would like you to reflow all the resistors that have a green circle (and more) and send me a photo when this is done.
I'm asking this because, for VCO-2 for example, you are able to change the frequency using the frequency knob so this leads to the fact that the expo converter works as expected. However octave CV does not work. On the Mini, the frequency knob output is not 'connected directly' with all the other CVs and particularly with the octave one. So the issue might be on the input resistors of the expo converter.

Also , please reflow solder joins of the two toggle switches : White/Pink noise switch and ... OSC3 CRTL switch. From the picture you sent the soldering looks bad and if this is not solder correclty you won't have any control over VCO-3 frequency.

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Post by Jop » Fri May 04, 2018 8:21 am

Before selecting a new transistor did you have a try adjusting R328 (cf picture below). Otherwise Q86 is the 'noise' transistor (cf picture below).
Thanks, yes R328 is maxed. Just swapped Q86 and placed a socket in there. The two other 3392's I have are of the same level. Maybe I should have gone for a 5K trimmer instead of a 2,2K now installed (couldn't trace the 2,5K). Anyway I installed a 2N3904 and noise level is good now :tu:

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SMonk
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Post by SMonk » Fri May 04, 2018 12:06 pm

jdelgoulet wrote:Test #6 :

- Apply a variable CV to the EXT-MOD input and check if frequency of all the VCOs change.


Now, even if you answered it already, I would like you to reflow all the resistors that have a green circle (and more) and send me a photo when this is done.
I'm asking this because, for VCO-2 for example, you are able to change the frequency using the frequency knob so this leads to the fact that the expo converter works as expected. However octave CV does not work. On the Mini, the frequency knob output is not 'connected directly' with all the other CVs and particularly with the octave one. So the issue might be on the input resistors of the expo converter.

Also , please reflow solder joins of the two toggle switches : White/Pink noise switch and ... OSC3 CRTL switch. From the picture you sent the soldering looks bad and if this is not solder correclty you won't have any control over VCO-3 frequency.
Found the problem. Let's just say that in the future i will make sure not to accidentally use conductive thermal grease on my tempcos, because 0 ohms resistance is quite different from 1000...
:doh: :doh: :doh:

Anyway, thank you for taking the time to try to help.

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Post by Broadwave » Sat May 05, 2018 3:47 am

SMonk wrote: Found the problem. Let's just say that in the future i will make sure not to accidentally use conductive thermal grease on my tempcos, because 0 ohms resistance is quite different from 1000...
:doh: :doh: :doh:
Glad you've fixed the problem :yay: - I put in a wrong transistor in the VCF, and it took almost a week to find it!

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Post by LED-man » Mon May 07, 2018 2:58 am

For thermal grease/Paste I prefer silk based paste.
I know some guys use very often PC CPU paste/glue/grease, but there’s very often silver, zinc and aluminum inside ;)
################################
TTSH Support Page and other DIY Projects:
https://www.DSL-man.de

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Post by Jop » Mon May 07, 2018 2:45 pm

Hi Patrick,

What is the brand/ model you use? I'm now preparing an order for Reichelt, do you a link maybe?

Thanks :tu:
For thermal grease/Paste I prefer silk based paste.

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LED-man
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Post by LED-man » Mon May 07, 2018 2:58 pm

################################
TTSH Support Page and other DIY Projects:
https://www.DSL-man.de

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Post by LED-man » Mon May 07, 2018 3:00 pm

Reichelt is very expensive for this..
https://m.reichelt.de/Waermeleit-Paste- ... tct=pos_15
################################
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Post by Jop » Mon May 07, 2018 3:25 pm

Thanks, I will check locally.

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Post by muted » Fri May 11, 2018 4:41 am

So Julian, I have a 4U (3U+1U) eurorack and some 1U tiles I would like to put to good use. Could I just hook some thonk-icon jacks to the output pins of the 3 oscillators to have all waveforms available simultaneously, or must I add additional circuity to make it work?

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Post by valgamaa » Wed Jun 20, 2018 7:56 am

I have been putting the finishing touches to my MME, and have turned my attention to case, PSU and MIDI interface. For the case I have chosen the Moog 60HP one, and have made some PCB's for the PSU. The mounting holes are spaced so that it will fit the internal rails with tubular spacers and self-tapping screws. If anyone is interested in buying either a PCB or full kit then contact me off-list. Here are some pictures of the PSU. (The 5V regulator and second header are for the MIDI interface I plan to use).

Image
Image
Image[/img]

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Post by Altitude909 » Wed Jun 20, 2018 8:04 am

That's a lot of capacitance for that DC-DC. What size are those caps? the NSD dual has a cap limit of 500uF per side. Switching DC-DC parts are not like linear regulators where you just throw smoothing caps everywhere, quite the opposite actually.

I'd lose the linear vReg for the midi and just go to a switching 7805 drop in and power it directly from the DC input. E series recoms are cheap and will be fine

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valgamaa
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Post by valgamaa » Wed Jun 20, 2018 8:23 am

The capacitors are 220uF on each rail. The large cap on the right is the input filter from the data sheet (with the inductor next to it).
My MIDI interface only requires 3mA, so I chose the line of least resistance (I didn't have a 78L05) to hand. Of course, there is nothing to stop anyone fitting the switching 7805 if they wish... but the MME doesn't need any of the 5V circuit at all, the relevance is that it fits the internal rails of the Moog case, so is of little interest for any other case.

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Post by jaidee » Sat Jun 23, 2018 5:15 pm

I'm in the process of calibrating and have found that VCO3 is not responding to CV either through the main CV or CV-3, although it does respond to changing the Octave switch and the Frequency knob.

What should I test??

Problem solved - I've reviewed the thread and have noted Altitude had the same problem … and resolved it by flipping the Osc control switch. Dohh!!

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Post by aabbcc » Tue Jun 26, 2018 6:32 am

Is anyone else providing the rare parts kit now since www.diysynth.de closed down :despair:

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