Synth-DIY Yahoo! Groups Archives

you can clean the pcbs with the iso and a stiff brush

where do you live

theres lots of 74 type logic series chips that deal with interfacing with the logic board and the analog board

when pressing keys do you get any filter vca noise as the filter chips can still activate with no audio this would show that the multiplex sample and holds are working and that no audio is getting to the dacs

an service tech synth engineer would use an oscilloscope on the machine he would look at the timings data and see if the chip is doing what it is supposed to be doing as he will be able to look at the oscilloscope and look at the service manual data to see if it matches

or an logic analyzer the first place i would look is the echip voice channel pins then from there look at the logic before the ribbon cable

then i would test the ribbon cable to see if im getting the correct signals at the cable if all was well there

then i would look at the analog board and the amd interface chip and the countless logic chips there is a lot of them

long time consuming test work

i just had todo the same to an sp1200 who a customer who knows a little about electronics managed to blow up several pal chips and the z80 because he tinkered not actually knowing what he was doing

On 6 August 2014 16:44, radiokomitet@... [emax] <emax@yahoogroups.com> wrote:

Yes, im sure that one has sequences... i pressed select button on sequencer side from front panel and there was a pretty long list.

External midi keyboard was my first idea yesterday. I connected ASR10 midi out with EMAX midi in and EMAX recived midi correctly but there was no sound.

Ok, Ive got my old friend in parts. I think its good moment to cleanup whole machine. I used isopropyl alcohol and tooth brush on pins and pins connectors... im little scared to unplug the flat connector of ribon cable next to E-Chip because im not sure if its possibe to take out.. What can i do more ? I used compressed air to whole field of the pcb's but its still kind of old dust on it... and a lot on the back sides (without chips) of PCB';s. Im not sure how can i clean them up. If any one got proven methods to share how to clean up elements of unit, I'll be grateful (front panel, keys, pcbs).

If i want to check pcb's with oscilloscope do i need to take to engineer whole unit or boards only?
Im mad at myself i never lick electonics knowledge in my life, i opended a lot of gear and pc's and macs... but never had soldering iron in my hand :( i feel like blind right now. From today its over.

Thank you again, i really appreciate your help.

Emax

Re: [emax] Re: E-MU EMAX 1000 Keyboard problem / No sound from outputs.

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