It's not just noise from the fan. A computer has an EMF that extends out several feet. Just take a transistor radio and hold it near the computer to listen to the noise it can induce into your system.
I think the Mark II was more. In any case, with a switching power supply (computer suplus - about $8) you can't have too much current. They are well regulated, unlike most wall-warts.
Deja vu all over again
This was all thrashed out on the now defunct Tascam BBS. I forgot the current, bur I believe it was between one and two amps. Get a surplus switching power supply that can deliver two amps to be sure. Most wall-warts can't deliver that much current.
They are output attenuators, made up of resistors wired in a "T" or "L" configuration, that reduce the level of the signal to the speaker with no effect on the impedance. Do a google search to find where to buy or how to make.
If your reciever has separate volume controls for the A and B...
Old electrolytic capacitors can often be "reformed" by reuse. The best way is to use a variac to bring up the supply voltage very slowly.
If Tascam cannot supply the tension arm, here is how I made mine:
Cut a piece of 1/32" brass to the same size as the left tension arm and braze or silver...
It would not be impossible to fabricate a new tensioner arm as I had to do until I acquired one from a junker I bought for parts.
If you have the original Machine (without solenoid control of the tansport) be prepared for trouble with the silver transport switch.
The tape reel clamps also tend...
Assuming your sateillites are correctly wired in series/parallel for the lowest impedance your reciever's output is capable of driving, about all you can do is add an L ot T pad to the main speakers to reduce their volume and live with what you get on the satellites at maximum gain.
You can't expect the same amplifier to power ten speakers at the same volume as the two main speakers. Arrange your switching so that only one pair of satellite speakers is powered at a time.