Yamaha Stagepas 300 failure mode

Hmm, seems to work if I delete the original text.

Anyway, the limiter might actually be doing its job and preventing the whole thing blowing up, you don't want to disable it.

Gareth.

This has been seen on other groups. The suspected mechanism is that the original post is in MIME-encoded form, and the reply is in plain text. So, if the replier's mail program just appends plain text to the MIME-encoded message, some newsreaders will fail to see that extra text as being significant, as there is no MIME description of what format it is in. I'm using Knode, and all of your replies showed up here, with your text in them. If you go back to one of these "empty" replies and tell your reader to "view source" you will probably see your message there. Curiously, I did this and the message is NOT in MIME format, so don't know why it doesn't show for you.

Jon

This has been seen on other groups. The suspected mechanism is that the original post is in MIME-encoded form, and the reply is in plain text. So, if the replier's mail program just appends plain text to the MIME-encoded message, some newsreaders will fail to see that extra text as being significant, as there is no MIME description of what format it is in. I'm using Knode, and all of your replies showed up here, with your text in them. If you go back to one of these "empty" replies and tell your reader to "view source" you will probably see your message there. Curiously, I did this and the message is NOT in MIME format, so don't know why it doesn't show for you.

Jon

Thanks, Jon.

My Windows 8 has been buggy from the start, Live Mail particularly so, always complaining it can't back up the database because it is in use by something else (???)

Live Mail is what I use to post on Usenet - I guess its teething problems.

You know the only improvement I can see that Windows 8 has over XP is that it boots up a lot quicker - seems to keep some kind of "snapshot" on file somewhere, otherwise it seems to do exactly the same job I ask of it, but with a whole load of bugs, and I can't find things any more.

Cheers,

Gareth.

I have seen the following problems occuring on StagePas 300 :

se they need longer cables. This won't ever work; Most industry standard ca bles having 6.3mm jacks are meant for guitars and other relevant instrument s,Conductors inside are thin and coaxial having enormous capacitance and ve ry large resistance.

You need to order your technician or build yourself a pair of REAL Loudspea ker (twin-lead and sufficient thickness for 150W power handling) cables hav ing mono 6,3mm jacks end to end. You won't burn your amp that way.

also -

I have noticed a problem w. my set that showed after 15 mins of operation t he following problem:

Sound cut off, replaced with low frequency hum (thus amplifier is still act ive), Limiter led (red on bar graph) stuck ON, Turning it off and after a f ew minutes back on solves the problem.

That problem was traced down to an 7915 voltage stabilizer on the main prea mp/psu board, having an output of -8V instead of -15 on normal operation an d after 15 minutes that voltage fell to 0 volts. Replacing the 7915 with an other fixes the problem (solid -15V on output). My Stagepas 300 has an 7915 with plastic casing (too large heat resistanse to heatsink, I guess, and a semiconductor fatigue resulted to that problem). It looks that using a met allic 7915 is possible as the heatsink is electrically isolated from the re st of the circuit on my revision, if in doubt use some mica - plastic ring isolator there.

Cheers.

The main speaker lead problem is one jack has to be reverse "polarised", so must be insulated as any stray metal ,eg drummer's snares , will short an amp to the nice shinning metal handle , conveniently placed next to the output sockets. One amp is invertyed relative to the other, to save on volume of rail caps required on peak demands

ause they need longer cables. This won't ever work; Most industry standard cables having 6.3mm jacks are meant for guitars and other relevant instrume nts,Conductors inside are thin and coaxial having enormous capacitance and very large resistance.

eaker (twin-lead and sufficient thickness for 150W power handling) cables h aving mono 6,3mm jacks end to end. You won't burn your amp that way.

the following problem:

ctive), Limiter led (red on bar graph) stuck ON, Turning it off and after a few minutes back on solves the problem.

eamp/psu board, having an output of -8V instead of -15 on normal operation and after 15 minutes that voltage fell to 0 volts. Replacing the 7915 with another fixes the problem (solid -15V on output). My Stagepas 300 has an 79

15 with plastic casing (too large heat resistanse to heatsink, I guess, and a semiconductor fatigue resulted to that problem). It looks that using a m etallic 7915 is possible as the heatsink is electrically isolated from the rest of the circuit on my revision, if in doubt use some mica - plastic rin g isolator there.

Mak, Did you replace the 7915 chip yourself or did you have it done in a shop. I don't trust myself to make this repair but the cutting out problem has m ade the Yamaha unit totally unreliable so I really need to try it. Any tip s would be greatly appreciated. Thanks J

Where are you located? Perhaps others in the area can assist.

Dan