whistling mac plus

Not needed to discharge that tube but if that gives you shivers when coming close to guts of that mac, build youself a discharging tool for that: Take a old red wire off a duff flyback snip it in half/half length terminate one in clip on terminal and a probe on other end then connecto all in series to that pack made of one or 2 10W 1meg ohms power resistors all covered up in epoxy and in tube because epoxy alone is too brittle. Discharging process: clip that to the tube grounding strap that go across from two corners and carefully slip under that rubber cup to touch that metallic spring hook that is stuck into the lipped metal cup on that tube surface. Discharge is very quick and less scary this way than a blue arc with a loud snap! Do by soldering and add a bit of new solder wire to all the connector pins, flyback pins and heavy component leads and any thing that are hot looking. Don't bother the logic board it's better designed anyway. This does usually doesn't address the shortcomings of this analog boards in all of common compact Macs; those damnable 3.9uF bipolar capacitor going bad, burning the pin 1 on yoke connector and cook the inductor L1 coil if not caught early. Again, the shortcomings in the PSU and in video circuit on that board. That, can be addressed all the potiential problem by getting a rebuild kit from CSS or Data Display Ltd (Canadian version of CSS. Not more than $30 in needed rebuild kit. The whistle noise is from either PSU components vibrating or the horizontal section components vibrating. Touch each components with plastic or wooden stick until that noise stops or change in pitch and you catch the baddie. :-) Oh, don't foget those ferrie cores on that flyback and anything like that on coils and transformers. Oh, Whistling could be sign of a bad flyback arcing internally or along the high voltage wire. Jason D. email: jpero(a)cgocable.net Pero, Jason D.