====== Tascam PS-3500 power supply ======

{{ tascam-m-3500:ps-3500.jpg?180x}} The Tascam M-3500 mixing console is powered by the PS-3500 power supply. Big surprise. Have a look at the following photo comparison before and after the cleaning.


===== Cleaning PCBs and components =====

A lot of stuff can enter the power supply through the venting and when the unit heats up you can smell all the years at once. As much as I like the smell of gear, especially when it's old, you certainly don't want all the additional odors that have accumulated. I simply used a household vacuum cleaner with a narrow tip and a brush to loosen the dust particles where they're hard to reach. It's not perfect but it's ok for me.

^  before  ^  after  ^
|  {{tascam-m-3500:ps-3500-1.jpg?300x}}  |  {{tascam-m-3500:ps-3500-2.jpg?300x}}  |
|  {{tascam-m-3500:ps-3500-3.jpg?300x}}  |  {{tascam-m-3500:ps-3500-4.jpg?300x}}  |
|  {{tascam-m-3500:ps-3500-5.jpg?300x}}  |  {{tascam-m-3500:ps-3500-6.jpg?300x}}  |
|  {{tascam-m-3500:ps-3500-7.jpg?300x}}  |  {{tascam-m-3500:ps-3500-8.jpg?300x}}  |
|  {{tascam-m-3500:ps-3500-9.jpg?300x}}  |  {{tascam-m-3500:ps-3500-10.jpg?300x}}  |

===== Assessment of capacitors =====

The capacitors don't look so bad but maybe I'll replace them nevertheless. The following electrolytics (all cans, 85°C) are used:

^  qty.  ^  type           ^
|  3x    |  22000 µF, 35V  |
|  1x    |  2200 µF, 25V   |
|  1x    |  1000 µF, 100V  |
|  2x    |  470 µF, 25V    |
|  2x    |  100 µF, 35V    |
|  1x    |  47 µF, 25V     |
|  1x    |  47 µF, 16V     |
|  1x    |  22 µF, 25V     |
|  1x    |  10 µF, 100V    |
|  1x    |  10 µF, 50V     |
|  2x    |  4.7 µF, 50V    |
|  2x    |  1 µF, 50V      |

It may be a good idea to replace them with 105°C types. The measurments proved a nicely performing PSU:

^  nominal  ^  measured  ^
|  +15V  |  +14,96V  |
|  -15V  |  -14,99V  |
|  +12V  |  +11,87V  |
|  +8V   |  +8,04V   |
|  +48V  |  +47,89V  |

I couldn't notice any 50Hz ripple as there was too much HF from computer and stuff around. I had removed the cover of the PSU's housing so maybe it just wasn't shielded enough. Maybe I should consider buying one of those so called power conditioners. Would that take care of the HF?