Ensoniq Mirage with Gotek possible issues.

mondo1976
Posts: 141
Joined: Mon Dec 28, 2015 3:54 pm

Re: Ensoniq Mirage with Gotek possible issues.

Post by mondo1976 » Wed Jul 27, 2016 3:42 pm

agent29 wrote:Im bamboozled as to why or how the FMT-2 OS loads perfectly but OS 3.2 takes ages to be recognized?
I'm not 100% sure this is true, but my assessment of the Mirage is that the FMT disks load into RAM straight from the floppy (using the CPU of course). That seems like a stupid statement, but what I mean is that all it requires is working RAM, floppy controller, floppy drive, and CPU.

The OS (to my vague understanding) loads piecemeal and runs as it loads. It also initializes other hardware (filters, etc.) as it loads, therefore if there's anything wrong or weird with other parts of the hardware beside RAM/CPU/FDC then stalls will occur at certain points in the OS loading routine.

I'm assuming your FDC/RAM/CPU are fine, but that the filters are having trouble calibrating or something similar. It could be something like the add-on filter cartridge (if you have one) too, it's hard to say with exactly the OS does without reversing it or monitoring the hardware on a logic level.

Oh, did the HFE you formatted via FMT-2 still boot (even if it took a while) properly? Usually formatting directly through the Gotek is a no-go.
Last edited by mondo1976 on Wed Jul 27, 2016 6:01 pm, edited 1 time in total.

agent29
Posts: 41
Joined: Sun May 08, 2016 10:42 am

Re: Ensoniq Mirage with Gotek possible issues.

Post by agent29 » Wed Jul 27, 2016 5:23 pm

Hi mondo1976,

Thanks for the info and your help, its taken a while but its now kicked my entire brain cell into touch. No I dont have the filter cartridge. From what I now understand the OS performs a type of Power on self test during boot including Filter calibration, I wasn't previously aware of this but now makes perfect sense..

It would appear the CEM3328's are multiplexed through 4051 multiplexers, but without the luxury of a schematic I can only surmise. When I return home I'll get the scope out and start probing, my hope is defective capacitors or a 4051 as I have one spare Roland JX10 board with a good number of 4051's I can salvage. If its a CEM filter ic im stuffed as I only have IR3109's.

mondo1976
Posts: 141
Joined: Mon Dec 28, 2015 3:54 pm

Re: Ensoniq Mirage with Gotek possible issues.

Post by mondo1976 » Wed Jul 27, 2016 6:00 pm

Now you're getting there :wink:

I'll keep my fingers crossed for the caps. Let us know what you discover, if you would.

agent29
Posts: 41
Joined: Sun May 08, 2016 10:42 am

Re: Ensoniq Mirage with Gotek possible issues.

Post by agent29 » Fri Jul 29, 2016 10:34 am

Well nothing conclusive as of yet, but as a matter of course I replaced three 4051 multiplexers with brand new IC's, no change :( I have also edited this post as I didnt explain myself very well.

Subsequently I have located the schematics for the DSK-8 and managed to investigate from there. Once powered I believe the drive loads diagnostics initially.

Once the green LED goes out diagnostics start. Signals are sent to two of the 4051 multplexers and these signals are passed through two accompanying TL084's to the filter ICs (one pair of 4051/TL084 for frequency and one for vcf Q).

Each individual 3360 is activated in turn resulting for me in an output on pin 9 of each of the filters with a sine wave of 800mv between 500-590 Hz. All 8 outputs are then decoupled through a 3.3uf Capacitor plus a 10k resistor and collectively summed through one quarter of the TL084 op-amp "U56".

This output is split using the dual compander/expander IC NE570 "U48", (one half for audio out and one half I presume for returning the signal back to the CPU through a Differential Multiplexer 4052 "U45". then processed by the remaining op-amps of "U56" TL084.

What the Schematic also showed me was that the same 4052 also provided multiplexing for both mod and pitchbend, which made me think.

Once the stock piano loaded I attempted to use Mod and pitchbend. Mod seemed to work but I have since discovered it provides either no modulation or max modulation regardless of position.

Upward transit of the pitchbend produced no increase in pitch, however downward transit provided an instant switch of roughly half a semitone lower only, as the two devices in this path are the Tl084 and 4052, I replaced the TL084 "U56" (no difference)

Its possible the 4052 is defective and not feeding back the data correctly from the filter tests, Thus not able to calibrate? well thats what I hope. I have a basic 2 channel Oscilloscope but without additional documentation Im unable to determine precisely what should and shouldn't be taking place. The fact the pitchbend doesnt work properly may support the theory of a defective multiplexer. Im now just waiting on a replacement 4052.

agent29
Posts: 41
Joined: Sun May 08, 2016 10:42 am

Re: Ensoniq Mirage with Gotek possible issues. Now Solved !!

Post by agent29 » Thu Sep 08, 2016 11:59 am

Well after a few months I finally got some time to look at the Mirage again. I discovered the track for the DA VREF Pin was damaged under the Piggyback board from a previous attempt at repair (the damage was obscured by the piggyback board itself), I bridged the damaged track and replaced the decoder and logic IC's as a matter of course ( as the board was off ). Needless to say the Mirage boots in around 6 seconds now using the Gotek HXC drive so im well chuffed, Thanks to mondo1976 for helping. :D

chrispoacher
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Joined: Tue Oct 04, 2016 7:16 pm

Re: Ensoniq Mirage with Gotek possible issues.

Post by chrispoacher » Wed Oct 05, 2016 6:37 pm

Glad you got it sorted, I have 2 Mirage's with the same fault but so far have not had the time to troubleshoot the faults. Both mine are MK1's which have the piggyback boards on.
Chris.

Ragg
Posts: 1
Joined: Fri Nov 25, 2016 9:36 pm

Re: Ensoniq Mirage with Gotek possible issues.

Post by Ragg » Fri Nov 25, 2016 9:44 pm

Hello guys.

I'va just noticed the existece of this gorup.I 0wn a mirage since the eighties and now is time to back it alive again. The mine is working properly, but I thik it would be better to use a floppy replacement, infact , I have not used it fron lot of years ago becasuse of the floppy involved, I'm really lazy about it.

I' like you to give me some information please, I really don't understand if you ar speaking a bout the chinesse units running out there or something special (what is XxC, a software emulator or something?) I think the floppy of the mirage is a single side double density one, not sure if a 1,44 emulator or even a 720 one would do the work. Any information will be wellcome.

I read in your comments about a 1,44 Gotek, but not sure what you mean about it, if it works or not.
Thanks in advance

mondo1976
Posts: 141
Joined: Mon Dec 28, 2015 3:54 pm

Re: Ensoniq Mirage with Gotek possible issues.

Post by mondo1976 » Sat Nov 26, 2016 2:20 am

The original HxC is a floppy emulator that is pretty much the gold standard for legacy floppy drive replacement. It's not a Chinese knockoff of anything, but something engineered from the ground up for just such a purpose. It's hard to go wrong with, but some people find it a tad pricey.

The Goteks that everyone on this forum are mentioning are not the standard Goteks that you see for sale everywhere for $23 or such. They are the same hardware as those, but are reprogrammed with custom firmware that turn them into HxC Goteks. In other words, a lot of the functionality of the original HxC units, but less expensive because they use generic hardware instead of the specialized HxC hardware.

The course of action is to either buy a "real" HxC, buy a pre-programmed HxC Gotek, or buy a cheap Gotek (from China, India, wherever) and program it yourself to become an HxC Gotek. The last option is the most cost effective, but you have to be somewhat tech savvy.

For what it's worth, the Mirage seems to work very well with the HxC Gotek units.

Admin010
Posts: 1
Joined: Thu Apr 20, 2017 10:07 am

Re: Ensoniq Mirage with Gotek possible issues.

Post by Admin010 » Thu Apr 20, 2017 10:09 am

thanks

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