Search found 93 matches

by crafter57
Tue Jun 18, 2019 7:48 am
Forum: HELP!
Topic: E-MU Morpheus and MidiQuest not communicating
Replies: 1
Views: 132

Re: E-MU Morpheus and MidiQuest not communicating

Had the same issue with my Vintage keys, Emu doesn't like fast sysex transfers, you have to slow it way down. What is your buffer setup in MQ?
by crafter57
Tue Jun 18, 2019 1:05 am
Forum: HELP!
Topic: Korg Poly-800 Chorus mod
Replies: 22
Views: 1635

Re: Korg Poly-800 Chorus mod

Hi Mooger, sorry for delay.. I tried a 10k limiting resistor + 100K pot in place of R69 and it made no difference.
by crafter57
Thu Jun 06, 2019 4:21 pm
Forum: HELP!
Topic: Korg Poly-800 Chorus mod
Replies: 22
Views: 1635

Re: Korg Poly-800 Chorus mod

Mooger, your analogy makes total sense for that sawtooth wave generator circuit. Those infos were the only thing I found while digging the net and yes there could be typos it could have been R58/R57 instead who knows? I guess Korg figured out the fixed resistors for that constant thick chorus when t...
by crafter57
Wed Jun 05, 2019 5:50 am
Forum: HELP!
Topic: Korg Poly-800 Chorus mod
Replies: 22
Views: 1635

Re: Korg Poly-800 Chorus mod

Mooger, sorry could not get to the drawings, but yes, 1 talks about cutting off the input to pin7 putting a potentiometer between pins6&7 and a cap between 5&7, the other example removing R67 & R68 and install a potentiometer as a voltage divider between D+ and D- with a 10K resistor between D+ and ...
by crafter57
Tue Jun 04, 2019 9:47 pm
Forum: HELP!
Topic: Korg Poly-800 Chorus mod
Replies: 22
Views: 1635

Re: Korg Poly-800 Chorus mod

Mooger, I found some info on this mod (2 ways), I'll work on some pics and get back to you before I attempt any changes as I don't know which will work best.
by crafter57
Tue Jun 04, 2019 6:30 am
Forum: HELP!
Topic: Korg Poly-800 Chorus mod
Replies: 22
Views: 1635

Re: Korg Poly-800 Chorus mod

Unfortunately nothing happened when I replaced C43..
hmm..I'm wondering if this is at all possible?
by crafter57
Fri May 31, 2019 2:48 am
Forum: HELP!
Topic: Dx7 strange problem, help me!
Replies: 6
Views: 1113

Re: Dx7 strange problem, help me!

Kudos to Rasputin for thinking Diodes..!! Mine has rubber contact issues henceforth my thoughts.
But as Mooger5 stated many possibilities for the same symptoms. Good Job, Glad the synth is fixed!!
by crafter57
Fri May 31, 2019 2:45 am
Forum: HELP!
Topic: Korg Poly-800 Chorus mod
Replies: 22
Views: 1635

Re: Korg Poly-800 Chorus mod

sorry for delay I had to move a behemoth (casio Privia px830) off of my bench as I did not have any space left.
So, I replaced C44 with the 10pf and still sounds the same, should I try bigger values? or perhaps C43..
by crafter57
Mon May 27, 2019 11:28 am
Forum: HELP!
Topic: Korg Poly-800 Chorus mod
Replies: 22
Views: 1635

Re: Korg Poly-800 Chorus mod

I put a 10p as that's all I had on hand but did not hear much of a difference. I'll have to head out to buy some bigger values. I'm lost on the feedback, I'll try to research more on it..
by crafter57
Sun May 26, 2019 8:36 am
Forum: HELP!
Topic: Korg Poly-800 Chorus mod
Replies: 22
Views: 1635

Re: Korg Poly-800 Chorus mod

Ok, here's the first draft, no totally sure about it and the pot values and also if I need limiting resistors?
flanger.jpg
, it would also be nice to put some led's for a visual effect ;)
by crafter57
Sat May 25, 2019 8:37 pm
Forum: HELP!
Topic: Dx7 strange problem, help me!
Replies: 6
Views: 1113

Re: Dx7 strange problem, help me!

Double triggering notes are due to the rubber contacts, they need to be replaced. I am experiencing exactly the same issue on my Casio Privia at the moment. You'll have to pull off all the keys and pull the rubber contacts, you can try cleaning them with alcohol but they're likely worn. I'm doing my...
by crafter57
Sat May 25, 2019 10:42 am
Forum: HELP!
Topic: Korg Poly-800 Chorus mod
Replies: 22
Views: 1635

Korg Poly-800 Chorus mod

So, while looking at the poly-800 chorus board circuit I realized it closely resembles some flanger circuits. So, I'm wondering if I can get a Flanger sound out of the Chorus board. The LFO can be modded with pots for rate/depth but is that all it takes or is there more for that flanger effect? How ...
by crafter57
Fri May 17, 2019 3:11 pm
Forum: HELP!
Topic: Oberheim Matrix-6 -- No display, no sound but PS seems to be fine
Replies: 4
Views: 862

Re: Oberheim Matrix-6 -- No display, no sound but PS seems to be fine

Hi, I can't remember as I've sold mine a long time ago but if its a VFD display (vacuum fluorescent display) the voltage requirements are anywhere from 12 - 30V or more, so 42V may not be wrong, if its not a VFD then perhaps its your transformer or maybe drawing more voltage due to some other proble...
by crafter57
Mon May 13, 2019 5:49 am
Forum: HELP!
Topic: Korg Poly 61 help locating broken DCO2
Replies: 1
Views: 707

Re: Korg Poly 61 help locating broken DCO2

Hi, you really need an oscilloscope to check if the pulse is arriving at DCO2. You have to check IC14 8253 pin13 output,(SIG6(2)) this signal of 266Hz will feed both IC103 & IC105, but this signal also goes thru CN11 connector pin5 if we follow convention, or maybe it's pin2?..the schematic is a lit...
by crafter57
Sun May 12, 2019 9:08 am
Forum: HELP!
Topic: Korg Poly-800 not working
Replies: 37
Views: 5919

Re: Korg Poly-800 not working

Well Mooger5, I finished the calibration and reloaded all sounds, seems to be working fine, no issues so far. not sure if I did step#4 Master oscillator adj. correctly I'll have to re-check it again as I only have a digital chromatic tuner. All other voltage measurements are close to specs. So final...