Tascam PS-3500 power supply

ps-3500.jpg 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
ps-3500-1.jpg ps-3500-2.jpg
ps-3500-3.jpg ps-3500-4.jpg
ps-3500-5.jpg ps-3500-6.jpg
ps-3500-7.jpg ps-3500-8.jpg
ps-3500-9.jpg ps-3500-10.jpg

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?

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