Author Topic: Today's Repair.  (Read 1706 times)

Scruffie

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Today's Repair.
« on: February 06, 2017, 03:32:58 PM »
I just had to show off because I finally got my hands on one of these, an A/DA Harmony Synthesizer, god damn is this a crazy circuit.

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culturejam

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Re: Today's Repair.
« Reply #1 on: February 06, 2017, 04:11:20 PM »
Damn.  :o

gordo

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Re: Today's Repair.
« Reply #2 on: February 06, 2017, 08:39:03 PM »
That's awesome!  Old school boards look kind of Picasso now don't they?  I'd still kill to get my hands on a Stereo Tapped Delay from them.  Best sound my old Marshall got back in the day was with the (at the time brand new) A/DA on the mic and an old place in Nashville called PolyFox.  Doubt the studio is even still around.

jkokura

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Re: Today's Repair.
« Reply #3 on: February 06, 2017, 10:52:10 PM »
It's still fairly well organized actually. Imagine what those guys could have done with 4 layer boards!

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alanp

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Re: Today's Repair.
« Reply #4 on: February 06, 2017, 10:54:59 PM »
So, Jacob. CJ, Scruffie.

Does this mean that you're all collaborating on a layout for this board for 1776 Effects? ;) :P
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Scruffie

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Re: Today's Repair.
« Reply #5 on: February 07, 2017, 04:12:06 AM »
It's still fairly well organized actually. Imagine what those guys could have done with 4 layer boards!

Jacob
It's a really nice layout, apart from some weird mistakes where traces just trail off to nowhere etc. but I guess doing a layout this big that can be forgiven.

So, Jacob. CJ, Scruffie.

Does this mean that you're all collaborating on a layout for this board for 1776 Effects? ;) :P
:P Yeah, someone just needs to trace it first as there's no schematic, fancy a crack?

I'd still kill to get my hands on a Stereo Tapped Delay from them.
I've always wanted to play through one of those too, i've been meaning to breadboard a stripped down version for a long time but can never decide which bits to strip out of it.
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Bret608

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Re: Today's Repair.
« Reply #6 on: February 07, 2017, 08:14:22 AM »
Now I've got to see if I can find a clip of this thing! That is just nuts. I see a lot of Reticon action on the board. Thanks for sharing!

Govmnt_Lacky

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Re: Today's Repair.
« Reply #7 on: February 07, 2017, 08:49:30 AM »
Piece of cake!  :o  ;D

From Premier Guitar:

"Of course, an effect this complex increases the likelihood of something going wrong. I’ve received a few inquiries on the Harmony Synth over the past couple of months, two from collectors looking to have their broken units repaired. We weren’t quite prepared to take this on ourselves, and with no full schematic readily available it’s proven difficult to find an experienced technician willing to take up the challenge. Even Electro-Harmonix design engineer Howard “Mick” Davis was less than enthusiastic about the prospect. Regarding repair work, he told me, “Most EH products are welcome, but the A/DA Harmony Synth is a pretty hairy unit that is not on my preferred list.”

If anyone can conquer this beast... it's you Scruff  8)
« Last Edit: February 07, 2017, 08:59:01 AM by Govmnt_Lacky »

Scruffie

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Re: Today's Repair.
« Reply #8 on: February 07, 2017, 09:23:00 AM »
Haha, thanks for the vote of confidence! It certainly is a daunting repair (although thanks to the build quality easy to do, the PCB just pops out from the wiring harness like a motherboard) 1 resistor, 1 cap a new SAD (my first ever dead one in years of repairs! Quite the mile stone) and a CMOS and opamp and i've got it passing some hideously noisy signal and delay at least now. Going to replace all the electros as a matter of course rather than try and rule them out individually next, they're 40 years old and a couple read near infinite resistance.

Some very strange stuff in it too, the BBD clocks aren't your usual delay pedal type but actually CMOS Schmitt oscillators and I simply have no idea how some bits are working from the limited tracing i've done yet they are.

Now I've got to see if I can find a clip of this thing! That is just nuts. I see a lot of Reticon action on the board. Thanks for sharing!
Just the 2 of them in parallel multiplex, the sound is... odd. It's a bit like an analog version of the earthquaker devices rainbow machine and has a weird tremolo on all the harmonizer settings and as it pulls 200mS out of 1024 stages of BBD the delay times can get very very dark. I think it's definitely a collector item for weirdness rather than something you'd want to use on stage.
« Last Edit: February 07, 2017, 09:25:22 AM by Scruffie »
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Scruffie

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Re: Today's Repair.
« Reply #9 on: February 08, 2017, 04:28:00 PM »
I conquered it 8)
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selfdestroyer

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Re: Today's Repair.
« Reply #10 on: February 08, 2017, 04:31:59 PM »
Awesome work Scruffie!

Jebus

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Re: Today's Repair.
« Reply #11 on: February 08, 2017, 08:23:33 PM »
Hah, never seen one of these before. The board looks really good and well organized. :)

nzCdog

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Re: Today's Repair.
« Reply #12 on: February 09, 2017, 05:17:23 PM »
Boom!  8)

Bret608

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Re: Today's Repair.
« Reply #13 on: February 10, 2017, 08:09:09 AM »
I knew you would!

You're right about the sound...there are a few decent clips out there and it is a weird beast. Sounds almost like a Lowrider with some slapback mixed in.