korg poly 800 not worth the cost to repair this vintage synthesiser MF#81

[@ScottsSynthStuff]

I know this sinking feeling, when you open up a synth and see a previous "repair" that has essentially destroyed it.

[@ThomasGrillo]

This was an excellent demonstration of how to recognize a permanently failed device. Thanks for sharing.

[@markusfuller]

ThankYou Thomas :-)

[@Dee_Just_Dee]

It's also a class act. Most people only want to show their successes.

[@orbithesun1]

Why did you have to record Poly 800 program file from a computer on to a tape recorder, couldn't you have just played the file from computer directly into the synth?

[@Michael_Smith-Red_No.5]

I don't think you failed on this one, but the person who shoved an open-lead component through a board improperly certainly did. Still, it was great to see a classic cracked open for us to see.

[@BertGrink]

Yeah i agree; knowing when you're up against insurmountable odds, and realising you can't fix it is prudence, not failure

[@puffzewm7880]

One thing to check is the the presets are filled with scrambled data. If you go through the parameters you will probably see that some of them have values beyond their range or strange characters. When the RAM blocks have bad data written to them they can't be written over with the preset tape. I've had something similar happen and to fix it I went the Patch 11 and set all the values to the proper range then copied patch 11 to the other slots. After this procedure I was able to transfer the factory sounds from tape. Don't give up on it yet! Thanks for the vid.

[@markusfuller]

Thanks Puffin Thomas. I have put it away for a rainy day. but I will remember your advice if I ever get it back on my desk. Many thanks from markus

[@mraduanemc]

Wow. That's super interesting! I'm going to remember that for later.

[@ClayMann]

This was so sad. It's such a great keyboard, really well made for the time. Damn shame it got abused beyond cost effective repair.

[@SteveShanafelt]

Definitely interesting. Watching your diagnostic process, even when the result is "Not worth it," was worth 16 minutes of my time.

[@markusfuller]

Thanks Steve

[@Pvaeerener]

It also means some self identification in my case as we used to repair computers some time ago and that is quite the same steps we would follow to track down errors in mainboards and stuff like that. Reminds me of good memories. Thank you, Markus. ☺

[@pontram]

Well a few years later (I wrote a comment 3 years ago) and they are 200-600 euros on ebay.

[@zerozeroisland]

Another great video! even with 'failed' repairs, there's always something to learn! I had a similar thing happen with a Chroma Polaris that was given to me. Just too much damage, circuit boards cracked, covered in rust, lots of components had signs of having overheated/fried. :( such a shame. I still keep it around, even though it weighs a ton, because maybe someday i'll be able to salvage at least one or two components out of it...

[@GaitaPonto]

well it can synth a typewriter almost perfectly.

[@bobbarcus8310]

I love my Poly 800 bought it new in Dec 1984 Still works perfect I took care of it No dust beer change inside battery 2 times I Never put the 6 batteries in to play remote They will ruin it they leak fast

[@markusfuller]

Yes it is a good synth and I feel sad that I could not save this one.

[@bisnetodeportugues]

My Korg Poly 800. is short-circuited. I can't find the Chips and transistors. Greetings from Brazil.

[@markusfuller]

sorry i gave away the pieces of this one in the video a long time ago and there is nothing left from it. my apologies.

[@bisnetodeportugues]

@@markusfuller okay. Thank you.

[@kay_lpzw]

Hey - I've once received a poly800 that had a bunch of problems! But mine wasn't as done as yours. It is working but I had to swap the RAM for a timerkeeper to make programs "stick" and some other stuff. If you still have that synth, i'd love to buy a few parts of it. (Chorus Board, Filter IC and some more). In parts shipping costs to Germany should be bearable Btw. love your channel. I'm an electronic engineer with the habit of hoarding things that needs fixing so I know the excitement of diving into synths and drum machines.

[@butcharmstrong9645]

I still have my Poly 800 that I purchased in 1984 and was excited to see this video. even tho mine isn't currently working either, I cant bear to "part" with it. It had the most lush sweet string sounds ever (that's what I wanted a synth for in the first place) and for such an inexpensive synth too. sorry that yours was actually DOA. I was so hoping to hear it again.

[@egodeathbliss]

I owned one of these back in the early '80's...first MIDI synth....had the tape backup/load etc... The LED lights should not be flashing/scrolling in the display. Too bad it wasn't recoverable....thing these days is to be sure and recycle it for parts to help keep another one alive somewhere.

[@PatriotOnTour]

This effect comes from the Videocam, interfering with the multiplexed LED of the Display.

[@RothmanHarv]

Love those Marantz cassette recorders.

[@markusfuller]

I have had that for years and it always comes in handy at least once a year :-)

[@BrooseWayniac]

I have 5 Mono D Batteries instead of a Buttonbattery and no Solderpoints in the middle of the Board like youve got there! Is this the Solution to Solder a ButtonBatterie upthere, so i dont need no 5 Mono Ds? Can anybody confirm?

[@HaydenWinnett321]

I'm not sure about this, but I remember getting a korg poly 61 a while back off ebay and when I first turned it on, it did the exact same thing - TAPE over the LED display, weird little pops and clicks coming from playing the keys. I realized that I had it in tape mode - there is a switch on the back. Switched it off and it worked completely as it should have after that. Don't know if that would be the same case here or not.

[@yingtianfu]

It is great to understand when to stop repairing something rather than going at it forever. Great video! Thank you for sharing!

[@andrewverran3498]

I recently found a little portable Sanyo radio/cassette player in my late mothers belongings, has mic, phones,dc and battery powered...gtreat to see there could possibly be a future use of the tape...YOU'RE use of that cassette tape spun me out to the max...GROOVY AS.

[@Eyepatchfilms]

I spent about 150 hours fixing a Poly61 that had battery damage and every cap had leaked. Then the power supply blew and killed a VCA. Still worth the effort to me after I got it all working again. With as many viewers as you have, might be worth it to fix and do a full atomohawk upgrade at the same time. I just wish the chassis on the Poly800 v1 wasn't so ugly.

[@markusfuller]

Hello. I would love to do a full repair of this but it would be expensive and take a lot of time and I work full time and can only do these videos in my spare time (which isn't very much time). It would take me months and the keyboard is only worth £150 in working order. it may cost me that just to fix it. so sorry but this will go into spare parts.

[@MacXpert74]

I was wondering why you used the tape recorder? You could just directly plug the audio-output from the computer into the tape load input on the synth. I've done this with my JP-6. Works just fine.

[@annother3350]

The computer is in a different room?

[@NutritionalZero]

Ah the Poly-800. The keyboard player in my longest surviving band had picked one up somewhere for a tenner or something. When the 80s revival hit and we figured we should have a synthesizer we put it in the rig. It was pretty unstable tuning-wise and we never made any headway programming it-the presets were always good enough for that new wave sound- but I'd love to find one of these cheap. Sometimes it's just perfect.

[@twkarches]

The keys are probably worth something for those with broken keys. I was given a Poly 800 which seems fine but has 2 broken keys.

[@michaelbauers8800]

A great thing is that in 2016, there's so many new analog synths. There was a time when analog synths were probably perceived as in short supply, but I can't imagine anyone feels that way today.

[@markusfuller]

Hi Michael, I agree it seems theres a new analog every month at the moment.

[@GeeksThroughoutTime]

Hi Markus, I wonder if you would do a tear down of a metal detector, and explain why there is such a difference in ability and cost between the high end and low end of the products.

[@minorglitch01]

Wow, and I thought my Poly800 was bad! A previous owner tried to mod mine and totally botched it. Replaced a cap with the wrong value, left loose wires inside, left a switch with no wires connected to it, and that same protection diode in mine had dark black leads with huge blobs of solder on them. Fortunately I was able to fix everything up and it works perfectly. Definitely a happier ending then your Poly800!

[@GrootsieTheDog]

What is the average cost of replacing a single encoder on a newer synth (Analog 4 MKII) thanks.

[@ArtMacabre197]

Tape loading reminds me a C64:)

[@skyprop]

My Moog Source

[@Insaneloop]

I have the second version but to listen the presets after loading the sysex or the cassette .. you have to restart the synth :) Cheers!

[@sootikins]

Love the sound of the data cassette playback! Brings back many strange memories... lol.

[@rot_studios]

ZX Spectrum? :D

[@markusfuller]

reminds me of the spectrum computers

[@sootikins]

I was actually thinking of a TS1000 (USA version of the ZX81)!

[@rot_studios]

Ah yes that one :) I live in Europe so those are very hard to get here. Got a ZX+ here.

[@cybernitemusic]

Great channel mate. Watching your troubleshooting and steps involved help me out a lot in my self education. I’ve repaired some gear now.

[@snolan1990]

It's got to be worth more than a tenner in parts. The keys alone you could probably sell for a few pounds each. Only trouble is that obviously takes time.

[@gorillaau]

Plenty of scope to brain transplant it and turn it into a midi controller. For a tenner that keyboard is a bargain.

[@dvamateur]

This is a beautiful Marantz tape machine!!! It fits so well aesthetically with the Korg Poly-800. I miss those type of things. There were some really beautiful products in the '80s. Can't forgive myself for giving away that gorgeous cream color Sony answering machine with two mini-tapes. It was beautiful. What do we have now? A plastic soap container type flat slab of things, most of them. Photo cameras and camcorders are still around, but writing is on the wall for those as well.

[@markusfuller]

I was at a car boot sale on sunday and there was a very large collection of quality cameras on sale. but the guy was selling then for £5 each and sadly sold none at all. they were olympus, Canon, Nicon's etc. such a pity really.

[@dvamateur]

I love Olympus and Pentax brands. Olympus is known for innovative cameras, usually smaller than the competition. And in case of Olympus, smaller was beautiful. Pentax made medium format cameras, which Canon or Nikon never seemed to have guts to make. By the way, I much appreciate that the Bitish and Australian pronounce Nikon correctly. Americans insist on mispronouncing Nikon all the time.

[@jupitermarx]

I'd love for you to break down a Alesis A6 Andromdea? I have one and started to take it apart but was very concerned about breaking the end caps, so I put all the screws back in and decided it might be better if I could watch how a professional would do it?

[@markusfuller]

If I ever get one I will certainly do a teardown :-)

[@jupitermarx]

Thanks so much! I really appreciate you responding to my question. I hope it's soon! I watch all your videos and you have a fan here in Raleigh NC USA

[@markusfuller]

Thanks Mark . much appreciated :-)

[@infindebula]

On the positive side, the cheaply made Poly 800 is far from rare. I've had about 5 of 'em over the years ... the last one I had wasn't making a sound so I sold it for 50 bucks. These days I keep company with a Poly-800-II, which is a much, much nicer instrument. In contrast to the original it has a handsome black enclosure, a filthy digital delay with modulation, programmable bass/treble EQ per patch, MIDI sysex, and the real kicker: exponential envelope curves (vs. linear on the original). So the mkII always sounds punchier, and has a more ethereal release stage - it's what the original should have been.

[@truthisheredealwiit952]

That chorus on the og though.

[@klompjes002]

my first 8 keys works ongly when i hold the first key what you think is wrong ?korg i3 old

[@Novous]

I have a Korg DW-6000 I purchased years ago with significant water damage (and possibly soda?). The whole metal bottom panel was significantly rusted out. My board looks eerily similar to yours inside! (Including the insane idea of directly soldering the CR2032 battery to the board, which means I've got to rig up a battery holder to fix it.) Any tips for diagnosing, cleaning up a Korg / analog synth with water damage? I tried cleaning with IPA but it couldn't get this white oxidation off. Even denatured alcohol wouldn't work no matter how hard I scrubbed, first with a tooth brush, then a harder brush. I found that a pencil eraser works! But it's almost impossible to clean between closely packed through-hole solder joints. I've never repaired a synth, so I welcome any tips you have in general! Thank you for your time!

[@markusfuller]

ouch it sounds like you have a long task ahead of you. if it was just alkaline from a battery then you would use white vinegar to neutralise it but water damage can be difficult as theres so many different ways it can wreck a board. some boards are a compressed paper but they tend to swell if damaged. im not sure what to say other than just keep going and clean best you can. Im sorry im not too helpful here but there is no guaranteed answer to the problem that will certainly work.

[@adamc1764]

Hi ok no problem, any advice at all do you know if they have a fuse?

[@markusfuller]

Hello Adam. I did not see any type of fuse inside this keyboard. I have read that many of them suffered faults with the power regulator so if that has died there would be nothing on the display at all. but they can be replaced and if you are lucky that may be the only fault.

[@Masterpg2007]

Not sure if you will answer, but recently my keyboard keys started malfunctioning, I opened it and cleaned also used some graphite on the key and the circuit that was worn out. It fixed for 5 months, now I'm going to do that again, do you have any suggestion if I should do something different or something besides the graphite and cleaning?

[@markusfuller]

Hello, Its really only a temporary fix with the graphite. if possible you should try and get the replacement circuit board with the carbon tracks on it though I know how difficult that can be sometimes.

[@Masterpg2007]

markusfuller Thanks for the answer, I'm gonna do a little reasearch because I have no idea how use those, my city is pretty small and the eletronics guy had no idea how to fix it too.

[@racecar06]

I just plugged in a KORG DW-8000. it powered up immediately.then....a loud bang....then no power ....then that putrid burning electrical smell.Any ideas what it might be?

[@racecar06]

Thanks for that :)

[@markusfuller]

yep smells like a capacitor to me

[@racecar06]

It worked out well in the end as a JX-3P was purchased instead. I prefer the old Roland gear anyway.It seems more reliable? Anyway, love your channel thanks for your reply & take care :)

[@instrumentalistjade8367]

Mine doesnt have a presets anymore? so im using it now as a midi controller

[@synthartist69]

If it would have been a bad battery, the poly would have still worked immediately after reloading the presets. Only after turning the machine off, would the sounds be lost once again, hence you would be back to the strange noises or no sound. Great video, thank you for posting...

[@erichkohl9317]

Oh man! Tomorrow I'm picking up a used Poly 800 mk2 from Guitar Center. The ad said "good condition." I sure hope it is!

[@Insaneloop]

After the factory patches loaded in, it needs a reset to work! Cheers

[@balebu1]

I am the original owner of one and I still have it. It does not need a reset after I load factory patches.

[@Tranzphonic]

Dear Mister Fuller, I have a Roland JX-305 with a broken PLAY button. also, i have had problems with the memory becoming volatile. most recently, the drum track would not play in pattern mode. i did some kind of system check which resulted in the patterns/patches being erased! but the drum tracks work in pattern mode now. what would be your rate (from the US) to ship and repair? i fear battery acid has leaked onto the board but NEW memories seem to remain after factory reset?!?

[@markusfuller]

Hello. Im truly sorry but I only repair in my spare time as i have other work to do. plus there are things here that have waited for repair for over 6 months because i do not get enough time off to do them , therefore I must regretfully say I could not really take on a repair for you. if i had more time and this was my only job I would do it for you but that is not possible. my sincere apologies.

[@Tranzphonic]

+markusfuller I'm chuffed you would even respond 😀. Thanks anyway. If you ever get the chance to crack open a JX-305 I'd love to see it!

[@nihonam]

Can You please make a tour on your house? I'm curious about your workshop and equipment, and audio bench and so on. It seems to be very special.

[@markusfuller]

Hi I dont think my house is anything interesting, all you see in the video is almost all the small workroom where I do all the video's from.other than what you see theres just a normal standard house (ok a few more keyboards here and there but they have all been in the videos) many thanks but I will certainly consider it for a future video.

[@nihonam]

Well, how about your audio rack ?

[@markusfuller]

Audio rack contains: Symetrix511A (noise reduction) . Behringer multicom pro & composer pro (both not in use anymore) - alesis midiverb4 - lexicon mx200 - aural exiter type c - and patchbay, but none have been used for a long time as the Allen & Heath QU-16 mixer now does all the work with its built in effects, EQs, compressors & gates etc. so the rack will eventually go. may keep the aural exiter though as it adds a little magic to a mix that cannot be explained. oh I just realised theres more racks under the desk.

[@kevincozens6837]

The first thing to do is properly solder the diode in place and clip its leads. The second thing is to measure the voltage coming out of the regulators. That one that is very hot might normally be hot or something on that power rail may be partially or fully shorted. It could be fun trying to pin down if there is some simple problem that can be fixed.

[@formercakid]

I have a Poly 800 and it powers on but sounds seems distorted. Do you have any idea what is the problem?

[@annother3350]

Turn it down a little 😉👍🏽

[@philipharrell549]

I wanted what would be better the yamaha dx7 or the korg poly 800

[@andrewscott1253]

IS there a switch on the back? The poly 61 has a mode switch on the back.

[@GER877]

Hola. Tengo un korg poly 800. Quería saber como calibrar los 3 potenciometros que están juntos en una placa aisladas. Ya que accidentalmente lo giré. Agradeceré su ayuda.

[@pauldavies6037]

I think somebody originally had the DC power input polarity the wrong way round and that protection diode would have blown o/c so will caused damaged to IC's not repairable now

[@mikefur3957]

The battery on my poly-61 leaked all over the board and ruined it. Maybe the battery in this synth was moved to pre-emptively prevent this?

[@PatriotOnTour]

As he said in this video: The early versions had no internal batterys. The Memory was supplied by Mono D Batterys. The litte Li-battery in this video looks like a battery-mod as in kzbin.info/www/bejne/eIvNZaGPp7x5iNE

[@jscan]

Not relevant as this unit usually uses a lithium 'button' battery whose leakage is not as deadly damaging as Poly61's NiCd cell was!

[@QrchackOfficial]

Judging by poor job on the reverse polarity protection, battery getting warm, +4VDC on the output and the voltage regulator being too hot to touch... why didn't you check for a short on the power input first?

[@alexprestin1293]

There would've been a battery on the board originally (on the two pads you point out at the beginning), but those old Korgs had a bad reputation for the batteries eventually rupturing and etching away the entire board along with the components. That's what happened here too.

[@arkangelct]

very good video, a question the stack is connected to R1 and D1?

[@yingtianfu]

Hello, I dont think you need to transfer the .wav file to tape. You can just plug it directly into the Korg poly 800 and it should work fine!

[@ninnon354]

Markus, have you tried to play it from another midi keyboard and to play an external soundsource with this keyboard ? it could simply have the MIDI LOCAL parameter set on OFF... as much silly this can be, it happens sometimes...

[@markusfuller]

Hello yes you are right that can happen but in this case some major chips have been killed by the diode leads placed across the circuit board. plus i tested some and the oscilloscope shows they are dead.

[@ninnon354]

R.I.P.. then... :_(

[@sneezer7972]

What speakers would it need I have one too

[@cyprn6600]

why did the reset sound needed to be on cassette? Couldn't you just plug it direct out from your DAw?

[@markusfuller]

yes you can easily just plug it into the computer but I wanted to do this the vintage way.

[@cyprn6600]

ooo i see! thanks

[@v66r]

Is the (non-chargable litium!) battery directly wired to the power supply jack?? m(

[@markusfuller]

Hi. no the battery is not directly connected to the power jack.

[@muppetpaster]

Why not plg in audio out straight into poly800?

[@traumaduo]

PS: you could also Play the preset file directly from your Computer into the poly800. are sure the Memory protection is not enabled? when Memory protection is on is says "good" after loading file, but the Memory can't be overwritten and still no Sound Comes out...so on the back there is a Switch...try that one...and if not just try to Programm a Sound with the Parameters...

[@markusfuller]

Hello I tried the memory protect both ways. plus I know about the audio direct as theres many people already commented about it. but I wanted to use the cassette method just like it was done in the vintage days. but thanks anyway.

[@jackdavies6821]

Love your videos Markus - thanks for doing them. By far some of the least intimidating tutorials for beginners :)

[@rot_studios]

Seeing those diode leads made me die a little inside, poor Korg!

[@markusfuller]

Yes I suddenly realised it was " Game over " when I saw the diode leads. Pity as these poly800s can sound quite good and I would love to have done the moogkiller circuit bending on this.

[@rot_studios]

Yeah, i would've loved to hear a composition on that, ah well. Can't all be winners :P

[@ferenctulics9688]

I'm sorry DrummingEvil, but I'm 110% sure those diode leads aren't from the Korg factory. Like markusfuller said, somebody else has already been in that keyboard... Nice keyboard..., I use to play with it in 1987 if I'm not mistaken..., nice memories....

[@superskier2]

I used to have one of these years ago and the led displays were constant not cycling like on yours. The tape loading sequence brought back good memories...lol Pity its unrepairable but you were in for trouble with only 4 screws holding it together, but at 10 quid it was worth a punt. You certainly find these instruments, just need to find a Jupiter 8 for 50 quid now. Love your vlogs Markus.

[@markusfuller]

oh yes jupiter 8 for £50 now i would certainly have a go at that. :-)

[@bluffchill2949]

I bought a black keys edition on ebay recently which worked out of the box, but opening it up, that troublesome diode from about 11:00 had broken clean in half! I guess someone must have fed it too much voltage, the wrong way round. Anyway it worked. I replaced the diode and did the Moogslayer mod. However, I can't seem to get it to accept a tape input to reset to factory settings. So I've a feeling the second that battery runs down, it's bye bye Poly 800...

[@markusfuller]

I donated mine to a friend who needed parts to bring his back to life, He fixed a separate battery housing inside so he can replace the battery when necessary, if the battery is replaced while the unit is powered on then it does not lose its memory. however im not sure why you cannot send in the factory backup maybe volume of the signal being put in is too low, the led display should flicker as the signal is being read.

[@bluffchill2949]

The signal flickers pretty well but always fails. It's a shame, as I have lots of custom WAVs that I've downloaded that I'd like to try. Then again, I have only tried it direct from the computer as opposed to from tape. Perhaps I'll dig out the old NAD andgive that a go!

[@tapecadets]

I still have a greatly broken poly800 myself that I somehow never have been able to fix. It just sort of randomly blew up in the middle of producing in my studio a long while ago and I've changed some chips that fixed it to some degree but still not fully perfect.. It's a difficult synth to fix !

[@markusfuller]

I guess I was hoping to load the factory settings and that would be fixed, pity theres so many hard to find chips in them, I would love to have this working.

[@tapecadets]

I think mine isn't as far dead yet, I have replaced an opamp in there to luckily fix the LFO to some places (it seems something blew in the power section) but from then on no presets whatsoever stay where they are. Every setting is always set as such that there's no sound until i change Attacks and etc. Honestly I think it's an alright synth, I had an inverted key one that I modded the slayer filter mod into (greatly advised to do this!) but other than that I think the sequencer was the only other good thing. Thought it sounded a bit wonky but that is in my opinion.

[@markusfuller]

Hi I changes a few parameters just incase there was something from the factory reset not getting through. but nothing happened apart from the background hiss. and 4volts dc on the left output.

[@tapecadets]

But the display showed numbers and such and reacted? If so I think the major important chips are probably alright. I've dug up the ol' schematic but it's a crappily scanned one. I'll let you know if perhaps I have an idea.

[@markusfuller]

yes the main digital controlchips seem to be working fine but its the oscillator/waveform chip etc that seem to do nothing at all. no life detected by the oscilloscope. trouble is they are really expensive and I have replached parts like this in the past and immediatly fried them because of another problem somewhere else on the board. I know I may seem like im giving up too easily but only because i have been down this rabbit hole before throwing money at something that cannot be fixed.

[@edgeeffect]

Couldn't you play the audio straight from your soundcard to the cassette port?

[@markusfuller]

Yes you can but I wanted to do it the old fashioned way with a cassette. like the good old days :-)

[@edgeeffect]

The way God intended! ;)

[@DrUmSensitive]

I've got two if those, one with reversed keys and one standard without the joystick. As with all my vintage Korg keyboards, unfortunately, the sound is either distorted or stops abruptly. Any ideas? Also, would you sell me that one for parts?

[@petercarrington948]

Love your videos, I find them very therapeutic 😂. Seriously, I really admire your electronic skills. Great stuff. We need more people like you who repair and don't just throw away!

[@CoTeCiOtm]

It was awful to see that damn diode there! Probably a former owner of the synth, without knowing anything about electronics got told "just replace that diode and it should work". Well, if that didn't kill the keyboard, the gooey substance spill certainly did.

[@PrinceWesterburg]

Did you try actually soldering in the diode? Its leads would be carrying half wave rectified AC to whatever it was touching, hence the 4v (4.5v?) DC on the output and overheating regulator. Take the board out, wash it and leave it in the sun / on a radiator for a day. Don't tell me you threw this keyboard out, probably nothing wrong with it!

[@Pamberjack_]

In my experience, you can just play the sounds directly from yr computer into the synth. While the tape part is very cool to watch, it's not a necessary step.

[@gunnerhoward3134]

I used to love my poly 800, used to have one with reversed black and white keys.

[@YouTubeSupportTeams]

if i seen screws missing from any item i was going to repair i wouldn't even touch it, my shop rule, just not worth the hassle but i know you didn't realise of course. great vid btw

[@Tron1731]

this is a bad ass synth please look on e bay for parts you can start by cleaning all the pcb with dish soap look for bad caps and open parts the chip sets are basically indestructible unless someone pluged it in to a wall socket check out the demo on the poly 800 thanks for the video you are awesome to watch and a great tech @ never give up you can do it!

[@markusfuller]

Hi some of the chips were killed because of the diode wires placed across the board from underneath. this will be used for spares to hopefully repair others in the future.

[@michaelturner4457]

The two 40 pin chips on the right hand side is the main CPU(Intel 8085) and a PIA. And if it's doing nothing, that does sound like a problem.

[@markusfuller]

sadly I am unable to check now as that keyboard ended up being broken down but some of the parts were posted off to other people to help repair their synths.

[@radlers]

I had a poly 800 that was junky and the battery had fermented all over the board. Lucky for me, nothing was ruined and I was able to clean it up.. The batteries for those actually had stand offs to hover over the board (hard to find). Sad state this one...

[@markusfuller]

I find white vinegar is great for removing battery acid ( well its actually Alkaline so the vinegar cancels it out) My poly 800 was donated to a viewer who has used parts to repair his so all is not lost. Best wishes from Markus

[@radlers]

Vinegar rules for cleaning! Cheers! Enjoyed your video.

[@Cincinnatijames]

I noticed when you went to tape load, you didn't mention turning the memory protection off. If the memory protection is on, the tape won't load, even if the tape load appears to be working correctly.

[@markusfuller]

Hi James. sorry you are right I should have mentioned that to people but can never remember to cover all the important things like what you have just said. thanks for pointing that out.

[@6or7breadsticks]

what did you do with the broken one? I wnat to fix it!

[@pontram]

Poly 800 is currently from 150 to 400 Euros in the bay, depending on its condition and location/continent. I would say, try to fix it and then wait a few years. Analog is rising constantly, even paraphonic ones like this old friend.

[@markusfuller]

pontram This one has already had parts donated to repair another poly800 so at least one out of 2 broken ones is running correctly now :-)

[@pontram]

Well, it seems that's a common fate. I bought a defect one myself, to repair mine (or vice versa, there was a huge parts exchange ;-)

[@JipBosch]

When the leads of that diode popped up I laughed so hard! It fried the circuit board.

[@floris1200]

nice vid but i had the same problem and weird voltages everywhere which can mislead you a lot. i replaced the voltage regulator and it work fine again

[@MarctheDarc]

I would not toss it, but rather look around for another that goes cheap, particularly if you can find 1 that seems to only have external damage, i.e. makes sound just fine but are kinda messed up. Would probably be fairly easy to combine the 2 for a fully working package. Btw. isn't that small battery supposed to a "special" rechargeable 1? I could be wrong, but pretty sure they used rechargeable batteries back in the day, which is why it would last fairly long when used regularly. Modern batteries like that aren't rechargeable unless you find special ones that are (obviously). So while they fit and have the correct current etc. when the synth tries to charge it, it gets extremely hot and can explode. So if the previous owner used a standard battery when making that mod, it could have exploded all over the insides, hence it looks like there's been battery acid all over. Otherwise the brown sticky dust is often from the home of a smoker. It leaves this weird brown tar-like substance everywhere that connects with the dust. I've seen some pretty bad cases when working on computers, and while disgusting and clogging up fans etc. it doesn't seem to conduct. Thanks and good luck :-)

[@markusfuller]

Hi Marc I do think you have a good idea there about the battery exploding in the past and maybe getting onto the board. that could certainly explain a few things. I will not throw it out but will most likely add it to the synth graveyard in my garage. but thanks for your suggestion its something I never even thought about. Best wishes from Markus.

[@cfcreative1]

Actually i fixed a few of these they play dead when the battery dies. Then you can restore them with a wav file you can download online and play into the tape input. Then they work like new. But they are a pretty basic analog synth to start with.

[@lloydpopp13]

I read somewhere u should put the c / d cells battery to keep the patches going on...

[@markusfuller]

true if you keep good batteries in it then it should hold its settings but as soon as they are removed or changed then you should have the power supply attached and turned on while you change the batteries over unless there is a good cr2032 internal battery fitted to hold its memory.

[@lloydpopp13]

Thanks for the reply markus! I just got me a Poly 800 no external batteries but stored patches after turned off so I'm lovin it! Anyway I try to clean the keyboards coz some notes didn't work... But I don't know how to remove the keyboard, ive experienced with yamaha DX which I just push n the keys slipped out. But I seems to can't find a way to slipped it out on korg Poly 800... Can u give a Lil guidance.... Anyway really enjoy your videos

[@markusfuller]

Hello LLOYD, sadly I have already donated my poly to another viewer that needed some parts so I cannot open it up and check how the keys are removed. you may find that the long thin circuit board that runs under the keys can be unscrewed and lifted out. that will contain the switchgear that needs cleaning instead of removing all the keys.

[@lloydpopp13]

Thank u so much I think I'll give it a try later! Anyway yeah I lost my patches after hours lol. I guess the external batteries do required to keep the patches. Thanks to modern technology n this video though I know load it via cellphone for just seconds... Thanks again markus

[@markusfuller]

A friend of mine has one of these and it has a 2xAA battery module with long wires on it leading to the solder points of where the old onboard battery was. therefore he has glued the 2xAA battery box away from the board so if they leak over time they will not destroy the tracks of the circuit board.

[@genuinefreewilly5706]

I have a poly ex-800 sound module, battery is dead and I would get just white noise sounds. I had to write all the sounds from scratch and save them or just leave it on. The battery was always an issue. Fortuneately its the easiest old module to write to Mine is still working but the display is hoopy an led is out. The old polysix keyboard was a beauty it was blue and black lots of knobs no midi? That was a vintage keyboard worth saving, alas it did not happen

[@ElectricApe]

Hi Markus. Excellent vid as usual. One quickie: why did you do DAW -> tape -> Poly rather than just DAW -> Poly?

[@markusfuller]

to be honest I tried both ways. both came up with GOOD in the display but i kept the part with cassette tape in the video as it was more old school style.

[@ElectricApe]

+markusfuller makes sense! Cheers

[@kletsgoo]

Would be interesting to take out the NJM2069 Filter IC, it's a very nice unit!

[@markusfuller]

sorry but I already passed this on to one of my subscribers as he needed the parts to fix his poly-800. but yes there are some interesting chips in that unit.

[@PTechnicalOriginal]

Big soft spot for the Poly 800 thanks, and don't feel no way. The numpti who was there before you, might as well have just shoved it in the bath. Can't save them all mate.

[@michielhooge7858]

hello I need the wave file where can i find that best regards m hoge

[@markusfuller]

Hello Michiel. I found it on google. I think I just typed in korg poly 800 factory reset wave and it came up with a link to youtube where someone has placed it as an audio file.

[@michielhooge7858]

Thanks mark the korg is a live

[@meagain2222]

This might seem stupid of me to say but that keyboard does not seem to have a speaker .....so how can you hear anything?You should plug in a headphone or external amp and speaker and maybe then you will hear something.

[@markusfuller]

meagain2222 Hello at about 3:10 in the video there are red and green cables plugged in which go to a mixing desk and then to speakers in that room, a lot of keyboards and synthesisers do not have speakers built in.

[@meagain2222]

Oh sorry didn't see that one.

[@otherunicorn]

I do hope you disposed of it in such a way as a third person won't try to fix it. I had a Seil Synth that had a failed voltage regulator dumping overvoltage through the entire logic board. As soon as I found that, I dumped it too. I also had overvoltage on a VCS-3. That one I fixed!

[@markusfuller]

Hi I have kept it in the garage for possible parts donations. it is in no condition for someone else to try and fix. (oh the VCS-3 wow what an amazing synth to have, thumbs up to you )

[@edencane]

Excellent outcome hahaha... I have a poly 800 and an ex 800...! I loved my poly when I first bought it.... then I sold it... then later I bought another in quite good nick... You know the story lol... keep the great videos... always enjoyable...!

[@gorillaau]

Mostly missing case screws indicates that the previous someone gave this repair a lot of attention to detail.

[@muppetpaster]

7:15 Is that a bit of Dave EEV Jones I hear??

[@SamLowryDZ-015]

Sticky brownish dust = dope smoker residue. Causes chips to over heat and fry

[@cidshroom]

Right when I saw those Diode leads just bent over everything else I had no hope it would work either. I don't know a ton about electronics, but I know that's a terrible thing to do!

[@markusfuller]

Yes when I saw that I suddenly though "this is a waste of time" pity really as they can sound reasonably good keyboards when they are working.

[@Heathcliff_hensel]

You know that looks like a repair that was suddenly abandoned. Like the repairman immediately stopped and just left it like that.

[@markusfuller]

yes I wish he had at least soldered the diode into place though and trimmed off the wires.

[@skyprop]

Stick a fork in it....It's DONE!