Need Roland EM 305 schematic

[fredcapo]

Trying to repair a Roland EM 305 low end synth. It crackles and statics after on for about a minute. Thinking caps...

[Enzo]

Why caps? Anything is possible, but on my list solder comes first, semiconductors right behind, then connectors, controls. Caps are way down my list. if it were a tube circuit, they might be higher up due to the voltage. But there is not much voltage in a synth, like maybe 15v tops.

Is it mechanically sensitive?

[Drewline]

Here's the service manual. Good luck.

[fredcapo]

Appears not to be an a mechanical or contact issue. Analog output at speaker, headphone jack, line out, both channel starts breaking up after powered on 30 seconds, then power cycling clears the static for a second. Hearsay there are cases of poorly made caps aging causing problems in similar devices.

[Jazz P Bass]

If you do suspect the power supply capacitors, measure them. (and look at them)

2005 was about the end of the bad caps.
A visual inspection will show a bulge at the top of the can (indicating a build up of hydrogen gas that is attempting to vent.)

A test of the power supply voltages will help to narrow it down.
If Vdc is low, it may be a cap going high on the ESR. (or a severe load on it, downstream)
Vac measurements will tell if the caps are doing there job of filtering the Vdc.

As luck would have it the power supply & the output section are all on one board.

Take note that the signal output goes through a relay.
Those contacts will have to be proven out.

[doctor]

As far as I know, the EM-305 is very different from the E-30.

[fredcapo]

I appreciate the input and docs, but yes not an EM30, but the EM305 is just a cheapo not worth repairing except it belongs to a good friend. Have not had time to get back on it, but will try following the signal from the DAC... Don't recall seeing any bloated caps...