Start by checking any and all tantalium caps for a short.

Bunch on ebay now....kinda pricy, but they are rare...

http://www.ebay.com/itm/C4570C-NEC-Ultr ... 1138302080

(can't get ebay button to work today...)

Can't find a Juno 1 schematic, but have the Juno 2, so the IC number may not be correct; Go to the dual op-amp right after the output of the voices (IC-3 on the Juno2). It has the summing amp and the hp filter. I'd recommend testing here first: PIN 2 - Input from the 6 voices NOISE = bad voice somew...

You've got an amp i'm sure. Rig up a cable with a 1/4 male on one end and on the other end a clip lead to the shield and some kind of home-made probe (small Phillips screwdriver, ice pick etc..with an insulated handle) and start following the output signal backwards until you lose the noise. DON'T P...

Welcome to the board! I had a 77, then traded it for an SY99...One of my all-time favorite synths Get the floppy belt here: http://www.syntaur.com/3223.html Some new sounds here: http://www.kidnepro.com/KN/Yamaha/SY77_TG77_list.html and here: http://www.voicecrystal.com/catalog.htm Owner's manual he...

The ESQ-1's filters are analog and DO have resonance - just (as set at the factory) can't quite be pushed into self-oscillation.

Also - although the SD's piano waves can be useful, they are blown out of the water by even a cheap piano module (Kurzweil MicroPiano for one)

SD-1: Full-featured sequencer, nice effects.

ESQ-1: That vintage 8-bit sound.

You need both.

Cooling spray at RadioShack, etc. After time - and many heat/cool cycles, op-amps (and other chips) can pull the tiny encapsulated leads loose. Cooling the plastic chip shrinks it and SOMETIMES will show up problems.

Try cleaning/re-seating all board connectors.Then try cooling spray on the op-amps, etc.

I bought one of the first Quadrasynths out. Later traded up to a QS+piano, then a QS8. Never had a moments problem with any of them. Bummer to program - with endless layers on menus. The 64 voices let you layer and split...I made use of the 16-way keyboard splits to program hits and sound effects on...

Welcome to the board!

Not much help - only aa LOT of work. I posted this sometime back:

http://www.vintagesynth.com/forum/viewt ... il#p673165

Welcome to the board! I am NOT playing "flame-the-newbie". I do think you are going to have immense trouble making two vintage synths into identical twins. Here's part of the problem: Each componet in the analog path is most likely manufactured with a tolerence of +/- 20%. That alone is often enough...

JayEm wrote:back from where exactly?

Back from wherever they sunk to while making the God-awful SH-201. Plasticky, flimsy, bendable, unfixable, disposable gimmick. I swear if you scraped off the Roland logo, you'd see "Mattell"....or maybe "Hello Kitty".

Yeah, he's slow as techtonic drift sometimes, but I've always gotten my orders.

so why korg and casio using expedient method in ds-8 and cz-series? Back in the day, Yamaha put on its war paint anytime someone else even thought about FM synthesis, so Casio came up with "phase distorsion" - in which the "FM" part is hidden deep inside the system. Korg's DS-8 and 707 DID use FM (...