Hi all, I've got a DP/4 which is stuck in test mode (the generic fault that plagues all(?) the Ensoniq stuff as it seems). Things I've tried so far and are *probably* okay: Replaced the EPROMS with v1.15. Replaced the panel to motherboard ribbons (both of them). Replaced the UART chip. Checked volta...

I've got experience in soldering and desoldering that's no issue in this case although I fully agree with you. I've already put the CPU IC in a socket while trying to decide if it's broken. My main concern is that most of the keyboard is tracking pitch so the CPU is not entirely dead. On the other h...

I've had my doubts on whether the CPU is working okay because I can't explain why part of keyboard is not functioning so the counters were my #2 thing after the CPU.
But I could indeed replace those first because they're so cheap and easy to find.

Hey all, I've got a Juno 6 with 2 major issues : 1) half of the keyboard is not working (top two octaves) 2) I see no waveforms anywhere I don't know how these issues could relate; they may be totally unrelated. I can hear keyboard tracking of the filter when it's self oscillation so part of the syn...

Hi all, I've been given a Quasimidi TechnoX which does not respond to MIDI, outputs no sound and has black squares on the LCD display. It powers on and all voltages are correct but no other sign of life apart from various clock signals and limited activity on the EPROM pins. My guess is that the the...

I'm searching for a disk named "Hard Disk Operator" for the Casio FZ20M sampler but I don't seem to find anything on the net.
Perhaps someone has it?
Without this disk I don't think I'm able to use a SCSI hard drive with my FZ20M

I opened it up and turns out that it doesn't have any encoders apart from the "program" selector encoder. All the other pots are just regular one-turn 10kB D-shaft potentiometers! Unfortunately deoxit isn't suitable for any pot (encoders should be fine) in my opinion since it kind of degrades the ca...

Hi!
Does anyone know what type of encoders the Novation K-station uses?
I could purchase some samples and test which one does the trick but I'd really avoid all that if I had a part number for these.
Thanks!

I had a similar clipping noise in an Ensoniq EPS-16 a while ago and turned out to be a shorted tantalum near the DAC. It wasn't a complete short but had very low resistance; it had no apparent visual damage. I believe it was on the -15V rail. Check all tantalums for any shorts, it may be obvious but...

I've seen similar NEC chips used in peripheral control duties in synths of this era stripped of their ROM capabilities, so it wouldn't be surprising for this also to be a generic one driven by nearby glue logic etc. I could be wrong so maybe Rasputin could chime in about it since he's way more knowl...

I went a bit further on this and replaced the CPU with another 8051 that should be working fine. No change. I also went ahead and saved an eprom dump of the current revision and flashed v4.00 eprom to the 27c64 which was already there. I don't know why I've read that I should use a 27c128 since the ...

Hi all, Just got a JX-3P which does not seem to respond to anything. It does not output sound, respond to keyboard or panel keypresses or even enter test mode. The LEDs that are lit when it turns on are correct (CHORUS, PRESET A, 1) and I can see address activity between RAM,CPU and various other te...

Ahh okay if it was plugged in backwards then it makes sense:P
Yeah do that I will check it later.
To check if it's bad just pull the output leg out of the socket and see what the signal look like vs the input.
It's probably something else..

If you haven't already please check all the tantalum caps as well.
I've seen tantalums fail in ensoniq machines.
Usually it's related to distortion or ADC issues and on the other rails not the 5V one but check regardless.

I think that either the a capacitive load of some sort has been "introduced" to the schmitt by a short maybe or there's some slightly excessive current draw/someone else's input resistance has lowered somehow. The thing is that you have a good rising edge but the rest of the pulse decays at the same...