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Subject: Re: [chromapolaris] OK - I Have Diagnostics Now And They Are Weird

From: Tracy Barber <adirondack_pc@...>
Date: 2018-06-03

This is what I am suspecting. It turns on, works somewhat, but then poops out intermittently. I tried to check the wires but I'm all thumbs in that arena. I can check little things, like batteries and Ohms, but where to put the leads on live wires is something I need help with. Like - Brown wire and orange wire - check for +5V - well, do you put the leads on the wires or do you ground one on the ground in the middle of the motherboard? Very cryptic, unless you're an electronics guy / gal.

I have a Fluke 87V. Doesn't say to check AC or DC, just check it. Sheesh... Someone else here said I was cryptic, well these docs are sure cryptic enough in certain areas. Other areas would have been nice to use when I was teaching. They spend more time on binary / hex descriptions than on what exactly to do for the adjustments.

Well, I just fixed my 2nd DX7 yesterday. Cleaned up the headphone area, changed the battery to a mod with replaceable battery and completely redid the slider from scratch (took it all apart) for Volume. What a difference. Smooth... So, I'm not a dummy, just dumb deciphering Greek.

Can you please give me a clue about some steps - maybe on Digital and Reference Level +5V? Then I can hack out the rest. In the meantime, I'll go out to YouTube to see if there are any Chroma hackers doing their thing.

Thanks!

Tracy

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> Hi, First time responding in forum. 

Welcome!

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Check the DC voltages with the wires
connected (under load) to circuit with power on. Voltages
should be as per manual. Then check AC rms
voltage on same output voltage and connections/conditions.
You should see mV on outputs. You are checking to see if
supply has bad/weak capacitors (in and outputs) as well as
possibly other defective components. If you find excessive
AC rms (ripple) then suggest you power down and replace all
in/out capacitors or the whole power supply with a
refurbished one if possible.
Lex