What I would do is to first disconnect the power supply board from the motherboard because there might be a short. Then check if you have DC voltages at the power supply outputs .
I you don't read anything, you should look for AC voltages at the transformer's secondary. You might have a bad power transformer. It could fail because of a shorted component in the power suppply or on the motherboard.
Check also if you have 120V at the transformer primary, beacause if you don't, you might have a bad coil in serie with the tranformer primary.
If you can read a schematics, here's the link:
http://homepages.abdn.ac.uk/mth192/pages/dx7/manuals/dx7-circuit.pdf
Nicolas
---In vintagesynthrepair@yahoogroups.com, <narfman96@...> wrote:
The mk1 power supply gets quite warm. This also can lead to bad solder connections.
---In vintagesynthrepair@yahoogroups.com, <kloopy@...> wrote:
I had an issue with power supply on my DX7 MK1 and it was dry joints on low power output. Hope that may help someone.
K
---In vintagesynthrepair@yahoogroups.com, <oldcrow@...> wrote:
That is glue. Tall parts were generally glued down so their high
center of gravity wouldn't end up cracking the board or otherwise weaken
their connection to the traces/pads.
Crow
/**/
synapticdistortion wrote:
center of gravity wouldn't end up cracking the board or otherwise weaken
their connection to the traces/pads.
Crow
/**/
synapticdistortion wrote:
>
>
> One thing that I've noticed is that there is a hard, tan-colored
> substance at the bottom of several of the caps. I can't tell if it's
> leakage, or some sort of thermal material that was placed there during
> manufacturing. The caps in question otherwise look fine (no bulges or
> splitting).
>
>
>