nice, what you fixing for clients?
Mostly solid state audio lately. Bass amps, samplers, refurbished a cool tape echo. Currently in the middle of recapping a 16 track Otari tape machine. But also just had someone drop off a PVM crt.
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Awesome! Love tape echoes, which one was it? I owned a Copicat for a while it was lovely. I made my own cassette tape echo a few years ago.
Cool. The last tape echo I did is an Ace Tone EC-10. Probably my favorite one I’ve worked on.
During one of these late night sessions on the MX50 I shorted a couple points when checking voltages in the power supply. So I’m now diagnosing which transistors I killed and replacing them. I’ll report back once I’ve got the psu repaired and I can revisit the original issue.
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Ok. Power supply is now back up. output is still inconsistent with lots of green.
I’m going through the calibrations and found that some of the trimmers don’t have any effect when I attempt to adjust per the manual. I exercised them a bit and saw no change. Then I figured I’d try deoxit and sure enough it worked! I’ve only tried it on one trimmer so far but it worked perfectly, so I’ll go back and check the others next.
After cleaning trimmers, no improvement. Here’s what it looks like. Left side of screen is A ch source 1 Y/C bar input. Right side is B ch source 2 composite ramp input (it scrolls vertically). Internal color bars look great on both channels, controls all seem to function as intended.
yeah. Sometimes the trimmers arent all of it unfortunately. It is very probably small signal capacitor degradation at this point, however, finding which one can be tricky.
There as a thread on here with a different panasonic mixer the AVE5 I think, but it will only be similar in design, if that.
Just wanted to post here to share my joy that I seem to have repaired my faulty MX30!
I was having intermittent problems anyway, but while it was kinda working I was poking around trying to find places to inject CV and foolishly dropped the probe which shorted +5v to ground. The unit would then only display a black screen, and the control board LEDs wouldn’t light up at all.
Disconnecting the power cable to the analog board made the control board work correctly, but still black screen (obvs).
I was skeptical, but going back and forth with Gemini helped me to figure that some kind of issue with a broken capacitor was leaking current onto the 5v line and likely preventing the CPU from starting up or making it crash. As I tested further I found that the fuse after the 5v regulator on the power board was dropping 2.5v across it, and the +5v bypass cap C25 seemed to be faulty. I haven’t done a proper soak test yet, but replacing those seems to have got the damn thing working again!
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This thread gives me hope! My MX-30 usually took 3 presses of the power button to turn on, but otherwise worked perfectly. Until recently, very sadly, wouldnt turn on anymore.
There was a low “hissing”? noise when the power was switched on from the back, and the lights flashed briefly when the power button was pressed, but nothing more. I hope it can still be saved.
ok i am not good with electricity but the fuse sparking when trying to power on is probably not positive
…well - some say the current flows from negative to postive (…)…
…no big drama as the fuse saved the machine from extended damage; i guess some capacitor is causing a short-circuit somewhere - so the next step would be to thourougly check the PCB for burn marks and/or blown electrical components…
…with a little luck you might be able to isolate the problem in no time and as long as you know which side of the soldering iron gets hot (avoid touching that side) even be able to replace the offending part…
…i am sure people here are willing to support if required…
thank you! :——-) luckily I have a friend helping out with my dumbass questions, next step for me is to get a voltage meter. I’ve soldered some wires before, at least, I’ll do a few practice solders before trying it on the MX and hope you are right about finding the offender.
Something I’ve wanted to learn how to get better at for a long time anyways, so I guess its time