DOD fx96 not work question(s) || unreg?

[unreg]

Ok, here’s how this conversation started in thetragichero’s what’re you workin' on today? thread sticky at the top of the coffee shop:

Apr 17, 2021 12:25:40 GMT -5 unreg said:

Very cool thetragichero! 👍😀

Your and frets’s posts have influenced me to try and repair my Dod fx96 pedal. I remember it was quite difficult to insert the 9V battery... so a long time ago I pulled on the cord to make it longer; it took force, but eventually the cord suddenly got much longer. The pedal no longer turns on after a new 9 volt has been inserted. After opening it up a few days ago I noticed that whoever assembled it must have crammed the positive red battery wire in between the shell and the edge of the circuit board when assembling it. That thin red wire has a sharp bend in it. I tested resistance and continuity and that battery-less 9V plug failed to register a reading on the positive wire. I’m going to snip out the sharp bend and strip each red wire end and try soldering them together. Maybe my pedal will work again! (Though, I’m unsure about editing a red wire... it might have charge in it?)

I could also get it to work by using a 9V power supply, but don’t have one and want to fix this problem.

Apr 17, 2021 12:35:33 GMT -5 blademaster2 said:

I would not hesitate to snip and re-install the battery wires (just ensure you do not get them reversed). If the snipped ones are too short you can splice new wires there, or even buy another pigtailed battery connector.

Ensure that the new connections do not short to themselves or the chassis, and are not reversed. That all you need to do - and there is no safety concern (especially when the battery is not connected yet).

Apr 17, 2021 13:07:52 GMT -5 thetragichero said:

that fx96 is an interesting analog delay. don't know of any others that intentionally get that grainy
i have an fx90 that i pick up about once per year to attempt to get working. passes signal whether in bypass or on, just doesn't delay. I'm wondering now if maybe it's in the switching circuit. it's about that time of year to take another crack at it

Apr 18, 2021 13:15:27 GMT -5 newey said:

Apr 17, 2021 12:35:33 GMT -5 blademaster2 said:

even buy another pigtailed battery connector.

That was my first thought, easier just to replace the whole battery connector, and those things can be had cheaply. I bought a whole bag of them (a dozen, maybe?) back whan I was assembling my bigger pedalboard. I reversed the pigtailed connector to connect male-to-female to the battery clip of a couple of pedals that lacked a jack for power input, so that I could then wire them for my one-spot power harness.

Apr 18, 2021 20:12:33 GMT -5 unreg said:

Thank you blademaster2, newey, thetragichero! Guess I’ll look for pig-tailed battery connectors; the cord is a bit short now and maybe the positive wire wasn’t soldered greatly. I made a thread in the effects devices forum.

—-
end of quotes... sry ashcatlt.
—-


Hi all! 😀

Last night I cut out the sharp bend and soldered both red and black battery cables back together. It still doesn’t work.

So I’ve opened it again:



With the black connected to the positive battery terminal (green circled) and holding the red touching the bare positive wire (marked by green arrow), I receive a resistance reading of 4.90k ohms. Now, that battery wire feeds into a white female plug that accepts 5 wires; another red wire comes out of that white plug and is soldered to the Input jack (at the green arrow).

Isn’t 4.90k ohms an insane amount of resistance? I’m unsure how to fix and unsure of problem.


Thank you for reading.

[unreg]

hi again.  This image tries to show the white plug.  Hopefully this will help?

If you can follow the red wires my above explanation may make more sense.

note: I hope this thread is ok here... it didn't say that questions about pedals are allowed.   Aaand, yes that light-yellowish wire, from the white plug, seems to have been removed, but that's how I received the pedal; it worked wonderfully.  

[newey]

Apr 18, 2021 22:01:36 GMT -5 unreg said:

note: I hope this thread is ok here... it didn't say that questions about pedals are allowed

It is fine here, and yes, pedal questions are allowed. Unfortunately, I have no answers for your problem, never had my nose inside one of those.

[ashcatlt]

What is actually happening or not happening or... I’m sorry, but this is like I walked into the middle of a conversation where I missed all the foundational information. Is it on some other thread somewhere?

Edit - I found it, but honestly let’s not do this. We can’t butt-u-me that any random person that comes through will have read the thread where this first popped up, or be bothered to search your recent posts just to figure out WTF is going on.

Anyway, the schematic says that header is as follows (from bottom to top in your picture):

1. Audio input
2. Ground *
3. Power (positive battery terminal)
4. N/C
5. Audio Output

I put the * by “ground” because what that actually is is the ring of that TRS jack which will connect to the bottom of the battery when a cable is inserted. Pretty sure that’s your issue here. At least explains why it won’t turn on. It appears to be wired correctly, but you can’t prove it till you plug into it.

[unreg]

Apr 19, 2021 10:27:56 GMT -5 ashcatlt said:

Anyway, the schematic says that header is as follows (from bottom to top in your picture):

1. Audio input
2. Ground *
3. Power (positive battery terminal)
4. N/C
5. Audio Output

I put the * by “ground” because what that actually is is the ring of that TRS jack which will connect to the bottom of the battery when a cable is inserted. Pretty sure that’s your issue here. At least explains why it won’t turn on. It appears to be wired correctly, but you can’t prove it till you plug into it.

Ahhh... hmmm... I didn’t even edit that cable wire.

The ground plate coming out the back of the TRS jack with the soldered red ground wire does move a tiny bit. That movement happened after I pulled hard on the battery cable and it suddenly became much longer. But, yesterday I couldn’t discover how to repair that wobbling.


Is there possibly a store that sells TRS jacks? Are all TRS jacks the same size? I’ll research later today; thank you so much ashcatlt! 👍😀

[unreg]

Obviously, I’ve never bought a TRS jack.

This jack looks good:
westcoastpedalboard.com/product/pedalboard-output-jacks-pure-tone-ptt-trs/

But, is “Stereo” correct? Guitar pedals inputs are mono right? This is a pedal parts company... so I’m confused. 😔


Ooh...

Aug 29, 2020 7:50:28 GMT -5 newey said:

Aug 28, 2020 20:22:42 GMT -5 ourclarioncall said:

I suppose it might eat up batteries tho

Just as with active pickups, you can use a TRS "stereo" type jack to cut power when no cable is plugged in, which will help a lot with battery life, provided you're not leaving the guitar plugged in for long periods.

Searched “TRS jack” and found this quote. 😀 ...So, my pedal might have a TRS stereo jack on its input so that power is cut when the cable is not plugged in?

[newey]

That jack is the right type- it's a 1/4" "TRS" jack, which is also called a "stereo jack". TRS stands for "Tip, ring, sleeve", denoting the 3 connections. A regular mono 1/4" jack is just a "TS" jack, i.e., "tip-sleeve", without the third "ring" connection.

TRS jack are used for stereo, where the tip carries one channel "hot" signal, the ring carries the other channel, and the sleeve is a common ground for both channels. They are also used in virtually every pedal ever made, where the 3rd ring connection is used to disconnect the 9V battery when no guitar cable is plugged in. Plugging in a mono guitar cable connects both the sleeve and the ring to the cable's sleeve connection, and so connects the battery negative only when a cable is inserted.

There are also "TRRS" jacks, with 2 separate ring connections. In a subminiature form, these are often used on the headphone jacks for cellphones, so that multiple functions can be accessed with one jack (headphones plus mic, for example).

[newey]

You edited your post while I was posting, and answered your own question.

EDIT:Your link to that TRS jack indicates they want $5.88 apiece. That seems a bit high. Digi-Key has Switchcraft ones for $2.88 each:

www.digikey.com/en/products/detail/tubedepot/P-SC-12B/10489798

[unreg]

That TRS jack must be stereo. After connecting the input cable again the pedal’s light turned on and my pedal works splendidly! 😀 PRAISE GOD!! 😃


The only “problem” now is that the pedal can’t turn off unless, the input cable is removed OR the battery is removed while the pedal is on... which makes zero sense; who would remove the battery while the pedal is on?


So the soldering works! 👍😀 Wish the pedal switch would work too. Saw there was a small black button that the pedal supposedly pushes down. It seems like the button is pressed; I hear a click noise.


EDIT: Now, I remember that the pedal press stopped turning off the switch a long time ago. Haven’t used this pedal in a long while.

[unreg]

Apr 19, 2021 19:34:34 GMT -5 newey said:

You edited your post while I was posting, and answered your own question.

EDIT:Your link to that TRS jack indicates they want $5.88 apiece. That seems a bit high. Digi-Key has Switchcraft ones for $2.88 each:

www.digikey.com/en/products/detail/tubedepot/P-SC-12B/10489798

Ooh, newey, your post appeared while I was writing mine! 👍 Thank you for your guidance and this cheaper TRS jack link! 😀 I think I don’t need a jack anymore.

[unreg]

Apr 19, 2021 10:27:56 GMT -5 ashcatlt said:

I put the * by “ground” because what that actually is is the ring of that TRS jack which will connect to the bottom of the battery when a cable is inserted. Pretty sure that’s your issue here. At least explains why it won’t turn on.

Could this issue also prevent it from turning off? Since it’s permanently on now.

—-
Maybe I do need a TRS jack newey... your post is both pleasantly and extremely helpful; thank you so much! 👍😀

[thetragichero]

if you've got power and it works leave the jack alone
could be any number of things causing it not to switch from a bad switch, undersized debounce capacitor which may not present itself until the switch gets worn (the black plastic ibanez pedals are notorious for this), or a failed component in the flip flop switching circuit. yours uses a cmos chip with a pair of mosfets and an inverter in it but this page gives a general idea how flip flop switching works: bossarea.com/how-the-flipflop-works/
easiest way to rule out a bad momentary switch? either multimeter with a continuity test or if the unit is on I'll touch the two solder joints on the switch with a screwdriver
debounce capacitor is 47nf so that should be sufficient, although you could always hold another 47nf capacitor to the solder joints of that capacitor (c36?) while pressing the switch with your finger and see if that'll get it to switch

[unreg]

I’ll leave it alone; thank you thetragichero! 😀😊 Your page and explanation is way over my head; but, maybe I’ll understand better as time passes. 👍

EDIT: Maybe I could try that continuity test... sometime... going to use the pedal; it is necessary now. 🙂

[unreg]

Apr 19, 2021 10:27:56 GMT -5 ashcatlt said:

I put the * by “ground” because what that actually is is the ring of that TRS jack which will connect to the bottom of the battery when a cable is inserted. Pretty sure that’s your issue here. At least explains why it won’t turn on. It appears to be wired correctly, but you can’t prove it till you plug into it.

Note: ash, you are amazing! 😀 Just reread this thread and discovered that you told me exactly what was wrong; just needed to plug in a cable to provide ground. Thank you so much! 👍😀