Vintage Synth Repair

hello

i have a yamaha dx21

the power supply seams to be broken, the main capacitor has exploded

does anyone know the value of this electro chemic capacitor

i can read 100uF 85° 200WV

is it right ?

thanks

Why not to read it in Service manual? You can find it on internet.


Japanese, US and Canada model has value of electrolytic cap in primary
circuit 100 uF/200 Volt.
General and German model has here 47 uF/400 Volt.


I would change all caps in PSU, soon or later there can be problem
with some of them:


2x 220 uF/35 Volt
2x 100 uF/25 Volt
2x 1000 uF/10 Volt


Good luck with the repair.


Daniel Forro




On May 1, 2016, at 6:04 AM, fainardi83@yahoo.com [vintagesynthrepair]
wrote:

> i have a yamaha dx21
>
> the power supply seams to be broken, the main capacitor has exploded
>
> does anyone know the value  of this electro chemic capacitor
>
> i can read 100uF 85° 200WV
>

That sounds like a perfectly reasonable capacitor value. For replacement, you need to consider the package configuration: radial (2 leads out of one end, most likely) or axial (leads out of opposite ends). Then there is size (newer capacitors are usually smaller physically so not much worry). Then you can go up but not down for the other 3. For example, 220uf at 250V, 105 deg C would be fine, in fact preferable especially the temp and voltage rating.
Last question is what, if anything else got damaged, e.g. rectifier diodes, etc.
I don't know the circuit but be very careful around high DC voltages!!! If you don't know what you are doing, change the cap and if it doesn't work, find a pro. This sounds like a switching power supply which can be very tough to debug, and again, have lethal voltages around.
Digikey will have many options for a replacement part.
-Hugh

Sad news - another great personality, important synthesizer performer  
and one of my heros has died - according to today's The Japan Times:  
Isao Tomita...


http://www.japantimes.co.jp/culture/2016/05/08/music/isao-tomita-japanese-pioneer-of-synthesizer-music-dies-at-84/


Daniel Forro