A basic overview of some faults on this AKAI AX-80 synthesizer.
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- čas přidán 22. 08. 2024
- This AKAI AX-80 was bought in a bad state from eBay. Lots of rubbish and crud inside the synth. Some ciggy wrappers too.
Some of the common faults on this underrated synth.
1. bad connections between VFD display boards and membrane switch board.
2. faulty voice IC's
3. faulty logic IC's
4. faulty TL082 op amps
5.whining HT LCD driver transformer
This synth like the Juno 106 and others uses a crystal and timer IC's to generate it's basic waveform, which is then shaped by analogue electronics. On this synth CEM 3372 mixer/filter/amp IC's then process to the output
Dude, thank god for you. Just found out the membranes on the right side of my AX quit working about a week ago, and this video really eased my doubts about not being able to fix it cheaply. I'm not a very good solderer (only done it once on some old breadboard) but that's why you make friends with tinkerers and other cool weirdos.
The AX80 is definitely worth the work, good luck
Inspirational video, thank you : ) motivates me to get my arse in gear to fix this thing! I bought an AX-80 advertised "fully-functional!" "no issues"..."works perfectly"..that has membrane problems 😐🖕🏾 Buttons 25-32 (ADSR sections) dead, unresponsive. Other than that it's cool. Hopefully resoldering interboard connectors fixes it. Akai should've used ribbon cables! It's the same crappy tin pin connectors Ensoniq stuff has that cause keyboard calibration errors etc. At least there are repair solutions, thankfully enough. And good people like yourself who make these videos to help others keep synths alive 👍🏻
hello, I appreciate the feedback and it helps push my channel quality up to better future videos. Yea the interconnects is a real weak spot. It's a relatively easy fix and quite satisfying though.
I also have an Ensoniq SQ-80 so will have to keep an eye out for those issues with the keyboard you mention.
I have this calling in life to rescue old synths, the ones stored in sheds and ebside water tanks. I need to get out more:)
@@waheex get out into _what_ is the question 🤣 a world of assholes? No thanks! 😂 Beach or hiking =definite YES though..lol. Better off spending time with synths + cat, for real. Far more satisfying, productive and beneficial : )
Not sure if SQ-80 has those crappy interconnects? on it's keyboard..but I'm certain the TS-10 does since mine was gravely affected. Causing issues where several random notes wouldn't sound when played (but did through midi) or it wouldn't boot etc. I've read the VFX has them also.
I was able to fix my AX-80. Turns out there was cracked solder joints on all 3 top-level board connectors-the right 2 patch select & left control/edit. One connector was completely severed from the board attached only by gravity. Where slightly pushing down on the buttons to edit a sound or activate CHORD MEMORY would break the connection just enough to produce intermittent parameter values and even lock the data wheel. I ended up removing those boards, laying them flat on level surface and patiently re-soldering each interconnect pin with a precision solder tip. Now it functions fantastic. Panel response time doesn't lag as before either it's instant. Not a bad way to spend Sunday ✌😀 with most of it playing the AX-80. I'm thinking of ordering the Tauntek ROM too 😺
@@rg2027x yep you said it. I have my shed my synths, tarantulas (that's a whole set of new videos:) and can quite easily spend several hours doing very little.
Pretty good you got the AX-80 fixed and repaired the bad joints.
It's a time consuming job but not at all bad. Just patiently doing each joint, then you know it's good for a load of years yet. The other synth with issues like this is the korg poly61, although it’s more to do with the molex connectors on that one.
I would recommend the ROM upgrade as the filter steps nicely in real time and the patch number doesn’t disappear when editing.
I have two AX-80’s so will maybe do a video on both of them as they sound different. Probably one in need of a tune but it sounds really off, weird and nice actually. All part of the fun
I just got mine and I have the same problem with the ADSR. Will be fixing soon! How did your repair end up going?
Have the same problem on mine opened it up to take a look at what the solder looked like and realized when the board was open all my membrane worked , The screws to open it up that hold the top panel in place seem to warp the shape of the case when they are tightened causing the boards connections to warp ..I left my screws in the back of the unit out and took the lower right screw out on the top and now they work ...temporary fix
This is super helpful, thanks. I just got an AX-80 with many of the same faults you describe.
glad to help, The AX-80's are very underated
A DCO is not digital. A digital Oscillator is when the sound is generated digitally and output via a DAC. A DCO is actually a VCO that has it's frequency timing controlled digitally. Instead of using a comparator to measure the voltage and then trigger the capacitor discharge when it reaches a certain level it uses an ADC to count the steps and then triggers the capacitor discharge when it reaches a certain value. This has the effect of quantizing the oscillator timing and making the frequency much more stable.
Appreciate the video! Recently got one of these out of a basement, seems to function well except, every time you select a patch, the fourth note up or down from the first note you play won't sound, continuing on every 4th note. Can't really find any techs in my area and it all looks like greek to me, if you have any insights would be greatly appreciated! Glad to see someone keeping old synths singing.
thanks for the feedback. It sounds like one of the voices has an issue. First up try and find the voice that's not working. Sometimes one of the voice IC's has died. Or could be a op amp (TL082) in the voice. They are in vertical rows. It you touch each IC and see if any are over warm, that could be a sign of a fail. Swapping IC's from one channel to another can help isolate a fault, if the problem moves with the chip, then that usually means it's got an issue. It's hard to say exactly as there are so many reasons why a voice may not sound. It could just be something is loose in it's socket and maybe needs re-seated. Try unplugging IC's and cleaning the legs, re-insert and see if any improvement.
Kit back that era were beautifully engineered right? .... 🎹
absolutely. It was a pleasure to work with and has good quality connectors which don't fail that often
Love my AX80, but it has an issue: some keys produce no sound. It doesn't seem to be a keyboard contacts or voice issue, because different keys go silent when I change to another patch. Hope you can advise - any ideas?
could be an addressing issue. Would really need the schematic studied to see what chips controlled this. Perhaps 4051. It's been a while sich I worked on this synth
Thanks for this video! I'm on my second AX80. I'm not knowledgable about repairs so I got the second. Thing is this one sounds colder and distorts, most likely at the filter stage. All voices react equally. Any thoughts what that might be?
hi
you might be able to use an audio probe to check the sound signal at various stages in the audio path. Might a bad op amp, tl072 kind of thing
Hey m8.. I know this is an old video but I have 2 ax80s I'm trying to get one working. Got it to the point where if you turn it off and on many times eventually you will luck into it coming on... random if the keys trigger sound but midi always does. When it doesn't boot all the way up it just has garbled output on the 7 seg displays. I checked all power from the supply board.. regulator.. all working. Any ideas?
I have had quite a lot of synths with bad RAM recently. I would look at replacing it and also check the clock signal is present at the CPU
This synth didn't have aftertouch, did it?
Hello my name is DJ and I am currently working on a AKAI AX-80. It was a mouse home and some wires were cut. On 1003a5010w board number P5 (gray shielding, blk,white wire) where does this wire go to. Please help!
Hi thanks for the video. My AX80 is in overall neat condition. Since I got it, there are just a couple of buttons that stopped working most of the time (around 25 to 32). Some rare times they quickly work shortly after i switch on. Is there an easy thing I can do to try to fix this knowing that I have no knowledge at all in electronics? thanks
the buttons are easy to replace, but usually it's just the links between the boards need resoldering. Try that first.
@@waheex so basically what i need to do is buy a soldering iron, open the synth and then resoldering the joints that match the deficient buttons?
@@shadychat pretty much, there's a picture on my web page here
www.mindburner.co.uk/synth/Akai_AX80.html
reflow the solder over the contacts and it might just fix the issue. An iron with a fine tip works best.
Where did you get the new OS from? I'd love real time control of the filter.
hi it's from Tauntek. Think it's free, if you can burn the chips
Mine has non working membrane buttons 21-32. I have exhaustingly checked all the connections between the wire bridges. They are not the problem. I do not know how to fix it other than I read online that IC-1, 74LS42 which scans the buttons can go bad. Seems like that would affect all the buttons but maybe not. Any ideas?
hi I would say that it's either the IC or more likely bad interconnectors. The 74 series, even old ones are highly reliable under normal circumstances, so check all the board connections first. Good luck