insulation tests

[diydidi]

Hi
What's with all the insulation testing mentioned in a lot of service manuals.
Is it really necessary?
Was looking at a Yamaha sub service manual today. On page 2 was the insulation testing procedure.
???

[Jazz P Bass]

Safety first.

[tedmich]

TWA Flight 800 !

[Mick Bailey]

Can you post the section you refer to (or a link)?

[J M Fahey]

Can you post the section you refer to (or a link)?

Also felt curious , so found and opened a Yamaha SW service manual: http://nice.kaze.com/yst-sw800_svm.pdf

Lo and behold, I does include an insulation test.

A very basic one by the way: .... less than 0.5mA leakage current when plugged into a 120V outlet, "in both positions of the plug" which implies a 2 pin symmetrical and ungrounded plug (the old 2 pin flatblade?)

FWIW "real" insulation tests demand "peak AC voltage + 1000V" or similar or straight "1500V for 120V systems, 2500 or 3000V for 240V ones", etc.

Maybe their Legal department wanted to say something.

Next suggestion is not to lick its plastic parts or the bottom of the boards because of possible cancer concerns.

No kidding.

Although I fully agree about not sucking or munching lead based solder .

Yes, they also say that.

[tedmich]

Next suggestion is not to lick its plastic parts or the bottom of the boards because of possible cancer concerns.

No kidding.

Although I fully agree about not sucking or munching lead based solder .

Yes, they also say that.

just great, now my two main diagnostic techniques are excluded! Better get a scope....

[g1]

The insulation testing is basically to make sure there is no shock hazard for a user making contact with the chassis.
In some areas I believe it is a legal requirement for repair procedures.

[J M Fahey]

Yes, probably.

In another Forum, i think it was TGP, there was a long and heated discussion (over 100 posts) in a thread started by a guy who has a '64 Dual reverb (not an exactly obscure or hard to find amp, before the current Retro Craze it was just another "Panwnshop special" old amp) , who was absolutely floored by his Tech decision to install a grounded 3 wire cord "without which it would not leave the shop".

He wanted to suicide or something because the Tech would need to (slightly) enlarge the chassis hole for the 3 wire cord (which of course is fatter ) and install an original Fender cable clamp, instead of the original (rotten) rubber grommet.

He was vary worried about the massive Capital loss he would incur because his "highly sought and collectable" amp would fall from the Gods Olympus to plain Mortals Earth because of that safety upgrade.

He didn't like my suggestion of either follow the Tech's suggestion (to which he's obliged by Law) or sign a Notarized affidavit that the amp was a Collector's Item, just to be exhibed or resold but never ever plugged to play.

He didn't like my other suggestion either: to get a Time Machine and go back to '64 , go figure.

Here we had another old-but-unremarkable-amp owner who spent about a Million Dollars to get his amp, which was bought from a somewhat known place and might have been used by "you-know-who", (based on the words of the sleazy seller ) up to you-know-who specs.

By the way, it was the Theater's "house amp" ,there available for anybody who forgot (or didn't care) to bring his own, so it was not 'specially selected" by any means .