The Crumar GDS Restoration Blog...

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Re: The Crumar GDS Restoration Blog...

Post by StepLogik » Mon Nov 17, 2014 2:58 pm

Seeing an antique computer boot off of one of those floppy emulators truly is a marvel :)

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Re: The Crumar GDS Restoration Blog...

Post by synthroom » Mon Nov 17, 2014 3:35 pm

The HxC is a really great addition to any vintage synth that uses floppies. And I can't recommend JB Emond's Fairlight HxC kit more highly - it's easy to install and it works great.

The sound clip from Brian's GDS sounds really nice too!
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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Fri Nov 21, 2014 7:40 pm

I spent the last couple of days cleaning and recapping the PSU chassis and the front panel board in the keyboard console in Brian's GDS. After replacing all of the tantalums and the PSU reservoir capacitors this part of the restoration is now complete.

Image

That's 95 capacitors replaced in the total and nearly as many again on the KS GDS!

Just like the KS GDS, the rubber dust cover strips on the 32 front panel sliders of Brian's beast were so badly perished they were falling apart on the slightest touch so I spent an afternoon staining my fingers black removing them piece by piece - definitely not a nice job.

Image

Today I devised a means of mounting the HxC disk emulator in place of the A drive under a blanking plate I cut to match the textured black front fascia. The 8" B-drive was reinstalled in its original position thus permitting floppies to be imaged as and when required. The HxC was then configured to emulate a twin disk setup and the B-drive temporarily disabled to keep the noise levels and unnecessary drive wear to a minimum.

Image

The HxC is currently storing newly imaged copies of the main CP/M 2.2 system boot disk also containing the Voice and Perform applications to run the GDS as well as a copy of the original 1979 voice disk that accompanied the KS GDS. Several more disk images are now stored on the SD card featuring the entire Synergy factory patch library retro-converted to GDS "voice and filter" format. Finally being able to make images of these extremely precious disks has been a great relief and very satisfying as it now means they are safely backed up on modern technology and that new 8" floppies can be made if and when they are required.

The virtual drive system has been installed in a totally reversible fashion so the system may be returned to a stock twin 8" disk configuration if required at a later date.

Image

Being able to play so many cherished Synergy sounds on the original GDS hardware they were developed on in the first place has been quite an experience!

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Re: The Crumar GDS Restoration Blog...

Post by synthroom » Fri Nov 21, 2014 8:31 pm

I'd suggest flipping the HxC mounting panel and the HxC over so that the bits you work with are at the top of the panel, and not the bottom.

The screen on JB's HxC Fairlight adaptor is in the top half of that panel. I have my Fairlight Mainframe on a stand with the Fairlight Keyboard and Monitor sitting on the Mainframe (so it's played standing up - photo of it without the HxC installed here: http://synthroom.com/ ), so the HxC screen is about knee-high off the floor. The only pain in using it is having to kneel to read the HxC display.

I don't know how you're planning on setting up the GDS system but getting the screen higher in the work environment could be a good thing...
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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Sat Nov 22, 2014 4:51 pm

synthroom wrote:I'd suggest flipping the HxC mounting panel and the HxC over so that the bits you work with are at the top of the panel, and not the bottom.

The screen on JB's HxC Fairlight adaptor is in the top half of that panel. I have my Fairlight Mainframe on a stand with the Fairlight Keyboard and Monitor sitting on the Mainframe (so it's played standing up - photo of it without the HxC installed here: http://synthroom.com/ ), so the HxC screen is about knee-high off the floor. The only pain in using it is having to kneel to read the HxC display.

I don't know how you're planning on setting up the GDS system but getting the screen higher in the work environment could be a good thing...
Where I agree this certainly makes sense on the Fairlight, in the case of the GDS, I wanted the HxC to be as low profile as possible. In fact at one point I was seriously considering mounting it in the rear panel!

Just like HxC on the EII the Fairlight makes significant use of the HxC simply loading one sound bank after another but the GDS is a pure synthesizer which means literally several hundred tiny sound patches can be stored on one disk image. With this in mind, in a twin disk emulation setup (ie. Boot OS and synth apps on A-drive and patches on B) you can run for hours on end simply accessing the same two disk images. The same is the case on the Kaypro with the Synergy - if you setup as a twin disk emulation you can have a second disk image with the entire factory sound library on one disk! (around 800 sound patches).

So in short, I'm not sure that ergonomics matter so much in this application and perhaps keeping HxC low profile is a little more of a priority.

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Re: The Crumar GDS Restoration Blog...

Post by Bitexion » Sat Nov 22, 2014 5:00 pm

What are you going to do with this beast when you've finished restoring it? Sell it for $100,000?

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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Sat Nov 22, 2014 5:34 pm

Bitexion wrote:What are you going to do with this beast when you've finished restoring it? Sell it for $100,000?
D'oh!.. it is actually extremely difficult to determine what something like this is worth.

I don't own either of these beasts - I'm just the crazy guy who is working on them.

Both of which are now over 80% complete on the restoration front.

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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Mon Dec 01, 2014 6:48 pm

A sample of the first rapid prototyped key contact actuator spigot turned up today. The part was printed on a Fused Deposition Modelling (FDM) machine in ABS plastic.

Placing the FDM part along side one of the plethora of broken originals a good match was observed.

Image

After drilling out the pilot hole for the self tapping fixing screw, the part fitted nicely in place on the end of the key lever and the return spring placed in the guide ramp on the actuator. The contact actuator fitted on the end of the actuator spigot as a satisfying interference fit.

Image

After a quick application of grease the key action on the key with the rapid prototyped part appeared to be very similar to the rest of the keys.

After a couple of thousand test actuations the part was removed for examination and appears to be undamaged so the plan is to give the go ahead for another 40 parts to be made.

Approximately 30 of the original key actuators are currently broken and so the remaining parts will be retained as spares.

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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Mon Dec 01, 2014 8:49 pm

Another big win!....

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After much research and experimentation I ordered some cloned replacement foam and foil key contact pads on eBay which were designed to fit the keys on the old Apple Lisa computer which also featured a much later series of the "solid state capacitive foam and foil" key action made by Cherry.

The parts turned up and I had a go fitting one this evening. To my delight they simply clipped into place on the 35 year old key sliders and on reassembly work perfectly!!

So now finally we have Mr Schulze's original ADDS Terminal for the GDS with all the keys working again! 8-)

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Re: The Crumar GDS Restoration Blog...

Post by ppg_wavecomputer » Mon Dec 01, 2014 11:38 pm

Marvellous.

One of the most stunning threads on the internet that I have come across in a long time!

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Re: The Crumar GDS Restoration Blog...

Post by desmond » Mon Dec 01, 2014 11:54 pm

Such a fascinating thread.

Really lets us non-hardware tech people understand the process and problem solving needed doing something like this...

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Re: The Crumar GDS Restoration Blog...

Post by HideawayStudio » Tue Dec 02, 2014 11:37 pm

The cabinet maker turned up today with the restored KS GDS Keyboard Console cabinet.

Where as it was decided to retain the original finish on Brian's GDS, the KS GDS console on the other hand was very badly damaged. What made the final decision to refinish the cabinet was that it turned out one end of it was almost completely broken off under the veneer and in urgent need of structural repair. What is very unusual about the cabinet design is that the wooden end caps are integral to the main structure and much of the wood inside these structures is milled out from solid plywood. Its not really clear why this was done - maybe to keep the weight down or possibly to make it easier to drop the keybed into the cabinet on assembly.

The cabinet was stripped down to its bare plywood structure and jigged and bonded before the black surfaces were sanded down and re-sprayed. The integral end cheeks where then re-veneered with in a hand cut African hard wood with a very similar grain size and texture to the original.

The console was reassembled this evening and it looks beautiful!

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Re: The Crumar GDS Restoration Blog...

Post by desmond » Tue Dec 02, 2014 11:59 pm

HideawayStudio wrote:The console was reassembled this evening and it looks beautiful!
It really does look amazing!

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Re: The Crumar GDS Restoration Blog...

Post by jbfairlight » Thu Dec 04, 2014 10:56 pm

Sublime !
Sur le ruban de Möbius

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Re: The Crumar GDS Restoration Blog...

Post by ppg_wavecomputer » Fri Dec 05, 2014 12:19 am

I'll have this one, please.

Stephen
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https://doombientmusic.bandcamp.com/

https://ramp1.bandcamp.com/

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