New Technical Problem - Dead Monotron Delay

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Re: New Technical Problem - Dead Monotron Delay

Post by ¾ dead »

It looks like there's a lot of gloop/flux residue.

The only suggestion I can come up with is to try to clean that crusty-looking portion of residue in the upper-right corner of the 2nd picture with some 90%+ isopropyl alcohol (a higher percentage is better. Less water, evaporates much faster), which might be difficult to find in supermarkets, given the state of the world right now.

A soft toothbrush or something similar will work for scrubbing. Make sure the alcohol is totally evaporated before re-assembling the unit.
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Re: New Technical Problem - Dead Monotron Delay

Post by crochambeau »

Yeah, that's just flux residue. Some formulations are spec'd as "no wash" in which the film of flux does no harm when left behind. It won't damage anything to clean it, but don't be surprised if it turns into a dull cloudy film after you spread it out on the PCB - and status results remain unavailable.

I forget what tooling/etc you have on hand and are familiar with (forgive me), do you have a voltmeter? If so, I spy on that board a few unmasked pads that are labeled as GND, VCC, and Vbias. What you want to do, is fill the battery tray, turn the unit ON and measure voltages between GND & VCC and GND & Vbias.

If you do not have voltages at those points, this is just a matter of figuring out where/why the power is blocked. If you DO have voltages at those points (VCC will probably read roughly double what Vbias does) and the unit remains inoperative it is indicative of a deeper problem that may benefit from some more training on your part.
When in doubt, add resistance.

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Re: New Technical Problem - Dead Monotron Delay

Post by The Mysterious Creep »

crochambeau wrote: Mon Sep 07, 2020 6:42 am Yeah, that's just flux residue. Some formulations are spec'd as "no wash" in which the film of flux does no harm when left behind. It won't damage anything to clean it, but don't be surprised if it turns into a dull cloudy film after you spread it out on the PCB - and status results remain unavailable.

I forget what tooling/etc you have on hand and are familiar with (forgive me), do you have a voltmeter? If so, I spy on that board a few unmasked pads that are labeled as GND, VCC, and Vbias. What you want to do, is fill the battery tray, turn the unit ON and measure voltages between GND & VCC and GND & Vbias.

If you do not have voltages at those points, this is just a matter of figuring out where/why the power is blocked. If you DO have voltages at those points (VCC will probably read roughly double what Vbias does) and the unit remains inoperative it is indicative of a deeper problem that may benefit from some more training on your part.
Unfortunately I do not have a voltmeter, and I left the Monotron at home because I couldn't get it working again. I'll return to it at the first opportunity.
Even if you took a few years and learned all the chords you'd still have a limited number of options. If you ignore the chords your options are infinite and you can master guitar playing in one day. - David Fair
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Re: New Technical Problem - Dead Monotron Delay

Post by crochambeau »

The Mysterious Creep wrote: Mon Sep 07, 2020 12:15 pm
crochambeau wrote: Mon Sep 07, 2020 6:42 am Yeah, that's just flux residue. Some formulations are spec'd as "no wash" in which the film of flux does no harm when left behind. It won't damage anything to clean it, but don't be surprised if it turns into a dull cloudy film after you spread it out on the PCB - and status results remain unavailable.

I forget what tooling/etc you have on hand and are familiar with (forgive me), do you have a voltmeter? If so, I spy on that board a few unmasked pads that are labeled as GND, VCC, and Vbias. What you want to do, is fill the battery tray, turn the unit ON and measure voltages between GND & VCC and GND & Vbias.

If you do not have voltages at those points, this is just a matter of figuring out where/why the power is blocked. If you DO have voltages at those points (VCC will probably read roughly double what Vbias does) and the unit remains inoperative it is indicative of a deeper problem that may benefit from some more training on your part.
Unfortunately I do not have a voltmeter, and I left the Monotron at home because I couldn't get it working again. I'll return to it at the first opportunity.
My "hot take" on this and the tape machine thread is that if you're intending on walking this path getting your hands on and getting comfortable with both a multimeter and a soldering iron will save your ass.

It's either that or enjoy deep pockets...

...or luck, but you know.
When in doubt, add resistance.

http://www.rochambeau.net/
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Re: New Technical Problem - Dead Monotron Delay

Post by The Mysterious Creep »

crochambeau wrote: Mon Sep 07, 2020 12:29 pm
The Mysterious Creep wrote: Mon Sep 07, 2020 12:15 pm
crochambeau wrote: Mon Sep 07, 2020 6:42 am Yeah, that's just flux residue. Some formulations are spec'd as "no wash" in which the film of flux does no harm when left behind. It won't damage anything to clean it, but don't be surprised if it turns into a dull cloudy film after you spread it out on the PCB - and status results remain unavailable.

I forget what tooling/etc you have on hand and are familiar with (forgive me), do you have a voltmeter? If so, I spy on that board a few unmasked pads that are labeled as GND, VCC, and Vbias. What you want to do, is fill the battery tray, turn the unit ON and measure voltages between GND & VCC and GND & Vbias.

If you do not have voltages at those points, this is just a matter of figuring out where/why the power is blocked. If you DO have voltages at those points (VCC will probably read roughly double what Vbias does) and the unit remains inoperative it is indicative of a deeper problem that may benefit from some more training on your part.
Unfortunately I do not have a voltmeter, and I left the Monotron at home because I couldn't get it working again. I'll return to it at the first opportunity.
My "hot take" on this and the tape machine thread is that if you're intending on walking this path getting your hands on and getting comfortable with both a multimeter and a soldering iron will save your ass.

It's either that or enjoy deep pockets...

...or luck, but you know.
Probably wise.
Even if you took a few years and learned all the chords you'd still have a limited number of options. If you ignore the chords your options are infinite and you can master guitar playing in one day. - David Fair
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Re: New Technical Problem - Dead Monotron Delay

Post by The Mysterious Creep »

crochambeau wrote: Mon Sep 07, 2020 6:42 am Yeah, that's just flux residue. Some formulations are spec'd as "no wash" in which the film of flux does no harm when left behind. It won't damage anything to clean it, but don't be surprised if it turns into a dull cloudy film after you spread it out on the PCB - and status results remain unavailable.

I forget what tooling/etc you have on hand and are familiar with (forgive me), do you have a voltmeter? If so, I spy on that board a few unmasked pads that are labeled as GND, VCC, and Vbias. What you want to do, is fill the battery tray, turn the unit ON and measure voltages between GND & VCC and GND & Vbias.

If you do not have voltages at those points, this is just a matter of figuring out where/why the power is blocked. If you DO have voltages at those points (VCC will probably read roughly double what Vbias does) and the unit remains inoperative it is indicative of a deeper problem that may benefit from some more training on your part.
Turns out I do have a voltage tester device, it was in the garage. Will try it once I figure out how it works.
Even if you took a few years and learned all the chords you'd still have a limited number of options. If you ignore the chords your options are infinite and you can master guitar playing in one day. - David Fair
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