Will do on that/
also from another thread i read..  I get dc on the speaker jack if a speaker is plugged in(or a dummy load. if nothing is connected to a speaker jacks  I get 0vdc.
Same on the mon and main out.

Thanks,
nosaj

I've got a Peavey xr600b   that had a shorted output transistor on it.

I replaced all 8 TO3's and the 4700/63v and the 1000/35v caps.
The + - 52 rails are good and the -+15rails are good.

Running some music in the AUX and Monitor inputs or any of the 6 channels
The volume is real low.  But if I lineout the amp to another amp it's decent sounding with  a little hiss when cranked up  ...  I diid look over the solder joints  nice and silvery.

The sand resistors tested ok on the board.  Any suggestions on how to proceed?

Thanks,
nosaj

Changing c966 made the difference I also shotgunned the rest of the smaller capxcon cap I didn't get last time.  So far turns on everytime, will check in a few days to be sure.

Thanks so much ,
nosaj

Wharfdale PM700 SMPS intermittant turn on
I've picked up the wharfdale PM700 PA again in hopes of making it stable. Sometimes it will turn on and just play fine other times you have to pop the on/off switch several times to get it running.

Monitoring the -+ 63 v rails and the 15v rails when it doesn't come on they produce on a few volts. The largest caps have been replaced. The little fan always comes on. I have this power supply schematic that utilizes the same smps controller chip and a lot of it looks very similiar to what I have.
From what little my brain has gathered SMPS supplies need a kick start to get them oscillating to produce the voltage kinda of like a startrun capacitor on a AC motor. But not sure where I should be checking.
Any helps would be greatly appreciated.

If the voltage regulators are iffy not putting out a clean 15v would that cause the SMPS to be intermittant?

Thanks,
Nosaj

The light bulb is not supposed to blow. It is just a visual indicator of an issue if one is there and yours says yes there is a problem.
The direct short could be in the power supply or elsewhere.  Do you have a schematic or exact model number?

Thanks,
nosaj

Farther up the thread that you attached to show someone else's work, best to verify before using it. But if yours is identical to the pics (power board), then it shouldn't be too inherently hard for you to do.

Start with disconnecting the Power transformer from the board and see if you are getting any voltage from there. All this figuring you have checked the fuse.

i used to want to have a schematic for everything sort of a roadmap of sorts, but sometimes you have to forgo one and trudge on with research or help.   Pictures help best, and you can use skitch to anotate.

nosaj

The bigger picture is that you have some work to do by tracing the circuit out if you want one.  But hey at the same time you get to learn something so it's a win win.  In the meantime if you want it fixed the Gents here will be more than happy to help someone who is willing to learn.
My thoughts would be a Dimbulb tester then  if the preamp and power amp are separable by a connector halfing the amp to narrow down.

nosaj

If you can identify the output transformer  then you could follow the leads to the tube or tubes to identify the output  and from the output you may or maynot have a phase invertor then to the preamp.  Basically tube numbers will help somewhat and a lot of tracing.

nosaj

Well i called the North American Parts dept and they gave me an email to send my workbench pics to.  The guy thought it looked like his bench a total mess .

They only sent schematics because not every company does a service manual.

nosaj

Have you contacted Laney?  They sent me schematics i needed after i showed them pics of my workbench.

nosaj

Check out this forum also. They guys are great and you may find many useful things in the classified.

Your never too old till your dead.
nosaj
http://antiqueradios.com/forums/index.php

http://antiqueradios.com/forums/viewtopic.php?f=2&t=288425&hilit=highlux

Update on wharfdale i was able to get another broken one and subbed the preamp from it. It is now working intermittantly.
Sometimes it takes 2 or 3 flips of on/off toggle to turn it on all the way(everytime the psu fans come on) It is a smps I have recapped the power supply as it was loaded with the capxcom counterfit caps.  i believe that it is a rail that is failing to come up but not sure how to go about it without a schematic.

Thanks,
nosaj

I was thinking I'd learn more by applying it to a breadboard, maybe in principle.

nosaj

Just to be sure I understand some  On that IC  out of Circuit I could breadboard it and then by grounding the inputs find the switch that is not switching IE no voltage change correct?

Yes I am starting to enjoy the learning. I really thank you for your Time.

nosaj

You are the man Enzo!!

Got a new chip in and voila!.

Thanks so much.

nosaj