[YamahaDX] DX7 Motherboard >>> #2 <<< In Need Of Eyes To Scan Photos [2 Attachments]

[[e-mail] [YamahaDX]]

This is the DX7 that turns on and tells me "Internal Voice Change Battery !" or other similar messages. The battery measures with a DVM at 2.9 - 3.n DVC. This is IN THE DX7 and using the solder to measure the voltage. Will not let me do anything with it. No button pushing, sounds, etc...

Any ideas are welcome. This goes along with the dialogs I've been posting lately. Removed the solder from the back side. And probably some other goodies as well.

Tracy

[danforcz [e-mail] [YamahaDX]]

Maybe like this:

1. There’s a missing trace where was that jumper point on the back side. If I’m not wrong, now it looks like there’s no connection between your “+" red wire from the battery to diode. So try to connect the red wire directly to diode.

2. Wires or component pins should always go through the hole and be soldered on both sides of PCB in the case there are traces. Check if there’s a continuity between your (rather and unnecessarily thick) black wire and “-“ field on the back side. Especially wires going out of PCB should be well connected through the holes. Doing it your way can easily damage trace, and be soon broken and without connection.

3. I don’t know anything about your background, but from your messages and pictures it seems that your knowledge and experience is not enough for such simple task like a changing the backup battery. For the next repairs maybe consider asking somebody more skilled. Expensive and nice instruments don’t deserve to be used for learning how to solder.
This is a friendly advice based on my own painful experience - I have also left a few damaged bodies waiting for revival
 :-) There are less expensive ways for getting skill...

Good luck and all the best!

Daniel Forro

Post by ***@yahoo.com [YamahaDX]
This is the DX7 that turns on and tells me "Internal Voice Change Battery !" or other similar messages. The battery measures with a DVM at 2.9 - 3.n DVC. This is IN THE DX7 and using the solder to measure the voltage. Will not let me do anything with it. No button pushing, sounds, etc...
Any ideas are welcome. This goes along with the dialogs I've been posting lately. Removed the solder from the back side. And probably some other goodies as well.
Tracy

[[e-mail] [YamahaDX]]

I have a photo or two here from some time ago. Hope they help. It definitely needs some TLC.

[Tracy Barber [e-mail] [YamahaDX]]

1. There’s a missing trace
where was that jumper point on the back side. If I’m not
wrong, now it looks like there’s no connection between
your “+" red wire from the battery to diode. So try
to connect the red wire directly to diode. 

Yes. I was looking at the DX7 board that I soldered CORRECTLY and now is in a board with a 2.8+ VDC and working fine.

2. Wires or component pins should
always go through the hole and be soldered on both sides of
PCB in the case there are traces. Check if there’s a
continuity between your (rather and unnecessarily thick)
black wire and “-“ field on the back side. Especially
wires going out of PCB should be well connected through the
holes. Doing it your way can easily damage trace, and be
soon broken and without connection.

With the board and battery installed, all measured 2.9 VDC. Something else got fried.

Yes again, I know that some of them have been like that since I got the boards and some made worse by 91% alcohol cleaning and picking around, getting previous solder splats off other traces and sordid crap like that as well as making the original holes a "little" bigger.

The black wire connects to the green trace that goes down to the diode. It came up when the original hole was found mangled. I tried to bridge the gap instead of using a wire to do the job. The solder on the back was removed to give a clearer picture of the back section. The other board is definitely worse with most of the trace missing. The 2nd board has the airplane strip with the rectangle at the end. The other side went poof...

3. I don’t know anything about
your background, but from your messages and pictures it
seems that your knowledge and experience is not enough for
such simple task like a changing the backup battery.

Thanks! That's why I have a working DX7, ESQ-M, Chroma Polaris (various things like new face plates), Korg DDD-5 and with transformer help, a Mirage working now. But credit I do not deserve. They stayed too long in storage and not played like they should have been.

For the next repairs maybe consider asking somebody more skilled.

Ooops, forgot my Moog Source but I should be careful with that one. That was my first "fix".

Expensive and nice instruments don’t deserve to be used
for learning how to solder.This is a friendly advice based
on my own painful experience - I have also left a few
damaged bodies waiting for revival
 :-) There are less
expensive ways for getting skill...

Your advice was not taken and I made the 2 DX7 boards worse for wear. Won't toss them, but will wait on them before spending any tech money on a 2nd DX7 when I know I can use it as a controller with the Special Edition Eprom installed and the 2nd board rewired. No patches, but what the heck. No. I'll keep them around for a little while and contemplate my mistakes. No joke. I don't want to spend $ / time either or ruin stuff as a test.

Thanks!

Tracy Barber

[Tracy Barber [e-mail] [YamahaDX]]

So, the 2 rectangles needed to be bridged. The Positive would then be connected (on mine) to the thing that looks like a landing strip, but at the rectangle end. The other board has that area worn down badly. But one board has the left side still there. Both of my board have the 1/2 rectangle trace to the right of the positive hole missing. Thought I could bypass that and go to the end. On yours, you have positive - rectangle - rectangle - negative. In another photo you have both the rectangles connected. comments?

My problem is getting the negative trace hooked to the black negative wire because it popped up and I have to make a blob to put the end of the trace in it to connect it. Yes? I thought of adding a small wire from the negative hole to the diode below it. They look like they are on the same "line".. comments?

Good to see which pins on the IC RAM chip to check as well. I guess that would apply to the 2 chips below that one as well, yes?

Thanks!

Tracy Barber

--------------------------------------------
On Thu, 6/28/18, ***@jps.net [YamahaDX] <***@yahoogroups.com> wrote:

Subject: Re: [YamahaDX] DX7 Motherboard >>> #2 <<< In Need Of Eyes To Scan Photos [5 Attachments]
To: ***@yahoogroups.com
Date: Thursday, June 28, 2018, 9:47 PM


 









[Attachment(s) from ***@jps.net
[YamahaDX] included below]


I have a photo or two here from some time ago. Hope
they help.  It definitely needs some TLC.









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