don`t power on how to fix it
my monotron do not power on testing it with a 3volt AcDc Adapter Could you help ,please-
or have i to throw it away?
crwdns2934109:0crwdne2934109:0
crwdns2889612:0crwdne2889612:0
1
841160
crwdns2933315:03crwdne2933315:0
crwdns2934051:0crwdne2934051:0
crwdns2934065:0crwdne2934065:0: 824crwdns2936485:0crwdne2936485:0
1.3crwdns2936485:0crwdne2936485:0
930
2.4crwdns2936485:0crwdne2936485:0
@dreye throwing stuff out is not an option. Let's investigate.You mentioned testing it with a 3V AC DC adapter. Is that what you have checked? What else have you looked at. Use this guide KORG Monotron Teardown to tear it down. Then take a couple of good pictures and post those with your Question. Lets see if we can identify any issues. Your Monotron will work with 3 V but it uses a boost circuit that brings the voltage to 5V. I would start with the boost circuit and check IC1 TPS61071
Adding images to an existing question
crwdns2930805:0crwdne2930805:0
Adding images to an existing question
crwdns2934079:0crwdne2934079:0
crwdns2937585:0crwdne2937585:0
—
2 - 5 minutes
crwdns2930805:0crwdne2930805:0
KORG Monotron Teardown
crwdns2934079:0crwdne2934079:0
crwdns2937801:0crwdne2937801:0
—
30 minutes
crwdns2934105:0crwdne2934105:0
crwdns2889612:0crwdne2889612:0
1
Thanks for answering ,i have made some pictures of my monotron ,i try to load them ,and try to use the teardown .sometimes i was really stupid in reading chematics so it could take time,
It was nice if you look at the pictures may be you can see a bug or something.thanks
@dreye of course we will do that. One big favor to ask you. Try to repost the pictures. they are just not big enough to make things out. Post as big as possible.
You will need a multimeter. Do you have one? if not, can you borrow one?
yes i have a multimeter ,what have i first have check with it,and i try to make a bigger picture ,in the later afternoon i have time to do that
@dreye we will have to check if the boost circuit works.
crwdns2934057:0crwdne2934057:0
crwdns2934065:0crwdne2934065:0: 509.7crwdns2936485:0crwdne2936485:0
11
394
1.5crwdns2936485:0crwdne2936485:0
crwdns2934105:0crwdne2934105:0
crwdns2889612:0crwdne2889612:0
2
hi Jayeff,
thanks for schematitic-link,.but i had have downloading the same Dokument yesterday morning .
but i still first have learn how to solved my problem,really don`t know what is the best Methode to
found the bug .. ,i have a multimeter only have to find out how to use that in this case
Connect the adapter to the device and then use the meter to see if there's 5V DC at the VCC test point as shown on the schematic or pin 5 of IC1 or on R3, C3 or C1.
If no good, check that there's 3V on pin 6 or pin 1of IC1.
If OK on pin 6 but not on pin 1 disconnect the adapter and use an Ohmmeter to check if L1 is OK and has continuity.
If no voltage at all, check that the earth multiple on the board connects back to the -ve terminal of the battery holder or adapter plug.
If the earth multiple is OK then check that the +ve terminal of the battery holder or the adapter plug connects to L1 and pin 6 of IC1
If there is 3V on pins 6 and I of IC1 and there is an Earth connection on pin 3 of IC1 but NO 5V on pin 5 of IC1 then IC1 is faulty.
Note: be careful and don't short out the pins on IC1 by bridging the meter test probe between 2 pins on the IC. Make sure that the probe touches 1 of the pins only when testing!
thanks for these instructions..so i han`t enough routine for this work and before i short out something i do it together with a friend on Wednesday .hewas relaxed enough to do this.
I will let you know which result result i get after doing that
Hello, thank you for this valuable tutorial.
I decided to give my Monotron that was stored in his box a little attention.
It was boxed without batteries to avoid leaking problems and sounded as it should last time it was played several years ago.
With batteries fully charged it powers on with lfo light 💡 ok but no sound from speaker or headphones jack.
I swapped batteries and opened it up to check for dry solder joints on jacks or leaking capacitors but saw nothing unusual.
Unfortunately I don’t have knowledge in electronics. I downloaded the diagram, I can solder but am at a loss when searching for faulty smd components.
Any help would be welcome.
Cheers !
crwdns2934105:0crwdne2934105:0
crwdns2889612:0crwdne2889612:0
0
crwdns2944067:02crwdne2944067:0
hi Jayeff,
thanks for schematitic-link,.but i had have downloading the same Dokument yesterday morning .
but i still first have learn how to solved my problem,really don`t know what is the best Methode to
found the bug ..
crwdns2934271:0crwdnd2934271:0 Dreye crwdne2934271:0
Hello, thank you for this valuable tutorial.
I have a Monotron that powers up but makes no sound at all from the speaker or the headphones output. I opened it to check for dry solders on output jack or leaking capacitors but found nothing suspect. I didn’t use for a couple years but it was boxed with the batteries out to avoid problems. Does anybody have any clues ? Thanks.
crwdns2934271:0crwdnd2934271:0 1milanz69 crwdne2934271:0